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Happs R, Hanes RJ, Bartling AW, Field JL, Harman-Ware AE, Clark RJ, Pendergast TH, Devos KM, Webb EG, Missaoui A, Xu Y, Makaju S, Shrestha V, Mazarei M, Stewart CN, Millwood RJ, Davison BH. Economic and Sustainability Impacts of Yield and Composition Variation in Bioenergy Crops: Switchgrass ( Panicum virgatum L.). ACS SUSTAINABLE CHEMISTRY & ENGINEERING 2024; 12:1897-1910. [PMID: 38333206 PMCID: PMC10848292 DOI: 10.1021/acssuschemeng.3c05770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 12/20/2023] [Accepted: 12/20/2023] [Indexed: 02/10/2024]
Abstract
Economically viable production of biobased products and fuels requires high-yielding, high-quality, sustainable process-advantaged crops, developed using bioengineering or advanced breeding approaches. Understanding which crop phenotypic traits have the largest impact on biofuel economics and sustainability outcomes is important for the targeted feedstock crop development. Here, we evaluated biomass yield and cell-wall composition traits across a large natural variant population of switchgrass (Panicum virgatum L.) grown across three common garden sites. Samples from 331 switchgrass genotypes were collected and analyzed for carbohydrate and lignin components. Considering plant survival and biomass after multiple years of growth, we found that 84 of the genotypes analyzed may be suited for commercial production in the southeastern U.S. These genotypes show a range of growth and compositional traits across the population that are apparently independent of each other. We used these data to conduct techno-economic analyses and life cycle assessments evaluating the performance of each switchgrass genotype under a standard cellulosic ethanol process model with pretreatment, added enzymes, and fermentation. We find that switchgrass yield per area is the largest economic driver of the minimum fuel selling price (MSFP), ethanol yield per hectare, global warming potential (GWP), and cumulative energy demand (CED). At any yield, the carbohydrate content is significant but of secondary importance. Water use follows similar trends but has more variability due to an increased dependence on the biorefinery model. Analyses presented here highlight the primary importance of plant yield and the secondary importance of carbohydrate content when selecting a feedstock that is both economical and sustainable.
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Affiliation(s)
- Renee
M. Happs
- Renewable
Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
- Center
for Bioenergy Innovation, Oak Ridge National
Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Rebecca J. Hanes
- Strategic
Energy Analysis Center, National Renewable
Energy Laboratory, Golden, Colorado 80401, United States
- Center
for Bioenergy Innovation, Oak Ridge National
Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Andrew W. Bartling
- Catalytic
Carbon and Transformation Center, National
Renewable Energy Laboratory, Golden, Colorado 80401, United States
- Center
for Bioenergy Innovation, Oak Ridge National
Laboratory, Oak Ridge, Tennessee 37830, United States
| | - John L. Field
- Environmental
Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
- Center
for Bioenergy Innovation, Oak Ridge National
Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Anne E. Harman-Ware
- Renewable
Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
- Center
for Bioenergy Innovation, Oak Ridge National
Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Robin J. Clark
- Environmental
Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
- Center
for Bioenergy Innovation, Oak Ridge National
Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Thomas H. Pendergast
- Institute
of Plant Breeding, Genetics and Genomics, University of Georgia, Athens, Georgia 30602, United States
- Department
of Crop and Soil Sciences, University of
Georgia, Athens, Georgia 30602, United States
- Department
of Plant Biology, University of Georgia, Athens, Georgia 30602, United States
- Center
for Bioenergy Innovation, Oak Ridge National
Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Katrien M. Devos
- Institute
of Plant Breeding, Genetics and Genomics, University of Georgia, Athens, Georgia 30602, United States
- Department
of Crop and Soil Sciences, University of
Georgia, Athens, Georgia 30602, United States
- Department
of Plant Biology, University of Georgia, Athens, Georgia 30602, United States
- Center
for Bioenergy Innovation, Oak Ridge National
Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Erin G. Webb
- Environmental
Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
- Center
for Bioenergy Innovation, Oak Ridge National
Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Ali Missaoui
- Institute
of Plant Breeding, Genetics and Genomics, University of Georgia, Athens, Georgia 30602, United States
- Department
of Crop and Soil Sciences, University of
Georgia, Athens, Georgia 30602, United States
- Center
for Bioenergy Innovation, Oak Ridge National
Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Yaping Xu
- Department
of Plant Sciences, University of Tennessee
Knoxville, Knoxville, Tennessee 37919, United States
- Center
for Bioenergy Innovation, Oak Ridge National
Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Shiva Makaju
- Institute
of Plant Breeding, Genetics and Genomics, University of Georgia, Athens, Georgia 30602, United States
- Department
of Crop and Soil Sciences, University of
Georgia, Athens, Georgia 30602, United States
- Center
for Bioenergy Innovation, Oak Ridge National
Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Vivek Shrestha
- Department
of Plant Sciences, University of Tennessee
Knoxville, Knoxville, Tennessee 37919, United States
- Center
for Bioenergy Innovation, Oak Ridge National
Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Mitra Mazarei
- Department
of Plant Sciences, University of Tennessee
Knoxville, Knoxville, Tennessee 37919, United States
- Center
for Bioenergy Innovation, Oak Ridge National
Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Charles Neal Stewart
- Department
of Plant Sciences, University of Tennessee
Knoxville, Knoxville, Tennessee 37919, United States
- Center
for Bioenergy Innovation, Oak Ridge National
Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Reginald J. Millwood
- Department
of Plant Sciences, University of Tennessee
Knoxville, Knoxville, Tennessee 37919, United States
- Center
for Bioenergy Innovation, Oak Ridge National
Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Brian H. Davison
- Biosciences
Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
- Center
for Bioenergy Innovation, Oak Ridge National
Laboratory, Oak Ridge, Tennessee 37830, United States
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Tiedge K, Destremps J, Solano-Sanchez J, Arce-Rodriguez ML, Zerbe P. Foxtail mosaic virus-induced gene silencing (VIGS) in switchgrass (Panicum virgatum L.). PLANT METHODS 2022; 18:71. [PMID: 35644680 PMCID: PMC9150325 DOI: 10.1186/s13007-022-00903-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 05/07/2022] [Indexed: 05/08/2023]
Abstract
BACKGROUND Although the genome for the allotetraploid bioenergy crop switchgrass (Panicum virgatum) has been established, limitations in mutant resources have hampered in planta gene function studies toward crop optimization. Virus-induced gene silencing (VIGS) is a versatile technique for transient genetic studies. Here we report the implementation of foxtail mosaic virus (FoMV)-mediated gene silencing in switchgrass in above- and below-ground tissues and at different developmental stages. RESULTS The study demonstrated that leaf rub-inoculation is a suitable method for systemic gene silencing in switchgrass. For all three visual marker genes, Magnesium chelatase subunit D (ChlD) and I (ChlI) as well as phytoene desaturase (PDS), phenotypic changes were observed in leaves, albeit at different intensities. Gene silencing efficiency was verified by RT-PCR for all tested genes. Notably, systemic gene silencing was also observed in roots, although silencing efficiency was stronger in leaves (~ 63-94%) as compared to roots (~ 48-78%). Plants at a later developmental stage were moderately less amenable to VIGS than younger plants, but also less perturbed by the viral infection. CONCLUSIONS Using FoMV-mediated VIGS could be achieved in switchgrass leaves and roots, providing an alternative approach for studying gene functions and physiological traits in this important bioenergy crop.
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Affiliation(s)
- Kira Tiedge
- Department of Plant Biology, University of California, Davis, USA.
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands.
| | | | | | | | - Philipp Zerbe
- Department of Plant Biology, University of California, Davis, USA
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Razar RM, Qi P, Devos KM, Missaoui AM. Genotyping-by-Sequencing and QTL Mapping of Biomass Yield in Two Switchgrass F 1 Populations (Lowland x Coastal and Coastal x Upland). FRONTIERS IN PLANT SCIENCE 2022; 13:739133. [PMID: 35665173 PMCID: PMC9162799 DOI: 10.3389/fpls.2022.739133] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Accepted: 04/06/2022] [Indexed: 06/15/2023]
Abstract
The prevalence of genetic diversity in switchgrass germplasm can be exploited to capture favorable alleles that increase its range of adaptation and biomass yield. The objectives of the study were to analyze the extent of polymorphism and patterns of segregation distortion in two F1 populations and use the linkage maps to locate QTL for biomass yield. We conducted genotyping-by-sequencing on two populations derived from crosses between the allotetraploid lowland genotype AP13 (a selection from "Alamo") and coastal genotype B6 (a selection from PI 422001) with 285 progeny (AB population) and between B6 and the allotetraploid upland VS16 (a selection from "Summer") with 227 progeny (BV population). As predictable from the Euclidean distance between the parents, a higher number of raw variants was discovered in the coastal × upland BV cross (6 M) compared to the lowland × coastal AB cross (2.5 M). The final number of mapped markers was 3,107 on the BV map and 2,410 on the AB map. More segregation distortion of alleles was seen in the AB population, with 75% distorted loci compared to 11% distorted loci in the BV population. The distortion in the AB population was seen across all chromosomes in both the AP13 and B6 maps and likely resulted from zygotic or post-zygotic selection for increased levels of heterozygosity. Our results suggest lower genetic compatibility between the lowland AP13 and the coastal B6 ecotype than between B6 and the upland ecotype VS16. Four biomass QTLs were mapped in the AB population (LG 2N, 6K, 6N, and 8N) and six QTLs in the BV population [LG 1N (2), 8N (2), 9K, and 9N]. The QTL, with the largest and most consistent effect across years, explaining between 8.4 and 11.5% of the variation, was identified on 6N in the AP13 map. The cumulative effect of all the QTLs explained a sizeable portion of the phenotypic variation in both AB and BV populations and the markers associated with them may potentially be used for the marker-assisted improvement of biomass yield. Since switchgrass improvement is based on increasing favorable allele frequencies through recurrent selection, the transmission bias within individuals and loci needs to be considered as this may affect the genetic gain if the favorable alleles are distorted.
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Affiliation(s)
- Rasyidah M. Razar
- Institute of Plant Breeding, Genetics and Genomics, University of Georgia, Athens, GA, United States
- Genetic Resources and Improvement Unit, RRIM Research Station, Malaysian Rubber Board, Selangor, Malaysia
| | - Peng Qi
- Institute of Plant Breeding, Genetics and Genomics, University of Georgia, Athens, GA, United States
- Department of Crop and Soil Sciences, University of Georgia, Athens, GA, United States
- Department of Plant Biology, University of Georgia, Athens, GA, United States
| | - Katrien M. Devos
- Institute of Plant Breeding, Genetics and Genomics, University of Georgia, Athens, GA, United States
- Department of Crop and Soil Sciences, University of Georgia, Athens, GA, United States
- Department of Plant Biology, University of Georgia, Athens, GA, United States
| | - Ali M. Missaoui
- Institute of Plant Breeding, Genetics and Genomics, University of Georgia, Athens, GA, United States
- Department of Crop and Soil Sciences, University of Georgia, Athens, GA, United States
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Poudel HP, Tilhou NW, Sanciangco MD, Vaillancourt B, Kaeppler SM, Buell CR, Casler MD. Genetic loci associated with winter survivorship in diverse lowland switchgrass populations. THE PLANT GENOME 2021; 14:e20159. [PMID: 34661986 DOI: 10.1002/tpg2.20159] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 08/26/2021] [Indexed: 06/13/2023]
Abstract
High winter mortality limits biomass yield of lowland switchgrass (Panicum virgatum L.) planted in the northern latitudes of North America. Breeding of cold tolerant switchgrass cultivars requires many years due to its perennial growth habit and the unpredictable winter selection pressure that is required to identify winter-hardy individuals. Identification of causal genetic variants for winter survivorship would accelerate the improvement of switchgrass biomass production. The objective of this study was to identify allelic variation associated with winter survivorship in lowland switchgrass populations using bulk segregant analysis (BSA). Twenty-nine lowland switchgrass populations were evaluated for winter survival at two locations in southern Wisconsin and 21 populations with differential winter survivorship were used for BSA. A maximum of 10% of the individuals (8-20) were bulked to create survivor and nonsurvivor DNA pools from each population and location. The DNA pools were evaluated using exome capture sequencing, and allele frequencies were used to conduct statistical tests. The BSA tests revealed nine quatitative trait loci (QTL) from tetraploid populations and seven QTL from octoploid populations. Many QTL were population-specific, but some were identified in multiple populations that originated across a broad geographic landscape. Four QTL (at positions 88 Mb on chromosome 2N, 115 Mb on chromosome 5K, and 1 and 100 Mb on chromosome 9N) were potentially the most useful QTL. Markers associated with winter survivorship in this study can be used to accelerate breeding cycles of lowland switchgrass populations and should lead to improvements in adaptation within USDA hardiness zones 4 and 5.
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Affiliation(s)
- Hari P Poudel
- Agriculture and Agri-Food Canada, Lethbridge, AB, Canada
| | - Neal W Tilhou
- Dep. of Agronomy, Univ. of Wisconsin-Madison, Madison, WI, USA
| | | | | | | | - C Robin Buell
- Dep. of Plant Biology, Michigan State Univ., East Lansing, MI, USA
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5
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Genome editing in fruit, ornamental, and industrial crops. Transgenic Res 2021; 30:499-528. [PMID: 33825100 DOI: 10.1007/s11248-021-00240-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 02/25/2021] [Indexed: 01/24/2023]
Abstract
The advent of genome editing has opened new avenues for targeted trait enhancement in fruit, ornamental, industrial, and all specialty crops. In particular, CRISPR-based editing systems, derived from bacterial immune systems, have quickly become routinely used tools for research groups across the world seeking to edit plant genomes with a greater level of precision, higher efficiency, reduced off-target effects, and overall ease-of-use compared to ZFNs and TALENs. CRISPR systems have been applied successfully to a number of horticultural and industrial crops to enhance fruit ripening, increase stress tolerance, modify plant architecture, control the timing of flower development, and enhance the accumulation of desired metabolites, among other commercially-important traits. As editing technologies continue to advance, so too does the ability to generate improved crop varieties with non-transgenic modifications; in some crops, direct transgene-free edits have already been achieved, while in others, T-DNAs have successfully been segregated out through crossing. In addition to the potential to produce non-transgenic edited crops, and thereby circumvent regulatory impediments to the release of new, improved crop varieties, targeted gene editing can speed up trait improvement in crops with long juvenile phases, reducing inputs resulting in faster market introduction to the market. While many challenges remain regarding optimization of genome editing in ornamental, fruit, and industrial crops, the ongoing discovery of novel nucleases with niche specialties for engineering applications may form the basis for additional and potentially crop-specific editing strategies.
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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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Wang Y, Dong W, Saha MC, Udvardi MK, Kang Y. Improved node culture methods for rapid vegetative propagation of switchgrass (Panicum virgatum L.). BMC PLANT BIOLOGY 2021; 21:128. [PMID: 33663376 PMCID: PMC7931530 DOI: 10.1186/s12870-021-02903-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 02/25/2021] [Indexed: 05/25/2023]
Abstract
BACKGROUND Switchgrass (Panicum virgatum L.) is an important bioenergy and forage crop. The outcrossing nature of switchgrass makes it infeasible to maintain a genotype through sexual propagation. Current asexual propagation protocols in switchgrass have various limitations. An easy and highly-efficient vegetative propagation method is needed to propagate large natural collections of switchgrass genotypes for genome-wide association studies (GWAS). RESULTS Micropropagation by node culture was found to be a rapid method for vegetative propagation of switchgrass. Bacterial and fungal contamination during node culture is a major cause for cultural failure. Adding the biocide, Plant Preservative Mixture (PPM, 0.2%), and the fungicide, Benomyl (5 mg/l), in the incubation solution after surface sterilization and in the culture medium significantly decreased bacterial and fungal contamination. In addition, "shoot trimming" before subculture had a positive effect on shoot multiplication for most genotypes tested. Using the optimized node culture procedure, we successfully propagated 330 genotypes from a switchgrass GWAS panel in three separate experiments. Large variations in shoot induction efficiency and shoot growth were observed among genotypes. Separately, we developed an in planta node culture method by stimulating the growth of aerial axillary buds into shoots directly on the parent plants, through which rooted plants can be generated within 6 weeks. By circumventing the tissue culture step and avoiding application of exterior hormones, the in planta node culture method is labor- and cost-efficient, easy to master, and has a high success rate. Plants generated by the in planta node culture method are similar to seedlings and can be used directly for various experiments. CONCLUSIONS In this study, we optimized a switchgrass node culture protocol by minimizing bacterial and fungal contamination and increasing shoot multiplication. With this improved protocol, we successfully propagated three quarters of the genotypes in a diverse switchgrass GWAS panel. Furthermore, we established a novel and high-throughput in planta node culture method. Together, these methods provide better options for researchers to accelerate vegetative propagation of switchgrass.
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Affiliation(s)
- Yongqin Wang
- Noble Research Institute, LLC, Ardmore, OK, 73401, USA
| | - Weihong Dong
- Noble Research Institute, LLC, Ardmore, OK, 73401, USA
| | - Malay C Saha
- Noble Research Institute, LLC, Ardmore, OK, 73401, USA
| | | | - Yun Kang
- Noble Research Institute, LLC, Ardmore, OK, 73401, USA.
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Pancaldi F, Trindade LM. Marginal Lands to Grow Novel Bio-Based Crops: A Plant Breeding Perspective. FRONTIERS IN PLANT SCIENCE 2020; 11:227. [PMID: 32194604 PMCID: PMC7062921 DOI: 10.3389/fpls.2020.00227] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 02/13/2020] [Indexed: 05/09/2023]
Abstract
The biomass demand to fuel a growing global bio-based economy is expected to tremendously increase over the next decades, and projections indicate that dedicated biomass crops will satisfy a large portion of it. The establishment of dedicated biomass crops raises huge concerns, as they can subtract land that is required for food production, undermining food security. In this context, perennial biomass crops suitable for cultivation on marginal lands (MALs) raise attraction, as they could supply biomass without competing for land with food supply. While these crops withstand marginal conditions well, their biomass yield and quality do not ensure acceptable economic returns to farmers and cost-effective biomass conversion into bio-based products, claiming genetic improvement. However, this is constrained by the lack of genetic resources for most of these crops. Here we first review the advantages of cultivating novel perennial biomass crops on MALs, highlighting management practices to enhance the environmental and economic sustainability of these agro-systems. Subsequently, we discuss the preeminent breeding targets to improve the yield and quality of the biomass obtainable from these crops, as well as the stability of biomass production under MALs conditions. These targets include crop architecture and phenology, efficiency in the use of resources, lignocellulose composition in relation to bio-based applications, and tolerance to abiotic stresses. For each target trait, we outline optimal ideotypes, discuss the available breeding resources in the context of (orphan) biomass crops, and provide meaningful examples of genetic improvement. Finally, we discuss the available tools to breed novel perennial biomass crops. These comprise conventional breeding methods (recurrent selection and hybridization), molecular techniques to dissect the genetics of complex traits, speed up selection, and perform transgenic modification (genetic mapping, QTL and GWAS analysis, marker-assisted selection, genomic selection, transformation protocols), and novel high-throughput phenotyping platforms. Furthermore, novel tools to transfer genetic knowledge from model to orphan crops (i.e., universal markers) are also conceptualized, with the belief that their development will enhance the efficiency of plant breeding in orphan biomass crops, enabling a sustainable use of MALs for biomass provision.
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Affiliation(s)
| | - Luisa M. Trindade
- Plant Breeding, Wageningen University & Research, Wageningen, Netherlands
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9
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Evaluation of Switchgrass Genotypes for Cold-Tolerant Seed Germination from Native Populations in the Northeast USA. PLANTS 2019; 8:plants8100394. [PMID: 31581729 PMCID: PMC6843356 DOI: 10.3390/plants8100394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 09/28/2019] [Accepted: 09/30/2019] [Indexed: 11/16/2022]
Abstract
The focus of this research was to evaluate genotypes for cold-tolerant germination from wild switchgrass (Panicum virgatum L.) populations collected in the Northeast USA. Switchgrass nurseries were established in 2008 and 2009 with seed collected from native stands of switchgrass in the Northeast USA between 1991 and 2008. Switchgrass seed harvested from individual genotypes was evaluated for cold-tolerant germination in a series of laboratory experiments. Germination assays of seed of 13 switchgrass genotypes harvested in the fall of 2016 are the primary focus of this reported research. The selected genotypes were evaluated for cold-tolerant seed germination in three experiments, during the spring of 2017, fall of 2017 and spring of 2018, (with and without stratification) using a 10/15 °C regime with a 12 h photoperiod. Germination tests showed that several genotypes had significantly higher percentage germination as well as faster germination rates expressed as T50 (number of days required to reach 50% maximum germination) when compared to Cave-in-Rock, a moderately sensitive cold-tolerant commercial cultivar established in the original switchgrass nursery as a control. A final germination test was conducted to compare seed from the original population (no selection cycle 0), with one of the top performing cold-tolerant germination genotypes, and a commercial cultivar, 'Espresso', developed for low seed dormancy and low temperature germination. In this test, the selected genotype had significantly higher percentage germination in the stratified treatment and was not significantly different than Espresso in the non-stratified test. These data indicate successful selection for cold-tolerant germination in switchgrass genotypes from native germplasm collected in the Northeast USA.
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