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Morgan MF, Diab J, Gilliham M, Mortimer JC. Green horizons: how plant synthetic biology can enable space exploration and drive on Earth sustainability. Curr Opin Biotechnol 2024; 86:103069. [PMID: 38341984 DOI: 10.1016/j.copbio.2024.103069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 12/27/2023] [Accepted: 01/09/2024] [Indexed: 02/13/2024]
Abstract
As humanity looks towards expanding activity from low Earth orbit to the Moon and beyond, resource use efficiency and self-sustainability will be critical to ensuring success in the long term. Furthermore, solutions developed for the stringent requirements of space will be equally valuable in meeting sustainability goals here on Earth. Advances in synthetic biology allow us to harness the complex metabolism of life to produce the materials we need in situ. Translating those lessons learned from microbial systems to more carbon-efficient photosynthetic organisms is an area of growing interest. Plants can be engineered to sustainably meet a range of needs, from fuels to materials and medicines.
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Affiliation(s)
- Matthew Fox Morgan
- School of Agriculture, Food and Wine & Waite Research Institute, University of Adelaide, Glen Osmond, SA 5064, Australia; ARC Centre of Excellent in Plants for Space, Australia
| | - Jonathan Diab
- School of Agriculture, Food and Wine & Waite Research Institute, University of Adelaide, Glen Osmond, SA 5064, Australia; ARC Centre of Excellent in Plants for Space, Australia
| | - Matthew Gilliham
- School of Agriculture, Food and Wine & Waite Research Institute, University of Adelaide, Glen Osmond, SA 5064, Australia; ARC Centre of Excellent in Plants for Space, Australia.
| | - Jenny C Mortimer
- School of Agriculture, Food and Wine & Waite Research Institute, University of Adelaide, Glen Osmond, SA 5064, Australia; ARC Centre of Excellent in Plants for Space, Australia; Joint BioEnergy Institute, CA, USA.
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Eckardt NA, Ainsworth EA, Bahuguna RN, Broadley MR, Busch W, Carpita NC, Castrillo G, Chory J, DeHaan LR, Duarte CM, Henry A, Jagadish SVK, Langdale JA, Leakey ADB, Liao JC, Lu KJ, McCann MC, McKay JK, Odeny DA, Jorge de Oliveira E, Platten JD, Rabbi I, Rim EY, Ronald PC, Salt DE, Shigenaga AM, Wang E, Wolfe M, Zhang X. Climate change challenges, plant science solutions. THE PLANT CELL 2023; 35:24-66. [PMID: 36222573 PMCID: PMC9806663 DOI: 10.1093/plcell/koac303] [Citation(s) in RCA: 42] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 09/29/2022] [Indexed: 06/16/2023]
Abstract
Climate change is a defining challenge of the 21st century, and this decade is a critical time for action to mitigate the worst effects on human populations and ecosystems. Plant science can play an important role in developing crops with enhanced resilience to harsh conditions (e.g. heat, drought, salt stress, flooding, disease outbreaks) and engineering efficient carbon-capturing and carbon-sequestering plants. Here, we present examples of research being conducted in these areas and discuss challenges and open questions as a call to action for the plant science community.
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Affiliation(s)
- Nancy A Eckardt
- Senior Features Editor, The Plant Cell, American Society of Plant Biologists, USA
| | - Elizabeth A Ainsworth
- USDA ARS Global Change and Photosynthesis Research Unit, Urbana, Illinois 61801, USA
| | - Rajeev N Bahuguna
- Centre for Advanced Studies on Climate Change, Dr Rajendra Prasad Central Agricultural University, Samastipur 848125, Bihar, India
| | - Martin R Broadley
- School of Biosciences, University of Nottingham, Nottingham, NG7 2RD, UK
- Rothamsted Research, West Common, Harpenden, Hertfordshire, AL5 2JQ, UK
| | - Wolfgang Busch
- Plant Molecular and Cellular Biology Laboratory, Salk Institute for Biological Studies, La Jolla, California 92037, USA
| | - Nicholas C Carpita
- Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado 80401, USA
| | - Gabriel Castrillo
- School of Biosciences, University of Nottingham, Nottingham, NG7 2RD, UK
- Future Food Beacon of Excellence, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Joanne Chory
- Plant Molecular and Cellular Biology Laboratory, Salk Institute for Biological Studies, La Jolla, California 92037, USA
- Howard Hughes Medical Institute, Salk Institute for Biological Studies, La Jolla, California 92037, USA
| | | | - Carlos M Duarte
- Red Sea Research Center (RSRC) and Computational Bioscience Research Center, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Amelia Henry
- International Rice Research Institute, Rice Breeding Innovations Platform, Los Baños, Laguna 4031, Philippines
| | - S V Krishna Jagadish
- Department of Plant and Soil Science, Texas Tech University, Lubbock, Texas 79410, USA
| | - Jane A Langdale
- Department of Biology, University of Oxford, Oxford, OX1 3RB, UK
| | - Andrew D B Leakey
- Department of Plant Biology, Department of Crop Sciences, and Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Illinois 61801, USA
| | - James C Liao
- Institute of Biological Chemistry, Academia Sinica, Taipei 11528, Taiwan
| | - Kuan-Jen Lu
- Institute of Biological Chemistry, Academia Sinica, Taipei 11528, Taiwan
| | - Maureen C McCann
- Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado 80401, USA
| | - John K McKay
- Department of Agricultural Biology, Colorado State University, Fort Collins, Colorado 80523, USA
| | - Damaris A Odeny
- The International Crops Research Institute for the Semi-Arid Tropics–Eastern and Southern Africa, Gigiri 39063-00623, Nairobi, Kenya
| | | | - J Damien Platten
- International Rice Research Institute, Rice Breeding Innovations Platform, Los Baños, Laguna 4031, Philippines
| | - Ismail Rabbi
- International Institute of Tropical Agriculture (IITA), PMB 5320 Ibadan, Oyo, Nigeria
| | - Ellen Youngsoo Rim
- Department of Plant Pathology and the Genome Center, University of California, Davis, California 95616, USA
| | - Pamela C Ronald
- Department of Plant Pathology and the Genome Center, University of California, Davis, California 95616, USA
- Innovative Genomics Institute, Berkeley, California 94704, USA
| | - David E Salt
- School of Biosciences, University of Nottingham, Nottingham, NG7 2RD, UK
- Future Food Beacon of Excellence, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Alexandra M Shigenaga
- Department of Plant Pathology and the Genome Center, University of California, Davis, California 95616, USA
| | - Ertao Wang
- National Key Laboratory of Plant Molecular Genetics, Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Marnin Wolfe
- Auburn University, Dept. of Crop Soil and Environmental Sciences, College of Agriculture, Auburn, Alabama 36849, USA
| | - Xiaowei Zhang
- National Key Laboratory of Plant Molecular Genetics, Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
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Al-Khairy D, Fu W, Alzahmi AS, Twizere JC, Amin SA, Salehi-Ashtiani K, Mystikou A. Closing the Gap between Bio-Based and Petroleum-Based Plastic through Bioengineering. Microorganisms 2022; 10:microorganisms10122320. [PMID: 36557574 PMCID: PMC9787566 DOI: 10.3390/microorganisms10122320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 11/17/2022] [Accepted: 11/21/2022] [Indexed: 11/25/2022] Open
Abstract
Bioplastics, which are plastic materials produced from renewable bio-based feedstocks, have been investigated for their potential as an attractive alternative to petroleum-based plastics. Despite the harmful effects of plastic accumulation in the environment, bioplastic production is still underdeveloped. Recent advances in strain development, genome sequencing, and editing technologies have accelerated research efforts toward bioplastic production and helped to advance its goal of replacing conventional plastics. In this review, we highlight bioengineering approaches, new advancements, and related challenges in the bioproduction and biodegradation of plastics. We cover different types of polymers, including polylactic acid (PLA) and polyhydroxyalkanoates (PHAs and PHBs) produced by bacterial, microalgal, and plant species naturally as well as through genetic engineering. Moreover, we provide detailed information on pathways that produce PHAs and PHBs in bacteria. Lastly, we present the prospect of using large-scale genome engineering to enhance strains and develop microalgae as a sustainable production platform.
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Affiliation(s)
- Dina Al-Khairy
- Division of Science and Math, New York University Abu Dhabi, Abu Dhabi 129188, United Arab Emirates
| | - Weiqi Fu
- Division of Science and Math, New York University Abu Dhabi, Abu Dhabi 129188, United Arab Emirates
- Department of Marine Science, Ocean College, Zhejiang University & Donghai Laboratory, Zhoushan 316021, China
| | - Amnah Salem Alzahmi
- Division of Science and Math, New York University Abu Dhabi, Abu Dhabi 129188, United Arab Emirates
- Center for Genomics and Systems Biology (CGSB), Institute Abu Dhabi, New York University Abu Dhabi, Abu Dhabi 129188, United Arab Emirates
| | - Jean-Claude Twizere
- Division of Science and Math, New York University Abu Dhabi, Abu Dhabi 129188, United Arab Emirates
- Laboratory of Viral Interactomes Networks, Unit of Molecular Biology of Diseases, Interdisciplinary Cluster for Applied Genoproteomics (GIGA Institute), University of Liège, 4000 Liège, Belgium
| | - Shady A. Amin
- Division of Science and Math, New York University Abu Dhabi, Abu Dhabi 129188, United Arab Emirates
- Center for Genomics and Systems Biology (CGSB), Institute Abu Dhabi, New York University Abu Dhabi, Abu Dhabi 129188, United Arab Emirates
| | - Kourosh Salehi-Ashtiani
- Division of Science and Math, New York University Abu Dhabi, Abu Dhabi 129188, United Arab Emirates
- Center for Genomics and Systems Biology (CGSB), Institute Abu Dhabi, New York University Abu Dhabi, Abu Dhabi 129188, United Arab Emirates
- Correspondence: (K.S.-A.); (A.M.)
| | - Alexandra Mystikou
- Division of Science and Math, New York University Abu Dhabi, Abu Dhabi 129188, United Arab Emirates
- Center for Genomics and Systems Biology (CGSB), Institute Abu Dhabi, New York University Abu Dhabi, Abu Dhabi 129188, United Arab Emirates
- Correspondence: (K.S.-A.); (A.M.)
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Yang X, Liu D, Lu H, Weston DJ, Chen JG, Muchero W, Martin S, Liu Y, Hassan MM, Yuan G, Kalluri UC, Tschaplinski TJ, Mitchell JC, Wullschleger SD, Tuskan GA. Biological Parts for Plant Biodesign to Enhance Land-Based Carbon Dioxide Removal. BIODESIGN RESEARCH 2021; 2021:9798714. [PMID: 37849951 PMCID: PMC10521660 DOI: 10.34133/2021/9798714] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 11/07/2021] [Indexed: 10/19/2023] Open
Abstract
A grand challenge facing society is climate change caused mainly by rising CO2 concentration in Earth's atmosphere. Terrestrial plants are linchpins in global carbon cycling, with a unique capability of capturing CO2 via photosynthesis and translocating captured carbon to stems, roots, and soils for long-term storage. However, many researchers postulate that existing land plants cannot meet the ambitious requirement for CO2 removal to mitigate climate change in the future due to low photosynthetic efficiency, limited carbon allocation for long-term storage, and low suitability for the bioeconomy. To address these limitations, there is an urgent need for genetic improvement of existing plants or construction of novel plant systems through biosystems design (or biodesign). Here, we summarize validated biological parts (e.g., protein-encoding genes and noncoding RNAs) for biological engineering of carbon dioxide removal (CDR) traits in terrestrial plants to accelerate land-based decarbonization in bioenergy plantations and agricultural settings and promote a vibrant bioeconomy. Specifically, we first summarize the framework of plant-based CDR (e.g., CO2 capture, translocation, storage, and conversion to value-added products). Then, we highlight some representative biological parts, with experimental evidence, in this framework. Finally, we discuss challenges and strategies for the identification and curation of biological parts for CDR engineering in plants.
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Affiliation(s)
- Xiaohan Yang
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Degao Liu
- Department of Genetics, Cell Biology and Development, Center for Precision Plant Genomics, and Center for Genome Engineering, University of Minnesota, Saint Paul, MN 55108, USA
| | - Haiwei Lu
- Department of Academic Education, Central Community College-Hastings, Hastings, NE 68902USA
| | - David J. Weston
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Jin-Gui Chen
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Wellington Muchero
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Stanton Martin
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Yang Liu
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Md Mahmudul Hassan
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Guoliang Yuan
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Udaya C. Kalluri
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Timothy J. Tschaplinski
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Julie C. Mitchell
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Stan D. Wullschleger
- Environmental Sciences Division and Climate Change Science Institute, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Gerald A. Tuskan
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
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In-planta production of the biodegradable polyester precursor 2-pyrone-4,6-dicarboxylic acid (PDC): Stacking reduced biomass recalcitrance with value-added co-product. Metab Eng 2021; 66:148-156. [PMID: 33895365 DOI: 10.1016/j.ymben.2021.04.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 04/18/2021] [Indexed: 02/07/2023]
Abstract
2-Pyrone-4,6-dicarboxylic acid (PDC), a chemically stable intermediate that naturally occurs during microbial degradation of lignin by bacteria, represents a promising building block for diverse biomaterials and polyesters such as biodegradable plastics. The lack of a chemical synthesis method has hindered large-scale utilization of PDC and metabolic engineering approaches for its biosynthesis have recently emerged. In this study, we demonstrate a strategy for the production of PDC via manipulation of the shikimate pathway using plants as green factories. In tobacco leaves, we first showed that transient expression of bacterial feedback-resistant 3-deoxy-D-arabinoheptulosonate 7-phosphate synthase (AroG) and 3-dehydroshikimate dehydratase (QsuB) produced high titers of protocatechuate (PCA), which was in turn efficiently converted into PDC upon co-expression of PCA 4,5-dioxygenase (PmdAB) and 4-carboxy-2-hydroxymuconate-6-semialdehyde dehydrogenase (PmdC) derived from Comamonas testosteroni. We validated that stable expression of AroG in Arabidopsis in a genetic background containing the QsuB gene enhanced PCA content in plant biomass, presumably via an increase of the carbon flux through the shikimate pathway. Further, introducing AroG and the PDC biosynthetic genes (PmdA, PmdB, and PmdC) into the Arabidopsis QsuB background, or introducing the five genes (AroG, QsuB, PmdA, PmdB, and PmdC) stacked on a single construct into wild-type plants, resulted in PDC titers of ~1% and ~3% dry weight in plant biomass, respectively. Consistent with previous studies of plants expressing QsuB, all PDC producing lines showed strong reduction in lignin content in stems. This low lignin trait was accompanied with improvements of biomass saccharification efficiency due to reduced cell wall recalcitrance to enzymatic degradation. Importantly, most transgenic lines showed no reduction in biomass yields. Therefore, we conclude that engineering plants with the proposed de-novo PDC pathway provides an avenue to enrich biomass with a value-added co-product while simultaneously improving biomass quality for the supply of fermentable sugars. Implementing this strategy into bioenergy crops has the potential to support existing microbial fermentation approaches that exploit lignocellulosic biomass feedstocks for PDC production.
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Mierziak J, Burgberger M, Wojtasik W. 3-Hydroxybutyrate as a Metabolite and a Signal Molecule Regulating Processes of Living Organisms. Biomolecules 2021; 11:biom11030402. [PMID: 33803253 PMCID: PMC8000602 DOI: 10.3390/biom11030402] [Citation(s) in RCA: 77] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 03/02/2021] [Accepted: 03/03/2021] [Indexed: 02/06/2023] Open
Abstract
3-hydroxybutyrate (3-HB) as a very important metabolite occurs in animals, bacteria and plants. It is well known that in animals, 3-HB is formed as a product of the normal metabolism of fatty acid oxidation and can therefore be used as an energy source in the absence of sufficient blood glucose. In microorganisms, 3-HB mainly serves as a substrate for the synthesis of polyhydroxybutyrate, which is a reserve material. Recent studies show that in plants, 3-HB acts as a regulatory molecule that most likely influences the expression of genes involved in DNA methylation, thereby altering DNA methylation levels. Additionally, in animals, 3-HB is not only an intermediate metabolite, but also an important regulatory molecule that can influence gene expression, lipid metabolism, neuronal function, and overall metabolic rate. Some of these effects are the direct effects of 3-HB itself, while others are indirect effects, regulated by the metabolites into which 3-HB is converted. One of the most important regulatory functions of 3-HB is the inhibition of the activity of histone deacetylases and thus the epigenetic regulation of many genes. Due to the number of functions of this compound, it also shows promising therapeutic properties.
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Lin CY, Donohoe BS, Bomble YJ, Yang H, Yunes M, Sarai NS, Shollenberger T, Decker SR, Chen X, McCann MC, Tucker MP, Wei H, Himmel ME. Iron incorporation both intra- and extra-cellularly improves the yield and saccharification of switchgrass (Panicum virgatum L.) biomass. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:55. [PMID: 33663584 PMCID: PMC7931346 DOI: 10.1186/s13068-021-01891-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Accepted: 01/27/2021] [Indexed: 06/12/2023]
Abstract
BACKGROUND Pretreatments are commonly used to facilitate the deconstruction of lignocellulosic biomass to its component sugars and aromatics. Previously, we showed that iron ions can be used as co-catalysts to reduce the severity of dilute acid pretreatment of biomass. Transgenic iron-accumulating Arabidopsis and rice plants exhibited higher iron content in grains, increased biomass yield, and importantly, enhanced sugar release from the biomass. RESULTS In this study, we used intracellular ferritin (FerIN) alone and in combination with an improved version of cell wall-bound carbohydrate-binding module fused iron-binding peptide (IBPex) specifically targeting switchgrass, a bioenergy crop species. The FerIN switchgrass improved by 15% in height and 65% in yield, whereas the FerIN/IBPex transgenics showed enhancement up to 30% in height and 115% in yield. The FerIN and FerIN/IBPex switchgrass had 27% and 51% higher in planta iron accumulation than the empty vector (EV) control, respectively, under normal growth conditions. Improved pretreatability was observed in FerIN switchgrass (~ 14% more glucose release than the EV), and the FerIN/IBPex plants showed further enhancement in glucose release up to 24%. CONCLUSIONS We conclude that this iron-accumulating strategy can be transferred from model plants and applied to bioenergy crops, such as switchgrass. The intra- and extra-cellular iron incorporation approach improves biomass pretreatability and digestibility, providing upgraded feedstocks for the production of biofuels and bioproducts.
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Affiliation(s)
- Chien-Yuan Lin
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
- Present Address: Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA 94608 USA
- Present Address: Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
| | - Bryon S. Donohoe
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Yannick J. Bomble
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Haibing Yang
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907 USA
- Present Address: South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650 China
| | - Manal Yunes
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
- Present Address: Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO 80309 USA
| | - Nicholas S. Sarai
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
- Present Address: Division of Chemistry and Chemical Engineering 210-41, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 USA
| | - Todd Shollenberger
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Stephen R. Decker
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Xiaowen Chen
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Maureen C. McCann
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907 USA
| | - Melvin P. Tucker
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Hui Wei
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Michael E. Himmel
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
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Carpita NC, McCann MC. Redesigning plant cell walls for the biomass-based bioeconomy. J Biol Chem 2020; 295:15144-15157. [PMID: 32868456 PMCID: PMC7606688 DOI: 10.1074/jbc.rev120.014561] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 08/30/2020] [Indexed: 01/28/2023] Open
Abstract
Lignocellulosic biomass-the lignin, cellulose, and hemicellulose that comprise major components of the plant cell well-is a sustainable resource that could be utilized in the United States to displace oil consumption from heavy vehicles, planes, and marine-going vessels and commodity chemicals. Biomass-derived sugars can also be supplied for microbial fermentative processing to fuels and chemicals or chemically deoxygenated to hydrocarbons. However, the economic value of biomass might be amplified by diversifying the range of target products that are synthesized in living plants. Genetic engineering of lignocellulosic biomass has previously focused on changing lignin content or composition to overcome recalcitrance, the intrinsic resistance of cell walls to deconstruction. New capabilities to remove lignin catalytically without denaturing the carbohydrate moiety have enabled the concept of the "lignin-first" biorefinery that includes high-value aromatic products. The structural complexity of plant cell-wall components also provides substrates for polymeric and functionalized target products, such as thermosets, thermoplastics, composites, cellulose nanocrystals, and nanofibers. With recent advances in the design of synthetic pathways, lignocellulosic biomass can be regarded as a substrate at various length scales for liquid hydrocarbon fuels, chemicals, and materials. In this review, we describe the architectures of plant cell walls and recent progress in overcoming recalcitrance and illustrate the potential for natural or engineered biomass to be used in the emerging bioeconomy.
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Affiliation(s)
- Nicholas C Carpita
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana, USA; Department of Biological Sciences, Purdue University, West Lafayette, Indiana, USA
| | - Maureen C McCann
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, USA; Center for Plant Biology, Purdue University, West Lafayette, Indiana, USA.
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Lu H, Yuan G, Strauss SH, Tschaplinski TJ, Tuskan GA, Chen JG, Yang X. Reconfiguring Plant Metabolism for Biodegradable Plastic Production. BIODESIGN RESEARCH 2020; 2020:9078303. [PMID: 37849903 PMCID: PMC10530661 DOI: 10.34133/2020/9078303] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 07/11/2020] [Indexed: 10/19/2023] Open
Abstract
For decades, plants have been the subject of genetic engineering to synthesize novel, value-added compounds. Polyhydroxyalkanoates (PHAs), a large class of biodegradable biopolymers naturally synthesized in eubacteria, are among the novel products that have been introduced to make use of plant acetyl-CoA metabolic pathways. It was hoped that renewable PHA production would help address environmental issues associated with the accumulation of nondegradable plastic wastes. However, after three decades of effort synthesizing PHAs, and in particular the simplest form polyhydroxybutyrate (PHB), and seeking to improve their production in plants, it has proven very difficult to reach a commercially profitable rate in a normally growing plant. This seems to be due to the growth defects associated with PHA production and accumulation in plant cells. Here, we review major breakthroughs that have been made in plant-based PHA synthesis using traditional genetic engineering approaches and discuss challenges that have been encountered. Then, from the point of view of plant synthetic biology, we provide perspectives on reprograming plant acetyl-CoA pathways for PHA production, with the goal of maximizing PHA yield while minimizing growth inhibition. Specifically, we suggest genetic elements that can be considered in genetic circuit design, approaches for nuclear genome and plastome modification, and the use of multiomics and mathematical modeling in understanding and restructuring plant metabolic pathways.
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Affiliation(s)
- Haiwei Lu
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Guoliang Yuan
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Steven H. Strauss
- Department of Forest Ecosystems and Society, Oregon State University, Corvallis, OR 97331, USA
| | - Timothy J. Tschaplinski
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Gerald A. Tuskan
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Jin-Gui Chen
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Xiaohan Yang
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- The Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
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Shafique S, Jabeen N, Ahmad KS, Irum S, Anwaar S, Ahmad N, Alam S, Ilyas M, Khan TF, Hussain SZ. Green fabricated zinc oxide nanoformulated media enhanced callus induction and regeneration dynamics of Panicum virgatum L. PLoS One 2020; 15:e0230464. [PMID: 32645102 PMCID: PMC7347099 DOI: 10.1371/journal.pone.0230464] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Accepted: 05/18/2020] [Indexed: 01/19/2023] Open
Abstract
The current study focuses on the usage of bio synthesized zinc oxide nanoparticles to increase the tissue culture efficiency of important forage grass Panicum virgatum. Zinc being a micronutrient enhanced the callogenesis and regeneration efficiency of Panicum virgatum at different concentrations. Here, we synthesized zinc oxide nanoparticles through Cymbopogon citratus leaves extract to evaluate the effect of zinc oxide nanoparticles on plant regeneration ability in switchgrass. X-ray diffraction (XRD) and attenuated total reflectance-Fourier transform infrared (ATR-FTIR) validate phase purity of green synthesize Zinc oxide nanoparticles whereas, electron microscopy (SEM) has illustrated the average size of particle 50±4 nm with hexagonal rod like shape. Energy dispersive spectroscopy X-ray (EDS) depicted major peaks of Zn (92.68%) while minor peaks refer to Oxygen (7.32%). ZnO-NPs demonstrated the incredibly promising results against callogenesis. Biosynthesized ZnO-NPs at optimum concentration showed very promising effect on plant regeneration ability. Both the explants, seeds and nodes showed dose dependent response and upon high doses exceeding 40 mg/L the results were recorded negative, whereas at 30 mg/L both explants demonstrated 70% and 76% regeneration frequency. The results conclude that ZnO-NPs enhance the plant growth and development and tailored the nutritive properties at nano-scale. Furthermore, eco-friendly approach of ZnO-NPs synthesis is strongly believed to improve in vitro regeneration frequencies in several other monocot plants.
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Affiliation(s)
- Saima Shafique
- Department of Biological Sciences, Applied Biotechnology and Genetic Engineering Lab, International Islamic University, Islamabad, Pakistan
- Department of Plant Breeding and Molecular Genetics, University of Poonch Rawalakot, Azad Jammu and Kashmir, Pakistan
| | - Nyla Jabeen
- Department of Biological Sciences, Applied Biotechnology and Genetic Engineering Lab, International Islamic University, Islamabad, Pakistan
- * E-mail: (NJ); (KSA)
| | - Khawaja Shafique Ahmad
- Department of Botany, University of Poonch, Rawalakot (UPR), Azad Jammu and Kashmir, Pakistan
- * E-mail: (NJ); (KSA)
| | - Samra Irum
- Department of Biological Sciences, Applied Biotechnology and Genetic Engineering Lab, International Islamic University, Islamabad, Pakistan
| | - Sadaf Anwaar
- Department of Biological Sciences, Applied Biotechnology and Genetic Engineering Lab, International Islamic University, Islamabad, Pakistan
| | - Naeem Ahmad
- Department of Physics, Spintronics Laboratory, International Islamic University, Islamabad, Pakistan
| | - Sadia Alam
- Department of Microbiology, University of Haripur, Haripur, Pakistan
| | - Muhammad Ilyas
- Department of Plant Breeding and Molecular Genetics, University of Poonch Rawalakot, Azad Jammu and Kashmir, Pakistan
| | - Talha Farooq Khan
- Department of Materials Science & Engineering, Institute of Space Technology Islamabad, Islamabad, Pakistan
| | - Syed Zaheer Hussain
- Department of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan
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Accumulation of high-value bioproducts in planta can improve the economics of advanced biofuels. Proc Natl Acad Sci U S A 2020; 117:8639-8648. [PMID: 32220956 PMCID: PMC7165473 DOI: 10.1073/pnas.2000053117] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Cellulosic biofuels have not yet reached cost parity with conventional petroleum fuels. One strategy to address this challenge is to generate valuable coproducts alongside biofuels. Engineering bioenergy crops to generate value-added bioproducts in planta can reduce input requirements relative to microbial chassis and skip costly deconstruction and conversion steps. Although rapid progress has been made in plant metabolic engineering, there has been no systematic analysis devoted to quantifying the impact of such engineered bioenergy crops on biorefinery economics. Here, we provide new insights into how bioproduct accumulation in planta affects biofuel selling prices. We present the range of bioproduct selling prices and accumulation rates needed to compensate for additional extraction steps and reach a target $2.50/gal minimum biofuel selling price. Coproduction of high-value bioproducts at biorefineries is a key factor in making biofuels more cost-competitive. One strategy for generating coproducts is to directly engineer bioenergy crops to accumulate bioproducts in planta that can be fractionated and recovered at biorefineries. Here, we develop quantitative insights into the relationship between bioproduct market value and target accumulation rates by investigating a set of industrially relevant compounds already extracted from plant sources with a wide range of market prices and applications, including <$10/kg (limonene, latex, and polyhydroxybutyrate [PHB]), $10 to $100/kg (cannabidiol), and >$100/kg (artemisinin). These compounds are used to identify a range of mass fraction thresholds required to achieve net economic benefits for biorefineries and the additional amounts needed to reach a target $2.50/gal biofuel selling price, using cellulosic ethanol production as a test case. Bioproduct market prices and recovery costs determine the accumulation threshold; we find that moderate- to high-value compounds (i.e., cannabidiol and artemisinin) offer net economic benefits at accumulation rates of just 0.01% dry weight (dwt) to 0.02 dwt%. Lower-value compounds, including limonene, latex, and PHB, require at least an order-of-magnitude greater accumulation to overcome additional extraction and recovery costs (0.3 to 1.2 dwt%). We also find that a diversified approach is critical. For example, global artemisinin demand could be met with fewer than 10 biorefineries, while global demand for latex is equivalent to nearly 180 facilities. Our results provide a roadmap for future plant metabolic engineering efforts aimed at increasing the value derived from bioenergy crops.
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Malik JA, Bhadauria M. Polyhydroxyalkanoates. HANDBOOK OF RESEARCH ON ENVIRONMENTAL AND HUMAN HEALTH IMPACTS OF PLASTIC POLLUTION 2020. [DOI: 10.4018/978-1-5225-9452-9.ch018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Human dependence on number of chemicals or chemical derivatives has increased alarmingly. Among the commodity chemicals, plastics are becoming independent for our modern lifestyle, as the usage of plastics is increasing worryingly. However, these synthetic plastics are extremely persistent in nature and accumulate in the environment, thereby leading to serious ecological problems. So, to build our economy sustainably, a need of replacement is necessary. Biomaterials in terms of bioplastics are an anticipated option, being synthesized and catabolized by different organisms with myriad biotechnological applications. Polyhydroxyalkanoates (PHAs) are among such biodegradable bioplastics, which are considered as an effective alternative for conventional plastics due to their similar mechanical properties of plastics. A range of microbes under different nutrient and environmental conditions produce PHAs significantly with the help of enzymes. PHA synthases encoded by phaC genes are the key enzymes that polymerize PHA monomers. Four major classes of PHA synthases can be distinguished based on their primary structures, as well as the number of subunits and substrate specificity. PHAs can also be produced from renewable feedstock under, unlike the petrochemically derived plastics that are produced by fractional distillation of depleting fossil fuels. Polyhydroxybutyrate (PHB) is the simplest yet best known polyester of PHAs, as the PHB derived bioplastics are heat tolerant, thus used to make heat tolerant and clear packaging film. They have several medical applications such as drug delivery, suture, scaffold and heart valves, tissue engineering, targeted drug delivery, and agricultural fields. Genetic modification (GM) may be necessary to achieve adequate yields. The selections of suitable bacterial strains, inexpensive carbon sources, efficient fermentation, and recovery processes are also some aspects important aspects taken into consideration for the commercialization of PHA. PHA producers have been reported to reside at various ecological niches with few among them also produce some byproducts like extracellular polymeric substances, rhamnolipids and biohydrogen gas. So, the metabolic engineering thereafter promises to bring a feasible solution for the production of “green plastic” in order to preserve petroleum reserves and diminish the escalating human and animal health concerns environmental implications.
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Evangeline S, Sridharan T. Biosynthesis and statistical optimization of polyhydroxyalkanoate (PHA) produced by Bacillus cereus VIT-SSR1 and fabrication of biopolymer films for sustained drug release. Int J Biol Macromol 2019; 135:945-958. [DOI: 10.1016/j.ijbiomac.2019.05.163] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 05/06/2019] [Accepted: 05/21/2019] [Indexed: 01/08/2023]
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Chen Q, Song GQ. Protocol for Agrobacterium-Mediated Transformation and Transgenic Plant Production of Switchgrass. Methods Mol Biol 2018; 1864:105-115. [PMID: 30415332 DOI: 10.1007/978-1-4939-8778-8_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
Abstract
Switchgrass (Panicum virgatum L.) is one of the most important bioenergy crops for lignocellulose ethanol production. Molecular breeding provides a powerful tool to supplement conventional switchgrass breeding by introducing or editing genes of interest. In this chapter, we describe Agrobacterium tumefaciens-mediated transformation protocols for lowland tetraploid switchgrass cultivar Alamo.
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Affiliation(s)
- QiuXia Chen
- Department of Horticulture, Plant Biotechnology Resource and Outreach Center, Michigan State University, East Lansing, MI, USA.
| | - Guo-Qing Song
- Department of Horticulture, Plant Biotechnology Resource and Outreach Center, Michigan State University, East Lansing, MI, USA
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15
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Gomes de Oliveira Dal'Molin C, Quek LE, Saa PA, Palfreyman R, Nielsen LK. From reconstruction to C 4 metabolic engineering: A case study for overproduction of polyhydroxybutyrate in bioenergy grasses. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2018; 273:50-60. [PMID: 29907309 DOI: 10.1016/j.plantsci.2018.03.027] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 02/27/2018] [Accepted: 03/01/2018] [Indexed: 06/08/2023]
Abstract
The compartmentalization of C4 plants increases photosynthetic efficiency, while constraining how material and energy must flow in leaf tissues. To capture this metabolic phenomenon, a generic plant metabolic reconstruction was replicated into four connected spatiotemporal compartments, namely bundle sheath (B) and mesophyll (M) across the day and night cycle. The C4 leaf model was used to explore how amenable polyhydroxybutyrate (PHB) production is with these four compartments working cooperatively. A strategic pattern of metabolite conversion and exchange emerged from a systems-level network that has very few constraints imposed; mainly the sequential two-step carbon capture in mesophyll, then bundle sheath and photosynthesis during the day only. The building of starch reserves during the day and their mobilization during the night connects day and night metabolism. Flux simulations revealed that PHB production did not require rerouting of metabolic pathways beyond what is already utilised for growth. PHB yield was sensitive to photoassimilation capacity, availability of carbon reserves, ATP maintenance, relative photosynthetic activity of B and M, and type of metabolites exchanged in the plasmodesmata, but not sensitive towards compartmentalization. Hence, the compartmentalization issues currently encountered are likely to be kinetic or thermodynamic limitations rather than stoichiometric.
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Affiliation(s)
- Cristiana Gomes de Oliveira Dal'Molin
- Australian Institute for Bioengineering and Nanotechnology, School of Chemical Engineering, University of Queensland, Brisbane, Queensland 4072, Australia.
| | - Lake-Ee Quek
- School of Mathematics and Statistics, The University of Sydney, New South Wales 2006, Australia
| | - Pedro A Saa
- Department of Chemical and Bioprocess Engineering, Pontificia Universidad Católica de Chile, Santiago, Casilla 306, Correo 22, Chile; Mathomics, Center for Mathematical Modeling, Universidad de Chile, Santiago, Chile
| | - Robin Palfreyman
- Australian Institute for Bioengineering and Nanotechnology, School of Chemical Engineering, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Lars Keld Nielsen
- Australian Institute for Bioengineering and Nanotechnology, School of Chemical Engineering, University of Queensland, Brisbane, Queensland 4072, Australia; Novo Nordisk Foundation Center for Biosustainability, The Technical University of Denmark, Lyngby, DK-2800, Denmark
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16
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Ambavaram MMR, Ali A, Ryan KP, Peoples O, Snell KD, Somleva MN. Novel transcription factors PvBMY1 and PvBMY3 increase biomass yield in greenhouse-grown switchgrass (Panicum virgatum L.). PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2018; 273:100-109. [PMID: 29907302 DOI: 10.1016/j.plantsci.2018.04.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 04/03/2018] [Accepted: 04/05/2018] [Indexed: 06/08/2023]
Abstract
Increasing crop yield requires the coordination of multiple metabolic pathways spanning photosynthetic carbon fixation, central carbon metabolism, and finally targeted carbon deposition to end product. In this study, we used a transcriptome-based gene regulatory association network to search for transcription factor genes that could play a role in increasing carbon flow through pathways associated with these processes to increase biomass yield in switchgrass. Two novel switchgrass transcription factors, PvBMY1 (BioMass Yield 1, belonging to the APETALA2/Ethylene Response Factor family of transcription factors) and PvBMY3 (BioMass Yield 3, a member of the Nuclear-Factor Y family of transcription factors), with predicted roles in the regulation of photosynthesis and related metabolism were identified. These genes were overexpressed in switchgrass to determine their impact on biomass yield. A significant increase in both aboveground and root biomass was observed in transgenic greenhouse grown plants compared to wild-type control plants with the best line producing 160% more aboveground biomass than controls. Transgenic lines with elevated electron transport rate of photosystems I and II as well as increased levels of starch and soluble sugars were identified.
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Affiliation(s)
| | - Aminat Ali
- Yield10 Bioscience, Inc., 19 Presidential Way, Woburn, MA 01801, United States
| | - Kieran P Ryan
- Yield10 Bioscience, Inc., 19 Presidential Way, Woburn, MA 01801, United States
| | - Oliver Peoples
- Yield10 Bioscience, Inc., 19 Presidential Way, Woburn, MA 01801, United States
| | - Kristi D Snell
- Yield10 Bioscience, Inc., 19 Presidential Way, Woburn, MA 01801, United States.
| | - Maria N Somleva
- Yield10 Bioscience, Inc., 19 Presidential Way, Woburn, MA 01801, United States
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17
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Wu CY, Lui WB, Peng J. Optimization of Extrusion Variables and Maleic Anhydride Content on Biopolymer Blends Based on Poly(hydroxybutyrate- co-hydroxyvalerate)/Poly(vinyl acetate) with Tapioca Starch. Polymers (Basel) 2018; 10:polym10080827. [PMID: 30960752 PMCID: PMC6403955 DOI: 10.3390/polym10080827] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 07/25/2018] [Indexed: 11/25/2022] Open
Abstract
Poly(3-hyroxybutyrate-co-3-hydroxyvalerate) (PHBV), poly(vinyl acetate) (PVAc), and tapioca starch are environment-friendly materials. The present study used these materials to produce biodegradable plastic pellets by melt extrusion. The tapioca starch content of composite formulations, the maleic anhydride content, and the screw speed of the extruder were chosen as variables for the extrusion process. A Box-Behnken response surface design was used to establish mathematical models to predict the relationship between the operating variables and the objective attributes (tensile strength, elongation at break, and water absorption) of the blends. Blend morphology was also assessed. The regression coefficients revealed that the extrusion parameters most significantly affecting extrudate responses were tapioca starch content and maleic anhydride content, both showing significant (p < 0.01) linear effects. The results of the analysis of variance found the models are in good agreement with experimental results as informed by high correlation coefficients (R2 > 0.9), with no significant lack of fit. From the numerical analysis, optimized operating variables (20.13% tapioca starch content, 10.14% maleic anhydride content, and a screw speed of 41.3 rpm) produced a product with optimum values of 16.4 MPa tensile strength, 13.2% elongation at break, and 30.94% water absorption.
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Affiliation(s)
- Chia-Yang Wu
- Department of Bio-Industrial Mechatronics Engineering, National Chung Hsing University, Taichung 402, Taiwan.
| | - Wai-Bun Lui
- Department of English, National Pei-Kang Agricultural and Industrial Vocational High School, Yunlin 651, Taiwan.
| | - Jinchyau Peng
- Department of Bio-Industrial Mechatronics Engineering, National Chung Hsing University, Taichung 402, Taiwan.
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18
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Liu W, Mazarei M, Ye R, Peng Y, Shao Y, Baxter HL, Sykes RW, Turner GB, Davis MF, Wang ZY, Dixon RA, Stewart CN. Switchgrass ( Panicum virgatum L.) promoters for green tissue-specific expression of the MYB4 transcription factor for reduced-recalcitrance transgenic switchgrass. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:122. [PMID: 29713381 PMCID: PMC5914048 DOI: 10.1186/s13068-018-1119-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Accepted: 04/16/2018] [Indexed: 05/09/2023]
Abstract
BACKGROUND Genetic engineering of switchgrass (Panicum virgatum L.) for reduced cell wall recalcitrance and improved biofuel production has been a long pursued goal. Up to now, constitutive promoters have been used to direct the expression of cell wall biosynthesis genes toward attaining that goal. While generally sufficient to gauge a transgene's effects in the heterologous host, constitutive overexpression often leads to undesirable plant phenotypic effects. Green tissue-specific promoters from switchgrass are potentially valuable to directly alter cell wall traits exclusively in harvestable aboveground biomass while not changing root phenotypes. RESULTS We identified and functionally characterized three switchgrass green tissue-specific promoters and assessed marker gene expression patterns and intensity in stably transformed rice (Oryza sativa L.), and then used them to direct the expression of the switchgrass MYB4 (PvMYB4) transcription factor gene in transgenic switchgrass to endow reduced recalcitrance in aboveground biomass. These promoters correspond to photosynthesis-related light-harvesting complex II chlorophyll-a/b binding gene (PvLhcb), phosphoenolpyruvate carboxylase (PvPEPC), and the photosystem II 10 kDa R subunit (PvPsbR). Real-time RT-PCR analysis detected their strong expression in the aboveground tissues including leaf blades, leaf sheaths, internodes, inflorescences, and nodes of switchgrass, which was tightly up-regulated by light. Stable transgenic rice expressing the GUS reporter under the control of each promoter (756-2005 bp in length) further confirmed their strong expression patterns in leaves and stems. With the exception of the serial promoter deletions of PvLhcb, all GUS marker patterns under the control of each 5'-end serial promoter deletion were not different from that conveyed by their respective promoters. All of the shortest promoter fragments (199-275 bp in length) conveyed strong green tissue-specific GUS expression in transgenic rice. PvMYB4 is a master repressor of lignin biosynthesis. The green tissue-specific expression of PvMYB4 via each promoter in transgenic switchgrass led to significant gains in saccharification efficiency, decreased lignin, and decreased S/G lignin ratios. In contrast to constitutive overexpression of PvMYB4, which negatively impacts switchgrass root growth, plant growth was not compromised in green tissue-expressed PvMYB4 switchgrass plants in the current study. CONCLUSIONS Each of the newly described green tissue-specific promoters from switchgrass has utility to change cell wall biosynthesis exclusively in aboveground harvestable biomass without altering root systems. The truncated green tissue promoters are very short and should be useful for targeted expression in a number of monocots to improve shoot traits while restricting gene expression from roots. Green tissue-specific expression of PvMYB4 is an effective strategy for improvement of transgenic feedstocks.
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Affiliation(s)
- Wusheng Liu
- Department of Plant Sciences, University of Tennessee, Knoxville, TN USA
- Department of Horticultural Science, North Carolina State University, Raleigh, NC USA
| | - Mitra Mazarei
- Department of Plant Sciences, University of Tennessee, Knoxville, TN USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN USA
| | - Rongjian Ye
- Department of Plant Sciences, University of Tennessee, Knoxville, TN USA
| | - Yanhui Peng
- Department of Plant Sciences, University of Tennessee, Knoxville, TN USA
| | - Yuanhua Shao
- Department of Plant Sciences, University of Tennessee, Knoxville, TN USA
| | - Holly L. Baxter
- Department of Plant Sciences, University of Tennessee, Knoxville, TN USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN USA
| | - Robert W. Sykes
- National Renewable Energy Laboratory, Golden, CO USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN USA
| | - Geoffrey B. Turner
- National Renewable Energy Laboratory, Golden, CO USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN USA
| | - Mark F. Davis
- National Renewable Energy Laboratory, Golden, CO USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN USA
| | - Zeng-Yu Wang
- Noble Research Institute, Ardmore, OK USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN USA
| | - Richard A. Dixon
- BioDiscovery Institute and Department of Biological Sciences, University of North Texas, Denton, TX USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN USA
| | - C. Neal Stewart
- Department of Plant Sciences, University of Tennessee, Knoxville, TN USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN USA
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Hui D, Yu CL, Deng Q, Dzantor EK, Zhou S, Dennis S, Sauve R, Johnson TL, Fay PA, Shen W, Luo Y. Effects of precipitation changes on switchgrass photosynthesis, growth, and biomass: A mesocosm experiment. PLoS One 2018; 13:e0192555. [PMID: 29420600 PMCID: PMC5805322 DOI: 10.1371/journal.pone.0192555] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 01/25/2018] [Indexed: 12/04/2022] Open
Abstract
Climate changes, including chronic changes in precipitation amounts, will influence plant physiology and growth. However, such precipitation effects on switchgrass, a major bioenergy crop, have not been well investigated. We conducted a two-year precipitation simulation experiment using large pots (95 L) in an environmentally controlled greenhouse in Nashville, TN. Five precipitation treatments (ambient precipitation, and -50%, -33%, +33%, and +50% of ambient) were applied in a randomized complete block design with lowland "Alamo" switchgrass plants one year after they were established from tillers. The growing season progression of leaf physiology, tiller number, height, and aboveground biomass were determined each growing season. Precipitation treatments significantly affected leaf physiology, growth, and aboveground biomass. The photosynthetic rates in the wet (+50% and +33%) treatments were significantly enhanced by 15.9% and 8.1%, respectively, than the ambient treatment. Both leaf biomass and plant height were largely increased, resulting in dramatically increases in aboveground biomass by 56.5% and 49.6% in the +50% and +33% treatments, respectively. Compared to the ambient treatment, the drought (-33% and -50%) treatments did not influence leaf physiology, but the -50% treatment significantly reduced leaf biomass by 37.8%, plant height by 16.3%, and aboveground biomass by 38.9%. This study demonstrated that while switchgrass in general is a drought tolerant grass, severe drought significantly reduces Alamo's growth and biomass, and that high precipitation stimulates its photosynthesis and growth.
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Affiliation(s)
- Dafeng Hui
- Department of Biological Sciences, Tennessee State University, Nashville, Tennessee, United States of America
| | - Chih-Li Yu
- Department of Biological Sciences, Tennessee State University, Nashville, Tennessee, United States of America
| | - Qi Deng
- Department of Biological Sciences, Tennessee State University, Nashville, Tennessee, United States of America
- Key Laboratory of Vegetation Restoration and Management, South China Botanical Garden, the Chinese Academy of Sciences, Guangzhou, China
| | - E. Kudjo Dzantor
- Department of Agricultural and Environmental Sciences, Tennessee State University, Nashville, Tennessee, United States of America
| | - Suping Zhou
- Department of Agricultural and Environmental Sciences, Tennessee State University, Nashville, Tennessee, United States of America
| | - Sam Dennis
- Department of Agricultural and Environmental Sciences, Tennessee State University, Nashville, Tennessee, United States of America
| | - Roger Sauve
- Department of Agricultural and Environmental Sciences, Tennessee State University, Nashville, Tennessee, United States of America
| | - Terrance L. Johnson
- Department of Biological Sciences, Tennessee State University, Nashville, Tennessee, United States of America
| | - Philip A. Fay
- Grassland Soil and Water Research Laboratory, United State Department of Agriculture, Temple, Texas, United States of America
| | - Weijun Shen
- Key Laboratory of Vegetation Restoration and Management, South China Botanical Garden, the Chinese Academy of Sciences, Guangzhou, China
| | - Yiqi Luo
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, United States of America
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Model of acetic acid-affected growth and poly(3-hydroxybutyrate) production by Cupriavidus necator DSM 545. J Biotechnol 2018; 268:12-20. [DOI: 10.1016/j.jbiotec.2018.01.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2017] [Revised: 01/04/2018] [Accepted: 01/09/2018] [Indexed: 01/14/2023]
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21
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Trends in the biomanufacture of polyhydroxyalkanoates with focus on downstream processing. Int J Biol Macromol 2018; 107:762-778. [DOI: 10.1016/j.ijbiomac.2017.09.054] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 08/30/2017] [Accepted: 09/15/2017] [Indexed: 11/18/2022]
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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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Lin N, Zhao S, Gan L, Chang PR, Xia T, Huang J. Preparation of fungus-derived chitin nanocrystals and their dispersion stability evaluation in aqueous media. Carbohydr Polym 2017; 173:610-618. [PMID: 28732905 DOI: 10.1016/j.carbpol.2017.06.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2017] [Revised: 05/06/2017] [Accepted: 06/05/2017] [Indexed: 11/29/2022]
Abstract
The chitin nanocrystal is a promising nano-reinforcing agent, but the parasitic pathogens carried on crabs and shrimp shells as main sources limit its application in some fields. In this study, the ChNs which avoided possible safety risks were extracted from mushrooms via protein/mineral-purification and subsequent HCl-hydrolysis. Such fungus-derived ChNs presented an α-chitin crystalline structure with a length of 143±24nm and a diameter of 10±2nm. Since the dispersion stability of ChNs suspension determines their further applications, this present study emphasized the dispersity of ChNs in aqueous media evaluated by the viscosity under steady-shear flow and UV-vis absorption, whose results indicated that ChNs in dispersion would aggregate when the concentration of homogeneous dispersion reached 0.5-0.6wt%. To explore the effect of electrostatic repulsion on interactions between nanoparticles, the maximum energy barriers for parallel and crossed orientations of ChNs in suspension were analyzed using a traditional DLVO theory with additions of NaCl solutions.
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Affiliation(s)
- Ning Lin
- School of Chemistry, Chemical Engineering and Life Sciences, Wuhan University of Technology, Wuhan 430070, China
| | - Shasha Zhao
- School of Chemistry, Chemical Engineering and Life Sciences, Wuhan University of Technology, Wuhan 430070, China
| | - Lin Gan
- School of Chemistry and Chemical Engineering, Joint International Research Laboratory of Biomass-Based Macromolecular Chemistry and Materials, Southwest University, Chongqing 400715, China
| | - Peter R Chang
- Bioproducts and Bioprocesses National Science Program, Agriculture and Agri-Food Canada, 107 Science Place, Saskatoon, Saskatchewan S7N 0X2, Canada
| | - Tao Xia
- School of Chemistry, Chemical Engineering and Life Sciences, Wuhan University of Technology, Wuhan 430070, China
| | - Jin Huang
- School of Chemistry and Chemical Engineering, Joint International Research Laboratory of Biomass-Based Macromolecular Chemistry and Materials, Southwest University, Chongqing 400715, China; School of Chemistry, Chemical Engineering and Life Sciences, Wuhan University of Technology, Wuhan 430070, China.
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24
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McQualter RB, Bellasio C, Gebbie LK, Petrasovits LA, Palfreyman RW, Hodson MP, Plan MR, Blackman DM, Brumbley SM, Nielsen LK. Systems biology and metabolic modelling unveils limitations to polyhydroxybutyrate accumulation in sugarcane leaves; lessons for C4 engineering. PLANT BIOTECHNOLOGY JOURNAL 2016; 14:567-580. [PMID: 26015295 DOI: 10.1111/pbi.12399] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Revised: 04/07/2015] [Accepted: 04/16/2015] [Indexed: 05/28/2023]
Abstract
In planta production of the bioplastic polyhydroxybutyrate (PHB) is one important way in which plant biotechnology can address environmental problems and emerging issues related to peak oil. However, high biomass C4 plants such as maize, switch grass and sugarcane develop adverse phenotypes including stunting, chlorosis and reduced biomass as PHB levels in leaves increase. In this study, we explore limitations to PHB accumulation in sugarcane chloroplasts using a systems biology approach, coupled with a metabolic model of C4 photosynthesis. Decreased assimilation was evident in high PHB-producing sugarcane plants, which also showed a dramatic decrease in sucrose and starch content of leaves. A subtle decrease in the C/N ratio was found which was not associated with a decrease in total protein content. An increase in amino acids used for nitrogen recapture was also observed. Based on the accumulation of substrates of ATP-dependent reactions, we hypothesized ATP starvation in bundle sheath chloroplasts. This was supported by mRNA differential expression patterns. The disruption in ATP supply in bundle sheath cells appears to be linked to the physical presence of the PHB polymer which may disrupt photosynthesis by scattering photosynthetically active radiation and/or physically disrupting thylakoid membranes.
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Affiliation(s)
- Richard B McQualter
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Qld, Australia
| | - Chandra Bellasio
- Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield, UK
| | - Leigh K Gebbie
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Qld, Australia
| | - Lars A Petrasovits
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Qld, Australia
| | - Robin W Palfreyman
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Qld, Australia
| | - Mark P Hodson
- Metabolomics Australia Queensland Node, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Qld, Australia
| | - Manuel R Plan
- Metabolomics Australia Queensland Node, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Qld, Australia
| | - Deborah M Blackman
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Qld, Australia
| | - Stevens M Brumbley
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Qld, Australia
| | - Lars K Nielsen
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Qld, Australia
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Rylott EL, Johnston EJ, Bruce NC. Harnessing microbial gene pools to remediate persistent organic pollutants using genetically modified plants--a viable technology? JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:6519-33. [PMID: 26283045 DOI: 10.1093/jxb/erv384] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
It has been 14 years since the international community came together to legislate the Stockholm Convention on Persistent Organic Pollutants (POPs), restricting the production and use of specific chemicals that were found to be environmentally stable, often bioaccumulating, with long-term toxic effects. Efforts are continuing to remove these pollutants from the environment. While incineration and chemical treatment can be successful, these methods require the removal of tonnes of soil, at high cost, and are damaging to soil structure and microbial communities. The engineering of plants for in situ POP remediation has had highly promising results, and could be a more environmentally-friendly alternative. This review discusses the characterization of POP-degrading bacterial pathways, and how the genes responsible have been harnessed using genetic modification (GM) to introduce these same abilities into plants. Recent advances in multi-gene cloning, genome editing technologies and expression in monocot species are accelerating progress with remediation-applicable species. Examples include plants developed to degrade 2,4,6-trinitrotoluene (TNT), hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), trichloroethylene (TCE), and polychlorinated biphenyls (PCBs). However, the costs and timescales needed to gain regulatory approval, along with continued public opposition, are considerable. The benefits and challenges in this rapidly developing and promising field are discussed.
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Affiliation(s)
- Elizabeth L Rylott
- Centre for Novel Agricultural Products, Department of Biology, University of York, Wentworth Way, York, YO10 5DD, UK
| | - Emily J Johnston
- Centre for Novel Agricultural Products, Department of Biology, University of York, Wentworth Way, York, YO10 5DD, UK
| | - Neil C Bruce
- Centre for Novel Agricultural Products, Department of Biology, University of York, Wentworth Way, York, YO10 5DD, UK
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Parveez GKA, Bahariah B, Ayub NH, Masani MYA, Rasid OA, Tarmizi AH, Ishak Z. Production of polyhydroxybutyrate in oil palm (Elaeis guineensis Jacq.) mediated by microprojectile bombardment of PHB biosynthesis genes into embryogenic calli. FRONTIERS IN PLANT SCIENCE 2015; 6:598. [PMID: 26322053 PMCID: PMC4531230 DOI: 10.3389/fpls.2015.00598] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2015] [Accepted: 07/20/2015] [Indexed: 05/22/2023]
Abstract
Biodegradable plastics, mainly polyhydroxybutyrate (PHB), which are traditionally produced by bacterial cells, have been produced in the cells of more than 15 plant species. Since the production of biodegradable plastics and the synthesis of oil in plants share the same substrate, acetyl-coenzyme A (acetyl-CoA), producing PHB in oil bearing crops, such as oil palm, will be advantageous. In this study, three bacterial genes, bktB, phaB, and phaC, which are required for the synthesis of PHB and selectable marker gene, bar, for herbicide Basta resistant, were transformed into embryogenic calli. A number of transformed embryogenic lines resistant to herbicide Basta were obtained and were later regenerated to produce few hundred plantlets. Molecular analyses, including polymerase chain reaction (PCR), Southern blot, and real-time PCR have demonstrated stable integration and expression of the transgenes in the oil palm genome. HPLC and Nile blue A staining analyses confirmed the synthesis of PHB in some of the plantlets.
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27
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Liu YR, Cen HF, Yan JP, Zhang YW, Zhang WJ. Inside out: high-efficiency plant regeneration and Agrobacterium-mediated transformation of upland and lowland switchgrass cultivars. PLANT CELL REPORTS 2015; 34:1099-108. [PMID: 25698105 DOI: 10.1007/s00299-015-1769-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 02/07/2015] [Accepted: 02/10/2015] [Indexed: 05/21/2023]
Abstract
Selection of pre-embryogenic callus from a core structure from mature seed-derived callus is the key for high-efficiency plant regeneration and transformation of switchgrass different cultivars. Switchgrass (Panicum virgatum L.) has been identified as a dedicated biofuel crop. For its trait improvement through biotechnological approaches, we have developed a highly efficient plant regeneration and genetic transformation protocol for both lowland and upland cultivars. We identified and separated a pre-embryogenic "core" structure from the seed-derived callus, which often leads to development of highly regenerative type II calluses. From the type II callus, plant regeneration rate of lowland cultivars Alamo and Performer reaches 95%, and upland cultivars Blackwell and Dacotah, 50 and 76%, respectively. The type II callus was also amenable for Agrobacterium-mediated transformation. Transformation efficiency of 72.8% was achieved for lowland cultivar Alamo, and 8.0% for upland cultivar Dacotah. PCR, Southern blot and GUS staining assays were performed to verify the transgenic events. High regenerative callus lines could be established in 3 months, and transgenic plants could be obtained in 2 months after Agrobacterium infection. To our knowledge, this is the first report on successful plant regeneration and recovery of transgenic plants from upland switchgrass cultivars by Agrobacterium-mediated transformation. The method presented here could be helpful in breaking through the bottleneck of regeneration and transformation of lowland and upland switchgrass cultivars and probably other recalcitrant grass crops.
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Affiliation(s)
- Yan-Rong Liu
- Department of Grassland Science, China Agricultural University, No. 2 Yuanmingyuan Xilu, Haidian District, Beijing, 100193, People's Republic of China
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Malik MR, Yang W, Patterson N, Tang J, Wellinghoff RL, Preuss ML, Burkitt C, Sharma N, Ji Y, Jez JM, Peoples OP, Jaworski JG, Cahoon EB, Snell KD. Production of high levels of poly-3-hydroxybutyrate in plastids of Camelina sativa seeds. PLANT BIOTECHNOLOGY JOURNAL 2015; 13:675-88. [PMID: 25418911 DOI: 10.1111/pbi.12290] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Accepted: 10/07/2014] [Indexed: 05/20/2023]
Abstract
Poly-3-hydroxybutyrate (PHB) production in plastids of Camelina sativa seeds was investigated by comparing levels of polymer produced upon transformation of plants with five different binary vectors containing combinations of five seed-specific promoters for expression of transgenes. Genes encoding PHB biosynthetic enzymes were modified at the N-terminus to encode a plastid targeting signal. PHB levels of up to 15% of the mature seed weight were measured in single sacrificed T1 seeds with a genetic construct containing the oleosin and glycinin promoters. A more detailed analysis of the PHB production potential of two of the best performing binary vectors in a Camelina line bred for larger seed size yielded lines containing up to 15% polymer in mature T2 seeds. Transmission electron microscopy showed the presence of distinct granules of PHB in the seeds. PHB production had varying effects on germination, emergence and survival of seedlings. Once true leaves formed, plants grew normally and were able to set seeds. PHB synthesis lowered the total oil but not the protein content of engineered seeds. A change in the oil fatty acid profile was also observed. High molecular weight polymer was produced with weight-averaged molecular weights varying between 600 000 and 1 500 000, depending on the line. Select lines were advanced to later generations yielding a line with 13.7% PHB in T4 seeds. The levels of polymer produced in this study are the highest reported to date in a seed and are an important step forward for commercializing an oilseed-based platform for PHB production.
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Affiliation(s)
| | - Wenyu Yang
- Donald Danforth Plant Science Center, Saint Louis, MO, USA
| | | | | | | | - Mary L Preuss
- Donald Danforth Plant Science Center, Saint Louis, MO, USA
- Department of Biological Sciences, Webster University, Saint Louis, MO, USA
| | | | | | - Yuanyuan Ji
- Metabolix Oilseeds Inc, Saskatoon, SK, Canada
| | - Joseph M Jez
- Donald Danforth Plant Science Center, Saint Louis, MO, USA
- Department of Biology, Washington University, Saint Louis, MO, USA
| | | | - Jan G Jaworski
- Donald Danforth Plant Science Center, Saint Louis, MO, USA
| | - Edgar B Cahoon
- Donald Danforth Plant Science Center, Saint Louis, MO, USA
- Center for Plant Science Innovation and Department of Biochemistry, University of Nebraska, Lincoln, NE, USA
| | - Kristi D Snell
- Metabolix Oilseeds Inc, Saskatoon, SK, Canada
- Metabolix Inc, Cambridge, MA, USA
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McQualter RB, Petrasovits LA, Gebbie LK, Schweitzer D, Blackman DM, Chrysanthopoulos P, Hodson MP, Plan MR, Riches JD, Snell KD, Brumbley SM, Nielsen LK. The use of an acetoacetyl-CoA synthase in place of a β-ketothiolase enhances poly-3-hydroxybutyrate production in sugarcane mesophyll cells. PLANT BIOTECHNOLOGY JOURNAL 2015; 13:700-707. [PMID: 25532451 DOI: 10.1111/pbi.12298] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Revised: 10/10/2014] [Accepted: 10/21/2014] [Indexed: 06/04/2023]
Abstract
Engineering the production of polyhydroxyalkanoates (PHAs) into high biomass bioenergy crops has the potential to provide a sustainable supply of bioplastics and energy from a single plant feedstock. One of the major challenges in engineering C4 plants for the production of poly[(R)-3-hydroxybutyrate] (PHB) is the significantly lower level of polymer produced in the chloroplasts of mesophyll (M) cells compared to bundle sheath (BS) cells, thereby limiting the full PHB yield-potential of the plant. In this study, we provide evidence that the access to substrate for PHB synthesis may limit polymer production in M chloroplasts. Production of PHB in M cells of sugarcane is significantly increased by replacing β-ketothiolase, the first enzyme in the bacterial PHA pathway, with acetoacetyl-CoA synthase. This novel pathway enabled the production of PHB reaching an average of 6.3% of the dry weight of total leaf biomass, with levels ranging from 3.6 to 11.8% of the dry weight (DW) of individual leaves. These yields are more than twice the level reported in PHB-producing sugarcane containing the β-ketothiolase and illustrate the importance of producing polymer in mesophyll plastids to maximize yield. The molecular weight of the polymer produced was greater than 2 × 10(6) Da. These results are a major step forward in engineering a high biomass C4 grass for the commercial production of PHB.
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Affiliation(s)
- Richard B McQualter
- Australian Institute for Bioengineering and Nanotechnology, the University of Queensland, Brisbane, Qld, Australia
| | - Lars A Petrasovits
- Australian Institute for Bioengineering and Nanotechnology, the University of Queensland, Brisbane, Qld, Australia
| | - Leigh K Gebbie
- Australian Institute for Bioengineering and Nanotechnology, the University of Queensland, Brisbane, Qld, Australia
| | | | - Deborah M Blackman
- Australian Institute for Bioengineering and Nanotechnology, the University of Queensland, Brisbane, Qld, Australia
| | - Panagiotis Chrysanthopoulos
- Metabolomics Australia Queensland Node, Australian Institute for Bioengineering and Nanotechnology, the University of Queensland, Brisbane, Qld, Australia
| | - Mark P Hodson
- Central Analytical Research Facility, Queensland University of Technology, Brisbane, Qld, Australia
| | - Manuel R Plan
- Central Analytical Research Facility, Queensland University of Technology, Brisbane, Qld, Australia
| | - James D Riches
- Metabolomics Australia Queensland Node, Australian Institute for Bioengineering and Nanotechnology, the University of Queensland, Brisbane, Qld, Australia
| | | | - Stevens M Brumbley
- Australian Institute for Bioengineering and Nanotechnology, the University of Queensland, Brisbane, Qld, Australia
| | - Lars K Nielsen
- Australian Institute for Bioengineering and Nanotechnology, the University of Queensland, Brisbane, Qld, Australia
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Snell KD, Singh V, Brumbley SM. Production of novel biopolymers in plants: recent technological advances and future prospects. Curr Opin Biotechnol 2015; 32:68-75. [DOI: 10.1016/j.copbio.2014.11.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 11/06/2014] [Indexed: 12/27/2022]
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Evaluation of feeding regimes to enhance PHA production using acetic and butyric acids by a pure culture of Cupriavidus necator. BIOTECHNOL BIOPROC E 2015. [DOI: 10.1007/s12257-014-0144-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Affiliation(s)
- Dirk Schweitzer
- Metabolix, 21 Erie Street, Cambridge, Massachusetts 02139, United States
| | - Kristi D. Snell
- Metabolix, 21 Erie Street, Cambridge, Massachusetts 02139, United States
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33
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Tilbrook K, Poirier Y, Gebbie L, Schenk PM, McQualter RB, Brumbley SM. Reduced peroxisomal citrate synthase activity increases substrate availability for polyhydroxyalkanoate biosynthesis in plant peroxisomes. PLANT BIOTECHNOLOGY JOURNAL 2014; 12:1044-1052. [PMID: 24944109 DOI: 10.1111/pbi.12211] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 04/25/2014] [Accepted: 05/01/2014] [Indexed: 06/03/2023]
Abstract
Polyhydroxyalkanoates (PHAs) are bacterial carbon storage polymers used as renewable, biodegradable plastics. PHA production in plants may be a way to reduce industrial PHA production costs. We recently demonstrated a promising level of peroxisomal PHA production in the high biomass crop species sugarcane. However, further production strategies are needed to boost PHA accumulation closer to commercial targets. Through exogenous fatty acid feeding of Arabidopsis thaliana plants that contain peroxisome-targeted PhaA, PhaB and PhaC enzymes from Cupriavidus necator, we show here that the availability of substrates derived from the β-oxidation cycle limits peroxisomal polyhydroxybutyrate (PHB) biosynthesis. Knockdown of peroxisomal citrate synthase activity using artificial microRNA increased PHB production levels approximately threefold. This work demonstrates that reduction of peroxisomal citrate synthase activity may be a valid metabolic engineering strategy for increasing PHA production in other plant species.
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Affiliation(s)
- Kimberley Tilbrook
- School of Biological Science, The University of Queensland, Brisbane, Qld, Australia; Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Qld, Australia; The Cooperative Research Centre for Sugar Industry Innovation through Biotechnology, The University of Queensland, Brisbane, Qld, Australia
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McQualter RB, Somleva MN, Gebbie LK, Li X, Petrasovits LA, Snell KD, Nielsen LK, Brumbley SM. Factors affecting polyhydroxybutyrate accumulation in mesophyll cells of sugarcane and switchgrass. BMC Biotechnol 2014; 14:83. [PMID: 25209261 PMCID: PMC4165624 DOI: 10.1186/1472-6750-14-83] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Accepted: 08/29/2014] [Indexed: 12/04/2022] Open
Abstract
Background Polyhydroxyalkanoates are linear biodegradable polyesters produced by bacteria as a carbon store and used to produce a range of bioplastics. Widespread polyhydroxyalkanoate production in C4 crops would decrease petroleum dependency by producing a renewable supply of biodegradable plastics along with residual biomass that could be converted into biofuels or energy. Increasing yields to commercial levels in biomass crops however remains a challenge. Previously, lower accumulation levels of the short side chain polyhydroxyalkanoate, polyhydroxybutyrate (PHB), were observed in the chloroplasts of mesophyll (M) cells compared to bundle sheath (BS) cells in transgenic maize (Zea mays), sugarcane (Saccharum sp.), and switchgrass (Panicum virgatum L.) leading to a significant decrease in the theoretical yield potential. Here we explore various factors which might affect polymer accumulation in mesophyll cells, including targeting of the PHB pathway enzymes to the mesophyll plastid and their access to substrate. Results The small subunit of Rubisco from pea effectively targeted the PHB biosynthesis enzymes to both M and BS chloroplasts of sugarcane and switchgrass. PHB enzyme activity was retained following targeting to M plastids and was equivalent to that found in the BS plastids. Leaf total fatty acid content was not affected by PHB production. However, when fatty acid synthesis was chemically inhibited, polymer accumulated in M cells. Conclusions In this study, we provide evidence that access to substrate and neither poor targeting nor insufficient activity of the PHB biosynthetic enzymes may be the limiting factor for polymer production in mesophyll chloroplasts of C4 plants.
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Affiliation(s)
| | | | | | | | | | | | | | - Stevens M Brumbley
- Australian Institute for Bioengineering and Nanotechnology, the University of Queensland, Brisbane QLD 4072, Australia.
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Somleva MN, Xu CA, Ryan KP, Thilmony R, Peoples O, Snell KD, Thomson J. Transgene autoexcision in switchgrass pollen mediated by the Bxb1 recombinase. BMC Biotechnol 2014; 14:79. [PMID: 25148894 PMCID: PMC4148497 DOI: 10.1186/1472-6750-14-79] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Accepted: 08/18/2014] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND Switchgrass (Panicum virgatum L.) has a great potential as a platform for the production of biobased plastics, chemicals and energy mainly because of its high biomass yield on marginal land and low agricultural inputs. During the last decade, there has been increased interest in the genetic improvement of this crop through transgenic approaches. Since switchgrass, like most perennial grasses, is exclusively cross pollinating and poorly domesticated, preventing the dispersal of transgenic pollen into the environment is a critical requisite for the commercial deployment of this important biomass crop. In this study, the feasibility of controlling pollen-mediated gene flow in transgenic switchgrass using the large serine site-specific recombinase Bxb1 has been investigated. RESULTS A novel approach utilizing co-transformation of two separate vectors was used to test the functionality of the Bxb1/att recombination system in switchgrass. In addition, two promoters with high pollen-specific activity were identified and thoroughly characterized prior to their introduction into a test vector explicitly designed for both autoexcision and quantitative analyses of recombination events. Our strategy for developmentally programmed precise excision of the recombinase and marker genes in switchgrass pollen resulted in the generation of transgene-excised progeny. The autoexcision efficiencies were in the range of 22-42% depending on the transformation event and assay used. CONCLUSION The results presented here mark an important milestone towards the establishment of a reliable biocontainment system for switchgrass which will facilitate the development of this crop as a biorefinery feedstock through advanced biotechnological approaches.
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Affiliation(s)
| | - Chang Ai Xu
- Metabolix, Inc., 21 Erie St., Cambridge, MA 02139, USA
| | - Kieran P Ryan
- Metabolix, Inc., 21 Erie St., Cambridge, MA 02139, USA
| | | | | | | | - James Thomson
- USDA-ARS-CIU, 800 Buchanan St., Albany, CA 94710, USA
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Schweitzer D, Mullen CA, Boateng AA, Snell KD. Biobased n-Butanol Prepared from Poly-3-hydroxybutyrate: Optimization of the Reduction of n-Butyl Crotonate to n-Butanol. Org Process Res Dev 2014. [DOI: 10.1021/op500156b] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Dirk Schweitzer
- Metabolix, 21 Erie St., Cambridge, Massachusetts 02139, United States
| | - Charles A. Mullen
- Eastern
Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, 600 E. Mermaid Lane, Wyndmoor, Pennsylvania 19038, United States
| | - Akwasi A. Boateng
- Eastern
Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, 600 E. Mermaid Lane, Wyndmoor, Pennsylvania 19038, United States
| | - Kristi D. Snell
- Metabolix, 21 Erie St., Cambridge, Massachusetts 02139, United States
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Gimeno J, Eattock N, Van Deynze A, Blumwald E. Selection and validation of reference genes for gene expression analysis in switchgrass (Panicum virgatum) using quantitative real-time RT-PCR. PLoS One 2014; 9:e91474. [PMID: 24621568 PMCID: PMC3951385 DOI: 10.1371/journal.pone.0091474] [Citation(s) in RCA: 95] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Accepted: 02/12/2014] [Indexed: 01/21/2023] Open
Abstract
Switchgrass (Panicum virgatum) has received a lot of attention as a forage and bioenergy crop during the past few years. Gene expression studies are in progress to improve new traits and develop new cultivars. Quantitative real time PCR (qRT-PCR) has emerged as an important technique to study gene expression analysis. For accurate and reliable results, normalization of data with reference genes is essential. In this work, we evaluate the stability of expression of genes to use as reference for qRT-PCR in the grass P. virgatum. Eleven candidate reference genes, including eEF-1α, UBQ6, ACT12, TUB6, eIF-4a, GAPDH, SAMDC, TUA6, CYP5, U2AF, and FTSH4, were validated for qRT-PCR normalization in different plant tissues and under different stress conditions. The expression stability of these genes was verified by the use of two distinct algorithms, geNorm and NormFinder. Differences were observed after comparison of the ranking of the candidate reference genes identified by both programs but eEF-1α, eIF-4a, CYP5 and U2AF are ranked as the most stable genes in the samples sets under study. Both programs discard the use of SAMDC and TUA6 for normalization. Validation of the reference genes proposed by geNorm and NormFinder were performed by normalization of transcript abundance of a group of target genes in different samples. Results show similar expression patterns when the best reference genes selected by both programs were used but differences were detected in the transcript abundance of the target genes. Based on the above research, we recommend the use of different statistical algorithms to identify the best reference genes for expression data normalization. The best genes selected in this study will help to improve the quality of gene expression data in a wide variety of samples in switchgrass.
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Affiliation(s)
- Jacinta Gimeno
- Department of Plant Sciences, University of California Davis, Davis, California, United States of America
| | - Nicholas Eattock
- Department of Plant Sciences, University of California Davis, Davis, California, United States of America
| | - Allen Van Deynze
- Department of Plant Sciences, University of California Davis, Davis, California, United States of America
| | - Eduardo Blumwald
- Department of Plant Sciences, University of California Davis, Davis, California, United States of America
- * E-mail:
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Hernandez-Garcia CM, Finer JJ. Identification and validation of promoters and cis-acting regulatory elements. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2014; 217-218:109-19. [PMID: 24467902 DOI: 10.1016/j.plantsci.2013.12.007] [Citation(s) in RCA: 317] [Impact Index Per Article: 31.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Revised: 12/03/2013] [Accepted: 12/05/2013] [Indexed: 05/18/2023]
Abstract
Studies of promoters that largely regulate gene expression at the transcriptional level are crucial for improving our basic understanding of gene regulation and will expand the toolbox of available promoters for use in plant biotechnology. In this review, we present a comprehensive analysis of promoters and their underlying mechanisms in transcriptional regulation, including epigenetic marks and chromatin-based regulation. Large-scale prediction of promoter sequences and their contributing cis-acting elements has become routine due to recent advances in transcriptomic technologies and genome sequencing of several plants. However, predicted regulatory sequences may or may not be functional and demonstration of the contribution of the element to promoter activity is essential for confirmation of regulatory sequences. Synthetic promoters and introns provide useful approaches for functional validation of promoter sequences. The development and improvement of gene expression tools for rapid, efficient, predictable, and high-throughput analysis of promoter components will be critical for confirmation of the functional regulatory element sequences identified through transcriptomic and genomic analyses.
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Affiliation(s)
- Carlos M Hernandez-Garcia
- Department of Horticulture and Crop Science, OARDC/The Ohio State University, 1680 Madison Avenue, Wooster, OH 44691, USA
| | - John J Finer
- Department of Horticulture and Crop Science, OARDC/The Ohio State University, 1680 Madison Avenue, Wooster, OH 44691, USA.
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Laycock B, Halley P, Pratt S, Werker A, Lant P. The chemomechanical properties of microbial polyhydroxyalkanoates. Prog Polym Sci 2014. [DOI: 10.1016/j.progpolymsci.2013.06.008] [Citation(s) in RCA: 137] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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King ZR, Bray AL, Lafayette PR, Parrott WA. Biolistic transformation of elite genotypes of switchgrass (Panicum virgatum L.). PLANT CELL REPORTS 2014; 33:313-22. [PMID: 24177598 DOI: 10.1007/s00299-013-1531-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2013] [Revised: 09/25/2013] [Accepted: 10/18/2013] [Indexed: 05/07/2023]
Abstract
Transformation of elite switchgrass (Panicum virgatum L.) genotypes would facilitate the characterization of genes related to cell wall recalcitrance to saccharification. However, transformation of explants from switchgrass plants has remained difficult. Therefore, the objective of this study was to develop a biolistic transformation protocol for elite genotypes. Three switchgrass genotypes (ST1, ST2, and AL2) were previously selected for tissue culture responsiveness. One genotype, SA37, was selected for further use due to its improved formation of callus amenable to transformation. Various medium sets were compared and a previously published medium set provided cultures with >96 % embryogenic callus, and data on transient and stable gene expression of RFP were used to optimize biolistic parameters, and further validate the switchgrass (PvUbi1) promoter. SA37 proved to be the most transformable, whereas eight transgenic calli on average were recovered per bombardment of 20 calli (40 % efficiency) when using a three-day day preculture step, 0.6 M osmotic adjustment medium, 4,482 kPa rupture disks and 0.4 μm gold particles which traveled 9 cm before hitting the target callus tissue. Regenerability was high, especially for ST2, for which it is possible to recover on average over 400 plants per half-gram callus tissue. It is now possible to routinely and efficiently engineer elite switchgrass genotypes using biolistic transformation.
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Affiliation(s)
- Zachary R King
- Institute for Plant Breeding, Genetics and Genomics, The University of Georgia, 111 Riverbend Road, Athens, GA, 30602, USA,
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Petrasovits LA, McQualter RB, Gebbie LK, Blackman DM, Nielsen LK, Brumbley SM. Chemical inhibition of acetyl coenzyme A carboxylase as a strategy to increase polyhydroxybutyrate yields in transgenic sugarcane. PLANT BIOTECHNOLOGY JOURNAL 2013; 11:1146-51. [PMID: 24112832 DOI: 10.1111/pbi.12109] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Revised: 07/21/2013] [Accepted: 07/24/2013] [Indexed: 05/11/2023]
Abstract
Polyhydroxybutyrate (PHB) is a naturally occurring bacterial polymer that can be used as a biodegradable replacement for some petrochemical-derived plastics. Polyhydroxybutyrate is produced commercially by fermentation, but to reduce production costs, efforts are underway to produce it in engineered plants, including sugarcane. However, PHB levels in this high-biomass crop are not yet commercially viable. Chemical ripening with herbicides is a strategy used to enhance sucrose production in sugarcane and was investigated here as a tool to increase PHB production. Class A herbicides inhibit ACCase activity and thus reduce fatty acid biosynthesis, with which PHB production competes directly for substrate. Treatment of PHB-producing transgenic sugarcane plants with 100 μM of the class A herbicide fluazifop resulted in a fourfold increase in PHB content in the leaves, which peaked ten days post-treatment. The minimum effective concentration of herbicide required to maximize PHB production was 30 μM for fluazifop and 70 μM for butroxydim when applied to saturation. Application of a range of class A herbicides from the DIM and FOP groups consistently resulted in increased PHB yields, particularly in immature leaf tissue. Butroxydim or fluazifop treatment of mature transgenic sugarcane grown under glasshouse conditions increased the total leaf biomass yield of PHB by 50%-60%. Application of an ACCase inhibitor in the form of a class A herbicide to mature sugarcane plants prior to harvest is a promising strategy for improving overall PHB yield. Further testing is required on field-grown transgenic sugarcane to more precisely determine the effectiveness of this strategy.
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Affiliation(s)
- Lars A Petrasovits
- Australian Institute for Bioengineering and Nanotechnology, the University of Queensland, Brisbane, Qld, Australia
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42
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Reddy MM, Vivekanandhan S, Misra M, Bhatia SK, Mohanty AK. Biobased plastics and bionanocomposites: Current status and future opportunities. Prog Polym Sci 2013. [DOI: 10.1016/j.progpolymsci.2013.05.006] [Citation(s) in RCA: 471] [Impact Index Per Article: 42.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Gahlawat G, Srivastava AK. Development of a mathematical model for the growth associated Polyhydroxybutyrate fermentation by Azohydromonas australica and its use for the design of fed-batch cultivation strategies. BIORESOURCE TECHNOLOGY 2013; 137:98-105. [PMID: 23587813 DOI: 10.1016/j.biortech.2013.03.023] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2012] [Revised: 03/04/2013] [Accepted: 03/06/2013] [Indexed: 06/02/2023]
Abstract
In the present investigation, batch cultivation of Azohydromonas australica DSM 1124 was carried out in a bioreactor for growth associated PHB production. The observed batch PHB production kinetics data was then used for the development of a mathematical model which adequately described the substrate limitation and inhibition during the cultivation. The statistical validity test demonstrated that the proposed mathematical model predictions were significant at 99% confidence level. The model was thereafter extrapolated to fed-batch to identify various nutrients feeding regimes during the bioreactor cultivation to improve the PHB accumulation. The distinct capability of the mathematical model to predict highly dynamic fed-batch cultivation strategies was demonstrated by experimental implementation of two fed-batch cultivation strategies. A significantly high PHB concentration of 22.65 g/L & an overall PHB content of 76% was achieved during constant feed rate fed-batch cultivation which is the highest PHB content reported so far using A. australica.
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Affiliation(s)
- Geeta Gahlawat
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
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44
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Lin Y, Pajak A, Marsolais F, McCourt P, Riggs CD. Characterization of a cruciferin deficient mutant of Arabidopsis and its utility for overexpression of foreign proteins in plants. PLoS One 2013; 8:e64980. [PMID: 23724110 PMCID: PMC3664629 DOI: 10.1371/journal.pone.0064980] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Accepted: 04/19/2013] [Indexed: 12/20/2022] Open
Abstract
Plant seeds naturally accumulate storage reserves (proteins, carbohydrates, lipids) that are mobilized during germination to provide energy and raw materials to support early seedling growth. Seeds have been exploited as bioreactors for the production to foreign materials, but stable, high level expression has been elusive, in part due to the intrinsic bias for producing the natural reserves in their typical proportions. To identify mutants governing seed filling, we screened a population of mutagenized Arabidopsis plants for a mutant that failed to fill its seeds. Here we report the identification of ssp1, a recessive, viable mutant that accumulates approximately 15% less protein than wildtype seeds. Molecular analyses revealed that ssp1 is due to the introduction of a premature stop codon in CRU3, one of the major cruciferin genes. Unlike many other reserve mutants or transgenic lines in which seed storage protein levels are reduced by antisense/RNAi technologies, ssp1 exhibits low level compensation by other reserves, and represents a mutant background that might prove useful for high level expression of foreign proteins. To test this hypothesis, we used a bean phytohemagglutinin (PHA) gene as a reporter and compared PHA expression levels in single copy insertion lines in ssp1 vs. wildtype. These near isogenic lines allow reporter protein levels to be compared without the confounding and sometimes unknown influences of transgene copy number and position effects on gene expression. The ssp1 lines consistently accumulated more PHA than the backcrossed counterparts, with increases ranging from 12% to 126%. This proof of principle study suggests that similar strategies in crop plants may improve the yield of foreign proteins of agronomic and economic interest.
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Affiliation(s)
- Yimei Lin
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Agnieszka Pajak
- Southern Crop Protection and Food Research Centre, Agriculture and Agri-Food Canada, London, Ontario, Canada
| | - Frédéric Marsolais
- Southern Crop Protection and Food Research Centre, Agriculture and Agri-Food Canada, London, Ontario, Canada
- Department of Biology, University of Western Ontario, London, Ontario, Canada
| | - Peter McCourt
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - C. Daniel Riggs
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
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Nageswara-Rao M, Soneji JR, Kwit C, Stewart CN. Advances in biotechnology and genomics of switchgrass. BIOTECHNOLOGY FOR BIOFUELS 2013; 6:77. [PMID: 23663491 PMCID: PMC3662616 DOI: 10.1186/1754-6834-6-77] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Accepted: 05/08/2013] [Indexed: 05/02/2023]
Abstract
Switchgrass (Panicum virgatum L.) is a C4 perennial warm season grass indigenous to the North American tallgrass prairie. A number of its natural and agronomic traits, including adaptation to a wide geographical distribution, low nutrient requirements and production costs, high water use efficiency, high biomass potential, ease of harvesting, and potential for carbon storage, make it an attractive dedicated biomass crop for biofuel production. We believe that genetic improvements using biotechnology will be important to realize the potential of the biomass and biofuel-related uses of switchgrass. Tissue culture techniques aimed at rapid propagation of switchgrass and genetic transformation protocols have been developed. Rapid progress in genome sequencing and bioinformatics has provided efficient strategies to identify, tag, clone and manipulate many economically-important genes, including those related to higher biomass, saccharification efficiency, and lignin biosynthesis. Application of the best genetic tools should render improved switchgrass that will be more economically and environmentally sustainable as a lignocellulosic bioenergy feedstock.
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Affiliation(s)
- Madhugiri Nageswara-Rao
- Department of Plant Sciences, The University of Tennessee, 252 Ellington Plant Sciences, 2431 Joe Johnson Dr., Knoxville, TN 37996, USA
- Department of Biological Sciences, Polk State College, Winter Haven, FL 33881, USA
| | - Jaya R Soneji
- Department of Biological Sciences, Polk State College, Winter Haven, FL 33881, USA
| | - Charles Kwit
- Department of Plant Sciences, The University of Tennessee, 252 Ellington Plant Sciences, 2431 Joe Johnson Dr., Knoxville, TN 37996, USA
| | - C Neal Stewart
- Department of Plant Sciences, The University of Tennessee, 252 Ellington Plant Sciences, 2431 Joe Johnson Dr., Knoxville, TN 37996, USA
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
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Laycock B, Halley P, Pratt S, Werker A, Lant P. The chemomechanical properties of microbial polyhydroxyalkanoates. Prog Polym Sci 2013. [DOI: 10.1016/j.progpolymsci.2012.06.003] [Citation(s) in RCA: 197] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Somleva MN, Peoples OP, Snell KD. PHA bioplastics, biochemicals, and energy from crops. PLANT BIOTECHNOLOGY JOURNAL 2013; 11:233-52. [PMID: 23294864 DOI: 10.1111/pbi.12039] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2012] [Revised: 11/21/2012] [Accepted: 11/28/2012] [Indexed: 05/09/2023]
Abstract
Large scale production of polyhydroxyalkanoates (PHAs) in plants can provide a sustainable supply of bioplastics, biochemicals, and energy from sunlight and atmospheric CO(2). PHAs are a class of polymers with various chain lengths that are naturally produced by some microorganisms as storage materials. The properties of these polyesters make them functionally equivalent to many of the petroleum-based plastics that are currently in the market place. However, unlike most petroleum-derived plastics, PHAs can be produced from renewable feedstocks and easily degrade in most biologically active environments. This review highlights research efforts over the last 20 years to engineer the production of PHAs in plants with a focus on polyhydroxybutryrate (PHB) production in bioenergy crops with C(4) photosynthesis. PHB has the potential to be a high volume commercial product with uses not only in the plastics and materials markets, but also in renewable chemicals and feed. The major challenges of improving product yield and plant fitness in high biomass yielding C(4) crops are discussed in detail.
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48
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Morandini P. Control limits for accumulation of plant metabolites: brute force is no substitute for understanding. PLANT BIOTECHNOLOGY JOURNAL 2013; 11:253-267. [PMID: 23301840 DOI: 10.1111/pbi.12035] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Revised: 11/13/2012] [Accepted: 11/19/2012] [Indexed: 06/01/2023]
Abstract
Which factors limit metabolite accumulation in plant cells? Are theories on flux control effective at explaining the results? Many biotechnologists cling to the idea that every pathway has a rate limiting enzyme and target such enzymes first in order to modulate fluxes. This often translates into large effects on metabolite concentration, but disappointing small increases in flux. Rate limiting enzymes do exist, but are rare and quite opposite to what predicted by biochemistry. In many cases however, flux control is shared among many enzymes. Flux control and concentration control can (and must) be distinguished and quantified for effective manipulation. Flux control for several 'building blocks' of metabolism is placed on the demand side, and therefore increasing demand can be very successful. Tampering with supply, particularly desensitizing supply enzymes, is usually not very effective, if not dangerous, because supply regulatory mechanisms function to control metabolite homeostasis. Some important, but usually unnoticed, metabolic constraints shape the responses of metabolic systems to manipulation: mass conservation, cellular resource allocation and, most prominently, energy supply, particularly in heterotrophic tissues. The theoretical basis for this view shall be explored with recent examples gathered from the manipulation of several metabolites (vitamins, carotenoids, amino acids, sugars, fatty acids, polyhydroxyalkanoates, fructans and sugar alcohols). Some guiding principles are suggested for an even more successful engineering of plant metabolism.
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Affiliation(s)
- Piero Morandini
- Department of Biosciences, University of Milan and CNR Institute of Biophysics, Milan, Italy.
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Wu X, Wu J, Luo Y, Bragg J, Anderson O, Vogel J, Gu YQ. Phylogenetic, Molecular, and Biochemical Characterization of Caffeic Acid o-Methyltransferase Gene Family in Brachypodium distachyon. INTERNATIONAL JOURNAL OF PLANT GENOMICS 2013; 2013:423189. [PMID: 23431288 PMCID: PMC3562662 DOI: 10.1155/2013/423189] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Revised: 12/03/2012] [Accepted: 12/07/2012] [Indexed: 05/02/2023]
Abstract
Caffeic acid o-methyltransferase (COMT) is one of the important enzymes controlling lignin monomer production in plant cell wall synthesis. Analysis of the genome sequence of the new grass model Brachypodium distachyon identified four COMT gene homologs, designated as BdCOMT1, BdCOMT2, BdCOMT3, and BdCOMT4. Phylogenetic analysis suggested that they belong to the COMT gene family, whereas syntenic analysis through comparisons with rice and sorghum revealed that BdCOMT4 on Chromosome 3 is the orthologous copy of the COMT genes well characterized in other grass species. The other three COMT genes are unique to Brachypodium since orthologous copies are not found in the collinear regions of rice and sorghum genomes. Expression studies indicated that all four Brachypodium COMT genes are transcribed but with distinct patterns of tissue specificity. Full-length cDNAs were cloned in frame into the pQE-T7 expression vector for the purification of recombinant Brachypodium COMT proteins. Biochemical characterization of enzyme activity and substrate specificity showed that BdCOMT4 has significant effect on a broad range of substrates with the highest preference for caffeic acid. The other three COMTs had low or no effect on these substrates, suggesting that a diversified evolution occurred on these duplicate genes that not only impacted their pattern of expression, but also altered their biochemical properties.
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Affiliation(s)
- Xianting Wu
- Western Regional Research Center, USDA-ARS, 800 Buchanan Street, Albany, CA 94710, USA
- Department of Plant Sciences, University of California, Davis, CA 95616, USA
| | - Jiajie Wu
- State Key Laboratory of Crop Biology, Shandong Agricultural University, 61 Daizong Avenue, Tai'an, Shandong 271018, China
| | - Yangfan Luo
- Western Regional Research Center, USDA-ARS, 800 Buchanan Street, Albany, CA 94710, USA
| | - Jennifer Bragg
- Western Regional Research Center, USDA-ARS, 800 Buchanan Street, Albany, CA 94710, USA
| | - Olin Anderson
- Western Regional Research Center, USDA-ARS, 800 Buchanan Street, Albany, CA 94710, USA
| | - John Vogel
- Western Regional Research Center, USDA-ARS, 800 Buchanan Street, Albany, CA 94710, USA
| | - Yong Q. Gu
- Western Regional Research Center, USDA-ARS, 800 Buchanan Street, Albany, CA 94710, USA
- *Yong Q. Gu:
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50
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Philp JC, Bartsev A, Ritchie RJ, Baucher MA, Guy K. Bioplastics science from a policy vantage point. N Biotechnol 2012; 30:635-46. [PMID: 23220474 DOI: 10.1016/j.nbt.2012.11.021] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Revised: 11/23/2012] [Accepted: 11/25/2012] [Indexed: 11/26/2022]
Abstract
Society is fundamentally ambivalent to the use of plastics. On the one hand, plastics are uniquely flexible materials that have seen them occupy a huge range of functions, from simple packing materials to complex engineering components. On the other hand, their durability has raised concerns about their end-of-life disposal. When that disposal route is landfill, their invulnerability to microbial decomposition, combined with relatively low density and high bulk, means that plastics will occupy increasing amounts of landfill space in a world where available suitable landfill sites is shrinking. The search for biodegradable plastics and their introduction to the marketplace would appear to be a suitable amelioration strategy for such a problem. And yet the uptake of biodegradable plastics has been slow. The term biodegradable itself has entered public controversy, with accidental and intended misuse of the term; the intended misuse has led to accusations and instances of 'greenwashing'. For this and other reasons standards for biodegradability and compostability testing of plastics have been sought. An environmental dilemma with more far-reaching implications is climate change. The need for rapid and deep greenhouse gas (GHG) emissions cuts is one of the drivers for the resurgence of industrial biotechnology generally, and the search for bio-based plastics more specifically. Bio-based has come to mean plastics based on renewable resources, but this need not necessarily imply biodegradability. If the primary purpose is GHG emissions savings, then once again plastics durability can be a virtue, if the end-of-life solution can be energy recovery during incineration or recycling. The pattern of production is shifting from the true biodegradable plastics to the bio-based plastics, and that trend is likely to persist into the future. This paper looks at aspects of the science of biodegradable and bio-based plastics from the perspective of policy advisers and makers. It is often said that the bioplastics suffer from a lack of a favourable policy regime when compared to the wide-ranging set of policy instruments that are available on both the supply and demand side of biofuels production. Some possible policy measures are discussed.
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Affiliation(s)
- Jim C Philp
- Science and Technology Policy Division, Directorate of Science, Technology and Industry, OECD, Paris, France.
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