Cell-Wall Composition and Accessibility to Hydrolytic Enzymes is Differentially Altered in Divergently Bred Switchgrass ( Panicum virgatum L.) Genotypes.

Gautam Sarath; Danny Akin; Robert Mitchell; Kenneth Vogel

Abstract  The aims of this study were to understand the genotypic variability in cell-wall composition and cell-wall accessibility to enzymes in select switchgrass plants obtained from two different populations derived from a base population of octaploid cultivars. Population C 3 was developed by three breeding generations for high digestibility and population C−1 developed by one generation of breeding for low digestibility. Above-ground biomass from 12 selected genotypes, three each with high or low digestibility within each population, was analyzed for their cell-wall aromatics and polysaccharides. The ratio of p-coumaric acid/ferulic acid was greater (P ≤ 0.05) for the high-lignin C−1 population over the low-lignin C 3 population, although the amounts of these two phenolics did not differ between populations. Combined values of guaiacyl syringyl-lignin were consistently higher in genotypes from the C−1 population as compared to the genotypes from the C 3 population. Overall, p-coumaric acid was released by enzymes in greater amounts than ferulic acid in all these genotypes. Genotypes in the C−1 population exhibited lower dry weight loss as compared to the genotypes in the C 3 population after enzymatic digestion, suggesting changes in cell-wall architecture. Overall, our data highlight the phenotypic plasticity coded by the switchgrass genome and suggest that combining dry matter digestibility with other more specific cell-wall traits could result in genotypes with greater utility as bioenergy feedstocks.

HYDROLASES; SWITCHGRASS; GENOTYPE-environment interaction; BIOMASS

Applied Biochemistry & Biotechnology, 2008, Vol 150, Issue 1, p1

0273-2289

Academic Journal

10.1007/s12010-008-8168-5