稻瘟病严重危害粮食作物安全生产，解析水稻稻瘟病的抗性机制可为保障粮食安全提供有力的理论依据和技术支撑。细胞壁是阻碍病原菌侵染的重要物理屏障，而其中的胞壁果胶则是病原菌突破细胞壁而顺利侵染的第一道关卡，其含量及修饰影响植物抗病性，但细胞壁果胶对水稻稻瘟病抗性的调控作用却鲜有报道，相关作用机制研究尚属空白。申请人前期比较了水稻感病材料在稻瘟菌侵染前后的全基因组表达谱，发现细胞壁果胶甲酯酶基因PME29在稻瘟病菌侵染后显著上调表达，呈稻瘟病诱导表达的特征。在此基础上，本项目拟分析水稻细胞壁在水稻稻瘟病抗性反应中的果胶甲酯酶修饰改变情况，以及果胶甲酯酶基因响应稻瘟菌侵染的表达模式，并针对果胶甲酯酶基因PME29，构建敲除和过表达突变体等遗传材料，以深入解析PME29在水稻抗稻瘟病中的作用。本研究将揭示细胞壁果胶甲酯化对水稻稻瘟菌抗性的调控机制，为稻瘟病抗病品种的选育提供重新的理论基础和依据。

Rice blast, caused by the Magnaporthe oryzae, is one of the most destructive rice diseases worldwide and seriously restricts the yield of rice. At the early stage of inflection, M oryzae penetrates the cuticle and epidermal cell wall by forming penetration peg. Pectin is the very first barrier of plant cell once penetrated the cuticle and accumulating evidence suggests that its content and structure can affect their disease resistance, but there are still few reports on how pectin responds to the rice blast. Our previous work has revealed that PME29，encoding a pectin methylesterase, is significantly induced during the infection of M oryzae in LTH. Based on this, we intend to take the LTH (susceptible) as materials and analyze the pattern of how pectin methylesterification responses to rice blast during infection, on the basis we want to further dig out the role of PME29 in rice blast by constructing series of related genetic materials and many other biochemical ways. Through this project we aim to elucidate the molecular and physiological mechanisms of cell wall pectin methylesterification in regulation of M oryzae invasion into rice and further enrich the mechanism of rice-M oryzae interactions. This study will provid reliable theoretical basis for breeding resistant rice varieties and developing environmentally friendly approaches for controlling rice blast.