Dalian Engineering Research Center for Carbohydrate Agricultural Preparations, Dalian Technology Innovation Center for Green Agriculture, Liaoning Provincial Key Laboratory of Carbohydrates, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Dalian Engineering Research Center for Carbohydrate Agricultural Preparations, Dalian Technology Innovation Center for Green Agriculture, Liaoning Provincial Key Laboratory of Carbohydrates, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China; College of Food Science and Engineering, Dalian Ocean University, Dalian 116023, China.
Int J Biol Macromol. 2024 Jan;254(Pt 1):127747. doi: 10.1016/j.ijbiomac.2023.127747. Epub 2023 Oct 29.
Rhizoctonia solani (R. solani) is an important pathogenic fungus that causes symptoms of sheath blight, and the polysaccharide-rich cell wall plays a major role in plant-pathogen interactions. However, the composition and structure of its cell wall polysaccharides are insufficiently understood, and its specific function in plant-pathogen interactions is unknown, which makes effective control of sheath blight difficult at present. Herein, five cell wall polysaccharides (WF-1, WF-2, CAF-1, HAF-1 and HAF 2-1) were sequentially extracted by boiling water, cold and hot alkali from R. solani AG1 IA. They were heteropolysaccharides containing mainly glucose, mannose and galactose and less fucose, with molecular weights above 1100 kDa. These five polysaccharides mainly composed of →4)-Glcp-(1→, →6)-Glcp-(1→, →4,6)-Glcp-(1→, →3,4)-Glcp-(1→, and Manp-(1→. Several polysaccharides, except WF-1, showed different induced resistance degrees on rice plant, with HAF 2-1 having the most significant effect. Further analysis using NMR confirmed that the backbone of HAF 2-1 mainly consisted of →4)-α-D-Glcp-(1→ and →6)-α-D-Glcp-(1→ with branches of →4,6)-D-Glcp-(1→. HAF 2-1 enhance the resistance of rice against R. solani through salicylic acid (SA)-mediated immune signaling pathway. This work improves our knowledge of the cell wall polysaccharides in plant pathogens and facilitates the study of pathogenic mechanisms and effective disease control.
腐霉菌（Rhizoctonia solani）是一种重要的致病真菌，可引起叶鞘腐烂病症状，其富含多糖的细胞壁在植物-病原体相互作用中起主要作用。然而，其细胞壁多糖的组成和结构了解不足，其在植物-病原体相互作用中的特定功能尚不清楚，这使得目前难以有效控制叶鞘腐烂病。在此，通过沸水、冷碱和热碱，从腐霉菌 AG1 IA 中依次提取了 5 种细胞壁多糖（WF-1、WF-2、CAF-1、HAF-1 和 HAF 2-1）。它们均为杂多糖，主要含有葡萄糖、甘露糖和半乳糖，以及较少的岩藻糖，分子量均大于 1100 kDa。这 5 种多糖主要由 →4)-Glcp-(1→、→6)-Glcp-(1→、→4,6)-Glcp-(1→、→3,4)-Glcp-(1→和 Manp-(1→组成。除 WF-1 外，几种多糖对水稻植株表现出不同程度的诱导抗性，其中 HAF 2-1 的效果最为显著。进一步使用 NMR 分析证实，HAF 2-1 的骨架主要由 →4)-α-D-Glcp-(1→和 →6)-α-D-Glcp-(1→组成，支链为 →4,6)-D-Glcp-(1→。HAF 2-1 通过水杨酸（SA）介导的免疫信号通路增强了水稻对腐霉菌的抗性。这项工作提高了我们对植物病原体细胞壁多糖的认识，有助于研究致病机制和有效控制疾病。
