稻瘟病菌SNARE蛋白MoSyn8调控分泌的毒性效应分子鉴定及其功能分析

Rice blast caused by Magnaporthe oryzae, is a destructive disease that severely threatens the production of rice crops worldwide. At the early stage of infection, the fungi secret numerous effectors to subvert host immunity which lead to the disease of Magnaporthe oryzae. SNARE protein-mediated intracellular vesicle transport is an important pathway for the pathogen to control the secretion of effectors. Despite such importance, however, the kinds and functions of effectors which controlled by the SNARE proteins are remain unknown. Previous work showed that SNARE protein MoSyn8 is involved in the secretion of avirulence effector (Avr-Pia and Avr-Piz-t) as well as pathogenicity of M.oryzae, but the effectors mediated by MoSyn8 are not well characterized. This project aims to identify the effectors regulated by the MoSyn8. We will reveal their amino acid sequence characteristics and the sequence polymorphism in field strains to evaluate the virulence of effectors. Further work will select the effectors which control the pathogenicity of M.oryzae and characterize their targets in the host which contribute to explain the mechanism of the effectors on the pathogenesis of M.oryzae and reveal the molecular mechanism of these effectors in suppressing host immunity. These results can provide evidences for revealing the pathogenesis of rice blast fungus. It is also valuable finding for characterization of virulence effectors and understanding their functions against host defense response to other pathogenic fungi.

稻瘟病菌侵染水稻早期分泌大量效应分子进入水稻体内，干扰水稻免疫反应，实现成功侵染引起水稻发病。SNARE蛋白介导的胞内囊泡运输是病菌控制效应分子外泌的重要途径，然而其控制哪些效应分子的分泌，及这些效应子的功能，鲜有报道。项目组前期研究发现SNARE蛋白MoSyn8参与调控病菌无毒效应分子(Avr-Pia和Avr-Piz-t)的分泌及致病力，但其控制分泌的毒性效应分子的种类及其功能仍不清楚。本项目将鉴定MoSyn8控制分泌的毒性效应分子，揭示其氨基酸序列特征与其在田间菌株的序列多态性，评价不同类型的效应分子对毒性的影响；针对性地选择1-2个受正向选择的效应分子，鉴定其寄主靶标，解析效应分子与靶标在该病菌致病中的作用机制，从而揭示这些效应分子干扰寄主免疫反应的分子机理。这些结果有助于进一步揭示该病菌的致病机理，对其他作物病原真菌毒性效应分子的鉴定及其抑制寄主免疫反应机制的解析具有重要参考价值。

稻瘟病菌侵染水稻早期分泌大量效应分子进入水稻体内，干扰水稻免疫反应，实现成功侵染引起水稻发病。SNARE蛋白介导的胞内囊泡运输是病菌控制效应分子外泌的重要途径，然而其控制哪些效应分子的分泌，及这些效应子的功能，鲜有报道。项目组前期研究发现SNARE蛋白MoSyn8参与调控病菌无毒效应分子(Avr-Pia和Avr-Piz-t)的分泌及致病力，但其控制分泌的毒性效应分子的种类及其功能仍不清楚。本项目鉴定到MoSyn8控制分泌的毒性效应分子MoCbd和MoIug140，并鉴定上述效应子在寄主中靶标，解析效应分子与靶标在该病菌致病中的作用机制，从而揭示这些效应分子干扰寄主免疫反应的分子机理。同时，该项目发现囊泡转运介导效应子分泌，并从中鉴定到一个调控寄主免疫的毒性效应子MoPrs。这些结果有助于进一步揭示该病菌的致病机理，对其他作物病原真菌毒性效应分子的鉴定及其抑制寄主免疫反应机制的解析具有重要参考价值。