An even pattern of xylan substitution is critical for interaction with cellulose in plant cell walls ...

• Main Authors: Grantham, NJ, Wurman-Rodrich, J, Terrett, OM, Lyczakowski, JJ, Stott, K, Iuga, D, Simmons, TJ, Durand-Tardif, M, Brown, SP, Dupree, R, Busse-Wicher, M, Dupree, P
• Format: Article in Journal/Newspaper
• Language: English
• Published: Nature Publishing Group 2017
• Subjects: Biofuels; Cell biology; Cell wall; Plant physiology; eskimo*
• Online Access: https://dx.doi.org/10.17863/cam.13865; https://www.repository.cam.ac.uk/handle/1810/267933

Xylan and cellulose are abundant polysaccharides in vascular plants and essential for secondary cell wall strength. Acetate or glucuronic acid decorations are exclusively found on even-numbered residues in most of the glucuronoxylan polymer. It has been proposed that this even-specific positioning of the decorations might permit docking of xylan onto the hydrophilic face of a cellulose microfibril. Consequently, xylan adopts a flattened ribbon-like twofold helical screw conformation when bound to cellulose in the cell wall. Here we show that ESKIMO1/XOAT1/TBL29, a xylan-specific O-acetyltransferase, is necessary for generation of the even pattern of acetyl esters on xylan in Arabidopsis. The reduced acetylation in the esk1 mutant deregulates the position-specific activity of the xylan glucuronosyltransferase GUX1, and so the even pattern of glucuronic acid on the xylan is lost. Solid-state NMR of intact cell walls shows that, without the even-patterned xylan decorations, xylan does not interact normally with ...