Plants

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GLBRC's Plants Research Area

Plants

At the GLBRC, Plants researchers are developing the next generation of biomass-trait-improved crops. Because crops will continue to be grown for food and feed in the future, research focused on enhancing plants with desirable energy traits must be pursued without sacrificing grain yield and quality.

Learn about the Center's research approach

Plants Leadership

Plants Lead

Ralph’s program is aimed at decreasing plant cell wall recalcitrance to processing and improving plant value to the biorefinery, largely by: detailing lignin structure, chemistry, and reactions; delineating the effects of perturbing lignin biosynthetic pathways; ‘redesigning’ lignins in planta to...

Plants Lead

Brandizzi is a professor in the Michigan State University-U.S. Department of Energy (MSU-DOE) Plant Research Laboratory, and brings over 15 years of academic research experience to her role at GLBRC. Prior to coming to Michigan, Brandizzi was an associate professor...

Project Overview

Primary root of live Arabidopsis thaliana seedlings grown with green fluorescence-tagged monolignol probeGLBRC Plants research is highly genomics-focused. Although most plants used in agriculture have been selected for improved production of food or fiber, future bioenergy crops will have different characteristics, including high-energy yield per hectare, ease of conversion to fuels, and agricultural sustainability. Thus, while the Center's long-term efforts focus primarily on dedicated bioenergy crops such as perennial grasses and short-rotation woody species, improving basic traits in all biomass-relevant crops including the grain annuals is a priority.

Plants research projects fall under three general categories:

  • Reducing lignocellulosic biomass recalcitrance through plant cell wall modification
  • Improving the value of the biomass grown for bioenergy production
  • Integrating these and other beneficial traits into bioenergy crops that exhibit improved nutrient use and stress tolerance for sustainable, perennialized production

Plants Publications

Establishment of a vernalization requirement in Brachypodium distachyon requires REPRESSOR OF VERNALIZATION1

Daniel P. Woods; Thomas S. Ream; Frédéric Bouché; Joohyun Lee; Nicholas Thrower; Curtis Wilkerson; Richard M. Amasino

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2017

A requirement for vernalization, the process by which prolonged cold exposure provides competence to flower, is an important adaptation to temperate climates that ensures flowering does not occur before the onset of winter. In temperate grasses, vernalization results in the up-regulation of VERNALIZATION1 (VRN1) to establish competence to flower; however, little is known about the mechanism underlying repression of VRN1 in the fall season, which is necessary to establish a vernalization requirement. Here, we report that a plant-specific gene containing a bromo-adjacent homology and transcriptional elongation factor S-II domain, which we named REPRESSOR OF VERNALIZATION1 (RVR1), represses VRN1 before vernalization in Brachypodium distachyon That RVR1 is upstream of VRN1 is supported by the observations that VRN1 is precociously elevated in an rvr1 mutant, resulting in rapid flowering without cold exposure, and the rapid-flowering rvr1 phenotype is dependent on VRN1 The precocious VRN1 expression in rvr1 is associated with reduced levels of the repressive chromatin modification H3K27me3 at VRN1, which is similar to the reduced VRN1 H3K27me3 in vernalized plants. Furthermore, the transcriptome of vernalized wild-type plants overlaps with that of nonvernalized rvr1 plants, indicating loss of rvr1 is similar to the vernalized state at a molecular level. However, loss of rvr1 results in more differentially expressed genes than does vernalization, indicating that RVR1 may be involved in processes other than vernalization despite a lack of any obvious pleiotropy in the rvr1 mutant. This study provides an example of a role for this class of plant-specific genes.

Functionality and molecular weight distribution of red oak lignin before and after pyrolysis and hydrogenation

Daniel J. McClelland; Ali Hussain Motagamwala; Yanding Li; Marjorie R. Rover; Ashley M. Wittrig; Chunping Wu; Scott Buchanan; Robert C. Brown; John Ralph; James A. Dumesic; George W. Huber

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2017

Genetic architecture of flowering-time variation in Brachypodium distachyon

Daniel P. Woods; Ryland Bednarek; Frédéric Bouché; Sean P. Gordon; John P. Vogel; David F. Garvin; Richard M. Amasino

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2017

The transition to reproductive development is a crucial step in the plant life cycle, and the timing of this transition is an important factor in crop yields. Here, we report new insights into the genetic control of natural variation in flowering time in Brachypodium distachyon, a non-domesticated pooid grass closely related to cereals such as wheat and barley. A recombinant inbred line (RIL) population derived from a cross between the rapid-flowering accession Bd21 and the delayed-flowering accession Bd1-1 were grown in a variety of environmental conditions to enable exploration of the genetic architecture of flowering time. A genotyping-by-sequencing (GBS) approach was used to develop SNP markers for genetic map construction, and quantitative trait loci (QTLs) that control differences in flowering time were identified. Many of the flowering time QTLs are detected across a range of photoperiod and vernalization conditions, suggesting that the genetic control of flowering within this population is robust. The two major QTLs identified in undomesticated B distachyon colocalize with VERNALIZATION1/PHYTOCHROME C and VERNALIZATION2, loci identified as flowering regulators in the domesticated crops wheat and barley. This suggests that variation in flowering time is controlled in part by a set of genes broadly conserved within pooid grasses.

Genome-wide associations with flowering time in switchgrass using exome-capture sequencing data

Paul P. Grabowski; Joseph Evans; Chris Daum; Shweta Deshpande; Kerrie W. Barry; Megan Kennedy; Guillaume Ramstein; Shawn M. Kaeppler; Robin Buell; Yiwei Jiang; Michael D. Casler

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2017

Flowering time is a major determinant of biomass yield in switchgrass (Panicum virgatum), a perennial bioenergy crop, because later flowering allows for an extended period of vegetative growth and increased biomass production. A better understanding of the genetic regulation of flowering time in switchgrass will aid the development of switchgrass varieties with increased biomass yields, particularly at northern latitudes, where late-flowering but southern-adapted varieties have high winter mortality. We use genotypes derived from recently published exome-capture sequencing, which mitigates challenges related to the large, highly repetitive and polyploid switchgrass genome, to perform genome-wide association studies (GWAS) using flowering time data from a switchgrass association panel in an effort to characterize the genetic architecture and genes underlying flowering time regulation in switchgrass. We identify associations with flowering time at multiple loci, including in a homolog of FLOWERING LOCUS T and in a locus containing TIMELESS, a homolog of a key circadian regulator in animals. Our results suggest that flowering time variation in switchgrass is due to variation at many positions across the genome. The relationship of flowering time and geographic origin indicates likely roles for genes in the photoperiod and autonomous pathways in generating switchgrass flowering time variation.

Hydroxystilbenes are monomers in palm fruit endocarp lignins

José Carlos Del Rio; Jorge Rencoret; Ana Gutiérrez; Hoon Kim; John Ralph

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2017

Lignin, the plant cell wall polymer that binds fibers together but makes processing difficult, is traditionally formed from three monomers, the so-called monolignols (p-coumaryl, coniferyl, and sinapyl alcohols). Recently we discovered, in grass lignins, a phenolic monomer that falls outside the canonical lignin biosynthetic pathway, the flavone tricin. As we show here, palm fruit (macaúba, carnauba, and coconut) endocarps contain lignin polymers derived in part from a previously unconsidered class of lignin monomers, the hydroxystilbenes, including the valuable compounds piceatannol and resveratrol. Piceatannol could be released from these lignins upon DFRC, a degradative method that cleaves β-ether bonds, indicating that at least a fraction is incorporated through labile ether bonds. NMR spectroscopy of products from the copolymerization of piceatannol and monolignols confirms the structures in the natural polymer, and demonstrates that piceatannol acts as an authentic monomer participating in coupling and cross-coupling reactions during lignification. Palm fruit endocarps therefore contain a new class of 'stilbenolignin' polymers, further expanding the definition of lignin and implying that compounds such as piceatannol and resveratrol are potentially available in what is now essentially a waste product.

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