Submitted to: Applied Biochemistry and Biotechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/29/2008
Publication Date: 7/1/2008
Citation: Sarath, G., Akin, D.E., Vogel, K.P., Mitchell, R. 2008. Cell wall composition and accessibility to hydrolytic enzymes is differentially altered in divergently bred switchgrass (Panicum virgatum L.) genotypes. Applied Biochemistry and Biotechnology. 2008 Jul; 150: 1-14. Interpretive Summary: Switchgrass biomass is primarily composed of cell wall constituents. The relative abundance of components such as cellulose lignin and phenolic acids can significantly influence biomass quality. In this paper baseline information on cell wall chemistry has been elucidated for a range of switchgrass plants. Our data highlight the different biomass-related quality parameters that can be exploited through breeding.
Technical Abstract: Switchgrass plants from two populations, C+3 developed by three breeding generations for high digestibility and C-1 developed by one generation of breeding for low digestibility, were used in this study Above ground biomass from 12 selected genotypes, 3 each with high or low digestibility within each population were 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 DMD with other more specific cell-wall traits could result in genotypes with greater utility as bioenergy feedstocks.