Identifying the catalytic components of cellulose synthase and the maize mixed-linkage beta-glucan synthase

Nicholas C Carpita

关键词: BARLEY;    CELL WALL;    CELLULOSE;    DEFECTS;    FLEXIBILITY;    GENES;    INTERACTIONS;    MAIZE;    MEMBRANES;    MUTANTS;    POLYPEPTIDES;    POLYSACCHARIDES;    PROTEINS;    SPECIFICITY;    SYNTHESIS plant cell walls;    cellulose biosynthesis;    beta-glucan biosynthesis;    Golgi proteomics;    VIGS;    regulation of cellulose synthesis;   

DOI  :  10.2172/951273
RP-ID  :  DE-FG02-05ER15654 Final Report
PID  :  OSTI ID: 951273
Others  :  TRN: US201104%%25

学科分类：生物科学（综合）

美国|英语

来源: SciTech Connect

【 摘 要 】

Five specific objectives of this project are to develop strategies to identify the genes that encode the catalytic components of "mixed-linkage" (1→3),(1→4)-beta-D-glucans in grasses, to determine the protein components of the synthase complex, and determine the biochemical mechanism of synthesis. We have used proteomic approaches to define intrinsic and extrinsic polypeptides of Golgi membranes that are associated with polysaccharide synthesis and trafficking. We were successful in producing recombinant catalytic domains of cellulose synthase genes and discovered that they dimerize upon concentration, indicating that two CesA proteins form the catalytic unit. We characterized a brittle stalk2 mutant as a defect in a COBRA-like protein that results in compromised lignin-cellulose interactions that decrease tissue flexibility. We used virus-induced gene silencing of barley cell wall polysaccharide synthesis by BSMV in an attempt to silence specific members of the cellulose synthase-like gene family. However, we unexpectedly found that regardless of the specificity of the target gene, whole gene interaction networks were silenced. We discovered the cause to be an antisense transcript of the cellulose synthase gene initiated small interfering RNAs that spread silencing to related genes.