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Lam LPY, Lui ACW, Bartley LE, Mikami B, Umezawa T, Lo C. Multifunctional 5-hydroxyconiferaldehyde O-methyltransferases (CAldOMTs) in plant metabolism. JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:1671-1695. [PMID: 38198655 DOI: 10.1093/jxb/erae011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 01/09/2024] [Indexed: 01/12/2024]
Abstract
Lignin, flavonoids, melatonin, and stilbenes are plant specialized metabolites with diverse physiological and biological functions, supporting plant growth and conferring stress resistance. Their biosynthesis requires O-methylations catalyzed by 5-hydroxyconiferaldehyde O-methyltransferase (CAldOMT; also called caffeic acid O-methyltransferase, COMT). CAldOMT was first known for its roles in syringyl (S) lignin biosynthesis in angiosperm cell walls and later found to be multifunctional. This enzyme also catalyzes O-methylations in flavonoid, melatonin, and stilbene biosynthetic pathways. Phylogenetic analysis indicated the convergent evolution of enzymes with OMT activities towards the monolignol biosynthetic pathway intermediates in some gymnosperm species that lack S-lignin and Selaginella moellendorffii, a lycophyte which produces S-lignin. Furthermore, neofunctionalization of CAldOMTs occurred repeatedly during evolution, generating unique O-methyltransferases (OMTs) with novel catalytic activities and/or accepting novel substrates, including lignans, 1,2,3-trihydroxybenzene, and phenylpropenes. This review summarizes multiple aspects of CAldOMTs and their related proteins in plant metabolism and discusses their evolution, molecular mechanism, and roles in biorefineries, agriculture, and synthetic biology.
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Affiliation(s)
- Lydia Pui Ying Lam
- Graduate School of Engineering Science, Akita University, Tegata Gakuen-machi 1-1, Akita City, Akita 010-0852, Japan
| | - Andy C W Lui
- Plant Breeding and Genetics Section, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, USA
| | - Laura E Bartley
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164, USA
| | - Bunzo Mikami
- Research Institute for Sustainable Humanosphere, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Toshiaki Umezawa
- Research Institute for Sustainable Humanosphere, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Clive Lo
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China
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2
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Shen C, Huang B, Hu L, Yuan H, Huang Y, Wang Y, Sun Y, Li Y, Zhang J, Xin J. Comparative transcriptome analysis and Arabidopsis thaliana overexpression reveal key genes associated with cadmium transport and distribution in root of two Capsicum annuum cultivars. JOURNAL OF HAZARDOUS MATERIALS 2024; 465:133365. [PMID: 38163407 DOI: 10.1016/j.jhazmat.2023.133365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2023] [Revised: 12/15/2023] [Accepted: 12/22/2023] [Indexed: 01/03/2024]
Abstract
The molecular mechanisms underlying high and low cadmium (Cd) accumulation in hot pepper cultivars remain unclear. In this study, comparative transcriptome analysis of root between high-Cd (J) and low-Cd (Z) cultivars was conducted under hydroponic cultivation with 0 and 0.4 mg/L Cd, respectively. The results showed that J enhanced the root uptake of Cd by elevating the expression of Nramp5 and counteracting Cd toxicity by increasing the expression of genes, such as NIR1, GLN1, and IAA9. Z reduced Cd accumulation by enhancing the cell wall lignin synthesis genes PAL, COMT, 4CL, LAC, and POD and the Cd transporters ABC, MTP1, and DTX1. Elevated expression of genes related to sulfur metabolism was observed in Z, potentially contributing to its ability to detoxify Cd. To investigate the function of CaCOMT1, an Arabidopsis thaliana overexpression line (OE-CaCOMT1) was constructed. The results revealed that OE-CaCOMT1 drastically increased the lignin content by 38-42% and reduced the translocation of Cd to the aboveground parts by 32%. This study provides comprehensive insights into the mechanisms underlying Cd accumulation in hot pepper cultivars using transcriptome analysis. Moreover, this study elucidates the critical function of CaCOMT1, providing a theoretical foundation for the production of low-Cd vegetables for food safety.
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Affiliation(s)
- Chuang Shen
- School of Chemical and Environmental Engineering, Hunan Institute of Technology, Hengyang 421002, China
| | - Baifei Huang
- School of Chemical and Environmental Engineering, Hunan Institute of Technology, Hengyang 421002, China
| | - Lu Hu
- Hunan Huanbaoqiao Ecology and Environment Engineering Co., Ltd., Changsha 410221, China
| | - Haiwei Yuan
- Hunan Huanbaoqiao Ecology and Environment Engineering Co., Ltd., Changsha 410221, China
| | - Yingying Huang
- School of Chemical and Environmental Engineering, Hunan Institute of Technology, Hengyang 421002, China
| | - Yanbin Wang
- School of Chemical and Environmental Engineering, Hunan Institute of Technology, Hengyang 421002, China
| | - Yingfang Sun
- School of Chemical and Environmental Engineering, Hunan Institute of Technology, Hengyang 421002, China
| | - Yi Li
- School of Chemical and Environmental Engineering, Hunan Institute of Technology, Hengyang 421002, China
| | - Jirong Zhang
- School of Chemical and Environmental Engineering, Hunan Institute of Technology, Hengyang 421002, China
| | - Junliang Xin
- School of Chemical and Environmental Engineering, Hunan Institute of Technology, Hengyang 421002, China.
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3
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Peracchi LM, Panahabadi R, Barros-Rios J, Bartley LE, Sanguinet KA. Grass lignin: biosynthesis, biological roles, and industrial applications. FRONTIERS IN PLANT SCIENCE 2024; 15:1343097. [PMID: 38463570 PMCID: PMC10921064 DOI: 10.3389/fpls.2024.1343097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 02/06/2024] [Indexed: 03/12/2024]
Abstract
Lignin is a phenolic heteropolymer found in most terrestrial plants that contributes an essential role in plant growth, abiotic stress tolerance, and biotic stress resistance. Recent research in grass lignin biosynthesis has found differences compared to dicots such as Arabidopsis thaliana. For example, the prolific incorporation of hydroxycinnamic acids into grass secondary cell walls improve the structural integrity of vascular and structural elements via covalent crosslinking. Conversely, fundamental monolignol chemistry conserves the mechanisms of monolignol translocation and polymerization across the plant phylum. Emerging evidence suggests grass lignin compositions contribute to abiotic stress tolerance, and periods of biotic stress often alter cereal lignin compositions to hinder pathogenesis. This same recalcitrance also inhibits industrial valorization of plant biomass, making lignin alterations and reductions a prolific field of research. This review presents an update of grass lignin biosynthesis, translocation, and polymerization, highlights how lignified grass cell walls contribute to plant development and stress responses, and briefly addresses genetic engineering strategies that may benefit industrial applications.
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Affiliation(s)
- Luigi M. Peracchi
- Department of Crop and Soil Sciences, Washington State University, Pullman, WA, United States
| | - Rahele Panahabadi
- Institute of Biological Chemistry, Washington State University, Pullman, WA, United States
| | - Jaime Barros-Rios
- Division of Plant Sciences and Interdisciplinary Plant Group, University of Missouri, Columbia, MO, United States
| | - Laura E. Bartley
- Institute of Biological Chemistry, Washington State University, Pullman, WA, United States
| | - Karen A. Sanguinet
- Department of Crop and Soil Sciences, Washington State University, Pullman, WA, United States
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4
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Happs R, Hanes RJ, Bartling AW, Field JL, Harman-Ware AE, Clark RJ, Pendergast TH, Devos KM, Webb EG, Missaoui A, Xu Y, Makaju S, Shrestha V, Mazarei M, Stewart CN, Millwood RJ, Davison BH. Economic and Sustainability Impacts of Yield and Composition Variation in Bioenergy Crops: Switchgrass ( Panicum virgatum L.). ACS SUSTAINABLE CHEMISTRY & ENGINEERING 2024; 12:1897-1910. [PMID: 38333206 PMCID: PMC10848292 DOI: 10.1021/acssuschemeng.3c05770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 12/20/2023] [Accepted: 12/20/2023] [Indexed: 02/10/2024]
Abstract
Economically viable production of biobased products and fuels requires high-yielding, high-quality, sustainable process-advantaged crops, developed using bioengineering or advanced breeding approaches. Understanding which crop phenotypic traits have the largest impact on biofuel economics and sustainability outcomes is important for the targeted feedstock crop development. Here, we evaluated biomass yield and cell-wall composition traits across a large natural variant population of switchgrass (Panicum virgatum L.) grown across three common garden sites. Samples from 331 switchgrass genotypes were collected and analyzed for carbohydrate and lignin components. Considering plant survival and biomass after multiple years of growth, we found that 84 of the genotypes analyzed may be suited for commercial production in the southeastern U.S. These genotypes show a range of growth and compositional traits across the population that are apparently independent of each other. We used these data to conduct techno-economic analyses and life cycle assessments evaluating the performance of each switchgrass genotype under a standard cellulosic ethanol process model with pretreatment, added enzymes, and fermentation. We find that switchgrass yield per area is the largest economic driver of the minimum fuel selling price (MSFP), ethanol yield per hectare, global warming potential (GWP), and cumulative energy demand (CED). At any yield, the carbohydrate content is significant but of secondary importance. Water use follows similar trends but has more variability due to an increased dependence on the biorefinery model. Analyses presented here highlight the primary importance of plant yield and the secondary importance of carbohydrate content when selecting a feedstock that is both economical and sustainable.
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Affiliation(s)
- Renee
M. Happs
- Renewable
Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
- Center
for Bioenergy Innovation, Oak Ridge National
Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Rebecca J. Hanes
- Strategic
Energy Analysis Center, National Renewable
Energy Laboratory, Golden, Colorado 80401, United States
- Center
for Bioenergy Innovation, Oak Ridge National
Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Andrew W. Bartling
- Catalytic
Carbon and Transformation Center, National
Renewable Energy Laboratory, Golden, Colorado 80401, United States
- Center
for Bioenergy Innovation, Oak Ridge National
Laboratory, Oak Ridge, Tennessee 37830, United States
| | - John L. Field
- Environmental
Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
- Center
for Bioenergy Innovation, Oak Ridge National
Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Anne E. Harman-Ware
- Renewable
Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
- Center
for Bioenergy Innovation, Oak Ridge National
Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Robin J. Clark
- Environmental
Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
- Center
for Bioenergy Innovation, Oak Ridge National
Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Thomas H. Pendergast
- Institute
of Plant Breeding, Genetics and Genomics, University of Georgia, Athens, Georgia 30602, United States
- Department
of Crop and Soil Sciences, University of
Georgia, Athens, Georgia 30602, United States
- Department
of Plant Biology, University of Georgia, Athens, Georgia 30602, United States
- Center
for Bioenergy Innovation, Oak Ridge National
Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Katrien M. Devos
- Institute
of Plant Breeding, Genetics and Genomics, University of Georgia, Athens, Georgia 30602, United States
- Department
of Crop and Soil Sciences, University of
Georgia, Athens, Georgia 30602, United States
- Department
of Plant Biology, University of Georgia, Athens, Georgia 30602, United States
- Center
for Bioenergy Innovation, Oak Ridge National
Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Erin G. Webb
- Environmental
Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
- Center
for Bioenergy Innovation, Oak Ridge National
Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Ali Missaoui
- Institute
of Plant Breeding, Genetics and Genomics, University of Georgia, Athens, Georgia 30602, United States
- Department
of Crop and Soil Sciences, University of
Georgia, Athens, Georgia 30602, United States
- Center
for Bioenergy Innovation, Oak Ridge National
Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Yaping Xu
- Department
of Plant Sciences, University of Tennessee
Knoxville, Knoxville, Tennessee 37919, United States
- Center
for Bioenergy Innovation, Oak Ridge National
Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Shiva Makaju
- Institute
of Plant Breeding, Genetics and Genomics, University of Georgia, Athens, Georgia 30602, United States
- Department
of Crop and Soil Sciences, University of
Georgia, Athens, Georgia 30602, United States
- Center
for Bioenergy Innovation, Oak Ridge National
Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Vivek Shrestha
- Department
of Plant Sciences, University of Tennessee
Knoxville, Knoxville, Tennessee 37919, United States
- Center
for Bioenergy Innovation, Oak Ridge National
Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Mitra Mazarei
- Department
of Plant Sciences, University of Tennessee
Knoxville, Knoxville, Tennessee 37919, United States
- Center
for Bioenergy Innovation, Oak Ridge National
Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Charles Neal Stewart
- Department
of Plant Sciences, University of Tennessee
Knoxville, Knoxville, Tennessee 37919, United States
- Center
for Bioenergy Innovation, Oak Ridge National
Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Reginald J. Millwood
- Department
of Plant Sciences, University of Tennessee
Knoxville, Knoxville, Tennessee 37919, United States
- Center
for Bioenergy Innovation, Oak Ridge National
Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Brian H. Davison
- Biosciences
Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
- Center
for Bioenergy Innovation, Oak Ridge National
Laboratory, Oak Ridge, Tennessee 37830, United States
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5
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Guo Y, Wang S, Yu K, Wang HL, Xu H, Song C, Zhao Y, Wen J, Fu C, Li Y, Wang S, Zhang X, Zhang Y, Cao Y, Shao F, Wang X, Deng X, Chen T, Zhao Q, Li L, Wang G, Grünhofer P, Schreiber L, Li Y, Song G, Dixon RA, Lin J. Manipulating microRNA miR408 enhances both biomass yield and saccharification efficiency in poplar. Nat Commun 2023; 14:4285. [PMID: 37463897 DOI: 10.1038/s41467-023-39930-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 06/30/2023] [Indexed: 07/20/2023] Open
Abstract
The conversion of lignocellulosic feedstocks to fermentable sugar for biofuel production is inefficient, and most strategies to enhance efficiency directly target lignin biosynthesis, with associated negative growth impacts. Here we demonstrate, for both laboratory- and field-grown plants, that expression of Pag-miR408 in poplar (Populus alba × P. glandulosa) significantly enhances saccharification, with no requirement for acid-pretreatment, while promoting plant growth. The overexpression plants show increased accessibility of cell walls to cellulase and scaffoldin cellulose-binding modules. Conversely, Pag-miR408 loss-of-function poplar shows decreased cell wall accessibility. Overexpression of Pag-miR408 targets three Pag-LACCASES, delays lignification, and modestly reduces lignin content, S/G ratio and degree of lignin polymerization. Meanwhile, the LACCASE loss of function mutants exhibit significantly increased growth and cell wall accessibility in xylem. Our study shows how Pag-miR408 regulates lignification and secondary growth, and suggest an effective approach towards enhancing biomass yield and saccharification efficiency in a major bioenergy crop.
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Affiliation(s)
- Yayu Guo
- State Key Laboratory of Tree Genetics and Breeding, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, 100083, China
| | - Shufang Wang
- State Key Laboratory of Tree Genetics and Breeding, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, 100083, China
- Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Keji Yu
- State Key Laboratory of Tree Genetics and Breeding, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, 100083, China
| | - Hou-Ling Wang
- State Key Laboratory of Tree Genetics and Breeding, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, 100083, China
| | - Huimin Xu
- State Key Laboratory of Tree Genetics and Breeding, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, 100083, China
- College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Chengwei Song
- State Key Laboratory of Tree Genetics and Breeding, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, 100083, China
- College of Agriculture, Henan University of Science and Technology, Luoyang, 471003, China
| | - Yuanyuan Zhao
- State Key Laboratory of Tree Genetics and Breeding, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, 100083, China
| | - Jialong Wen
- Beijing Key Laboratory of Lignocellulosic Chemistry, Beijing Forestry University, Beijing, 100083, China
| | - Chunxiang Fu
- Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
| | - Yu Li
- Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
| | - Shuizhong Wang
- Beijing Key Laboratory of Lignocellulosic Chemistry, Beijing Forestry University, Beijing, 100083, China
| | - Xi Zhang
- State Key Laboratory of Tree Genetics and Breeding, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, 100083, China
| | - Yan Zhang
- State Key Laboratory of Tree Genetics and Breeding, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, 100083, China
| | - Yuan Cao
- State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, Beijing, 100091, China
| | - Fenjuan Shao
- State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, Beijing, 100091, China
| | - Xiaohua Wang
- Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Xin Deng
- Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Tong Chen
- Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Qiao Zhao
- Shenzhen Key Laboratory of Synthetic Genomics, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Lei Li
- School of Life Sciences and School of Advanced Agricultural Sciences, Peking University, Beijing, 100871, China
| | - Guodong Wang
- National Centre for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Paul Grünhofer
- Department of Ecophysiology, Institute of Cellular and Molecular Botany, University of Bonn, Kirschallee 1, 53115, Bonn, Germany
| | - Lukas Schreiber
- Department of Ecophysiology, Institute of Cellular and Molecular Botany, University of Bonn, Kirschallee 1, 53115, Bonn, Germany
| | - Yue Li
- State Key Laboratory of Tree Genetics and Breeding, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, 100083, China
| | - Guoyong Song
- Beijing Key Laboratory of Lignocellulosic Chemistry, Beijing Forestry University, Beijing, 100083, China
| | - Richard A Dixon
- State Key Laboratory of Tree Genetics and Breeding, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, 100083, China.
- BioDiscovery Institute and Department of Biological Sciences, University of North Texas, Denton, TX, 76203, USA.
| | - Jinxing Lin
- State Key Laboratory of Tree Genetics and Breeding, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, 100083, China.
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6
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Chromosome-scale genome assembly provides insights into the molecular mechanisms of tissue development of Populus wilsonii. Commun Biol 2022; 5:1125. [PMID: 36284165 PMCID: PMC9596445 DOI: 10.1038/s42003-022-04106-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 10/12/2022] [Indexed: 11/12/2022] Open
Abstract
Populus wilsonii is an important species of section Leucoides, and the natural populations mainly grow in southwest China. In this study, a single genotype of wild P. wilsonii was sequenced and assembled at genome size of 477.35 Mb in 19 chromosomes with contig N50 of 16.3 Mb. A total of 38,054 genes were annotated, and 49.95% of the genome was annotated as repetitive elements. Phylogenetic analysis identified that the divergence between P. wilsonii and the ancestor of P. deltoides and P. trichocarpa was 12 (3–23) Mya. 4DTv and Ks distributions supported the occurrence of the salicoid WGD event (~65 Mya). The highly conserved collinearity supports the close evolutionary relationship among these species. Some key enzyme-encoding gene families related to the biosynthesis of lignin and flavonoids were expanded and highly expressed in the stems or leaves, which probably resist the damage of the natural environment. In addition, some key gene families related to cellulose biosynthesis were highly expressed in stems, accounting for the high cellulose content of P. wilsonii variety. Our findings provided deep insights into the genetic evolution of P. wilsonii and will contribute to further biological research and breeding as well as for other poplars in Salicaceae. A genome assembly for the Chinese poplar tree, Populus wilsonii, provides a unique resource to guide research into poplar development and breeding efforts.
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7
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Li Y, Xiong W, He F, Qi T, Sun Z, Liu Y, Bai S, Wang H, Wu Z, Fu C. Down-regulation of PvSAMS impairs S-adenosyl-L-methionine and lignin biosynthesis, and improves cell wall digestibility in switchgrass. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:4157-4169. [PMID: 35383829 DOI: 10.1093/jxb/erac147] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 04/05/2022] [Indexed: 06/14/2023]
Abstract
S-adenosyl- l-methionine (SAM) is the methyl donor involved in the biosynthesis of guaiacyl (G) and syringyl (S) lignins in vascular plants. SAM is synthesized from methionine through the catalysis of the enzyme S-adenosylmethionine synthase (SAMS). However, the detailed function of SAMS in lignin biosynthesis has not been widely investigated in plants, particularly in monocot species. In this study, we identified PvSAMS genes from switchgrass (Panicum virgatum L.), an important dual-purpose fodder and biofuel crop, and generated numerous transgenic switchgrass lines through PvSAMS RNA interference technology. Down-regulation of PvSAMS reduced the contents of SAM, G-lignins, and S-lignins in the transgenic switchgrass. The methionine and glucoside derivatives of caffeoyl alcohol were found to accumulate in the transgenic plants. Moreover, down-regulation of PvSAMS in switchgrass resulted in brownish stems associated with reduced lignin content and improved cell wall digestibility. Furthermore, transcriptomic analysis revealed that most sulfur deficiency-responsive genes were differentially expressed in the transgenic switchgrass, leading to a significant increase in total sulfur content; thus implying an important role of SAMS in the methionine cycle, lignin biosynthesis, and sulfur assimilation. Taken together, our results suggest that SAMS is a valuable target in lignin manipulation, and that manipulation of PvSAMS can simultaneously regulate the biosynthesis of SAM and methylated monolignols in switchgrass.
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Affiliation(s)
- Yu Li
- Shandong Provincial Key Laboratory of Energy Genetics and CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, 266101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Wangdan Xiong
- Shandong Provincial Key Laboratory of Energy Genetics and CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, 266101, China
- Grassland Agri-Husbandry Research Center, College of Grassland Science, Qingdao Agricultural University, Qingdao, China
| | - Feng He
- Shandong Provincial Key Laboratory of Energy Genetics and CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, 266101, China
| | - Tianxiong Qi
- Shandong Provincial Key Laboratory of Energy Genetics and CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, 266101, China
| | - Zhen Sun
- Shandong Provincial Key Laboratory of Energy Genetics and CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, 266101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yuchen Liu
- Shandong Provincial Key Laboratory of Energy Genetics and CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, 266101, China
| | - Shiqie Bai
- Sichuan Academy of Grassland Science, Chengdu, 611731, China
| | - Honglun Wang
- CAS Key Laboratory of Tibetan Medicine Research, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, China
| | - Zhenying Wu
- Shandong Provincial Key Laboratory of Energy Genetics and CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, 266101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Chunxiang Fu
- Shandong Provincial Key Laboratory of Energy Genetics and CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, 266101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
- CAS Key Laboratory of Tibetan Medicine Research, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, China
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8
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Zhang S, Xia Z, Li C, Wang X, Lu X, Zhang W, Ma H, Zhou X, Zhang W, Zhu T, Liu P, Liu G, Wang W, Xia T. Chromosome-Scale Genome Assembly Provides Insights into Speciation of Allotetraploid and Massive Biomass Accumulation of Elephant Grass (Pennisetum purpureum Schum.). Mol Ecol Resour 2022; 22:2363-2378. [PMID: 35347881 DOI: 10.1111/1755-0998.13612] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 03/02/2022] [Accepted: 03/23/2022] [Indexed: 11/29/2022]
Abstract
Elephant grass (Pennisetum purpureum Schum) is an important forage, biofuels and industrial plant widely distributed in tropical and subtropical areas globally. It is characterized with robust growth and high biomass. We sequenced its allopolyploid genome and assembled 2.07 Gb into A' and B sub-genomes of 14 chromosomes with scaffold N50 of 8.47 Mb, yielding a total of 77,139 genes. The allotetraploid speciation occurred approximately 15 MYA after the divergence between Setaria italica and Pennisetum glaucum, according to a phylogenetic analysis of Pennisetum species. Double whole-genome duplication (WGD) and polyploidization events resulted in large scale gene expansion, especially in the key steps of growth and biomass accumulation. Integrated transcriptome profiling revealed the functional divergence between sub-genomes A' and B. A' sub-genome mainly contributed to plant growth, development and photosynthesis, whereas the B sub-genome was primarily responsible for effective transportation and resistance to stimulation. Some key gene families related to cellulose biosynthesis were expanded and highly expressed in stems, which could explain the high cellulose content in elephant grass. Our findings provide deep insights into genetic evolution of elephant grass and will aid future biological research and breeding, even for other grasses in the family Poaceae.
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Affiliation(s)
- Shengkui Zhang
- State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Jinan, 250353, Shandong, PR China.,School of Bioengineering, Qilu University of Technology, Jinan, 250353, Shandong, PR China
| | - Zhiqiang Xia
- College of Tropical Crops, Hainan University, Haikou, 570228, Hainan, PR China
| | - Can Li
- State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Jinan, 250353, Shandong, PR China.,School of Bioengineering, Qilu University of Technology, Jinan, 250353, Shandong, PR China
| | - Xiaohan Wang
- State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Jinan, 250353, Shandong, PR China.,School of Bioengineering, Qilu University of Technology, Jinan, 250353, Shandong, PR China
| | - Xianqin Lu
- State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Jinan, 250353, Shandong, PR China.,School of Bioengineering, Qilu University of Technology, Jinan, 250353, Shandong, PR China
| | - Wenqing Zhang
- State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Jinan, 250353, Shandong, PR China.,School of Bioengineering, Qilu University of Technology, Jinan, 250353, Shandong, PR China
| | - Haizhen Ma
- State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Jinan, 250353, Shandong, PR China.,School of Bioengineering, Qilu University of Technology, Jinan, 250353, Shandong, PR China
| | - Xincheng Zhou
- Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haiko, 571101, Hainan, PR China
| | - Weixiong Zhang
- Department of Computer Science and Engineering, Department of Genetics, Washington University, St. Louis, MO, USA
| | - Tingting Zhu
- Department of Plant Sciences, University of California, Davis, CA, 95616, USA
| | - Pandao Liu
- Institute of Tropical Crops Genetic Resources, Chinese Academy of Tropical Agricultural Sciences, Danzhou, 571700, Hainan, PR China
| | - Guodao Liu
- Institute of Tropical Crops Genetic Resources, Chinese Academy of Tropical Agricultural Sciences, Danzhou, 571700, Hainan, PR China
| | - Wenquan Wang
- College of Tropical Crops, Hainan University, Haikou, 570228, Hainan, PR China.,Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haiko, 571101, Hainan, PR China
| | - Tao Xia
- State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Jinan, 250353, Shandong, PR China.,School of Bioengineering, Qilu University of Technology, Jinan, 250353, Shandong, PR China
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9
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Saha P, Lin F, Thibivilliers S, Xiong Y, Pan C, Bartley LE. Phenylpropanoid Biosynthesis Gene Expression Precedes Lignin Accumulation During Shoot Development in Lowland and Upland Switchgrass Genotypes. FRONTIERS IN PLANT SCIENCE 2021; 12:640930. [PMID: 34434200 PMCID: PMC8380989 DOI: 10.3389/fpls.2021.640930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Accepted: 04/14/2021] [Indexed: 06/13/2023]
Abstract
Efficient conversion of lignocellulosic biomass into biofuels is influenced by biomass composition and structure. Lignin and other cell wall phenylpropanoids, such as para-coumaric acid (pCA) and ferulic acid (FA), reduce cell wall sugar accessibility and hamper biochemical fuel production. Toward identifying the timing and key parameters of cell wall recalcitrance across different switchgrass genotypes, this study measured cell wall composition and lignin biosynthesis gene expression in three switchgrass genotypes, A4 and AP13, representing the lowland ecotype, and VS16, representing the upland ecotype, at three developmental stages [Vegetative 3 (V3), Elongation 4 (E4), and Reproductive 3 (R3)] and three segments (S1-S3) of the E4 stage under greenhouse conditions. A decrease in cell wall digestibility and an increase in phenylpropanoids occur across development. Compared with AP13 and A4, VS16 has significantly less lignin and greater cell wall digestibility at the V3 and E4 stages; however, differences among genotypes diminish by the R3 stage. Gini correlation analysis across all genotypes revealed that lignin and pCA, but also pectin monosaccharide components, show the greatest negative correlations with digestibility. Lignin and pCA accumulation is delayed compared with expression of phenylpropanoid biosynthesis genes, while FA accumulation coincides with expression of these genes. The different cell wall component accumulation profiles and gene expression correlations may have implications for system biology approaches to identify additional gene products with cell wall component synthesis and regulation functions.
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Affiliation(s)
- Prasenjit Saha
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, United States
| | - Fan Lin
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, United States
| | - Sandra Thibivilliers
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, United States
| | - Yi Xiong
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, United States
| | - Chongle Pan
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, United States
- School of Computer Science, University of Oklahoma, Norman, OK, United States
| | - Laura E. Bartley
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, United States
- Research Institute for the Sustainable Humanosphere, Kyoto University, Kyoto, Japan
- Institute of Biological Chemistry, Washington State University, Pullman, WA, United States
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10
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Kim D, Yoo CG, Schwarz J, Dhekney S, Kozak R, Laufer C, Ferrier D, Mackay S, Ashcraft M, Williams R, Kim S. Effect of lignin-blocking agent on enzyme hydrolysis of acid pretreated hemp waste. RSC Adv 2021; 11:22025-22033. [PMID: 35480814 PMCID: PMC9034124 DOI: 10.1039/d1ra03412j] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 06/06/2021] [Indexed: 01/07/2023] Open
Abstract
Hemp wastes (stems and branches), fractionated after hemp flower extraction for the production of cannabidiol oil, were utilized as a potentially renewable resource for the sugar flatform process. Hydrolysis of cellulose from the acid pretreated hemp biomass using a commercial enzyme was tested and evaluated for its chemical composition, morphological change, and sugar recovery. Acid pretreated hemp stems and branches, containing 1% glucan (w/v) solids, were hydrolyzed for 72 h using 25 mg enzyme protein per g glucan. A 54% glucose conversion was achieved from the treated branches versus a 71% yield from the treated stems. Raw branches and stems yielded 35% and 38% glucose, respectively. Further tests with a lignin-blocking additive (e.g. bovine serum albumin) resulted in a 72% glucose yield increase for stem hydrolysis using 10 mg enzyme protein per g glucan. While pretreatment promotes amorphous hemicellulose decrease and cellulose decomposition, it causes enzyme inhibition/deactivation due to potential inhibitors (phenols and lignin-derived compounds). This study confirms the addition of non-catalytic proteins enhances the cellulose conversion by avoiding non-productive binding of enzymes to the lignin and lignin-derived molecules, with lignin content determining the degree of inhibition and conversion efficiency.
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Affiliation(s)
- Daehwan Kim
- Department of Biology, Hood College Frederick MD 21701 USA
| | - Chang Geun Yoo
- Department of Chemical Engineering, State University of New York - College of Environmental Science and Forestry Syracuse NY 13210 USA
| | - Jurgen Schwarz
- Department of Agriculture, Food and Resource Sciences, University of Maryland Eastern Shore Princess Anne MD 21853 USA
| | - Sadanand Dhekney
- Department of Agriculture, Food and Resource Sciences, University of Maryland Eastern Shore Princess Anne MD 21853 USA
| | - Robert Kozak
- Atlantic Biomass Conversions, LLC Frederick MD 21701 USA
| | - Craig Laufer
- Department of Biology, Hood College Frederick MD 21701 USA
| | - Drew Ferrier
- Department of Biology, Hood College Frederick MD 21701 USA
| | - Skylar Mackay
- Department of Biology, Hood College Frederick MD 21701 USA
| | | | | | - Sinyeon Kim
- MtheraPharma Co., Ltd. Seoul 07793 Republic of Korea
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11
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Bing RG, Sulis DB, Wang JP, Adams MW, Kelly RM. Thermophilic microbial deconstruction and conversion of natural and transgenic lignocellulose. ENVIRONMENTAL MICROBIOLOGY REPORTS 2021; 13:272-293. [PMID: 33684253 PMCID: PMC10519370 DOI: 10.1111/1758-2229.12943] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 02/25/2021] [Accepted: 02/28/2021] [Indexed: 06/12/2023]
Abstract
The potential to convert renewable plant biomasses into fuels and chemicals by microbial processes presents an attractive, less environmentally intense alternative to conventional routes based on fossil fuels. This would best be done with microbes that natively deconstruct lignocellulose and concomitantly form industrially relevant products, but these two physiological and metabolic features are rarely and simultaneously observed in nature. Genetic modification of both plant feedstocks and microbes can be used to increase lignocellulose deconstruction capability and generate industrially relevant products. Separate efforts on plants and microbes are ongoing, but these studies lack a focus on optimal, complementary combinations of these disparate biological systems to obtain a convergent technology. Improving genetic tools for plants have given rise to the generation of low-lignin lines that are more readily solubilized by microorganisms. Most focus on the microbiological front has involved thermophilic bacteria from the genera Caldicellulosiruptor and Clostridium, given their capacity to degrade lignocellulose and to form bio-products through metabolic engineering strategies enabled by ever-improving molecular genetics tools. Bioengineering plant properties to better fit the deconstruction capabilities of candidate consolidated bioprocessing microorganisms has potential to achieve the efficient lignocellulose deconstruction needed for industrial relevance.
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Affiliation(s)
- Ryan G. Bing
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695
| | - Daniel B. Sulis
- Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, NC 27695
| | - Jack P. Wang
- Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, NC 27695
| | - Michael W.W. Adams
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602
| | - Robert M. Kelly
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695
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12
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Breeding Targets to Improve Biomass Quality in Miscanthus. Molecules 2021; 26:molecules26020254. [PMID: 33419100 PMCID: PMC7825460 DOI: 10.3390/molecules26020254] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Revised: 12/31/2020] [Accepted: 01/01/2021] [Indexed: 01/02/2023] Open
Abstract
Lignocellulosic crops are attractive bioresources for energy and chemicals production within a sustainable, carbon circular society. Miscanthus is one of the perennial grasses that exhibits great potential as a dedicated feedstock for conversion to biobased products in integrated biorefineries. The current biorefinery strategies are primarily focused on polysaccharide valorization and require severe pretreatments to overcome the lignin barrier. The need for such pretreatments represents an economic burden and impacts the overall sustainability of the biorefinery. Hence, increasing its efficiency has been a topic of great interest. Inversely, though pretreatment will remain an essential step, there is room to reduce its severity by optimizing the biomass composition rendering it more exploitable. Extensive studies have examined the miscanthus cell wall structures in great detail, and pinpointed those components that affect biomass digestibility under various pretreatments. Although lignin content has been identified as the most important factor limiting cell wall deconstruction, the effect of polysaccharides and interaction between the different constituents play an important role as well. The natural variation that is available within different miscanthus species and increased understanding of biosynthetic cell wall pathways have specified the potential to create novel accessions with improved digestibility through breeding or genetic modification. This review discusses the contribution of the main cell wall components on biomass degradation in relation to hydrothermal, dilute acid and alkaline pretreatments. Furthermore, traits worth advancing through breeding will be discussed in light of past, present and future breeding efforts.
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13
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Li F, Piasecki C, Millwood RJ, Wolfe B, Mazarei M, Stewart CN. High-Throughput Switchgrass Phenotyping and Biomass Modeling by UAV. FRONTIERS IN PLANT SCIENCE 2020; 11:574073. [PMID: 33193511 PMCID: PMC7606849 DOI: 10.3389/fpls.2020.574073] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 09/16/2020] [Indexed: 05/28/2023]
Abstract
Unmanned aerial vehicle (UAV) technology is an emerging powerful approach for high-throughput plant phenotyping field-grown crops. Switchgrass (Panicum virgatum L.) is a lignocellulosic bioenergy crop for which studies on yield, sustainability, and biofuel traits are performed. In this study, we exploited UAV-based imagery (LiDAR and multispectral approaches) to measure plant height, perimeter, and biomass yield in field-grown switchgrass in order to make predictions on bioenergy traits. Manual ground truth measurements validated the automated UAV results. We found UAV-based plant height and perimeter measurements were highly correlated and consistent with the manual measurements (r = 0.93, p < 0.001). Furthermore, we found that phenotyping parameters can significantly improve the natural saturation of the spectral index of the optical image for detecting high-density plantings. Combining plant canopy height (CH) and canopy perimeter (CP) parameters with spectral index (SI), we developed a robust and standardized biomass yield model [biomass = (m × SI) × CP × CH] where the m is an SI-sensitive coefficient linearly varying with the plant phenological changing stage. The biomass yield estimates obtained from this model were strongly correlated with manual measurements (r = 0.90, p < 0.001). Taking together, our results provide insights into the capacity of UAV-based remote sensing for switchgrass high-throughput phenotyping in the field, which will be useful for breeding and cultivar development.
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Affiliation(s)
- Fei Li
- Department of Plant Sciences, University of Tennessee, Knoxville, Knoxville, TN, United States
- Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Cristiano Piasecki
- Department of Plant Sciences, University of Tennessee, Knoxville, Knoxville, TN, United States
- Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Reginald J. Millwood
- Department of Plant Sciences, University of Tennessee, Knoxville, Knoxville, TN, United States
- Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Benjamin Wolfe
- Department of Plant Sciences, University of Tennessee, Knoxville, Knoxville, TN, United States
- Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Mitra Mazarei
- Department of Plant Sciences, University of Tennessee, Knoxville, Knoxville, TN, United States
- Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - C. Neal Stewart
- Department of Plant Sciences, University of Tennessee, Knoxville, Knoxville, TN, United States
- Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, United States
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14
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Kline LM, Voothuluru P, Lenaghan SC, Burris JN, Soliman M, Tetard L, Stewart CN, Rials TG, Labbé N. A Robust Method to Quantify Cell Wall Bound Phenolics in Plant Suspension Culture Cells Using Pyrolysis-Gas Chromatography/Mass Spectrometry. FRONTIERS IN PLANT SCIENCE 2020; 11:574016. [PMID: 33013999 PMCID: PMC7509179 DOI: 10.3389/fpls.2020.574016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 08/18/2020] [Indexed: 06/11/2023]
Abstract
The wide-scale production of renewable fuels from lignocellulosic feedstocks continues to be hampered by the natural recalcitrance of biomass. Therefore, there is a need to develop robust and reliable methods to characterize and quantify components that contribute to this recalcitrance. In this study, we utilized a method that incorporates pyrolysis with successive gas chromatography and mass spectrometry (Py-GC/MS) to assess lignification in cell suspension cultures. This method was compared with other standard techniques such as acid-catalyzed hydrolysis, acetyl bromide lignin determination, and nitrobenzene oxidation for quantification of cell wall bound phenolic compounds. We found that Py-GC/MS can be conducted with about 250 µg of tissue sample and provides biologically relevant data, which constitutes a substantial advantage when compared to the 50-300 mg of tissue needed for the other methods. We show that when combined with multivariate statistical analyses, Py-GC/MS can distinguish cell wall components of switchgrass (Panicum virgatum) suspension cultures before and after inducing lignification. The deposition of lignin precursors on uninduced cell walls included predominantly guaiacyl-based units, 71% ferulic acid, and 5.3% p-coumaric acid. Formation of the primary and partial secondary cell wall was supported by the respective ~15× and ~1.7× increases in syringyl-based and guaiacyl-based precursors, respectively, in the induced cells. Ferulic acid was decreased by half after induction. These results provide the proof-of-concept for quick and reliable cell wall compositional analyses using Py-GC/MS and could be targeted for either translational genomics or for fundamental studies focused on understanding the molecular and physiological mechanisms regulating plant cell wall production and biomass recalcitrance.
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Affiliation(s)
- Lindsey M. Kline
- Center for Renewable Carbon, University of Tennessee, Knoxville, TN, United States
| | - Priya Voothuluru
- Center for Renewable Carbon, University of Tennessee, Knoxville, TN, United States
| | - Scott C. Lenaghan
- Center for Renewable Carbon, University of Tennessee, Knoxville, TN, United States
- Department of Food Science, University of Tennessee, Knoxville, TN, United States
- Center for Agricultural Synthetic Biology, University of Tennessee Institute of Agriculture, Knoxville, TN, United States
| | - Jason N. Burris
- Department of Food Science, University of Tennessee, Knoxville, TN, United States
- Center for Agricultural Synthetic Biology, University of Tennessee Institute of Agriculture, Knoxville, TN, United States
- Department of Plant Sciences, University of Tennessee, Knoxville, TN, United States
| | - Mikhael Soliman
- Nanoscience Technology Center, Department of Physics, University of Central Florida, Orlando, FL, United States
| | - Laurene Tetard
- Nanoscience Technology Center, Department of Physics, University of Central Florida, Orlando, FL, United States
| | - C. Neal Stewart
- Center for Agricultural Synthetic Biology, University of Tennessee Institute of Agriculture, Knoxville, TN, United States
- Department of Plant Sciences, University of Tennessee, Knoxville, TN, United States
| | - Timothy G. Rials
- Center for Renewable Carbon, University of Tennessee, Knoxville, TN, United States
| | - Nicole Labbé
- Center for Renewable Carbon, University of Tennessee, Knoxville, TN, United States
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15
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Ladeira Ázar RIS, Bordignon-Junior SE, Laufer C, Specht J, Ferrier D, Kim D. Effect of Lignin Content on Cellulolytic Saccharification of Liquid Hot Water Pretreated Sugarcane Bagasse. Molecules 2020; 25:molecules25030623. [PMID: 32023910 PMCID: PMC7037451 DOI: 10.3390/molecules25030623] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 01/22/2020] [Accepted: 01/28/2020] [Indexed: 11/16/2022] Open
Abstract
Lignin contributes to the rigid structure of the plant cell wall and is partially responsible for the recalcitrance of lignocellulosic materials to enzymatic digestion. Overcoming this recalcitrance is one the most critical issues in a sugar-flat form process. This study addresses the effect of low lignin sugarcane bagasse on enzymatic hydrolysis after liquid hot water pretreatment at 190 °C and 20 min (severity factor: 3.95). The hydrolysis of bagasse from a sugarcane line selected for a relatively low lignin content, gave an 89.7% yield of cellulose conversion to glucose at 40 FPU/g glucan versus a 68.3% yield from a comparably treated bagasse from the high lignin bred line. A lower enzyme loading of 5 FPU/g glucan (equivalent to 3.2 FPU/g total solids) resulted in 31.4% and 21.9% conversion yields, respectively, for low and high lignin samples, suggesting the significance of lignin content in the saccharification process. Further increases in the enzymatic conversion of cellulose to glucose were achieved when the bagasse sample was pre-incubated with a lignin blocking agent, e.g., bovine serum albumin (50 mg BSA/g glucan) at 50 °C for 1 h prior to an actual saccharification. In this work, we have demonstrated that even relatively small differences in lignin content can result in considerably increased sugar production, which supports the dissimilarity of bagasse lignin content and its effects on cellulose digestibility. The increased glucose yields with the addition of BSA helped to decrease the inhibition of non-productive absorption of cellulose enzymes onto lignin and solid residual lignin fractions.
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Affiliation(s)
- Rafaela I. S. Ladeira Ázar
- Department of Biochemistry and Molecular Biology, BIOAGRO, Federal University of Viçosa, Viçosa, Minas Gerais 36570-000, Brazil;
| | - Sidnei Emilio Bordignon-Junior
- Laboratory of Biochemistry and Applied Microbiology, São Paulo State University (UNESP), IBILCE, 2265 Cristóvão Colombo, São José do Rio Preto 15054-000, São Paulo, Brazil;
| | - Craig Laufer
- Department of Biology, Hood College, 401 Rosemont Avenue, Frederick, MD 21701, USA; (C.L.); (J.S.); (D.F.)
| | - Jordan Specht
- Department of Biology, Hood College, 401 Rosemont Avenue, Frederick, MD 21701, USA; (C.L.); (J.S.); (D.F.)
| | - Drew Ferrier
- Department of Biology, Hood College, 401 Rosemont Avenue, Frederick, MD 21701, USA; (C.L.); (J.S.); (D.F.)
| | - Daehwan Kim
- Department of Biology, Hood College, 401 Rosemont Avenue, Frederick, MD 21701, USA; (C.L.); (J.S.); (D.F.)
- Correspondence: ; Tel.: +1-765-637-8603; Fax: +1-301-696-3667
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16
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Mazarei M, Baxter HL, Srivastava A, Li G, Xie H, Dumitrache A, Rodriguez M, Natzke JM, Zhang JY, Turner GB, Sykes RW, Davis MF, Udvardi MK, Wang ZY, Davison BH, Blancaflor EB, Tang Y, Stewart CN. Silencing Folylpolyglutamate Synthetase1 ( FPGS1) in Switchgrass ( Panicum virgatum L.) Improves Lignocellulosic Biofuel Production. FRONTIERS IN PLANT SCIENCE 2020; 11:843. [PMID: 32636863 PMCID: PMC7317012 DOI: 10.3389/fpls.2020.00843] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 05/26/2020] [Indexed: 05/12/2023]
Abstract
Switchgrass (Panicum virgatum L.) is a lignocellulosic perennial grass with great potential in bioenergy field. Lignocellulosic bioenergy crops are mostly resistant to cell wall deconstruction, and therefore yield suboptimal levels of biofuel. The one-carbon pathway (also known as C1 metabolism) is critical for polymer methylation, including that of lignin and hemicelluloses in cell walls. Folylpolyglutamate synthetase (FPGS) catalyzes a biochemical reaction that leads to the formation of folylpolyglutamate, an important cofactor for many enzymes in the C1 pathway. In this study, the putatively novel switchgrass PvFPGS1 gene was identified and its functional role in cell wall composition and biofuel production was examined by RNAi knockdown analysis. The PvFPGS1-downregulated plants were analyzed in the field over three growing seasons. Transgenic plants with the highest reduction in PvFPGS1 expression grew slower and produced lower end-of-season biomass. Transgenic plants with low-to-moderate reduction in PvFPGS1 transcript levels produced equivalent biomass as controls. There were no significant differences observed for lignin content and syringyl/guaiacyl lignin monomer ratio in the low-to-moderately reduced PvFPGS1 transgenic lines compared with the controls. Similarly, sugar release efficiency was also not significantly different in these transgenic lines compared with the control lines. However, transgenic plants produced up to 18% more ethanol while maintaining congruent growth and biomass as non-transgenic controls. Severity of rust disease among transgenic and control lines were not different during the time course of the field experiments. Altogether, the unchanged lignin content and composition in the low-to-moderate PvFPGS1-downregulated lines may suggest that partial downregulation of PvFPGS1 expression did not impact lignin biosynthesis in switchgrass. In conclusion, the manipulation of PvFPGS1 expression in bioenergy crops may be useful to increase biofuel potential with no growth penalty or increased susceptibility to rust in feedstock.
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Affiliation(s)
- Mitra Mazarei
- Department of Plant Sciences, The University of Tennessee, Knoxville, TN, United States
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Holly L. Baxter
- Department of Plant Sciences, The University of Tennessee, Knoxville, TN, United States
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Avinash Srivastava
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Noble Research Institute, Ardmore, OK, United States
| | - Guifen Li
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Noble Research Institute, Ardmore, OK, United States
| | - Hongli Xie
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Noble Research Institute, Ardmore, OK, United States
| | - Alexandru Dumitrache
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Miguel Rodriguez
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Jace M. Natzke
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Ji-Yi Zhang
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Noble Research Institute, Ardmore, OK, United States
| | - Geoffrey B. Turner
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- National Renewable Energy Laboratory, Golden, CO, United States
| | - Robert W. Sykes
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- National Renewable Energy Laboratory, Golden, CO, United States
| | - Mark F. Davis
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- National Renewable Energy Laboratory, Golden, CO, United States
| | - Michael K. Udvardi
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Noble Research Institute, Ardmore, OK, United States
| | - Zeng-Yu Wang
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Noble Research Institute, Ardmore, OK, United States
| | - Brian H. Davison
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Elison B. Blancaflor
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Noble Research Institute, Ardmore, OK, United States
| | - Yuhong Tang
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Noble Research Institute, Ardmore, OK, United States
- *Correspondence: Yuhong Tang,
| | - Charles Neal Stewart
- Department of Plant Sciences, The University of Tennessee, Knoxville, TN, United States
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Charles Neal Stewart Jr.,
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17
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Xu S, Ottinger SL, Schaeffer SM, DeBruyn JM, Stewart CN, Mazarei M, Jagadamma S. Effects of field-grown transgenic switchgrass carbon inputs on soil organic carbon cycling. PeerJ 2019; 7:e7887. [PMID: 31637134 PMCID: PMC6800523 DOI: 10.7717/peerj.7887] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 09/12/2019] [Indexed: 11/20/2022] Open
Abstract
Genetic engineering has been used to decrease the lignin content and to change the lignin composition of switchgrass (Panicum virgatum L.) to decrease cell wall recalcitrance to enable more efficient cellulosic biofuel production. Previous greenhouse and field studies showed that downregulation of the gene encoding switchgrass caffeic acid O-methyltransferase (COMT) and overexpression of the switchgrass PvMYB4 (MYB4) gene effectively improved ethanol yield. To understand potential environmental impacts of cultivating these transgenic bioenergy crops in the field, we quantified the effects of field cultivation of transgenic switchgrass on soil organic carbon (SOC) dynamics. Total and active SOC as well as soil respiration were measured in soils grown with two COMT-downregulated transgenic lines (COMT2 and COMT3), three MYB4-overexpressed transgenic lines (L1, L6, and L8), and their corresponding non-transgenic controls. No differences in total SOC, dissolved organic carbon (DOC), and permanganate oxidizable carbon (POXC) were detected between transgenic and non-transgenic treatments for both COMT (10.4-11.1 g kg-1 for SOC, 60.0-64.8 mg kg-1 for DOC, and 299-384 mg kg-1 for POXC) and MYB4 lines (6.89-8.21 g kg-1 for SOC, 56.0-61.1 mg kg-1 for DOC, and 177-199 mg kg-1 for POXC). Soil CO2-carbon (CO2-C) production from the COMT2 transgenic line was not significantly different from its non-transgenic control. In contrast, the COMT3 transgenic line had greater soil CO2-C production than its non-transgenic control (210 vs. 165 µg g-1) after 72 days of laboratory incubation. Combining the improvement in ethanol yield and biomass production reported in previous studies with negligible change in SOC and soil respiration, COMT2 could be a better biofuel feedstock than COMT3 for environmental conservation and cost-effective biofuel production. On the other hand, MYB4 transgenic line L8 produced more biomass and total ethanol per hectare while it released more CO2-C than the control (253 vs. 207 µg g-1). Long-term in situ monitoring of transgenic switchgrass systems using a suite of soil and environmental variables is needed to determine the sustainability of growing genetically modified bioenergy crops.
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Affiliation(s)
- Sutie Xu
- Department of Biosystems Engineering and Soil Science, University of Tennessee, Knoxville, TN, USA
| | - Sarah L Ottinger
- Department of Biosystems Engineering and Soil Science, University of Tennessee, Knoxville, TN, USA
| | - Sean M Schaeffer
- Department of Biosystems Engineering and Soil Science, University of Tennessee, Knoxville, TN, USA
| | - Jennifer M DeBruyn
- Department of Biosystems Engineering and Soil Science, University of Tennessee, Knoxville, TN, USA
| | - C Neal Stewart
- Department of Plant Sciences, University of Tennessee, Knoxville, TN, USA.,BioEnergy Science Center and Center for Bioenergy Innovations, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Mitra Mazarei
- Department of Plant Sciences, University of Tennessee, Knoxville, TN, USA.,BioEnergy Science Center and Center for Bioenergy Innovations, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Sindhu Jagadamma
- Department of Biosystems Engineering and Soil Science, University of Tennessee, Knoxville, TN, USA
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18
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Mohapatra S, Mishra SS, Bhalla P, Thatoi H. Engineering grass biomass for sustainable and enhanced bioethanol production. PLANTA 2019; 250:395-412. [PMID: 31236698 DOI: 10.1007/s00425-019-03218-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Accepted: 06/18/2019] [Indexed: 06/09/2023]
Abstract
Bioethanol from lignocellulosic biomass is a promising step for the future energy requirements. Grass is a potential lignocellulosic biomass which can be utilised for biorefinery-based bioethanol production. Grass biomass is a suitable feedstock for bioethanol production due to its all the year around production, requirement of less fertile land and noninterference with food system. However, the processes involved, i.e. pretreatment, enzymatic hydrolysis and fermentation for bioethanol production from grass biomass, are both time consuming and costly. Developing the grass biomass in planta for enhanced bioethanol production is a promising step for maximum utilisation of this valuable feedstock and, thus, is the focus of the present review. Modern breeding techniques and transgenic processes are attractive methods which can be utilised for development of the feedstock. However, the outcomes are not always predictable and the time period required for obtaining a robust variety is generation dependent. Sophisticated genome editing technologies such as synthetic genetic circuits (SGC) or clustered regularly interspaced short palindromic repeats (CRISPR) systems are advantageous for induction of desired traits/heritable mutations in a foreseeable genome location in the 1st mutant generation. Although, its application in grass biomass for bioethanol is limited, these sophisticated techniques are anticipated to exhibit more flexibility in engineering the expression pattern for qualitative and qualitative traits. Nevertheless, the fundamentals rendered by the genetics of the transgenic crops will remain the basis of such developments for obtaining biorefinery-based bioethanol concepts from grass biomass. Grasses which are abundant and widespread in nature epitomise attractive lignocellulosic feedstocks for bioethanol production. The complexity offered by the grass cell wall in terms of lignin recalcitrance and its binding to polysaccharides forms a barricade for its commercialization as a biofuel feedstock. Inspired by the possibilities for rewiring the genetic makeup of grass biomass for reduced lignin and lignin-polysaccharide linkages along with increase in carbohydrates, innovative approaches for in planta modifications are forging ahead. In this review, we highlight the progress made in the field of transgenic grasses for bioethanol production and focus our understanding on improvements of simple breeding techniques and post-harvest techniques for development in shortening of lignin-carbohydrate and carbohydrate-carbohydrate linkages. Further, we discuss about the designer lignins which are aimed for qualitable lignins and also emphasise on remodelling of polysaccharides and mixed-linkage glucans for enhancing carbohydrate content and in planta saccharification efficiency. As a final point, we discuss the role of synthetic genetic circuits and CRISPR systems in targeted improvement of cell wall components without compromising the plant growth and health. It is anticipated that this review can provide a rational approach towards a better understanding of application of in planta genetic engineering aspects for designing synthetic genetic circuits which can promote grass feedstocks for biorefinery-based bioethanol concepts.
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Affiliation(s)
- Sonali Mohapatra
- Department of Biotechnology, College of Engineering and Technology, Biju Patnaik University of Technology, Bhubaneswar, 751003, India.
| | - Suruchee Samparana Mishra
- Department of Biotechnology, College of Engineering and Technology, Biju Patnaik University of Technology, Bhubaneswar, 751003, India
| | - Prerna Bhalla
- Bhupat and Jyoti Mehta School of Biosciences Building, Indian Institute of Technology Madras, Chennai, India
| | - Hrudayanath Thatoi
- Department of Biotechnology, North Orissa University, Sriram Chandra Vihar, Takatpur, Baripada, 757003, Odisha, India
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19
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Peng X, Liu H, Chen P, Tang F, Hu Y, Wang F, Pi Z, Zhao M, Chen N, Chen H, Zhang X, Yan X, Liu M, Fu X, Zhao G, Yao P, Wang L, Dai H, Li X, Xiong W, Xu W, Zheng H, Yu H, Shen S. A Chromosome-Scale Genome Assembly of Paper Mulberry (Broussonetia papyrifera) Provides New Insights into Its Forage and Papermaking Usage. MOLECULAR PLANT 2019; 12:661-677. [PMID: 30822525 DOI: 10.1016/j.molp.2019.01.021] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2018] [Revised: 01/18/2019] [Accepted: 01/20/2019] [Indexed: 05/21/2023]
Abstract
Paper mulberry (Broussonetia papyrifera) is a well-known woody tree historically used for Cai Lun papermaking, one of the four great inventions of ancient China. More recently, Paper mulberry has also been used as forage to address the shortage of feedstuff because of its digestible crude fiber and high protein contents. In this study, we obtained a chromosome-scale genome assembly for Paper mulberry using integrated approaches, including Illumina and PacBio sequencing platform as well as Hi-C, optical, and genetic maps. The assembled Paper mulberry genome consists of 386.83 Mb, which is close to the estimated size, and 99.25% (383.93 Mb) of the assembly was assigned to 13 pseudochromosomes. Comparative genomic analysis revealed the expansion and contraction in the flavonoid and lignin biosynthetic gene families, respectively, accounting for the enhanced flavonoid and decreased lignin biosynthesis in Paper mulberry. Moreover, the increased ratio of syringyl-lignin to guaiacyl-lignin in Paper mulberry underscores its suitability for use in medicine, forage, papermaking, and barkcloth making. We also identified the root-associated microbiota of Paper mulberry and found that Pseudomonas and Rhizobia were enriched in its roots and may provide the source of nitrogen for its stems and leaves via symbiotic nitrogen fixation. Collectively, these results suggest that Paper mulberry might have undergone adaptive evolution and recruited nitrogen-fixing microbes to promote growth by enhancing flavonoid production and altering lignin monomer composition. Our study provides significant insights into genetic basis of the usefulness of Paper mulberry in papermaking and barkcloth making, and as forage. These insights will facilitate further domestication and selection as well as industrial utilization of Paper mulberry worldwide.
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Affiliation(s)
- Xianjun Peng
- Key Laboratory of Plant Resources, Institute of Botany, The Chinese Academy of Sciences, Beijing 100093, China
| | - Hui Liu
- Key Laboratory of Plant Resources, Institute of Botany, The Chinese Academy of Sciences, Beijing 100093, China
| | - Peilin Chen
- Key Laboratory of Plant Resources, Institute of Botany, The Chinese Academy of Sciences, Beijing 100093, China
| | - Feng Tang
- Key Laboratory of Plant Resources, Institute of Botany, The Chinese Academy of Sciences, Beijing 100093, China
| | - Yanmin Hu
- Key Laboratory of Plant Resources, Institute of Botany, The Chinese Academy of Sciences, Beijing 100093, China
| | - Fenfen Wang
- Key Laboratory of Plant Resources, Institute of Botany, The Chinese Academy of Sciences, Beijing 100093, China
| | - Zhi Pi
- Key Laboratory of Plant Resources, Institute of Botany, The Chinese Academy of Sciences, Beijing 100093, China
| | - Meiling Zhao
- Key Laboratory of Plant Resources, Institute of Botany, The Chinese Academy of Sciences, Beijing 100093, China
| | - Naizhi Chen
- Key Laboratory of Plant Resources, Institute of Botany, The Chinese Academy of Sciences, Beijing 100093, China
| | - Hui Chen
- Key Laboratory of Plant Resources, Institute of Botany, The Chinese Academy of Sciences, Beijing 100093, China
| | - Xiaokang Zhang
- Key Laboratory of Plant Resources, Institute of Botany, The Chinese Academy of Sciences, Beijing 100093, China
| | - Xueqing Yan
- Key Laboratory of Plant Resources, Institute of Botany, The Chinese Academy of Sciences, Beijing 100093, China
| | - Min Liu
- Biomarker Technologies Corporation, Beijing 101300, China
| | - Xiaojun Fu
- Biomarker Technologies Corporation, Beijing 101300, China
| | - Guofeng Zhao
- Biomarker Technologies Corporation, Beijing 101300, China
| | - Pu Yao
- Biomarker Technologies Corporation, Beijing 101300, China
| | - Lili Wang
- Biomarker Technologies Corporation, Beijing 101300, China
| | - He Dai
- Biomarker Technologies Corporation, Beijing 101300, China
| | - Xuming Li
- Biomarker Technologies Corporation, Beijing 101300, China
| | - Wei Xiong
- Quick Green Bio-Tec Co., Ltd., Dalian 116600, China
| | - Wencai Xu
- Beijing Jonathan Science and Technology Development Co., Ltd., Beijing 101314, China
| | - Hongkun Zheng
- Biomarker Technologies Corporation, Beijing 101300, China
| | - Haiyan Yu
- Biomarker Technologies Corporation, Beijing 101300, China.
| | - Shihua Shen
- Key Laboratory of Plant Resources, Institute of Botany, The Chinese Academy of Sciences, Beijing 100093, China; ChuangGou Science & Technology Co. Ltd., Beijing 100049, China.
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20
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Xie H, Engle NL, Venketachalam S, Yoo CG, Barros J, Lecoultre M, Howard N, Li G, Sun L, Srivastava AC, Pattathil S, Pu Y, Hahn MG, Ragauskas AJ, Nelson RS, Dixon RA, Tschaplinski TJ, Blancaflor EB, Tang Y. Combining loss of function of FOLYLPOLYGLUTAMATE SYNTHETASE1 and CAFFEOYL- COA 3- O- METHYLTRANSFERASE1 for lignin reduction and improved saccharification efficiency in Arabidopsis thaliana. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:108. [PMID: 31073332 PMCID: PMC6498598 DOI: 10.1186/s13068-019-1446-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Accepted: 04/20/2019] [Indexed: 05/07/2023]
Abstract
BACKGROUND Downregulation of genes involved in lignin biosynthesis and related biochemical pathways has been used as a strategy to improve biofuel production. Plant C1 metabolism provides the methyl units used for the methylation reactions carried out by two methyltransferases in the lignin biosynthetic pathway: caffeic acid 3-O-methyltransferase (COMT) and caffeoyl-CoA 3-O-methyltransferase (CCoAOMT). Mutations in these genes resulted in lower lignin levels and altered lignin compositions. Reduced lignin levels can also be achieved by mutations in the C1 pathway gene, folylpolyglutamate synthetase1 (FPGS1), in both monocotyledons and dicotyledons, indicating a link between the C1 and lignin biosynthetic pathways. To test if lignin content can be further reduced by combining genetic mutations in C1 metabolism and the lignin biosynthetic pathway, fpgs1ccoaomt1 double mutants were generated and functionally characterized. RESULTS Double fpgs1ccoaomt1 mutants had lower thioacidolysis lignin monomer yield and acetyl bromide lignin content than the ccoaomt1 or fpgs1 mutants and the plants themselves displayed no obvious long-term negative growth phenotypes. Moreover, extracts from the double mutants had dramatically improved enzymatic polysaccharide hydrolysis efficiencies than the single mutants: 15.1% and 20.7% higher than ccoaomt1 and fpgs1, respectively. The reduced lignin and improved sugar release of fpgs1ccoaomt1 was coupled with changes in cell-wall composition, metabolite profiles, and changes in expression of genes involved in cell-wall and lignin biosynthesis. CONCLUSION Our observations demonstrate that additional reduction in lignin content and improved sugar release can be achieved by simultaneous downregulation of a gene in the C1 (FPGS1) and lignin biosynthetic (CCOAOMT) pathways. These improvements in sugar accessibility were achieved without introducing unwanted long-term plant growth and developmental defects.
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Affiliation(s)
- Hongli Xie
- Noble Research Institute, LLC, 2510 Sam Noble Parkway, Ardmore, OK 73401 USA
- BioEnergy Science Center, United States Department of Energy, Oak Ridge, TN 37831 USA
| | - Nancy L. Engle
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- BioEnergy Science Center, United States Department of Energy, Oak Ridge, TN 37831 USA
- The Center for Bioenergy Innovation, United States Department of Energy, Oak Ridge, TN 37831 USA
| | - Sivasankari Venketachalam
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602 USA
- BioEnergy Science Center, United States Department of Energy, Oak Ridge, TN 37831 USA
- The Center for Bioenergy Innovation, United States Department of Energy, Oak Ridge, TN 37831 USA
| | - Chang Geun Yoo
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- BioEnergy Science Center, United States Department of Energy, Oak Ridge, TN 37831 USA
- The Center for Bioenergy Innovation, United States Department of Energy, Oak Ridge, TN 37831 USA
| | - Jaime Barros
- BioDiscovery Institute and Department of Biological Sciences, University of North Texas, Denton, TX 76203 USA
- BioEnergy Science Center, United States Department of Energy, Oak Ridge, TN 37831 USA
- The Center for Bioenergy Innovation, United States Department of Energy, Oak Ridge, TN 37831 USA
| | - Mitch Lecoultre
- Noble Research Institute, LLC, 2510 Sam Noble Parkway, Ardmore, OK 73401 USA
- BioEnergy Science Center, United States Department of Energy, Oak Ridge, TN 37831 USA
| | - Nikki Howard
- Noble Research Institute, LLC, 2510 Sam Noble Parkway, Ardmore, OK 73401 USA
- BioEnergy Science Center, United States Department of Energy, Oak Ridge, TN 37831 USA
| | - Guifen Li
- Noble Research Institute, LLC, 2510 Sam Noble Parkway, Ardmore, OK 73401 USA
| | - Liang Sun
- Noble Research Institute, LLC, 2510 Sam Noble Parkway, Ardmore, OK 73401 USA
| | - Avinash C. Srivastava
- Noble Research Institute, LLC, 2510 Sam Noble Parkway, Ardmore, OK 73401 USA
- BioEnergy Science Center, United States Department of Energy, Oak Ridge, TN 37831 USA
| | - Sivakumar Pattathil
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602 USA
- BioEnergy Science Center, United States Department of Energy, Oak Ridge, TN 37831 USA
| | - Yunqiao Pu
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- BioEnergy Science Center, United States Department of Energy, Oak Ridge, TN 37831 USA
- The Center for Bioenergy Innovation, United States Department of Energy, Oak Ridge, TN 37831 USA
| | - Michael G. Hahn
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602 USA
- BioEnergy Science Center, United States Department of Energy, Oak Ridge, TN 37831 USA
- The Center for Bioenergy Innovation, United States Department of Energy, Oak Ridge, TN 37831 USA
| | - Arthur J. Ragauskas
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- BioEnergy Science Center, United States Department of Energy, Oak Ridge, TN 37831 USA
- The Center for Bioenergy Innovation, United States Department of Energy, Oak Ridge, TN 37831 USA
| | - Richard S. Nelson
- Noble Research Institute, LLC, 2510 Sam Noble Parkway, Ardmore, OK 73401 USA
- BioEnergy Science Center, United States Department of Energy, Oak Ridge, TN 37831 USA
| | - Richard A. Dixon
- BioDiscovery Institute and Department of Biological Sciences, University of North Texas, Denton, TX 76203 USA
- BioEnergy Science Center, United States Department of Energy, Oak Ridge, TN 37831 USA
- The Center for Bioenergy Innovation, United States Department of Energy, Oak Ridge, TN 37831 USA
| | - Timothy J. Tschaplinski
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- BioEnergy Science Center, United States Department of Energy, Oak Ridge, TN 37831 USA
- The Center for Bioenergy Innovation, United States Department of Energy, Oak Ridge, TN 37831 USA
| | - Elison B. Blancaflor
- Noble Research Institute, LLC, 2510 Sam Noble Parkway, Ardmore, OK 73401 USA
- BioEnergy Science Center, United States Department of Energy, Oak Ridge, TN 37831 USA
| | - Yuhong Tang
- Noble Research Institute, LLC, 2510 Sam Noble Parkway, Ardmore, OK 73401 USA
- BioEnergy Science Center, United States Department of Energy, Oak Ridge, TN 37831 USA
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21
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Lignin engineering to improve saccharification and digestibility in grasses. Curr Opin Biotechnol 2019; 56:223-229. [DOI: 10.1016/j.copbio.2019.02.013] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 02/12/2019] [Accepted: 02/13/2019] [Indexed: 11/19/2022]
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22
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Wu Z, Wang N, Hisano H, Cao Y, Wu F, Liu W, Bao Y, Wang Z, Fu C. Simultaneous regulation of F5H in COMT-RNAi transgenic switchgrass alters effects of COMT suppression on syringyl lignin biosynthesis. PLANT BIOTECHNOLOGY JOURNAL 2019; 17:836-845. [PMID: 30267599 PMCID: PMC6419721 DOI: 10.1111/pbi.13019] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 09/12/2018] [Accepted: 09/24/2018] [Indexed: 05/06/2023]
Abstract
Ferulate 5-hydroxylase (F5H) catalyses the hydroxylation of coniferyl alcohol and coniferaldehyde for the biosynthesis of syringyl (S) lignin in angiosperms. However, the coordinated effects of F5H with caffeic acid O-methyltransferase (COMT) on the metabolic flux towards S units are largely unknown. We concomitantly regulated F5H expression in COMT-down-regulated transgenic switchgrass (Panicum virgatum L.) lines and studied the coordination of F5H and COMT in lignin biosynthesis. Down-regulation of F5H in COMT-RNAi transgenic switchgrass plants further impeded S lignin biosynthesis and, consequently, increased guaiacyl (G) units and reduced 5-OH G units. Conversely, overexpression of F5H in COMT-RNAi transgenic plants reduced G units and increased 5-OH units, whereas the deficiency of S lignin biosynthesis was partially compensated or fully restored, depending on the extent of COMT down-regulation in switchgrass. Moreover, simultaneous regulation of F5H and COMT expression had different effects on cell wall digestibility of switchgrass without biomass loss. Our results indicate that up-regulation and down-regulation of F5H expression, respectively, have antagonistic and synergistic effects on the reduction in S lignin resulting from COMT suppression. The coordinated effects between lignin genes should be taken into account in future studies aimed at cell wall bioengineering.
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Affiliation(s)
- Zhenying Wu
- Shandong Provincial Key Laboratory of Energy GeneticsKey Laboratory of BiofuelsQingdao Institute of Bioenergy and Bioprocess TechnologyChinese Academy of SciencesQingdaoShandongChina
| | - Nengfei Wang
- Key Lab of Marine Bioactive SubstancesThe First Institute of OceanographyState Oceanic AdministrationQingdaoShandongChina
| | - Hiroshi Hisano
- Noble Research Institute, LLCArdmoreOKUSA
- Institute of Plant Science and ResourcesOkayama UniversityKurashikiOkayamaJapan
| | - Yingping Cao
- Shandong Provincial Key Laboratory of Energy GeneticsKey Laboratory of BiofuelsQingdao Institute of Bioenergy and Bioprocess TechnologyChinese Academy of SciencesQingdaoShandongChina
| | - Fengyan Wu
- Noble Research Institute, LLCArdmoreOKUSA
| | - Wenwen Liu
- Shandong Provincial Key Laboratory of Energy GeneticsKey Laboratory of BiofuelsQingdao Institute of Bioenergy and Bioprocess TechnologyChinese Academy of SciencesQingdaoShandongChina
| | - Yan Bao
- Shandong Provincial Key Laboratory of Energy GeneticsKey Laboratory of BiofuelsQingdao Institute of Bioenergy and Bioprocess TechnologyChinese Academy of SciencesQingdaoShandongChina
| | | | - Chunxiang Fu
- Shandong Provincial Key Laboratory of Energy GeneticsKey Laboratory of BiofuelsQingdao Institute of Bioenergy and Bioprocess TechnologyChinese Academy of SciencesQingdaoShandongChina
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23
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Abstract
Efficient plant protoplast production from cell suspension cultures, leaf, and stem tissue allows for single-cell plant biology. Since protoplasts do not have cell walls, they can be readily transformed to enable rapid assessment of regulatory elements, synthetic constructs, gene expression, and more recently genome-editing tools and approaches. Historically, enzymatic cell wall digestion has been both expensive and laborious. Protoplast production, transformation, and analysis of fluorescence have recently been automated using an integrated robotic system. Here we describe its use for bulk protoplast isolation, counting, transformation, and analysis at very low cost for high-throughput experiments.
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Affiliation(s)
- Scott C Lenaghan
- Department of Food Science, University of Tennessee, Knoxville, TN, USA.
- Department of Mechanical, Aerospace, and Biomedical Engineering, University of Tennessee, Knoxville, TN, USA.
| | - C Neal Stewart
- Department of Plant Sciences, University of Tennessee, Knoxville, TN, USA.
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24
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Holwerda EK, Worthen RS, Kothari N, Lasky RC, Davison BH, Fu C, Wang ZY, Dixon RA, Biswal AK, Mohnen D, Nelson RS, Baxter HL, Mazarei M, Muchero W, Tuskan GA, Cai CM, Gjersing EE, Davis MF, Himmel ME, Wyman CE, Gilna P, Lynd LR. Multiple levers for overcoming the recalcitrance of lignocellulosic biomass. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:15. [PMID: 30675183 PMCID: PMC6335785 DOI: 10.1186/s13068-019-1353-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Accepted: 01/04/2019] [Indexed: 05/03/2023]
Abstract
BACKGROUND The recalcitrance of cellulosic biomass is widely recognized as a key barrier to cost-effective biological processing to fuels and chemicals, but the relative impacts of physical, chemical and genetic interventions to improve biomass processing singly and in combination have yet to be evaluated systematically. Solubilization of plant cell walls can be enhanced by non-biological augmentation including physical cotreatment and thermochemical pretreatment, the choice of biocatalyst, the choice of plant feedstock, genetic engineering of plants, and choosing feedstocks that are less recalcitrant natural variants. A two-tiered combinatoric investigation of lignocellulosic biomass deconstruction was undertaken with three biocatalysts (Clostridium thermocellum, Caldicellulosiruptor bescii, Novozymes Cellic® Ctec2 and Htec2), three transgenic switchgrass plant lines (COMT, MYB4, GAUT4) and their respective nontransgenic controls, two Populus natural variants, and augmentation of biological attack using either mechanical cotreatment or cosolvent-enhanced lignocellulosic fractionation (CELF) pretreatment. RESULTS In the absence of augmentation and under the conditions tested, increased total carbohydrate solubilization (TCS) was observed for 8 of the 9 combinations of switchgrass modifications and biocatalysts tested, and statistically significant for five of the combinations. Our results indicate that recalcitrance is not a trait determined by the feedstock only, but instead is coequally determined by the choice of biocatalyst. TCS with C. thermocellum was significantly higher than with the other two biocatalysts. Both CELF pretreatment and cotreatment via continuous ball milling enabled TCS in excess of 90%. CONCLUSION Based on our results as well as literature studies, it appears that some form of non-biological augmentation will likely be necessary for the foreseeable future to achieve high TCS for most cellulosic feedstocks. However, our results show that this need not necessarily involve thermochemical processing, and need not necessarily occur prior to biological conversion. Under the conditions tested, the relative magnitude of TCS increase was augmentation > biocatalyst choice > plant choice > plant modification > plant natural variants. In the presence of augmentation, plant modification, plant natural variation, and plant choice exhibited a small, statistically non-significant impact on TCS.
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Affiliation(s)
- Evert K. Holwerda
- Thayer School of Engineering, Dartmouth College, 14 Engineering drive, Hanover, NH 03755 USA
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Robert S. Worthen
- Thayer School of Engineering, Dartmouth College, 14 Engineering drive, Hanover, NH 03755 USA
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Ninad Kothari
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- Department of Chemical and Environmental Engineering and Center for Environmental Research and Technology, Bourns College of Engineering, University of California Riverside, Riverside, CA 92521 USA
| | - Ronald C. Lasky
- Thayer School of Engineering, Dartmouth College, 14 Engineering drive, Hanover, NH 03755 USA
| | - Brian H. Davison
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Chunxiang Fu
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- Genomics Division, Noble Research Institute, Ardmore, OK 73401 USA
| | - Zeng-Yu Wang
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- Genomics Division, Noble Research Institute, Ardmore, OK 73401 USA
| | - Richard A. Dixon
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- Department of Biological Sciences, University of North Texas, Denton, TX 76203 USA
| | - Ajaya K. Biswal
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602 USA
| | - Debra Mohnen
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602 USA
| | - Richard S. Nelson
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- Genomics Division, Noble Research Institute, Ardmore, OK 73401 USA
| | - Holly L. Baxter
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- Department of Plant Sciences, University of Tennessee at Knoxville, Knoxville, TN 37996 USA
| | - Mitra Mazarei
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- Department of Plant Sciences, University of Tennessee at Knoxville, Knoxville, TN 37996 USA
| | - Wellington Muchero
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Gerald A. Tuskan
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Charles M. Cai
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- Department of Chemical and Environmental Engineering and Center for Environmental Research and Technology, Bourns College of Engineering, University of California Riverside, Riverside, CA 92521 USA
| | - Erica E. Gjersing
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- Bioenergy Science and Technology, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Mark F. Davis
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- Bioenergy Science and Technology, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Michael E. Himmel
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- Bioenergy Science and Technology, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Charles E. Wyman
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- Department of Chemical and Environmental Engineering and Center for Environmental Research and Technology, Bourns College of Engineering, University of California Riverside, Riverside, CA 92521 USA
| | - Paul Gilna
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Lee R. Lynd
- Thayer School of Engineering, Dartmouth College, 14 Engineering drive, Hanover, NH 03755 USA
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
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25
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Li G, Jones KC, Eudes A, Pidatala VR, Sun J, Xu F, Zhang C, Wei T, Jain R, Birdseye D, Canlas PE, Baidoo EEK, Duong PQ, Sharma MK, Singh S, Ruan D, Keasling JD, Mortimer JC, Loqué D, Bartley LE, Scheller HV, Ronald PC. Overexpression of a rice BAHD acyltransferase gene in switchgrass (Panicum virgatum L.) enhances saccharification. BMC Biotechnol 2018; 18:54. [PMID: 30180895 PMCID: PMC6123914 DOI: 10.1186/s12896-018-0464-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Accepted: 08/27/2018] [Indexed: 11/10/2022] Open
Abstract
Background Switchgrass (Panicum virgatum L.) is a promising bioenergy feedstock because it can be grown on marginal land and produces abundant biomass. Recalcitrance of the lignocellulosic components of the switchgrass cell wall to enzymatic degradation into simple sugars impedes efficient biofuel production. We previously demonstrated that overexpression of OsAT10, a BAHD acyltransferase gene, enhances saccharification efficiency in rice. Results Here we show that overexpression of the rice OsAT10 gene in switchgrass decreased the levels of cell wall-bound ferulic acid (FA) in green leaf tissues and to a lesser extent in senesced tissues, and significantly increased levels of cell wall-bound p-coumaric acid (p-CA) in green leaves but decreased its level in senesced tissues of the T0 plants under greenhouse conditions. The engineered switchgrass lines exhibit an approximate 40% increase in saccharification efficiency in green tissues and a 30% increase in senesced tissues. Conclusion Our study demonstrates that overexpression of OsAT10, a rice BAHD acyltransferase gene, enhances saccharification of lignocellulosic biomass in switchgrass. Electronic supplementary material The online version of this article (10.1186/s12896-018-0464-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Guotian Li
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.,Department of Plant Pathology and the Genome Center, University of California, Davis, CA, 95616, USA
| | - Kyle C Jones
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.,Department of Plant Pathology and the Genome Center, University of California, Davis, CA, 95616, USA
| | - Aymerick Eudes
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | | | - Jian Sun
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.,Biomass Science and Conversion Technology Department, Sandia National Laboratories, CA94551, Livermore, USA
| | - Feng Xu
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Chengcheng Zhang
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, 73019, USA
| | - Tong Wei
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.,Department of Plant Pathology and the Genome Center, University of California, Davis, CA, 95616, USA
| | - Rashmi Jain
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.,Department of Plant Pathology and the Genome Center, University of California, Davis, CA, 95616, USA
| | - Devon Birdseye
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Patrick E Canlas
- Department of Plant Pathology and the Genome Center, University of California, Davis, CA, 95616, USA
| | - Edward E K Baidoo
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Phat Q Duong
- Department of Plant Pathology and the Genome Center, University of California, Davis, CA, 95616, USA
| | - Manoj K Sharma
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.,Department of Plant Pathology and the Genome Center, University of California, Davis, CA, 95616, USA.,School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
| | - Seema Singh
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.,Biomass Science and Conversion Technology Department, Sandia National Laboratories, CA94551, Livermore, USA
| | - Deling Ruan
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.,Department of Plant Pathology and the Genome Center, University of California, Davis, CA, 95616, USA
| | - Jay D Keasling
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.,Department of Bioengineering and Department of Chemical & Biomolecular Engineering, University of California, Berkeley, CA, 94720, USA
| | - Jenny C Mortimer
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Dominique Loqué
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Laura E Bartley
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, 73019, USA
| | - Henrik V Scheller
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.,Department of Plant and Microbial Biology, University of California, Berkeley, CA, 94720, USA
| | - Pamela C Ronald
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA. .,Department of Plant Pathology and the Genome Center, University of California, Davis, CA, 95616, USA.
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26
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Mazarei M, Baxter HL, Li M, Biswal AK, Kim K, Meng X, Pu Y, Wuddineh WA, Zhang JY, Turner GB, Sykes RW, Davis MF, Udvardi MK, Wang ZY, Mohnen D, Ragauskas AJ, Labbé N, Stewart CN. Functional Analysis of Cellulose Synthase CesA4 and CesA6 Genes in Switchgrass ( Panicum virgatum) by Overexpression and RNAi-Mediated Gene Silencing. FRONTIERS IN PLANT SCIENCE 2018; 9:1114. [PMID: 30127793 PMCID: PMC6088197 DOI: 10.3389/fpls.2018.01114] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 07/10/2018] [Indexed: 05/11/2023]
Abstract
Switchgrass (Panicum virgatum L.) is a leading lignocellulosic bioenergy feedstock. Cellulose is a major component of the plant cell walls and the primary substrate for saccharification. Accessibility of cellulose to enzymatic breakdown into fermentable sugars is limited by the presence of lignin in the plant cell wall. In this study, putatively novel switchgrass secondary cell wall cellulose synthase PvCesA4 and primary cell wall PvCesA6 genes were identified and their functional role in cellulose synthesis and cell wall composition was examined by overexpression and knockdown of the individual genes in switchgrass. The endogenous expression of PvCesA4 and PvCesA6 genes varied among including roots, leaves, stem, and reproductive tissues. Increasing or decreasing PvCesA4 and PvCesA6 expression to extreme levels in the transgenic lines resulted in decreased biomass production. PvCesA6-overexpressing lines had reduced lignin content and syringyl/guaiacyl lignin monomer ratio accompanied by increased sugar release efficiency, suggesting an impact of PvCesA6 expression levels on lignin biosynthesis. Cellulose content and cellulose crystallinity were decreased, while xylan content was increased in PvCesA4 and PvCesA6 overexpression or knockdown lines. The increase in xylan content suggests that the amount of non-cellulosic cell wall polysaccharide was modified in these plants. Taken together, the results show that the manipulation of the cellulose synthase genes alters the cell wall composition and availability of cellulose as a bioprocessing substrate.
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Affiliation(s)
- Mitra Mazarei
- Department of Plant Sciences, University of Tennessee, Knoxville, Knoxville, TN, United States
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Holly L. Baxter
- Department of Plant Sciences, University of Tennessee, Knoxville, Knoxville, TN, United States
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Mi Li
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Biosciences Division, Joint Institute for Biological Science, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Ajaya K. Biswal
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, United States
| | - Keonhee Kim
- Center for Renewable Carbon, University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Xianzhi Meng
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Yunqiao Pu
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Biosciences Division, Joint Institute for Biological Science, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Wegi A. Wuddineh
- Department of Plant Sciences, University of Tennessee, Knoxville, Knoxville, TN, United States
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Ji-Yi Zhang
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Noble Research Institute, Ardmore, OK, United States
| | - Geoffrey B. Turner
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- National Renewable Energy Laboratory, Golden, CO, United States
| | - Robert W. Sykes
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- National Renewable Energy Laboratory, Golden, CO, United States
| | - Mark F. Davis
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- National Renewable Energy Laboratory, Golden, CO, United States
| | - Michael K. Udvardi
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Noble Research Institute, Ardmore, OK, United States
| | - Zeng-Yu Wang
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Noble Research Institute, Ardmore, OK, United States
| | - Debra Mohnen
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, United States
| | - Arthur J. Ragauskas
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Biosciences Division, Joint Institute for Biological Science, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Nicole Labbé
- Center for Renewable Carbon, University of Tennessee, Knoxville, Knoxville, TN, United States
| | - C. Neal Stewart
- Department of Plant Sciences, University of Tennessee, Knoxville, Knoxville, TN, United States
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, United States
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27
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Ko JK, Jung JH, Altpeter F, Kannan B, Kim HE, Kim KH, Alper HS, Um Y, Lee SM. Largely enhanced bioethanol production through the combined use of lignin-modified sugarcane and xylose fermenting yeast strain. BIORESOURCE TECHNOLOGY 2018; 256:312-320. [PMID: 29455099 DOI: 10.1016/j.biortech.2018.01.123] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 01/24/2018] [Accepted: 01/25/2018] [Indexed: 05/26/2023]
Abstract
The recalcitrant structure of lignocellulosic biomass is a major barrier in efficient biomass-to-ethanol bioconversion processes. The combination of feedstock engineering via modification in the lignin synthesis pathway of sugarcane and co-fermentation of xylose and glucose with a recombinant xylose utilizing yeast strain produced 148% more ethanol compared to that of the wild type biomass and control strain. The lignin reduced biomass led to a substantially increased release of fermentable sugars (glucose and xylose). The engineered yeast strain efficiently co-utilized glucose and xylose for fermentation, elevating ethanol yields. In this study, it was experimentally demonstrated that the combined efforts of engineering both feedstock and microorganisms largely enhances the bioconversion of lignocellulosic feedstock to bioethanol. This strategy will significantly improve the economic feasibility of lignocellulosic biofuels production.
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Affiliation(s)
- Ja Kyong Ko
- Clean Energy Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Je Hyeong Jung
- Center for Natural Products Convergence Research, Korea Institute of Science and Technology (KIST), Gangneung 25451, Republic of Korea
| | - Fredy Altpeter
- Agronomy Department, Genetics Institute, Plant Molecular and Cellular Biology Program, University of Florida, IFAS, PO Box 110300, Gainesville, FL 32611, USA
| | - Baskaran Kannan
- Agronomy Department, Genetics Institute, Plant Molecular and Cellular Biology Program, University of Florida, IFAS, PO Box 110300, Gainesville, FL 32611, USA
| | - Ha Eun Kim
- Department of Biotechnology, Graduate School, Korea University, Seoul 02841, Republic of Korea
| | - Kyoung Heon Kim
- Department of Biotechnology, Graduate School, Korea University, Seoul 02841, Republic of Korea
| | - Hal S Alper
- McKetta Department of Chemical Engineering, The University of Texas at Austin, 200 E Dean Keeton St. Stop C0400, Austin, TX 78712, USA; Institute for Cellular and Molecular Biology, The University of Texas at Austin, 2500 Speedway Avenue, Austin, TX 78712, USA
| | - Youngsoon Um
- Clean Energy Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea; Clean Energy and Chemical Engineering, Korea University of Science and Technology, Daejeon 34113, Republic of Korea
| | - Sun-Mi Lee
- Clean Energy Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea; Clean Energy and Chemical Engineering, Korea University of Science and Technology, Daejeon 34113, Republic of Korea.
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28
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Kannan B, Jung JH, Moxley GW, Lee S, Altpeter F. TALEN-mediated targeted mutagenesis of more than 100 COMT copies/alleles in highly polyploid sugarcane improves saccharification efficiency without compromising biomass yield. PLANT BIOTECHNOLOGY JOURNAL 2018; 16:856-866. [PMID: 28905511 PMCID: PMC5866949 DOI: 10.1111/pbi.12833] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 08/23/2017] [Accepted: 09/01/2017] [Indexed: 05/02/2023]
Abstract
Sugarcane is the world's most efficient feedstock for commercial production of bioethanol due to its superior biomass production and accumulation of sucrose in stems. Integrating first- and second-generation ethanol conversion processes will enhance the biofuel yield per unit area by utilizing both sucrose and cell wall-bound sugars for fermentation. RNAi suppression of the lignin biosynthetic gene caffeic acid O-methyltransferase (COMT) has been demonstrated to improve bioethanol production from lignocellulosic biomass. Genome editing has been used in a number of crops for creation of loss of function phenotypes but is very challenging in sugarcane due to its highly polyploid genome. In this study, a conserved region of COMT was targeted with a single-transcription activator-like effector nuclease (TALEN) pair for multi-allelic mutagenesis to modify lignin biosynthesis in sugarcane. Field-grown TALEN-mediated COMT mutants showed up to 19.7% lignin reduction and significantly decreased syringyl to guaiacyl (S/G) ratio resulting in an up to 43.8% improved saccharification efficiency. Biomass production of COMT mutant lines with superior saccharification efficiency did not differ significantly from the original cultivar under replicated field conditions. Sanger sequencing of cloned COMT amplicons (1351-1657 bp) revealed co-editing of 107 of the 109 unique COMT copies/alleles in vegetative progeny of line CB6 using a single TALEN pair. Line CB6 combined altered cell wall composition and drastically improved saccharification efficiency with good agronomic performance. These findings confirm the feasibility of co-mutagenesis of a very large number of target alleles/copies for improvement in crops with complex genomes.
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Affiliation(s)
- Baskaran Kannan
- Agronomy DepartmentIFAS, University of FloridaGainesvilleFLUSA
| | - Je Hyeong Jung
- Agronomy DepartmentIFAS, University of FloridaGainesvilleFLUSA
- Present address:
Center for Natural Products Convergence ResearchKorea Institute of Science and Technology (KIST)GangneungGangwon‐doSouth Korea
| | | | - Sun‐Mi Lee
- Clean Energy Research CenterKorea Institute of Science and Technology (KIST)SeoulSouth Korea
| | - Fredy Altpeter
- Agronomy DepartmentIFAS, University of FloridaGainesvilleFLUSA
- Plant Molecular and Cellular Biology ProgramIFAS, University of FloridaGainesvilleFLUSA
- Genetics InstituteUniversity of FloridaGainesvilleFLUSA
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29
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Sugar release and growth of biofuel crops are improved by downregulation of pectin biosynthesis. Nat Biotechnol 2018; 36:249-257. [DOI: 10.1038/nbt.4067] [Citation(s) in RCA: 104] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 01/02/2018] [Indexed: 01/17/2023]
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30
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Baxter HL, Mazarei M, Dumitrache A, Natzke JM, Rodriguez M, Gou J, Fu C, Sykes RW, Turner GB, Davis MF, Brown SD, Davison BH, Wang Z, Stewart CN. Transgenic miR156 switchgrass in the field: growth, recalcitrance and rust susceptibility. PLANT BIOTECHNOLOGY JOURNAL 2018; 16:39-49. [PMID: 28436149 PMCID: PMC5785337 DOI: 10.1111/pbi.12747] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 03/16/2017] [Accepted: 04/10/2017] [Indexed: 05/02/2023]
Abstract
Sustainable utilization of lignocellulosic perennial grass feedstocks will be enabled by high biomass production and optimized cell wall chemistry for efficient conversion into biofuels. MicroRNAs are regulatory elements that modulate the expression of genes involved in various biological functions in plants, including growth and development. In greenhouse studies, overexpressing a microRNA (miR156) gene in switchgrass had dramatic effects on plant architecture and flowering, which appeared to be driven by transgene expression levels. High expressing lines were extremely dwarfed, whereas low and moderate-expressing lines had higher biomass yields, improved sugar release and delayed flowering. Four lines with moderate or low miR156 overexpression from the prior greenhouse study were selected for a field experiment to assess the relationship between miR156 expression and biomass production over three years. We also analysed important bioenergy feedstock traits such as flowering, disease resistance, cell wall chemistry and biofuel production. Phenotypes of the transgenic lines were inconsistent between the greenhouse and the field as well as among different field growing seasons. One low expressing transgenic line consistently produced more biomass (25%-56%) than the control across all three seasons, which translated to the production of 30% more biofuel per plant during the final season. The other three transgenic lines produced less biomass than the control by the final season, and the two lines with moderate expression levels also exhibited altered disease susceptibilities. Results of this study emphasize the importance of performing multiyear field studies for plants with altered regulatory transgenes that target plant growth and development.
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Affiliation(s)
- Holly L. Baxter
- Department of Plant SciencesUniversity of TennesseeKnoxvilleTNUSA
- BioEnergy Science Center (BESC)Oak Ridge National LaboratoryOak RidgeTNUSA
| | - Mitra Mazarei
- Department of Plant SciencesUniversity of TennesseeKnoxvilleTNUSA
- BioEnergy Science Center (BESC)Oak Ridge National LaboratoryOak RidgeTNUSA
| | - Alexandru Dumitrache
- BioEnergy Science Center (BESC)Oak Ridge National LaboratoryOak RidgeTNUSA
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTNUSA
| | - Jace M. Natzke
- BioEnergy Science Center (BESC)Oak Ridge National LaboratoryOak RidgeTNUSA
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTNUSA
| | - Miguel Rodriguez
- BioEnergy Science Center (BESC)Oak Ridge National LaboratoryOak RidgeTNUSA
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTNUSA
| | - Jiqing Gou
- BioEnergy Science Center (BESC)Oak Ridge National LaboratoryOak RidgeTNUSA
- Samuel Roberts Noble FoundationArdmoreOKUSA
| | - Chunxiang Fu
- BioEnergy Science Center (BESC)Oak Ridge National LaboratoryOak RidgeTNUSA
- Samuel Roberts Noble FoundationArdmoreOKUSA
| | - Robert W. Sykes
- BioEnergy Science Center (BESC)Oak Ridge National LaboratoryOak RidgeTNUSA
- National Renewable Energy LaboratoryGoldenCOUSA
| | - Geoffrey B. Turner
- BioEnergy Science Center (BESC)Oak Ridge National LaboratoryOak RidgeTNUSA
- National Renewable Energy LaboratoryGoldenCOUSA
| | - Mark F. Davis
- BioEnergy Science Center (BESC)Oak Ridge National LaboratoryOak RidgeTNUSA
- National Renewable Energy LaboratoryGoldenCOUSA
| | - Steven D. Brown
- BioEnergy Science Center (BESC)Oak Ridge National LaboratoryOak RidgeTNUSA
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTNUSA
| | - Brian H. Davison
- BioEnergy Science Center (BESC)Oak Ridge National LaboratoryOak RidgeTNUSA
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTNUSA
| | - Zeng‐Yu Wang
- BioEnergy Science Center (BESC)Oak Ridge National LaboratoryOak RidgeTNUSA
- Samuel Roberts Noble FoundationArdmoreOKUSA
| | - C. Neal Stewart
- Department of Plant SciencesUniversity of TennesseeKnoxvilleTNUSA
- BioEnergy Science Center (BESC)Oak Ridge National LaboratoryOak RidgeTNUSA
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31
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Lin CY, Donohoe BS, Ahuja N, Garrity DM, Qu R, Tucker MP, Himmel ME, Wei H. Evaluation of parameters affecting switchgrass tissue culture: toward a consolidated procedure for Agrobacterium-mediated transformation of switchgrass ( Panicum virgatum). PLANT METHODS 2017; 13:113. [PMID: 29270209 PMCID: PMC5735814 DOI: 10.1186/s13007-017-0263-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 12/06/2017] [Indexed: 05/21/2023]
Abstract
BACKGROUND Switchgrass (Panicum virgatum), a robust perennial C4-type grass, has been evaluated and designated as a model bioenergy crop by the U.S. DOE and USDA. Conventional breeding of switchgrass biomass is difficult because it displays self-incompatible hindrance. Therefore, direct genetic modifications of switchgrass have been considered the more effective approach to tailor switchgrass with traits of interest. Successful transformations have demonstrated increased biomass yields, reduction in the recalcitrance of cell walls and enhanced saccharification efficiency. Several tissue culture protocols have been previously described to produce transgenic switchgrass lines using different nutrient-based media, co-cultivation approaches, and antibiotic strengths for selection. RESULTS After evaluating the published protocols, we consolidated these approaches and optimized the process to develop a more efficient protocol for producing transgenic switchgrass. First, seed sterilization was optimized, which led to a 20% increase in yield of induced calluses. Second, we have selected a N6 macronutrient/B5 micronutrient (NB)-based medium for callus induction from mature seeds of the Alamo cultivar, and chose a Murashige and Skoog-based medium to regenerate both Type I and Type II calluses. Third, Agrobacterium-mediated transformation was adopted that resulted in 50-100% positive regenerated transformants after three rounds (2 weeks/round) of selection with antibiotic. Genomic DNA PCR, RT-PCR, Southern blot, visualization of the red fluorescent protein and histochemical β-glucuronidase (GUS) staining were conducted to confirm the positive switchgrass transformants. The optimized methods developed here provide an improved strategy to promote the production and selection of callus and generation of transgenic switchgrass lines. CONCLUSION The process for switchgrass transformation has been evaluated and consolidated to devise an improved approach for transgenic switchgrass production. With the optimization of seed sterilization, callus induction, and regeneration steps, a reliable and effective protocol is established to facilitate switchgrass engineering.
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Affiliation(s)
- Chien-Yuan Lin
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Bryon S. Donohoe
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Neha Ahuja
- Department of Biology, Colorado State University, Fort Collins, CO 80523 USA
| | - Deborah M. Garrity
- Department of Biology, Colorado State University, Fort Collins, CO 80523 USA
| | - Rongda Qu
- Department of Crop and Soil Sciences, North Carolina State University, Raleigh, NC 27695-7287 USA
| | - Melvin P. Tucker
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO USA
| | - Michael E. Himmel
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Hui Wei
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
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32
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Gilna P, Lynd LR, Mohnen D, Davis MF, Davison BH. Progress in understanding and overcoming biomass recalcitrance: a BioEnergy Science Center (BESC) perspective. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:285. [PMID: 29213324 PMCID: PMC5707806 DOI: 10.1186/s13068-017-0971-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 11/15/2017] [Indexed: 06/07/2023]
Abstract
The DOE BioEnergy Science Center has operated as a virtual center with multiple partners for a decade targeting overcoming biomass recalcitrance. BESC has redefined biomass recalcitrance from an observable phenotype to a better understood and manipulatable fundamental and operational property. These manipulations are the result of deeper biological understanding and can be combined with other advanced biotechnology improvements in biomass conversion to improve bioenergy processes and markets. This article provides an overview of key accomplishments in overcoming recalcitrance via better plants, better microbes, and better tools and combinations. A perspective on the aspects of successful center operation is presented.
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Affiliation(s)
- Paul Gilna
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- Biosciences Division, Oak Ridge National Laboratory, 1 Bethel Valley Road, Bldg. 1505, Rm. 100A, Oak Ridge, TN 37831-6037 USA
| | - Lee R. Lynd
- Biosciences Division, Oak Ridge National Laboratory, 1 Bethel Valley Road, Bldg. 1505, Rm. 100A, Oak Ridge, TN 37831-6037 USA
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755 USA
| | - Debra Mohnen
- Biosciences Division, Oak Ridge National Laboratory, 1 Bethel Valley Road, Bldg. 1505, Rm. 100A, Oak Ridge, TN 37831-6037 USA
- Complex Carbohydrate Research Center and Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602 USA
| | - Mark F. Davis
- Biosciences Division, Oak Ridge National Laboratory, 1 Bethel Valley Road, Bldg. 1505, Rm. 100A, Oak Ridge, TN 37831-6037 USA
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Brian H. Davison
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- Biosciences Division, Oak Ridge National Laboratory, 1 Bethel Valley Road, Bldg. 1505, Rm. 100A, Oak Ridge, TN 37831-6037 USA
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33
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Akinosho H, Yee K, Rodriguez M, Muchero W, Yoo CG, Li M, Thompson O, Pu Y, Brown S, Mielenz J, Ragauskas AJ. Lignin Exhibits Recalcitrance‐Associated Features Following the Consolidated Bioprocessing of
Populus trichocarpa
Natural Variants. ChemistrySelect 2017. [DOI: 10.1002/slct.201701572] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Hannah Akinosho
- BioEnergy Science Center Oak Ridge National Laboratory Oak Ridge TN 37831
- Biosciences Division Oak Ridge National Laboratory Oak Ridge TN 37831
- Department of Chemistry and Biochemistry, G eorgia Institute of Technology Atlanta GA 30332
| | - Kelsey Yee
- BioEnergy Science Center Oak Ridge National Laboratory Oak Ridge TN 37831
- Biosciences Division Oak Ridge National Laboratory Oak Ridge TN 37831
| | - Miguel Rodriguez
- BioEnergy Science Center Oak Ridge National Laboratory Oak Ridge TN 37831
- Biosciences Division Oak Ridge National Laboratory Oak Ridge TN 37831
| | - Wellington Muchero
- BioEnergy Science Center Oak Ridge National Laboratory Oak Ridge TN 37831
- Biosciences Division Oak Ridge National Laboratory Oak Ridge TN 37831
| | - Chang Geun Yoo
- Department of Chemical and Biomolecular Engineering & Department of Forestry Center for Renewable Carbon at Wildlife, and Fisheries University of Tennessee Knoxville TN 37996
- BioEnergy Science Center Oak Ridge National Laboratory Oak Ridge TN 37831
- Biosciences Division Oak Ridge National Laboratory Oak Ridge TN 37831
| | - Mi Li
- Department of Chemical and Biomolecular Engineering & Department of Forestry Center for Renewable Carbon at Wildlife, and Fisheries University of Tennessee Knoxville TN 37996
- BioEnergy Science Center Oak Ridge National Laboratory Oak Ridge TN 37831
- Biosciences Division Oak Ridge National Laboratory Oak Ridge TN 37831
| | - Olivia Thompson
- BioEnergy Science Center Oak Ridge National Laboratory Oak Ridge TN 37831
- Biosciences Division Oak Ridge National Laboratory Oak Ridge TN 37831
| | - Yunqiao Pu
- BioEnergy Science Center Oak Ridge National Laboratory Oak Ridge TN 37831
- Biosciences Division Oak Ridge National Laboratory Oak Ridge TN 37831
| | - Steven Brown
- BioEnergy Science Center Oak Ridge National Laboratory Oak Ridge TN 37831
- Biosciences Division Oak Ridge National Laboratory Oak Ridge TN 37831
| | - Johnathan Mielenz
- BioEnergy Science Center Oak Ridge National Laboratory Oak Ridge TN 37831
- Biosciences Division Oak Ridge National Laboratory Oak Ridge TN 37831
| | - Arthur J. Ragauskas
- Department of Chemical and Biomolecular Engineering & Department of Forestry Center for Renewable Carbon at Wildlife, and Fisheries University of Tennessee Knoxville TN 37996
- BioEnergy Science Center Oak Ridge National Laboratory Oak Ridge TN 37831
- Biosciences Division Oak Ridge National Laboratory Oak Ridge TN 37831
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Gou J, Fu C, Liu S, Tang C, Debnath S, Flanagan A, Ge Y, Tang Y, Jiang Q, Larson PR, Wen J, Wang ZY. The miR156-SPL4 module predominantly regulates aerial axillary bud formation and controls shoot architecture. THE NEW PHYTOLOGIST 2017; 216:829-840. [PMID: 28877340 DOI: 10.1111/nph.14758] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 07/23/2017] [Indexed: 05/06/2023]
Abstract
Grasses possess basal and aerial axillary buds. Previous studies have largely focused on basal bud (tiller) formation but scarcely touched on aerial buds, which may lead to aerial branch development. Genotypes with and without aerial buds were identified in switchgrass (Panicum virgatum), a dedicated bioenergy crop. Bud development was characterized using scanning electron microscopy. Microarray, RNA-seq and quantitative reverse transcription polymerase chain reaction (RT-qPCR) were used to identify regulators of bud formation. Gene function was characterized by down-regulation and overexpression. Overexpression of miR156 induced aerial bud formation in switchgrass. Various analyses revealed that SQUAMOSA PROMOTER BINDING PROTEIN LIKE4 (SPL4), one of the miR156 targets, directly regulated aerial axillary bud initiation. Down-regulation of SPL4 promoted aerial bud formation and increased basal buds, while overexpression of SPL4 seriously suppressed bud formation and tillering. RNA-seq and RT-qPCR identified potential downstream genes of SPL4. Unlike all previously reported genes acting as activators of basal bud initiation, SPL4 acts as a suppressor for the formation of both aerial and basal buds. The miR156-SPL4 module predominantly regulates aerial bud initiation and partially controls basal bud formation. Genetic manipulation of SPL4 led to altered plant architecture with increased branching, enhanced regrowth after cutting and improved biomass yield.
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Affiliation(s)
- Jiqing Gou
- Forage Improvement Division, The Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, OK, 73401, USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Chunxiang Fu
- Forage Improvement Division, The Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, OK, 73401, USA
- Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, 266101, China
| | - Sijia Liu
- Forage Improvement Division, The Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, OK, 73401, USA
- Department of Grassland Science, College of Animal Science and Technology, China Agricultural University, Beijing, 100193, China
| | - Chaorong Tang
- Forage Improvement Division, The Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, OK, 73401, USA
- Rubber Research Institute, Chinese Academy of Tropical Agricultural Sciences, Danzhou, Hainan, 571737, China
| | - Smriti Debnath
- Forage Improvement Division, The Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, OK, 73401, USA
| | - Amy Flanagan
- Forage Improvement Division, The Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, OK, 73401, USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Yaxin Ge
- Forage Improvement Division, The Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, OK, 73401, USA
| | - Yuhong Tang
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
- Plant Biology Division, The Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, OK, 73401, USA
| | - Qingzhen Jiang
- Plant Biology Division, The Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, OK, 73401, USA
| | - Preston R Larson
- Samuel Roberts Noble Microscopy Laboratory, University of Oklahoma, Norman, OK, 73019, USA
| | - Jiangqi Wen
- Plant Biology Division, The Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, OK, 73401, USA
| | - Zeng-Yu Wang
- Forage Improvement Division, The Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, OK, 73401, USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
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Biotechnological Strategies to Improve Plant Biomass Quality for Bioethanol Production. BIOMED RESEARCH INTERNATIONAL 2017; 2017:7824076. [PMID: 28951875 PMCID: PMC5603102 DOI: 10.1155/2017/7824076] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 07/13/2017] [Accepted: 07/19/2017] [Indexed: 11/17/2022]
Abstract
The transition from an economy dependent on nonrenewable energy sources to one with higher diversity of renewables will not be a simple process. It requires an important research effort to adapt to the dynamics of the changing energy market, sort costly processes, and avoid overlapping with social interest markets such as food and livestock production. In this review, we analyze the desirable traits of raw plant materials for the bioethanol industry and the molecular biotechnology strategies employed to improve them, in either plants already under use (as maize) or proposed species (large grass families). The fundamentals of these applications can be found in the mechanisms by which plants have evolved different pathways to manage carbon resources for reproduction or survival in unexpected conditions. Here, we review the means by which this information can be used to manipulate these mechanisms for commercial uses, including saccharification improvement of starch and cellulose, decrease in cell wall recalcitrance through lignin modification, and increase in plant biomass.
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Bioavailability of Carbohydrate Content in Natural and Transgenic Switchgrasses for the Extreme Thermophile Caldicellulosiruptor bescii. Appl Environ Microbiol 2017. [PMID: 28625990 DOI: 10.1128/aem.00969-17] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Improving access to the carbohydrate content of lignocellulose is key to reducing recalcitrance for microbial deconstruction and conversion to fuels and chemicals. Caldicellulosiruptor bescii completely solubilizes naked microcrystalline cellulose, yet this transformation is impeded within the context of the plant cell wall by a network of lignin and hemicellulose. Here, the bioavailability of carbohydrates to C. bescii at 70°C was examined for reduced lignin transgenic switchgrass lines COMT3(+) and MYB Trans, their corresponding parental lines (cultivar Alamo) COMT3(-) and MYB wild type (WT), and the natural variant cultivar Cave-in-Rock (CR). Transgenic modification improved carbohydrate solubilization by C. bescii to 15% (2.3-fold) for MYB and to 36% (1.5-fold) for COMT, comparable to the levels achieved for the natural variant, CR (36%). Carbohydrate solubilization was nearly doubled after two consecutive microbial fermentations compared to one microbial step, but it never exceeded 50% overall. Hydrothermal treatment (180°C) prior to microbial steps improved solubilization 3.7-fold for the most recalcitrant line (MYB WT) and increased carbohydrate recovery to nearly 50% for the least recalcitrant lines [COMT3(+) and CR]. Alternating microbial and hydrothermal steps (T→M→T→M) further increased bioavailability, achieving carbohydrate solubilization ranging from 50% for MYB WT to above 70% for COMT3(+) and CR. Incomplete carbohydrate solubilization suggests that cellulose in the highly lignified residue was inaccessible; indeed, residue from the T→M→T→M treatment was primarily glucan and inert materials (lignin and ash). While C. bescii could significantly solubilize the transgenic switchgrass lines and natural variant tested here, additional or alternative strategies (physical, chemical, enzymatic, and/or genetic) are needed to eliminate recalcitrance.IMPORTANCE Key to a microbial process for solubilization of plant biomass is the organism's access to the carbohydrate content of lignocellulose. Economically viable routes will characteristically minimize physical, chemical, and biological pretreatment such that microbial steps contribute to the greatest extent possible. Recently, transgenic versions of plants and trees have been developed with the intention of lowering the barrier to lignocellulose conversion, with particular focus on lignin content and composition. Here, the extremely thermophilic bacterium Caldicellulosiruptor bescii was used to solubilize natural and genetically modified switchgrass lines, with and without the aid of hydrothermal treatment. For lignocellulose conversion, it is clear that the microorganism, plant biomass substrate, and processing steps must all be considered simultaneously to achieve optimal results. Whether switchgrass lines engineered for low lignin or natural variants with desirable properties are used, conversion will depend on microbial access to crystalline cellulose in the plant cell wall.
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Liu S, Fu C, Gou J, Sun L, Huhman D, Zhang Y, Wang ZY. Simultaneous Downregulation of MTHFR and COMT in Switchgrass Affects Plant Performance and Induces Lesion-Mimic Cell Death. FRONTIERS IN PLANT SCIENCE 2017; 8:982. [PMID: 28676804 PMCID: PMC5476930 DOI: 10.3389/fpls.2017.00982] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 05/24/2017] [Indexed: 05/11/2023]
Abstract
Switchgrass (Panicum virgatum) has been developed into a model lignocellulosic bioenergy crop. Downregulation of caffeic acid O-methyltransferase (COMT), a key enzyme in lignin biosynthesis, has been shown to alter lignification and increase biofuel yield in switchgrass. Methylenetetrahydrofolate reductase (MTHFR) mediates C1 metabolism and provides methyl units consumed by COMT. It was predicted that co-silencing of MTHFR and COMT would impact lignification even more than either of the single genes. However, our results showed that strong downregulation of MTHFR in a COMT-deficient background led to altered plant growth and development, but no significant change in lignin content or composition was found when compared with COMT plants. Another unexpected finding was that the double MTHFR/COMT downregulated plants showed a novel lesion-mimic leaf phenotype. Molecular analyses revealed that the lesion-mimic phenotype was caused by the synergistic effect of MTHFR and COMT genes, with MTHFR playing a predominant role. Microarray analysis showed significant induction of genes related to oxidative and defense responses. The results demonstrated the lack of additive effects of MTHFR and COMT on lignification. Furthermore, this research revealed an unexpected role of the two genes in the modulation of lesion-mimic cell death as well as their synergistic effects on agronomic performance.
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Affiliation(s)
- Sijia Liu
- Department of Grassland Science, China Agricultural University, National Energy R&D Center for BiomassBeijing, China
- Forage Improvement Division, The Samuel Roberts Noble Foundation, ArdmoreOK, United States
| | - Chunxiang Fu
- Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of SciencesQingdao, China
| | - Jiqing Gou
- Forage Improvement Division, The Samuel Roberts Noble Foundation, ArdmoreOK, United States
- BioEnergy Science Center, Oak Ridge National Laboratory (DOE), Oak RidgeTN, United States
| | - Liang Sun
- Computing Services, The Samuel Roberts Noble Foundation, ArdmoreOK, United States
| | - David Huhman
- Plant Biology Division, The Samuel Roberts Noble Foundation, ArdmoreOK, United States
| | - Yunwei Zhang
- Department of Grassland Science, China Agricultural University, National Energy R&D Center for BiomassBeijing, China
| | - Zeng-Yu Wang
- Forage Improvement Division, The Samuel Roberts Noble Foundation, ArdmoreOK, United States
- BioEnergy Science Center, Oak Ridge National Laboratory (DOE), Oak RidgeTN, United States
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Dumitrache A, Natzke J, Rodriguez M, Yee KL, Thompson OA, Poovaiah CR, Shen H, Mazarei M, Baxter HL, Fu C, Wang Z, Biswal AK, Li G, Srivastava AC, Tang Y, Stewart CN, Dixon RA, Nelson RS, Mohnen D, Mielenz J, Brown SD, Davison BH. Transgenic switchgrass (Panicum virgatum L.) targeted for reduced recalcitrance to bioconversion: a 2-year comparative analysis of field-grown lines modified for target gene or genetic element expression. PLANT BIOTECHNOLOGY JOURNAL 2017; 15:688-697. [PMID: 27862852 PMCID: PMC5425389 DOI: 10.1111/pbi.12666] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Revised: 10/27/2016] [Accepted: 11/16/2016] [Indexed: 05/17/2023]
Abstract
Transgenic Panicum virgatum L. silencing (KD) or overexpressing (OE) specific genes or a small RNA (GAUT4-KD, miRNA156-OE, MYB4-OE, COMT-KD and FPGS-KD) was grown in the field and aerial tissue analysed for biofuel production traits. Clones representing independent transgenic lines were established and senesced tissue was sampled after year 1 and 2 growth cycles. Biomass was analysed for wall sugars, recalcitrance to enzymatic digestibility and biofuel production using separate hydrolysis and fermentation. No correlation was found between plant carbohydrate content and biofuel production pointing to overriding structural and compositional elements that influence recalcitrance. Biomass yields were greater for all lines in the second year as plants establish in the field and standard amounts of biomass analysed from each line had more glucan, xylan and less ethanol (g/g basis) in the second- versus the first-year samples, pointing to a broad increase in tissue recalcitrance after regrowth from the perennial root. However, biomass from second-year growth of transgenics targeted for wall modification, GAUT4-KD, MYB4-OE, COMT-KD and FPGS-KD, had increased carbohydrate and ethanol yields (up to 12% and 21%, respectively) compared with control samples. The parental plant lines were found to have a significant impact on recalcitrance which can be exploited in future strategies. This summarizes progress towards generating next-generation bio-feedstocks with improved properties for microbial and enzymatic deconstruction, while providing a comprehensive quantitative analysis for the bioconversion of multiple plant lines in five transgenic strategies.
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Millwood R, Nageswara-Rao M, Ye R, Terry-Emert E, Johnson CR, Hanson M, Burris JN, Kwit C, Stewart CN. Pollen-mediated gene flow from transgenic to non-transgenic switchgrass (Panicum virgatum L.) in the field. BMC Biotechnol 2017; 17:40. [PMID: 28464851 PMCID: PMC5414321 DOI: 10.1186/s12896-017-0363-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 04/25/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Switchgrass is C4 perennial grass species that is being developed as a cellulosic bioenergy feedstock. It is wind-pollinated and considered to be an obligate outcrosser. Genetic engineering has been used to alter cell walls for more facile bioprocessing and biofuel yield. Gene flow from transgenic cultivars would likely be of regulatory concern. In this study we investigated pollen-mediated gene flow from transgenic to nontransgenic switchgrass in a 3-year field experiment performed in Oliver Springs, Tennessee, U.S.A. using a modified Nelder wheel design. The planted area (0.6 ha) contained sexually compatible pollen source and pollen receptor switchgrass plants. One hundred clonal switchgrass 'Alamo' plants transgenic for an orange-fluorescent protein (OFP) and hygromycin resistance were used as the pollen source; whole plants, including pollen, were orange-fluorescent. To assess pollen movement, pollen traps were placed at 10 m intervals from the pollen-source plot in the four cardinal directions extending to 20 m, 30 m, 30 m, and 100 m to the north, south, west, and east, respectively. To assess pollination rates, nontransgenic 'Alamo 2' switchgrass clones were planted in pairs adjacent to pollen traps. RESULTS In the eastward direction there was a 98% decrease in OFP pollen grains from 10 to 100 m from the pollen-source plot (Poisson regression, F1,8 = 288.38, P < 0.0001). At the end of the second and third year, 1,820 F1 seeds were collected from pollen recipient-plots of which 962 (52.9%) germinated and analyzed for their transgenic status. Transgenic progeny production detected in each pollen-recipient plot decreased with increased distance from the edge of the transgenic plot (Poisson regression, F1,15 = 12.98, P < 0.003). The frequency of transgenic progeny detected in the eastward plots (the direction of the prevailing wind) ranged from 79.2% at 10 m to 9.3% at 100 m. CONCLUSIONS In these experiments we found transgenic pollen movement and hybridization rates to be inversely associated with distance. However, these data suggest pollen-mediated gene flow is likely to occur up to, at least, 100 m. This study gives baseline data useful to determine isolation distances and other management practices should transgenic switchgrass be grown commercially in relevant environments.
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Affiliation(s)
- Reginald Millwood
- Department of Plant Sciences, University of Tennessee, 252 Ellington Plant Sciences, 2431 Joe Johnson Dr., Knoxville, TN, 37996, USA
| | - Madhugiri Nageswara-Rao
- Department of Plant Sciences, University of Tennessee, 252 Ellington Plant Sciences, 2431 Joe Johnson Dr., Knoxville, TN, 37996, USA.,Department of Biology, New Mexico State University, PO Box 30001, MSC 3AF, Las Cruces, NM, USA
| | - Rongjian Ye
- Department of Plant Sciences, University of Tennessee, 252 Ellington Plant Sciences, 2431 Joe Johnson Dr., Knoxville, TN, 37996, USA
| | - Ellie Terry-Emert
- Department of Plant Sciences, University of Tennessee, 252 Ellington Plant Sciences, 2431 Joe Johnson Dr., Knoxville, TN, 37996, USA
| | - Chelsea R Johnson
- Department of Plant Sciences, University of Tennessee, 252 Ellington Plant Sciences, 2431 Joe Johnson Dr., Knoxville, TN, 37996, USA
| | - Micaha Hanson
- Department of Plant Sciences, University of Tennessee, 252 Ellington Plant Sciences, 2431 Joe Johnson Dr., Knoxville, TN, 37996, USA
| | - Jason N Burris
- Department of Plant Sciences, University of Tennessee, 252 Ellington Plant Sciences, 2431 Joe Johnson Dr., Knoxville, TN, 37996, USA
| | - Charles Kwit
- Department of Forestry, Wildlife and Fisheries, University of Tennessee, 274 Ellington Plant Sciences, 2431 Joe Johnson Dr., Knoxville, TN, 37996, USA
| | - C Neal Stewart
- Department of Plant Sciences, University of Tennessee, 252 Ellington Plant Sciences, 2431 Joe Johnson Dr., Knoxville, TN, 37996, USA.
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Li M, Pu Y, Yoo CG, Gjersing E, Decker SR, Doeppke C, Shollenberger T, Tschaplinski TJ, Engle NL, Sykes RW, Davis MF, Baxter HL, Mazarei M, Fu C, Dixon RA, Wang ZY, Neal Stewart C, Ragauskas AJ. Study of traits and recalcitrance reduction of field-grown COMT down-regulated switchgrass. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:12. [PMID: 28053668 PMCID: PMC5209956 DOI: 10.1186/s13068-016-0695-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Accepted: 12/23/2016] [Indexed: 05/22/2023]
Abstract
BACKGROUND The native recalcitrance of plants hinders the biomass conversion process using current biorefinery techniques. Down-regulation of the caffeic acid O-methyltransferase (COMT) gene in the lignin biosynthesis pathway of switchgrass reduced the thermochemical and biochemical conversion recalcitrance of biomass. Due to potential environmental influences on lignin biosynthesis and deposition, studying the consequences of physicochemical changes in field-grown plants without pretreatment is essential to evaluate the performance of lignin-altered plants. We determined the chemical composition, cellulose crystallinity and the degree of its polymerization, molecular weight of hemicellulose, and cellulose accessibility of cell walls in order to better understand the fundamental features of why biomass is recalcitrant to conversion without pretreatment. The most important is to investigate whether traits and features are stable in the dynamics of field environmental effects over multiple years. RESULTS Field-grown COMT down-regulated plants maintained both reduced cell wall recalcitrance and lignin content compared with the non-transgenic controls for at least 3 seasons. The transgenic switchgrass yielded 35-84% higher total sugar release (enzymatic digestibility or saccharification) from a 72-h enzymatic hydrolysis without pretreatment and also had a 25-32% increase in enzymatic sugar release after hydrothermal pretreatment. The COMT-silenced switchgrass lines had consistently lower lignin content, e.g., 12 and 14% reduction for year 2 and year 3 growing season, respectively, than the control plants. By contrast, the transgenic lines had 7-8% more xylan and galactan contents than the wild-type controls. Gel permeation chromatographic results revealed that the weight-average molecular weights of hemicellulose were 7-11% lower in the transgenic than in the control lines. In addition, we found that silencing of COMT in switchgrass led to 20-22% increased cellulose accessibility as measured by the Simons' stain protocol. No significant changes were observed on the arabinan and glucan contents, cellulose crystallinity, and cellulose degree of polymerization between the transgenic and control plants. With the 2-year comparative analysis, both the control and transgenic lines had significant increases in lignin and glucan contents and hemicellulose molecular weight across the growing seasons. CONCLUSIONS The down-regulation of COMT in switchgrass resulting in a reduced lignin content and biomass recalcitrance is stable in a field-grown trial for at least three seasons. Among the determined affecting factors, the reduced biomass recalcitrance of the COMT-silenced switchgrass, grown in the field conditions for two and three seasons, was likely related to the decreased lignin content and increased biomass accessibility, whereas the cellulose crystallinity and degree of its polymerization and hemicellulose molecular weights did not contribute to the reduction of recalcitrance significantly. This finding suggests that lignin down-regulation in lignocellulosic feedstock confers improved saccharification that translates from greenhouse to field trial and that lignin content and biomass accessibility are two significant factors for developing a reduced recalcitrance feedstock by genetic modification.
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Affiliation(s)
- Mi Li
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory (ORNL), Oak Ridge, TN USA
- BioSciences Division, ORNL, Oak Ridge, TN USA
- UT-ORNL Joint Institute for Biological Sciences, Oak Ridge, TN USA
| | - Yunqiao Pu
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory (ORNL), Oak Ridge, TN USA
- BioSciences Division, ORNL, Oak Ridge, TN USA
- UT-ORNL Joint Institute for Biological Sciences, Oak Ridge, TN USA
| | - Chang Geun Yoo
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory (ORNL), Oak Ridge, TN USA
- BioSciences Division, ORNL, Oak Ridge, TN USA
- UT-ORNL Joint Institute for Biological Sciences, Oak Ridge, TN USA
| | - Erica Gjersing
- Biosciences Center, National Renewable Energy Laboratory (NREL), Golden, CO USA
| | - Stephen R. Decker
- Biosciences Center, National Renewable Energy Laboratory (NREL), Golden, CO USA
| | - Crissa Doeppke
- Biosciences Center, National Renewable Energy Laboratory (NREL), Golden, CO USA
| | - Todd Shollenberger
- Biosciences Center, National Renewable Energy Laboratory (NREL), Golden, CO USA
| | - Timothy J. Tschaplinski
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory (ORNL), Oak Ridge, TN USA
- BioSciences Division, ORNL, Oak Ridge, TN USA
- UT-ORNL Joint Institute for Biological Sciences, Oak Ridge, TN USA
| | - Nancy L. Engle
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory (ORNL), Oak Ridge, TN USA
- BioSciences Division, ORNL, Oak Ridge, TN USA
- UT-ORNL Joint Institute for Biological Sciences, Oak Ridge, TN USA
| | | | | | - Holly L. Baxter
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory (ORNL), Oak Ridge, TN USA
- Department of Plant Sciences, University of Tennessee, Knoxville, TN USA
| | - Mitra Mazarei
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory (ORNL), Oak Ridge, TN USA
- Department of Plant Sciences, University of Tennessee, Knoxville, TN USA
| | - Chunxiang Fu
- Forage Improvement Division, The Samuel Roberts Noble Foundation, Ardmore, OK USA
| | - Richard A. Dixon
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory (ORNL), Oak Ridge, TN USA
- BioDiscovery Institute and Department of Biological Sciences, University of North Texas, Denton, TX USA
| | - Zeng-Yu Wang
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory (ORNL), Oak Ridge, TN USA
- Forage Improvement Division, The Samuel Roberts Noble Foundation, Ardmore, OK USA
| | - C. Neal Stewart
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory (ORNL), Oak Ridge, TN USA
- Department of Plant Sciences, University of Tennessee, Knoxville, TN USA
| | - Arthur J. Ragauskas
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory (ORNL), Oak Ridge, TN USA
- BioSciences Division, ORNL, Oak Ridge, TN USA
- UT-ORNL Joint Institute for Biological Sciences, Oak Ridge, TN USA
- Department of Chemical and Biomolecular Engineering & Department of Forestry, Wildlife and Fisheries, University of Tennessee, Knoxville, TN USA
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Nelson RS, Stewart CN, Gou J, Holladay S, Gallego-Giraldo L, Flanagan A, Mann DGJ, Hisano H, Wuddineh WA, Poovaiah CR, Srivastava A, Biswal AK, Shen H, Escamilla-Treviño LL, Yang J, Hardin CF, Nandakumar R, Fu C, Zhang J, Xiao X, Percifield R, Chen F, Bennetzen JL, Udvardi M, Mazarei M, Dixon RA, Wang ZY, Tang Y, Mohnen D, Davison BH. Development and use of a switchgrass ( Panicum virgatum L.) transformation pipeline by the BioEnergy Science Center to evaluate plants for reduced cell wall recalcitrance. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:309. [PMID: 29299059 PMCID: PMC5740764 DOI: 10.1186/s13068-017-0991-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 12/05/2017] [Indexed: 05/02/2023]
Abstract
BACKGROUND The mission of the BioEnergy Science Center (BESC) was to enable efficient lignocellulosic-based biofuel production. One BESC goal was to decrease poplar and switchgrass biomass recalcitrance to biofuel conversion while not affecting plant growth. A transformation pipeline (TP), to express transgenes or transgene fragments (constructs) in these feedstocks with the goal of understanding and decreasing recalcitrance, was considered essential for this goal. Centralized data storage for access by BESC members and later the public also was essential. RESULTS A BESC committee was established to codify procedures to evaluate and accept genes into the TP. A laboratory information management system (LIMS) was organized to catalog constructs, plant lines and results from their analyses. One hundred twenty-eight constructs were accepted into the TP for expression in switchgrass in the first 5 years of BESC. Here we provide information on 53 of these constructs and the BESC TP process. Eleven of the constructs could not be cloned into an expression vector for transformation. Of the remaining constructs, 22 modified expression of the gene target. Transgenic lines representing some constructs displayed decreased recalcitrance in the field and publications describing these results are tabulated here. Transcript levels of target genes and detailed wall analyses from transgenic lines expressing six additional tabulated constructs aimed toward modifying expression of genes associated with wall structure (xyloglucan and lignin components) are provided. Altered expression of xyloglucan endotransglucosylase/hydrolases did not modify lignin content in transgenic plants. Simultaneous silencing of two hydroxycinnamoyl CoA:shikimate hydroxycinnamoyl transferases was necessary to decrease G and S lignin monomer and total lignin contents, but this reduced plant growth. CONCLUSIONS A TP to produce plants with decreased recalcitrance and a LIMS for data compilation from these plants were created. While many genes accepted into the TP resulted in transgenic switchgrass without modified lignin or biomass content, a group of genes with potential to improve lignocellulosic biofuel yields was identified. Results from transgenic lines targeting xyloglucan and lignin structure provide examples of the types of information available on switchgrass lines produced within BESC. This report supplies useful information when developing coordinated, large-scale, multi-institutional reverse genetic pipelines to improve crop traits.
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Affiliation(s)
- Richard S. Nelson
- Noble Research Institute, LLC, Ardmore, OK 73401 USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - C. Neal Stewart
- Department of Plant Sciences, University of Tennessee, Knoxville, TN 37996 USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Jiqing Gou
- Noble Research Institute, LLC, Ardmore, OK 73401 USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Susan Holladay
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Lina Gallego-Giraldo
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- BioDiscovery Institute and Department of Biological Sciences, University of North Texas, Denton, TX 76203 USA
| | - Amy Flanagan
- Noble Research Institute, LLC, Ardmore, OK 73401 USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - David G. J. Mann
- Department of Plant Sciences, University of Tennessee, Knoxville, TN 37996 USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Hiroshi Hisano
- Noble Research Institute, LLC, Ardmore, OK 73401 USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Wegi A. Wuddineh
- Department of Plant Sciences, University of Tennessee, Knoxville, TN 37996 USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Charleson R. Poovaiah
- Department of Plant Sciences, University of Tennessee, Knoxville, TN 37996 USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Avinash Srivastava
- Noble Research Institute, LLC, Ardmore, OK 73401 USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Ajaya K. Biswal
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602 USA
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602 USA
| | - Hui Shen
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- BioDiscovery Institute and Department of Biological Sciences, University of North Texas, Denton, TX 76203 USA
| | - Luis L. Escamilla-Treviño
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- BioDiscovery Institute and Department of Biological Sciences, University of North Texas, Denton, TX 76203 USA
| | - Jiading Yang
- Noble Research Institute, LLC, Ardmore, OK 73401 USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - C. Frank Hardin
- Noble Research Institute, LLC, Ardmore, OK 73401 USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Rangaraj Nandakumar
- Noble Research Institute, LLC, Ardmore, OK 73401 USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Chunxiang Fu
- Noble Research Institute, LLC, Ardmore, OK 73401 USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Jiyi Zhang
- Noble Research Institute, LLC, Ardmore, OK 73401 USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Xirong Xiao
- Noble Research Institute, LLC, Ardmore, OK 73401 USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Ryan Percifield
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- Department of Genetics, University of Georgia, Athens, GA 30602 USA
| | - Fang Chen
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- BioDiscovery Institute and Department of Biological Sciences, University of North Texas, Denton, TX 76203 USA
| | - Jeffrey L. Bennetzen
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- Department of Genetics, University of Georgia, Athens, GA 30602 USA
| | - Michael Udvardi
- Noble Research Institute, LLC, Ardmore, OK 73401 USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Mitra Mazarei
- Department of Plant Sciences, University of Tennessee, Knoxville, TN 37996 USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Richard A. Dixon
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- BioDiscovery Institute and Department of Biological Sciences, University of North Texas, Denton, TX 76203 USA
| | - Zeng-Yu Wang
- Noble Research Institute, LLC, Ardmore, OK 73401 USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Yuhong Tang
- Noble Research Institute, LLC, Ardmore, OK 73401 USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Debra Mohnen
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602 USA
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602 USA
| | - Brian H. Davison
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
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Johnson CR, Millwood RJ, Tang Y, Gou J, Sykes RW, Turner GB, Davis MF, Sang Y, Wang ZY, Stewart CN. Field-grown miR156 transgenic switchgrass reproduction, yield, global gene expression analysis, and bioconfinement. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:255. [PMID: 29213314 PMCID: PMC5707911 DOI: 10.1186/s13068-017-0939-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 10/19/2017] [Indexed: 05/09/2023]
Abstract
BACKGROUND Genetic engineering has been effective in altering cell walls for biofuel production in the bioenergy crop, switchgrass (Panicum virgatum). However, regulatory issues arising from gene flow may prevent commercialization of engineered switchgrass in the eastern United States where the species is native. Depending on its expression level, microRNA156 (miR156) can reduce, delay, or eliminate flowering, which may serve to decrease transgene flow. In this unique field study of transgenic switchgrass that was permitted to flower, two low (T14 and T35) and two medium (T27 and T37) miR156-overexpressing 'Alamo' lines with the transgene under the control of the constitutive maize (Zea mays) ubiquitin 1 promoter, along with nontransgenic control plants, were grown in eastern Tennessee over two seasons. RESULTS miR156 expression was positively associated with decreased and delayed flowering in switchgrass. Line T27 did not flower during the 2-year study. Line T37 did flower, but not all plants produced panicles. Flowering was delayed in T37, resulting in 70.6% fewer flowers than controls during the second field year with commensurate decreased seed yield: 1205 seeds per plant vs. 18,539 produced by each control. These results are notable given that line T37 produced equivalent vegetative aboveground biomass to the controls. miR156 transcript abundance of field-grown plants was congruent with greenhouse results. The five miR156 SQUAMOSA PROMOTER BINDING PROTEIN-LIKE (SPL) target genes had suppressed expression in one or more of the transgenic lines. Line T27, which had the highest miR156 overexpression, showed significant downregulation for all five SPL genes. On the contrary, line T35 had the lowest miR156 overexpression and had no significant change in any of the five SPL genes. CONCLUSIONS Because of the research field's geographical features, this study was the first instance of any genetically engineered trait in switchgrass, in which experimental plants were allowed to flower in the field in the eastern U.S.; USDA-APHIS-BRS regulators allowed open flowering. We found that medium overexpression of miR156, e.g., line T37, resulted in delayed and reduced flowering accompanied by high biomass production. We propose that induced miR156 expression could be further developed as a transgenic switchgrass bioconfinement tool to enable eventual commercialization.
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Affiliation(s)
- Chelsea R. Johnson
- Department of Plant Sciences, University of Tennessee, Knoxville, TN USA
| | - Reginald J. Millwood
- Department of Plant Sciences, University of Tennessee, Knoxville, TN USA
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN USA
| | - Yuhong Tang
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN USA
- Noble Research Institute, Ardmore, OK USA
| | - Jiqing Gou
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN USA
- Noble Research Institute, Ardmore, OK USA
| | - Robert W. Sykes
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN USA
- National Renewable Energy Laboratory, Golden, CO USA
| | - Geoffrey B. Turner
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN USA
- National Renewable Energy Laboratory, Golden, CO USA
| | - Mark F. Davis
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN USA
- National Renewable Energy Laboratory, Golden, CO USA
| | - Yi Sang
- Department of Plant Sciences, University of Tennessee, Knoxville, TN USA
| | - Zeng-Yu Wang
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN USA
- Noble Research Institute, Ardmore, OK USA
| | - C. Neal Stewart
- Department of Plant Sciences, University of Tennessee, Knoxville, TN USA
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN USA
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Willis JD, Grant JN, Mazarei M, Kline LM, Rempe CS, Collins AG, Turner GB, Decker SR, Sykes RW, Davis MF, Labbe N, Jurat-Fuentes JL, Stewart CN. The TcEG1 beetle ( Tribolium castaneum) cellulase produced in transgenic switchgrass is active at alkaline pH and auto-hydrolyzes biomass for increased cellobiose release. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:230. [PMID: 29213306 PMCID: PMC5707894 DOI: 10.1186/s13068-017-0918-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 09/28/2017] [Indexed: 05/17/2023]
Abstract
BACKGROUND Genetically engineered biofuel crops, such as switchgrass (Panicum virgatum L.), that produce their own cell wall-digesting cellulase enzymes would reduce costs of cellulosic biofuel production. To date, non-bioenergy plant models have been used in nearly all studies assessing the synthesis and activity of plant-produced fungal and bacterial cellulases. One potential source for cellulolytic enzyme genes is herbivorous insects adapted to digest plant cell walls. Here we examine the potential of transgenic switchgrass-produced TcEG1 cellulase from Tribolium castaneum (red flour beetle). This enzyme, when overproduced in Escherichia coli and Saccharomyces cerevisiae, efficiently digests cellulose at optima of 50 °C and pH 12.0. RESULTS TcEG1 that was produced in green transgenic switchgrass tissue had a range of endoglucanase activity of 0.16-0.05 units (µM glucose release/min/mg) at 50 °C and pH 12.0. TcEG1 activity from air-dried leaves was unchanged from that from green tissue, but when tissue was dried in a desiccant oven (46 °C), specific enzyme activity decreased by 60%. When transgenic biomass was "dropped-in" into an alkaline buffer (pH 12.0) and allowed to incubate at 50 °C, cellobiose release was increased up to 77% over non-transgenic biomass. Saccharification was increased in one transgenic event by 28%, which had a concurrent decrease in lignin content of 9%. Histological analysis revealed an increase in cell wall thickness with no change to cell area or perimeter. Transgenic plants produced more, albeit narrower, tillers with equivalent dry biomass as the control. CONCLUSIONS This work describes the first study in which an insect cellulase has been produced in transgenic plants; in this case, the dedicated bioenergy crop switchgrass. Switchgrass overexpressing the TcEG1 gene appeared to be morphologically similar to its non-transgenic control and produced equivalent dry biomass. Therefore, we propose TcEG1 transgenics could be bred with other transgenic germplasm (e.g., low-lignin lines) to yield new switchgrass with synergistically reduced recalcitrance to biofuel production. In addition, transgenes for other cell wall degrading enzymes may be stacked with TcEG1 in switchgrass to yield complementary cell wall digestion features and complete auto-hydrolysis.
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Affiliation(s)
- Jonathan D. Willis
- Department of Plant Sciences, University of Tennessee, Knoxville, TN 37996 USA
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Joshua N. Grant
- Department of Plant Sciences, University of Tennessee, Knoxville, TN 37996 USA
| | - Mitra Mazarei
- Department of Plant Sciences, University of Tennessee, Knoxville, TN 37996 USA
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Lindsey M. Kline
- Center for Renewable Carbon, University of Tennessee, Knoxville, TN 37996 USA
| | - Caroline S. Rempe
- Department of Plant Sciences, University of Tennessee, Knoxville, TN 37996 USA
- UT-ORNL Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, TN 37996 USA
| | - A. Grace Collins
- Department of Plant Sciences, University of Tennessee, Knoxville, TN 37996 USA
| | - Geoffrey B. Turner
- The National Research Energy Laboratory, Golden, CO 80401 USA
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Stephen R. Decker
- The National Research Energy Laboratory, Golden, CO 80401 USA
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Robert W. Sykes
- The National Research Energy Laboratory, Golden, CO 80401 USA
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Mark F. Davis
- The National Research Energy Laboratory, Golden, CO 80401 USA
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Nicole Labbe
- Center for Renewable Carbon, University of Tennessee, Knoxville, TN 37996 USA
| | - Juan L. Jurat-Fuentes
- Department of Entomology and Plant Pathology, University of Tennessee, Knoxville, TN 37996 USA
| | - C. Neal Stewart
- Department of Plant Sciences, University of Tennessee, Knoxville, TN 37996 USA
- UT-ORNL Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, TN 37996 USA
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
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Park JJ, Yoo CG, Flanagan A, Pu Y, Debnath S, Ge Y, Ragauskas AJ, Wang ZY. Defined tetra-allelic gene disruption of the 4-coumarate:coenzyme A ligase 1 (Pv4CL1) gene by CRISPR/Cas9 in switchgrass results in lignin reduction and improved sugar release. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:284. [PMID: 29213323 PMCID: PMC5708096 DOI: 10.1186/s13068-017-0972-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 11/18/2017] [Indexed: 05/02/2023]
Abstract
BACKGROUND The development of genome editing technologies offers new prospects in improving bioenergy crops like switchgrass (Panicum virgatum). Switchgrass is an outcrossing species with an allotetraploid genome (2n = 4x = 36), a complexity which forms an impediment to generating homozygous knock-out plants. Lignin, a major component of the plant cell wall and a contributor to cellulosic feedstock's recalcitrance to decomposition, stands as a barrier to efficient biofuel production by limiting enzyme access to cell wall polymers during the fermentation process. RESULTS We developed a CRISPR/Cas9 genome editing system in switchgrass to target a key enzyme involved in the early steps of monolignol biosynthesis, 4-Coumarate:coenzyme A ligase (4CL). Three 4CL genes, Pv4CL1, Pv4CL2, and Pv4CL3, were identified in switchgrass. Expression analysis revealed that Pv4CL1 transcripts were more abundant in the stem than in the leaf, while Pv4CL2 transcripts were barely detectable and Pv4CL3 was mainly expressed in the leaf. Pv4CL1 was selected as the target for CRISPR/Cas9 editing because of its preferential expression in highly lignified stem tissues. Specific guide RNA was constructed to target Pv4CL1. After introducing the construct into switchgrass calli, 39 transgenic plants were regenerated. Using two rounds of PCR screening and sequencing, four plants were confirmed to have tetra-allelic mutations simultaneously. The Pv4CL1 knock-out plants had reduced cell wall thickness, an 8-30% reduction in total lignin content, a 7-11% increase in glucose release, and a 23-32% increase in xylose release. CONCLUSION This study established a successful CRISPR/Cas9 system in switchgrass with mutation efficiency reaching 10%. The system allows the precise targeting of the selected Pv4CL1 gene to create switchgrass knock-out mutant plants with decreased lignin content and reduced recalcitrance.
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Affiliation(s)
- Jong-Jin Park
- Noble Research Institute, Ardmore, OK 73401 USA
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Chang Geun Yoo
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- Joint Institute for Biological Sciences, Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830 USA
| | - Amy Flanagan
- Noble Research Institute, Ardmore, OK 73401 USA
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Yunqiao Pu
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- Joint Institute for Biological Sciences, Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830 USA
| | | | - Yaxin Ge
- Noble Research Institute, Ardmore, OK 73401 USA
| | - Arthur J. Ragauskas
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- Joint Institute for Biological Sciences, Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830 USA
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, TN 37996 USA
- Center for Renewable Carbon, Department of Forestry, Wildlife, and Fisheries, University of Tennessee Institute of Agriculture, Knoxville, TN 37996 USA
| | - Zeng-Yu Wang
- Noble Research Institute, Ardmore, OK 73401 USA
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
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Thomas VA, Kothari N, Bhagia S, Akinosho H, Li M, Pu Y, Yoo CG, Pattathil S, Hahn MG, Raguaskas AJ, Wyman CE, Kumar R. Comparative evaluation of Populus variants total sugar release and structural features following pretreatment and digestion by two distinct biological systems. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:292. [PMID: 29225697 PMCID: PMC5718110 DOI: 10.1186/s13068-017-0975-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 11/25/2017] [Indexed: 05/18/2023]
Abstract
BACKGROUND Populus natural variants have been shown to realize a broad range of sugar yields during saccharification, however, the structural features responsible for higher sugar release from natural variants are not clear. In addition, the sugar release patterns resulting from digestion with two distinct biological systems, fungal enzymes and Clostridium thermocellum, have yet to be evaluated and compared. This study evaluates the effect of structural features of three natural variant Populus lines, which includes the line BESC standard, with respect to the overall process of sugar release for two different biological systems. RESULTS Populus natural variants, SKWE 24-2 and BESC 876, showed higher sugar release from hydrothermal pretreatment combined with either enzymatic hydrolysis or Clostridium thermocellum fermentation compared to the Populus natural variant, BESC standard. However, C. thermocellum outperformed the fungal cellulases yielding 96.0, 95.5, and 85.9% glucan plus xylan release from SKWE 24-2, BESC 876, and BESC standard, respectively. Among the feedstock properties evaluated, cellulose accessibility and glycome profiling provided insights into factors that govern differences in sugar release between the low recalcitrant lines and the BESC standard line. However, because this distinction was more apparent in the solids after pretreatment than in the untreated biomass, pretreatment was necessary to differentiate recalcitrance among Populus lines. Glycome profiling analysis showed that SKWE 24-2 contained the most loosely bound cell wall glycans, followed by BESC 876, and BESC standard. Additionally, lower molecular weight lignin may be favorable for effective hydrolysis, since C. thermocellum reduced lignin molecular weight more than fungal enzymes across all Populus lines. CONCLUSIONS Low recalcitrant Populus natural variants, SKWE 24-2 and BESC 876, showed higher sugar yields than BESC standard when hydrothermal pretreatment was combined with biological digestion. However, C. thermocellum was determined to be a more robust and effective biological catalyst than a commercial fungal cellulase cocktail. As anticipated, recalcitrance was not readily predicted through analytical methods that determined structural properties alone. However, combining structural analysis with pretreatment enabled the identification of attributes that govern recalcitrance, namely cellulose accessibility, xylan content in the pretreated solids, and non-cellulosic glycan extractability.
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Affiliation(s)
- Vanessa A. Thomas
- Department of Chemical and Environmental Engineering, Bourns College of Engineering, University of California Riverside, Riverside, CA 92507 USA
- Center for Environmental Research and Technology (CE-CERT), Bourns College of Engineering, University of California Riverside, Riverside, CA 92507 USA
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Ninad Kothari
- Department of Chemical and Environmental Engineering, Bourns College of Engineering, University of California Riverside, Riverside, CA 92507 USA
- Center for Environmental Research and Technology (CE-CERT), Bourns College of Engineering, University of California Riverside, Riverside, CA 92507 USA
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Samarthya Bhagia
- Department of Chemical and Environmental Engineering, Bourns College of Engineering, University of California Riverside, Riverside, CA 92507 USA
- Center for Environmental Research and Technology (CE-CERT), Bourns College of Engineering, University of California Riverside, Riverside, CA 92507 USA
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Hannah Akinosho
- School of Chemistry and Biochemistry & Renewable Bioproducts Institute, Atlanta, GA 30332 USA
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Mi Li
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- UT-ORNL Joint Institute for Biological Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Yunqiao Pu
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- UT-ORNL Joint Institute for Biological Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Chang Geun Yoo
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- UT-ORNL Joint Institute for Biological Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Sivakumar Pattathil
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602 USA
- Present Address: Mascoma LLC (Lallemand Inc.), 67 Etna Road, Lebanon, NH 03766 USA
| | - Michael G. Hahn
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602 USA
| | - Arthur J. Raguaskas
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- UT-ORNL Joint Institute for Biological Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- Department of Chemical and Biomolecular Engineering, Center for Renewable Carbon, University of Tennessee, Knoxville, TN 37996 USA
- Department of Forestry, Wildlife, and Fisheries, Center for Renewable Carbon, University of Tennessee, Knoxville, TN 37996 USA
| | - Charles E. Wyman
- Department of Chemical and Environmental Engineering, Bourns College of Engineering, University of California Riverside, Riverside, CA 92507 USA
- Center for Environmental Research and Technology (CE-CERT), Bourns College of Engineering, University of California Riverside, Riverside, CA 92507 USA
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Rajeev Kumar
- Center for Environmental Research and Technology (CE-CERT), Bourns College of Engineering, University of California Riverside, Riverside, CA 92507 USA
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
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Chen S, Kaeppler SM, Vogel KP, Casler MD. Selection Signatures in Four Lignin Genes from Switchgrass Populations Divergently Selected for In Vitro Dry Matter Digestibility. PLoS One 2016; 11:e0167005. [PMID: 27893787 PMCID: PMC5125650 DOI: 10.1371/journal.pone.0167005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 11/07/2016] [Indexed: 12/28/2022] Open
Abstract
Switchgrass is undergoing development as a dedicated cellulosic bioenergy crop. Fermentation of lignocellulosic biomass to ethanol in a bioenergy system or to volatile fatty acids in a livestock production system is strongly and negatively influenced by lignification of cell walls. This study detects specific loci that exhibit selection signatures across switchgrass breeding populations that differ in in vitro dry matter digestibility (IVDMD), ethanol yield, and lignin concentration. Allele frequency changes in candidate genes were used to detect loci under selection. Out of the 183 polymorphisms identified in the four candidate genes, twenty-five loci in the intron regions and four loci in coding regions were found to display a selection signature. All loci in the coding regions are synonymous substitutions. Selection in both directions were observed on polymorphisms that appeared to be under selection. Genetic diversity and linkage disequilibrium within the candidate genes were low. The recurrent divergent selection caused excessive moderate allele frequencies in the cycle 3 reduced lignin population as compared to the base population. This study provides valuable insight on genetic changes occurring in short-term selection in the polyploid populations, and discovered potential markers for breeding switchgrass with improved biomass quality.
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Affiliation(s)
- Shiyu Chen
- Department of Agronomy, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Shawn M. Kaeppler
- Department of Agronomy, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Department of Energy, Great Lakes Bioenergy Research Center, Madison, Wisconsin, United States of America
| | - Kenneth P. Vogel
- USDA-ARS, Grain, Forage, and Bioenergy Research Unit, Lincoln, Nebraska, United States of America
- Department of Agronomy & Horticulture, University of Nebraska, Lincoln, Nebraska, United States of America
| | - Michael D. Casler
- Department of Energy, Great Lakes Bioenergy Research Center, Madison, Wisconsin, United States of America
- USDA-ARS, U.S. Dairy Forage Research Center, Madison, Wisconsin, United States of America
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Jung JH, Kannan B, Dermawan H, Moxley GW, Altpeter F. Precision breeding for RNAi suppression of a major 4-coumarate:coenzyme A ligase gene improves cell wall saccharification from field grown sugarcane. PLANT MOLECULAR BIOLOGY 2016; 92:505-517. [PMID: 27549390 DOI: 10.1007/s11103-016-0527-y] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 08/08/2016] [Indexed: 05/02/2023]
Abstract
Sugarcane (Saccharum spp. hybrids) is a major feedstock for commercial bioethanol production. The recent integration of conversion technologies that utilize lignocellulosic sugarcane residues as well as sucrose from stem internodes has elevated bioethanol yields. RNAi suppression of lignin biosynthetic enzymes is a successful strategy to improve the saccharification of lignocellulosic biomass. 4-coumarate:coenzyme A ligase (4CL) is a key enzyme in the biosynthesis of phenylpropanoid metabolites, such as lignin and flavonoids. Identifying a major 4CL involved in lignin biosynthesis among multiple isoforms with functional divergence is key to manipulate lignin biosynthesis. In this study, two full length 4CL genes (Sh4CL1 and Sh4CL2) were isolated and characterized in sugarcane. Phylogenetic, expression and RNA interference (RNAi) analysis confirmed that Sh4CL1 is a major lignin biosynthetic gene. An intragenic precision breeding strategy may facilitate the regulatory approval of the genetically improved events and was used for RNAi suppression of Sh4CL1. Both, the RNAi inducing cassette and the expression cassette for the mutated ALS selection marker consisted entirely of DNA sequences from sugarcane or the sexually compatible species Sorghum bicolor. Field grown sugarcane with intragenic RNAi suppression of Sh4CL1 resulted in reduction of the total lignin content by up to 16.5 % along with altered monolignol ratios without reduction in biomass yield. Mature, field grown, intragenic sugarcane events displayed 52-76 % improved saccharification efficiency of lignocellulosic biomass compared to wild type (WT) controls. This demonstrates for the first time that an intragenic approach can add significant value to lignocellulosic feedstocks for biofuel and biochemical production.
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Affiliation(s)
- Je Hyeong Jung
- Agronomy Department, IFAS, University of Florida, PO Box 110500, Gainesville, FL, 32611, USA
- Institute of Life Science and Natural Resources, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul, 02841, South Korea
| | - Baskaran Kannan
- Agronomy Department, IFAS, University of Florida, PO Box 110500, Gainesville, FL, 32611, USA
| | - Hugo Dermawan
- Agronomy Department, IFAS, University of Florida, PO Box 110500, Gainesville, FL, 32611, USA
| | | | - Fredy Altpeter
- Agronomy Department, IFAS, University of Florida, PO Box 110500, Gainesville, FL, 32611, USA.
- Plant Molecular and Cellular Biology Program, IFAS, University of Florida, PO Box 110300, Gainesville, FL, 32611, USA.
- University of Florida Genetics Institute, PO Box 103610, Gainesville, FL, 32610, USA.
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Dlugosz EM, Lenaghan SC, Stewart CN. A Robotic Platform for High-throughput Protoplast Isolation and Transformation. J Vis Exp 2016:54300. [PMID: 27768035 PMCID: PMC5092064 DOI: 10.3791/54300] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Over the last decade there has been a resurgence in the use of plant protoplasts that range from model species to crop species, for analysis of signal transduction pathways, transcriptional regulatory networks, gene expression, genome-editing, and gene-silencing. Furthermore, significant progress has been made in the regeneration of plants from protoplasts, which has generated even more interest in the use of these systems for plant genomics. In this work, a protocol has been developed for automation of protoplast isolation and transformation from a 'Bright Yellow' 2 (BY-2) tobacco suspension culture using a robotic platform. The transformation procedures were validated using an orange fluorescent protein (OFP) reporter gene (pporRFP) under the control of the Cauliflower mosaic virus 35S promoter (35S). OFP expression in protoplasts was confirmed by epifluorescence microscopy. Analyses also included protoplast production efficiency methods using propidium iodide. Finally, low-cost food-grade enzymes were used for the protoplast isolation procedure, circumventing the need for lab-grade enzymes that are cost-prohibitive in high-throughput automated protoplast isolation and analysis. Based on the protocol developed in this work, the complete procedure from protoplast isolation to transformation can be conducted in under 4 hr, without any input from the operator. While the protocol developed in this work was validated with the BY-2 cell culture, the procedures and methods should be translatable to any plant suspension culture/protoplast system, which should enable acceleration of crop genomics research.
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Affiliation(s)
| | - Scott C Lenaghan
- Center for Renewable Carbon, University of Tennessee, Knoxville; Department of Mechanical, Aerospace, and Biomedical Engineering, University of Tennessee, Knoxville;
| | - C Neal Stewart
- Department of Plant Sciences, University of Tennessee, Knoxville
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Jung JH, Altpeter F. TALEN mediated targeted mutagenesis of the caffeic acid O-methyltransferase in highly polyploid sugarcane improves cell wall composition for production of bioethanol. PLANT MOLECULAR BIOLOGY 2016; 92:131-42. [PMID: 27306903 PMCID: PMC4999463 DOI: 10.1007/s11103-016-0499-y] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2015] [Accepted: 05/30/2016] [Indexed: 05/18/2023]
Abstract
Sugarcane (Saccharum spp. hybrids) is a prime crop for commercial biofuel production. Advanced conversion technology utilizes both, sucrose accumulating in sugarcane stems as well as cell wall bound sugars for commercial ethanol production. Reduction of lignin content significantly improves the conversion of lignocellulosic biomass into ethanol. Conventional mutagenesis is not expected to confer reduction in lignin content in sugarcane due to its high polyploidy (x = 10-13) and functional redundancy among homo(eo)logs. Here we deploy transcription activator-like effector nuclease (TALEN) to induce mutations in a highly conserved region of the caffeic acid O-methyltransferase (COMT) of sugarcane. Capillary electrophoresis (CE) was validated by pyrosequencing as reliable and inexpensive high throughput method for identification and quantitative characterization of TALEN mediated mutations. Targeted COMT mutations were identified by CE in up to 74 % of the lines. In different events 8-99 % of the wild type COMT were converted to mutant COMT as revealed by pyrosequencing. Mutation frequencies among mutant lines were positively correlated to lignin reduction. Events with a mutation frequency of 99 % displayed a 29-32 % reduction of the lignin content compared to non-transgenic controls along with significantly reduced S subunit content and elevated hemicellulose content. CE analysis displayed similar peak patterns between primary COMT mutants and their vegetative progenies suggesting that TALEN mediated mutations were faithfully transmitted to vegetative progenies. This is the first report on genome editing in sugarcane. The findings demonstrate that targeted mutagenesis can improve cell wall characteristics for production of lignocellulosic ethanol in crops with highly complex genomes.
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Affiliation(s)
- Je Hyeong Jung
- Agronomy Department, University of Florida, IFAS, PO Box 110300, Gainesville, FL, 32611, USA
- Institute of Life Science and Natural Resources, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea
| | - Fredy Altpeter
- Agronomy Department, University of Florida, IFAS, PO Box 110300, Gainesville, FL, 32611, USA.
- Plant Molecular and Cellular Biology Program, University of Florida, IFAS, PO Box 110300, Gainesville, FL, 32611, USA.
- Agronomy Department, University of Florida-IFAS, PO Box 103610, Gainesville, FL, 32611, USA.
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50
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Zhu H, Luo W, Ciesielski PN, Fang Z, Zhu JY, Henriksson G, Himmel ME, Hu L. Wood-Derived Materials for Green Electronics, Biological Devices, and Energy Applications. Chem Rev 2016; 116:9305-74. [DOI: 10.1021/acs.chemrev.6b00225] [Citation(s) in RCA: 876] [Impact Index Per Article: 109.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Hongli Zhu
- Department
of Materials Science and Engineering, University of Maryland, College Park, Maryland 20742, United States
- Department
of Mechanical and Industrial Engineering, Northeastern University, Boston, Massachusetts 02115, United States
| | - Wei Luo
- Department
of Materials Science and Engineering, University of Maryland, College Park, Maryland 20742, United States
| | - Peter N. Ciesielski
- Biosciences
Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States
| | - Zhiqiang Fang
- Department
of Materials Science and Engineering, University of Maryland, College Park, Maryland 20742, United States
| | - J. Y. Zhu
- Forest
Products Laboratory, USDA Forest Service, Madison, Wisconsin 53726, United States
| | - Gunnar Henriksson
- Division
of Wood Chemistry and Pulp Technology, Department of Fiber and Polymer
Technology, Royal Institute of Technology, KTH, Stockholm, Sweden
| | - Michael E. Himmel
- Biosciences
Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States
| | - Liangbing Hu
- Department
of Materials Science and Engineering, University of Maryland, College Park, Maryland 20742, United States
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