Thursday, May 3, 2012: 8:30 AM
Waterbury Ballroom, 2nd fl (Sheraton New Orleans)
We are using Arabidopsis and rice as model systems to identify and biochemically characterize selected target genes that are predicted to have a role in the synthesis and modification of 4-O-methyl-glucuronoxylan (GX) in dicots and arabinoxylan in grasses, respectively. To this end, we used in silico expression analyses to identify a series of candidate genes which are highly expressed during secondary cell wall formation. For Arabidopsis, the corresponding homozygous mutants were then obtained and used to determine the effects of the mutations on secondary cell wall GX structure and recalcitrance. The results of these studies allowed us to separate the mutants into chemotypic groups based on the affect of the mutation on GX average degree of polymerization, altered sidechain substitution and/or composition, and GX hetero/homodispersity. The effects of these mutations on the structure of secondary cell wall xylan and cell wall recalcitrance are under investigation. We have expanded this approach to grasses using RNAi in rice as a model. The knowledge gained from work with model monocots and dicots will be used to develop strategies to engineer the cell walls of poplar and switchgrass energy crops to improve their bioprocessing characteristics.