Inactivation of OsIRX10 Leads to Decreased Xylan Content in Rice Culm Cell Walls and Improved Biomass Saccharification

摘要

Xylan polysaccharides constitute the major non-cellulosic components in secondary cell walls of dicots and in both primary and secondary cell walls of grasses (Scheller and Ulvskov, 2010). Xylan is composed of a linear backbone of β(1–4)-linked xylose (Xyl). In grasses, the xylan backbone is substituted with O3-linked and O2-linked arabinose residues and, to a lesser extent, α(1–3)-linked glucuronic acid residues. A unique feature of grass xylans is the presence of hydroxycinnamate esters (ferulic and p-coumaric acid residues) attached to C5 of some of the arabinosyl residues (Carpita, 1996; Vogel, 2008; Scheller and Ulvskov, 2010). Xylan contributes to the recalcitrance of plant cell walls to enzymatic degradation probably through direct interaction with cellulose microfibrils and also through formation of ferulate cross-links (Iiyama et al., 1994; Yin et al., 2011).