Biochemical and physiological flexibility accompanies reduced cellulose biosynthesis in the model grass Brachypodium distachyon

How do grasses make cellulose for cell walls? Brabham and colleagues have been examining the genes.

Despite the fact that the majority of terrestrial biomass is produced by grasses, few studies have investigated the process of cellulose biosynthesis in monocotyledonous species. The family Poaceae is the most economically important group of plants and includes crops such as cereals, forage grasses, biofuel feedstocks and a variety of weed species. Most studies on cellulose biosynthesis have focussed on the model eudicot Arabidopsis thaliana. From these studies there is now a good understanding of the genes involved in cellulose biosynthesis and it is worth noting that, based on phylogenetic studies, cellulose biosynthetic genes appear quite conserved across monocotyledons and dicotyledonous plants. There are however some important differences. Specifically, a cellulose synthesis inhibitor that is effective in eudicots has little effect in grasses, suggesting that structural or functional differences may exist in the cellulose biosynthetic machinery of monocot species.

A model of CESA1 revealing the location of the mutation S830N (purple) within the cytoplasmic region. Image credit: Brabham et al.

In a recent study published in AoBP, Brabham et al. sought to gain functional insights into the role of the CELLULOSE SYNTHASE CESA1 gene in the model grass species Brachypodium distachyon using S830N mutants produced with TILLING and SCAMPRing. Whole-plant physiological studies were used to learn about the impact of reduced cellulose biosynthesis in these mutants. Consistent with a phenotype linked to the primary cell wall, the upper stems of cellulose deficient mutants were biomechanically weaker, but the lower stem tissue exhibited no significant change in biomechanical properties. These plants also had significantly higher numbers of nodes. This study provides fundamental information about the nature of cellulose biosynthesis in grasses and the authors conclude that practical applications may be foreseeable, for example increasing stem strength to prevent lodging.

Researcher highlight

Image credit: The University of Kentucky Magazine

Dr. Seth DeBolt is eager to improve our knowledge of the key chemical components that determine quality in alcoholic beverages. As a graduate student specializing in viticulture, he divided his time between the University of Adelaide and the University of California, Davis. With both institutions based in prominent wine-growing regions, he was able to conduct groundbreaking research, discovering the tartaric acid pathway in wine grapes.

Dr. DeBolt is now the director of the Distillation, Wine and Brewing Undergraduate Certificate Program at the University of Kentucky and is collaborating on a variety of projects across campus and within the spirits industry focusing on bourbon whiskey production, flavor and quality. He is also interested in the fundamental mechanisms by which plants create shape and form structure, focusing on structural carbohydrates and how these can be used by humans.

For more information on Seth and his work please visit his lab website: http://www.uky.edu/Ag/Horticulture/DeBolt%20Lab/Site/Welcome.html