水稻纹枯病菌诱导水稻程序化死亡的作用机制

Rice Sheath Blight Pathogen is one of the most devastating crop diseases causing such as sheath blight, banded leaf, aerial blight and brown patch. It brings the huge yield losses in important crops: rice, maize and soybean cultivars each year, and makes the economic, food problems in the globe. Seriously, once the crops are infected, the grain qualities will also decrease rapidly. Management of this devastating pathogen is challenged by lacking of the high resistant genes in crops and the risks of chemical pesticides in ecological environment. Although many scientists did so much work, the study on the pathogenicity, evolution and biology is still lagged for the complex. For the breeders, this is a big problem met during the breeding program. So we study the pathogenicity for its great agricultural significance.. We used a whole-genome shotgun (WGS) sequencing strategy and the Illumina Genome Analyser (GA) sequencing technology. A subset of secreted proteins from pathogens is expected to determine the progress and success of the infection. The 965 potentially secreted proteins (9.17% of the proteome) of R. solani AG1 IA were analysed by prediction algorithms. During rice–fungus interaction, 234 secreted proteins showed a twofold or greater difference in expression during the early infection progress. To identify the novel potential effectors, we selected 45 twofold or greater upregulated candidate genes encoding secreted proteins for testing. The expressed proteins were inoculated into rice, maize and soybean leaves. Among them, A protein, SPE1 caused cell death phenotypes after inoculation at 48 h. Meanwhile, it showed host-specific toxin characteristic for different hosts (rice, maize and soybean), including different rice cultivars, and caused different degrees of necrosis phenotypes. The effector gene was shown to be undergoing rapid evolution including duplication, diversification, deletions and poit mutations. The strong evidence of positive diversifying selection in the effector gene was confirmed. The biological function, target, the key gene will be revealed through the molecular methods and technologies, such as, southern blot, RNAi, immunolocalization, QT-PCR. The availability of effector will allow rice geneticists and breeders to identify and evaluate, in the germplasm, the mechanism by which R. solani infects crops. The candidate effector trigging the host defence reaction, is expected to be applied in molecular breeding strategies to select the multiple resistant breeding materials. The effector provides a fundamental tool for the investigation of the PHI, as well as vital information for the general characterization of necrotroph–plant interactions, and it serves as a model for studying the pathogenic mechanisms..

纹枯病是水稻、玉米、大豆等重要农作物的重要病害，给世界粮食和经济造成严重损失，但纹枯病相关致病分子机制尚不明确。. 经前期预测验证获得新型水稻纹枯病分泌效应蛋白SPE1，效应蛋白具有寄主专化性HST，快速进化和正向选择的特点，在病原菌侵染初期识别并诱导水稻寄主产生程序化死亡PCD反应。项目拟采用免疫荧光定位、荧光共聚焦、RNAi、RT-PCR、Southern杂交、荧光定量PCR等技术从细胞、分子角度阐明水稻纹枯病菌效应因子的生物学功能，揭示SPE1诱导水稻发生程序化死亡PCD的作用机制，探索效应因子在水稻寄主ETI信号途径中引发免疫反应的机制，丰富完善水稻纹枯病致病理论，为水稻纹枯病研究提供新思路，及水稻纹枯病防治提供新策略与新药筛选提供新靶点。

纹枯病是水稻、玉米、大豆等重要农作物的重要病害，给世界粮食和经济造成严重损失,本项目从用荧光定位、荧光共聚焦、RNAi、RT-PCR、Southern杂交、荧光定量PCR等技术从细胞分子水平揭示水稻纹枯病菌效应因子引发寄主产生PCD 生物功能, 阐明了SPE1 诱导水稻发生程序化死亡PCD 的作用机制，从而证实效应因子通过ETI 途径诱导水稻产生免疫反应。项目一方面为水稻纹枯病效应因子在农业生产上的应用提供理论依据；另一方面为病原菌效应因子在寄主中转运与寄主互作研究提供新理论和新模型。本项目分别确定了确定水稻纹枯病效应蛋白引发水稻PCD 的HST 活性，效应蛋白SPE1 引发水稻寄主PCD 反应生物学功能，明确效应蛋白SPE1 引发水稻寄主PCD 反应分子机制。本项目利用水稻纹枯病效应因子在核心种质筛选到一批抗性材料在育种上应用。本项目共发表论文5篇，培养博士研究生2名，硕士研究生2名。构建公共数据库网站1个，申请国家发明专利1项，达到并完成项目所规定的目标。