Down-regulation of UDP-arabinopyranose mutase reduces the proportion of arabinofuranose present in rice cell walls
Down-regulation of UDP-arabinopyranose mutase reduces the proportion of arabinofuranose present in rice cell walls
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DOI：
10.1016/j.phytochem.2011.07.012
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发表时间：
2011-11-01
期刊：
影响因子：
3.8
通讯作者：
Ishii, Tadashi
中科院分区：
文献类型：
--
作者：
Konishi, Tomoyuki;Aohara, Tsutomu;Ishii, Tadashi
阿拉伯木聚糖可占草细胞壁质量的25%。这些多糖与自身以及与纤维素和木质素的相互作用被认为会影响壁的物理性质，并增加壁对生化转化为可发酵糖的抵抗力。阿拉伯木聚糖的骨架由1,4-连接的β - d -木糖基残基组成，其中一些在O-2或O-3上被单个阿拉伯木糖基（咸味）残基取代。arabinofuranosyltransferases可能将Araf残基从UDP-Araf转移到木聚糖骨架上。UDP-Araf本身是由udp -阿拉伯吡喃糖（UDP-Arap）通过udp -阿拉伯吡喃糖突变酶（UAM）形成的。本研究利用RNA干扰（RNAi）抑制水稻UAM的表达，从而减少可用于细胞壁合成的UDP-Araf的数量。一些转基因植株的细胞壁中Araf的比例降低，木聚糖主链的取代程度降低，细胞壁中阿魏酸和对香豆酸的含量降低了25%至80%。Araf含量减少25%的转基因植株矮化且不育。(C) 2011 Elsevier Ltd.版权所有。
Arabinoxylans may account for up to 25% of the mass of grass cell walls. The interactions of these polysaccharides with themselves and with cellulose and lignin is believed to affect the walls physical properties and increase the walls resistance to biochemical conversion to fermentable sugars. Arabinoxylans have a backbone composed of 1,4-linked beta-D-xylosyl residues, some of which are substituted at O-2 or O-3 with single arabinofuranosyl (Aral) residues. The Araf residues are likely transferred from UDP-Araf to the xylan backbone by arabinofuranosyltransferases. UDP-Araf is itself formed from UDP-arabinopyranose (UDP-Arap) by UDP-arabinopyranose mutase (UAM). In this study, RNA interference (RNAi) was used to suppress UAM expression in rice plants and thereby reduce the amounts of UDP-Araf available for cell wall synthesis. Several of the transgenic plants had reduced proportions of Araf in their walls together with a decrease in the extent of substitution of the xylan backbone, and a reduction of between 25% and 80% in ferulic acid and p-coumaric acid contents of the cell walls. Those transgenic plants with >25% reduction in the amounts of Araf were dwarfed and infertile. (C) 2011 Elsevier Ltd. All rights reserved.