Ajaya K. Biswal, Byron Crowe, Kerry Hosmer Caffall, Sivakumar Pattathil, Utku Avci, Michael G. Hahn, Debra Mohnen

Complex Carbohydrate Research Center, BioEnergy Science Center (BESC), University of Georgia, 315 Riverbend Road, Athens, GA 30602, USA

The plant cell wall is a complex polysaccharide and protein matrix that has evolved over millions of years to resist deconstruction by pathogens and humankind.  Synthesis of the plant cell wall is controlled by the production of activated sugar substrates and by the action of glycosyltransferases that synthesize diverse cell wall polysaccharides.  The synthesized polymers are also modified by a series of methyl, acetyl and other transferases to yield the polymers found in intact cell walls.  We have identified a gene, via studies of Arabidopsis thaliana mutants, that encodes a plant polysaccharide metabolizing enzyme which appears to modify plant biomass recalcitrance.  Multiple sets of data will be presented, including transcript expression profiling, characterization of growth and cell wall phenotypes of multiple homozygous T-DNA mutant lines, as well as wall glycosyl residue composition analyses and reactivity of walls from mutant and wild type plants with cell wall glycan-directed monoclonal antibodies.  The data show that the mutants are modified in the tenacity of polymer association in the wall.  Taken together these results suggest that the identified gene is a high priority putative recalcitrance gene target for modifying plant biomass to facilitate production of biofuels and biopolymers. [The BioEnergy Science Center is supported by the Office of Biological and Environmental Research in the DOE Office of Science,  grant DE-PS02-06ER64304; additional funding from NSF MCB award 0646109]