Zhong Ruiqin, Zhou Dayong, Chen Lirong, Rose John P, Wang Bi-Cheng, Ye Zheng-Hua
Department of Plant Biology, University of Georgia, Athens, GA 30602, USA.
Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA.
Plants (Basel). 2024 Aug 19;13(16):2304. doi: 10.3390/plants13162304.
Plant cell walls are largely composed of polysaccharide polymers, including cellulose, hemicelluloses (xyloglucan, xylan, mannan, and mixed-linkage β-1,3/1,4-glucan), and pectins. Among these cell wall polysaccharides, xyloglucan, xylan, mannan, and pectins are often -acetylated, and polysaccharide -acetylation plays important roles in cell wall assembly and disease resistance. Genetic and biochemical analyses have implicated the involvement of three groups of proteins in plant cell wall polysaccharide -acetylation: trichome birefringence-like (TBL)/domain of unknown function 231 (DUF231), reduced wall acetylation (RWA), and altered xyloglucan 9 (AXY9). Although the exact roles of RWAs and AXY9 are yet to be identified, members of the TBL/DUF231 family have been found to be -acetyltransferases responsible for the -acetylation of xyloglucan, xylan, mannan, and pectins. Here, we provide a comprehensive overview of the occurrence of -acetylated cell wall polysaccharides, the biochemical properties, structural features, and evolution of cell wall polysaccharide -acetyltransferases, and the potential biotechnological applications of manipulations of cell wall polysaccharide acetylation. Further in-depth studies of the biochemical mechanisms of cell wall polysaccharide -acetylation will not only enrich our understanding of cell wall biology, but also have important implications in engineering plants with increased disease resistance and reduced recalcitrance for biofuel production.
植物细胞壁主要由多糖聚合物组成，包括纤维素、半纤维素（木葡聚糖、木聚糖、甘露聚糖和混合连接的β-1,3/1,4-葡聚糖）和果胶。在这些细胞壁多糖中，木葡聚糖、木聚糖、甘露聚糖和果胶常常被乙酰化，多糖乙酰化在细胞壁组装和抗病性中发挥重要作用。遗传和生化分析表明，三类蛋白质参与了植物细胞壁多糖的乙酰化过程：类毛状体双折射蛋白（TBL）/功能未知结构域231（DUF231）、细胞壁乙酰化降低蛋白（RWA）和木葡聚糖改变蛋白9（AXY9）。尽管RWA和AXY9的确切作用尚未明确，但已发现TBL/DUF231家族成员是负责木葡聚糖、木聚糖、甘露聚糖和果胶乙酰化的乙酰转移酶。在此，我们全面概述了乙酰化细胞壁多糖的存在情况、细胞壁多糖乙酰转移酶的生化特性、结构特征和进化，以及细胞壁多糖乙酰化操作的潜在生物技术应用。对细胞壁多糖乙酰化生化机制的进一步深入研究不仅将丰富我们对细胞壁生物学的理解，而且对培育抗病性增强且生物燃料生产中难降解性降低的植物具有重要意义。
