Highlights

GLBRC's Publications

Highlights

Our researchers consistently turn out new and innovative research that can lead to publications and new technology. On this page we'll highlight new research publications and/or activities in the GLBRC that underscore the great work that our researchers are doing.

In this study, we further characterized a mutant gene (wri1-1) in the plant Arabidopsis that leads to strong reduction in seed oil content. We also identified a primary root defect and confirmed altered homeostasis in auxin, a growth regulator that plays an important role in plant development. 

In this study, we identified flowering time gene candidates that could be employed to manipulate flowering time in upland, cold-tolerant switchgrass cultivars, with the goal of increasing total biomass yield for these northern accessions. 

In this study, we tested Zip-lignin poplar vs. wild-type hybrid poplar to determine if Zip-lignin’s strategic lignin modifications, specifically engineered to reduce recalcitrance, enhance chemical pulping efficiencies. As predicted, Zip-lignin poplar demonstrated improved processing. 

Assessing and predicting field-scale soil N2O (nitrous oxide) emissions remains imprecise because much of N2O production occurs within very small soil volumes called “hotspots.” In this study, we found that water absorption by plant residue creates unique conditions that can result in accelerated N2O emissions.

Recent discoveries indicate that lignification is a flexible mechanism and that plants are capable of using a variety of phenolic compounds for the formation of lignin polymers. In this study, we report the occurrence of a new class of polyphenolic compounds – hydroxystilbenes – the second such class arising from outside the monolignol biosynthetic pathway, in the lignins of palm fruit endocarps.

Stem length is a key trait for various sorghum genotypes, impacting biomass yield, plant architecture, and other important crop features. In this study, we identified the gene encoded by Dw2, a locus known to affect stem internode length; this gene encodes a protein kinase homologous to a member of the AGC protein kinase family in the plant Arabidopsis.

Cellulosic bioenergy offers environmental benefits not available from other biofuels, but requires substantial amounts of land and creates the potential for environmental harm. It is therefore important to understand how different bioenergy crop and management choices will simultaneously affect climate mitigation, biodiversity, reactive nitrogen loss, and water use in future biofuel landscapes.

To improve bioenergy crop composition and yield, we seek to understand activation of the unfolded protein response (UPR) and its impact on the ability of plant cells to accumulate easily digestible carbohydrates such as mixed-linkage glucan (MLG). Here we identify a Brachypodium UPR transcription factor, UPR genes responsive to chemical or heat stress, and impacts of heat stress on MLG accumulation.

Bioenergy sorghum accumulates 75% of shoot biomass in its stem internodes. To identify genes and molecular mechanisms that modulate the extent of internode growth, we conducted microscopic and transcriptomic analyses of four successive sub-apical vegetative internodes representing different stages of internode development of the bioenergy sorghum genotype R.07020.

To develop bioenergy crops that produce extra lipids for extraction as oil biofuel, we examined whether lipid transport complexes of plants with different lipid acyl composition have diverged in their function. 

We used transposon sequencing (Tn-seq) to identify essential genes in the bacterium Rhodobacter sphaeroides under several growth conditions. We then used that data to evaluate and refine an existing genome-scale metabolic model, providing more precise systems-level understanding of the diverse metabolic lifestyles of this bacterium. 

To better understand flowering time control in temperate grasses, we sought to identify which genes prevent a grass from flowering until it has undergone prolonged cold exposure. After screening for and identifying mutants in the grass species Brachypodium distachyon, we identified a mutant that flowers rapidly without cold exposure, and described and characterized a new gene we named REPRESSOR OF VERNALIZATION1 (RVR1). 

Microbial production of lipids in high yield presents a significant challenge, often falling short of what can be theoretically obtained. This study characterized high-lipid mutant variants of Rhodobacter sphaeroides and showed that alterations to the bacterial cell envelope can result in increased accumulation of lipids relative to the parent strain.

Researchers show that the three main components of plant biomass can be converted to high value products in economically favorable yields when using the solvent gamma-valerolactone (GVL) to break apart the biomass. Researchers show that the three main components of plant biomass can be converted to high value products in economically favorable yields when using the solvent gamma-valerolactone (GVL) to break apart the biomass. 

Introducing ester linkages into the lignin polymer backbone that decrease biomass recalcitrance in poplar has the potential to reduce the energy and/or amount of ionic liquids required for effective pretreatment.

Pretreating lignocellulosic biomass using microbes such as C. thermocellum enables a one-pot process for breaking down sugars and fermenting those sugars for fuel and chemicals. In this study, we examined the bacterium’s efficiency in breaking down cellulose in industrially relevant pretreated biomass, finding that pretreatments that remove both lignin and hemicellulose can help improve the specific activity of the bacterium’s cellulosomal enzymes.

In this study, we examined features of a lignin biosynthetic mutant in maize that we hypothesized could result in an increase in the levels of more readily cleavable ester bonds (“zip-lignin”) in the lignin backbone. The maize ccr1 mutant displayed reduced total lignin content with no growth penalties, higher zip-lignin levels, and higher levels of sugar release. 

To help identify better management practices for more productive bioenergy cropping systems, we used two switchgrass sites to investigate the causes of biomass loss over time, and identified plant components contributing to nitrogen (N) loss or retention at different harvest times. 

Depolymerizing lignin, the complex phenolic polymer fortifying plant cell walls, is challenging, making lignin a major barrier to gaining access to stored energy in lignocellulosic materials. Here we reveal unprecedentedly rapid lignin depolymerization and degradation in an ancient fungus-cultivating termite system; we combine laboratory-feeding experiments with step-wise structural and chemical analyses performed while the woody material is digested in this symbiotic system.

Glycoside hydrolases (GH) are enzymes that release sugar from cellulose, hemicellulose, and other polysaccharides. Understanding the specificity of GH enzyme reactions in the context of the plant cell wall is essential to providing more efficient ways to deconstruct plant biomass for biofuels production.

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