中国农业科学院作物科学研究所
国家自然科学基金项目(面上项目,重点项目,重大项目)
National Natural Science Foundation of China (32172004)
腐生型真菌(necrotrophic fungi)是威胁小麦生产的一大类毁灭性病原菌,其通过分泌毒素和细胞壁降解酶诱导寄主细胞死亡以摄取营养。与活体营养型病原菌不同,该类真菌独特的“先杀后食”致病策略使得经典的“基因对基因”抗性模型难以完全阐释其防御机理。系统梳理腐生型真菌的致病策略及小麦的防御机制,对加速我国小麦抗病遗传改良具有重要的意义。本研究梳理了腐生或半腐生型病原菌的致病策略;总结了以细胞壁加固、有丝分裂原活化蛋白激酶(MAPK,mitogen-activated protein kinase)信号级联及茉莉酸(JA,jasmonic acid)/乙烯(ET,ethylene)信号主导的通用性防御模型和以毒素降解酶的解毒作用、感病因子的功能缺失以及免疫负调控因子的解除为主的特异性防御机制;在此基础上,构建了小麦应对腐生型真菌侵染的“通用-特异”分层协同防御模型,明确了通用性防御模型在限制病原菌早期定殖中的核心作用,探究了特异性抗性位点如何通过信号反馈增强基础免疫,形成时空整合的防御网络。最后,针对腐生型真菌的致病共性,提出了基于通用性防御与特异性抗性整合的广谱抗病育种策略,旨在为培育持久抗性的小麦新品种提供理论依据。
Necrotrophic fungi represent a major class of devastating pathogens threatening wheat production, inducing host cell death to absorb nutrients through the secretion of toxins and cell wall-degrading enzymes. Unlike biotrophic pathogens, the unique "kill-before-feeding" pathogenic strategy of these fungi makes the classic "gene-for-gene" resistance model insufficient to fully elucidate their defense mechanisms. A systematic review of the pathogenic strategies of necrotrophic fungi and wheat defense mechanisms is of significant value for accelerating the genetic improvement of disease resistance in wheat. This study clarifies the pathogenic strategies of necrotrophic or heminecrotrophic pathogens; summarizes a general defense model dominated by cell wall reinforcement, mitogen-activated protein kinase (MAPK) signaling cascades, and jasmonic acid (JA)/ethylene (ET) signaling, as well as specific defense mechanisms primarily involving detoxification by toxin-degrading enzymes, loss-of-function of susceptibility factors, and the alleviation of negative immune regulators. On this basis, a "general-specific" layered synergistic defense model for wheat against necrotrophic fungi is constructed, highlighting the core role of the general defense model in limiting early pathogen colonization and exploring how specific resistance loci enhance basal immunity through signal feedback to form a spatiotemporally integrated defense network. Finally, targeting the pathogenic commonalities of necrotrophic fungi, broad-spectrum disease resistance breeding strategies based on the integration of general defense and specific resistance are proposed, aiming to provide a theoretical basis for breeding new wheat varieties with durable resistance.
