11-22: Identifying GAUT promoters and associated transcription factors and characterization of two Arabidopsis and Populus GAUTs

One focus of the BioEnergy Science Center (BESC) is to gain an understanding of plant cell wall biosynthesis to enable the decrease of plant biomass recalcitrance to deconstruction.  Plant walls are composed of proteins and polysaccharides whose synthesis is regulated by multiple transcription factor (TF) families.  Pectins are complex polysaccharides that contribute to wall biochemical and physical properties. The pectic polysaccharide homogalacturonan is synthesized by galacturonosyltransferase 1 (GAUT1) and other GAUT gene family members are proposed to function in pectin and matrix polysaccharide synthesis. GAUT genes are expressed in cells containing both primary and secondary walls.  To identify transcription factors that regulate the GAUTs and may be recalcitrance targets, promoter regions for all 15 Arabidopsis GAUTs were identified and analyzed for TF binding sites.  Multiple TF families and 14 TF genes along with several conserved motifs were identified and are being characterized to ascertain function in regulating GAUT gene expression.  We also identified two GAUT gene candidates for improving plant biomass for biofuel production.  The cell wall composition and growth phenotypes of these Arabidopsis and Populus gaut mutants are being characterized.  The Arabidopsis mutants have an early and tall inflorescence phenotype and marked changes in wall composition and Glycome Profiling compared to wild type plants. Funding is from DOE center grant DOE DE-FG02-09ER20097 and BioEnergy Science Center grant DE-PS02-06ER64304. The BioEnergy Science Center is a U.S. Department of Energy Bioenergy Research Center supported by the Office of Biological and Environmental Research in the DOE Office of Science.