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Down-Regulation of PoGT47C Expression in Poplar Results in a Reduced Glucuronoxylan Content and an Increased Wood Digestibility by Cellulase
Citation:
Lee, C., Q. TENG, W. Huang, R. Zhong, AND Z. H. Ye. Down-Regulation of PoGT47C Expression in Poplar Results in a Reduced Glucuronoxylan Content and an Increased Wood Digestibility by Cellulase. Plant and Cell Physiology. Oxford Journals, 50(6):1075-1089, (2009).
Impact/Purpose:
The mission of the ERD Metabolomics Team is to study the impact of stressors on various species using NMR and other advanced analytical approaches to characterize changes in endogenous metabolites. The main focus is to define responses in ecologically-relevant organisms (e.g., small fish) upon exposure to potentially toxic xenobiotic chemicals.
Description:
Xylan is the second most abundant polysaccharide in dicot wood. Unraveling the biosynthetic pathway of xylan is important not only for our understanding of the process of wood formation but also for our rational engineering of wood for biofuel production. Although several glycosyltransferases are implicated in glucuronoxylan (GX) biosynthesis in Arabidopsis, whether their close orthologs in woody tree species are essential for GX biosynthesis during wood formation has not been investigated. In fact, no studies have been reported to evaluate the effects of alterations in secondary wall-associated glycosyltransferases on wood formation in tree species. In this report, we demonstrate that PoGT47C, a poplar glycosyltransferase belonging to family GT47, is essential for the normal biosynthesis of GX and the normal secondary wall thickening in the wood of the hybrid poplar Populus alba × tremula. RNA interference (RNAi) inhibition of PoGT47C resulted in a drastic reduction in the thickness of secondary walls, a deformation of vessels and a decreased amount of GX in poplar wood. The transgenic wood was found to yield more glucose by cellulase digestion than the wild-type wood, indicating that the GX reduction in wood reduces the recalcitrance of wood to cellulase digestion. Together, these results provide direct evidence demonstrating that the PoGT47C glycosyltransferase is essential for normal GX biosynthesis in poplar wood and that GX modification could improve the digestibility of wood cellulose by cellulase.
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Down-Regulation of PoGT47C Expression in Poplar Results in a Reduced Glucuronoxylan Content and an Increased Wood Digestibility by Cellulase