苹果树腐烂病菌酸调控蛋白的鉴定及其致病性功能分析

Apple Valsa canker, caused by fungi Valsa mali, is one of the most devastating diseases in China apple growing region. However, pathogenetic mechanism of V. mali is still not clear. Studying the molecular mechanism of the pathogenicity will set solid foundation for disease management. Previous reports found that lots of phytopathogenic fungi are able to secrete organic acids or ammonia that acidify or alkalinize their host ambient pH environment to regulate an arsenal of enzymes to increase their pathogenicity. This arsenal includes genes and processes that compromise host defenses, contribute to intracellular signaling, produce cell wall-degrading enzymes, regulate specific transporters, induce redox protectant systems, and generate factors needed by the pathogen to effectively cope with the hostile environment found within the host. Previous studies have shown that a large amount of acid have been produced by V. mali during pathogenesis. Based on these results, we can speculate a lot of proteins regulated by the acid should be present and also play important roles in the pathogenicity of V. mali. This project plan to identify proteins regulated by organic acid using the integrated analysis of RNA-seq and iTRAQ, describe the acid responsive network of proteins related to the pathogenecity of V. mali, and characterize the putative pathogenicity related proteins and their roles. These results may reveal the novel regulatory mechanisms of pathogenecity, which will help us develop more precisely targeted disease management strategies.

由真菌黑腐皮壳 (Valsa mali) 引起的苹果树腐烂病是我国苹果产区危害严重的病害之一。目前对该病害的分子致病机理尚不清楚，解析其分子致病机理可以为该病害的防治提供坚实的理论基础。研究表明，许多真菌在致病过程中通过产生酸或者氨来调节其寄主体内的pH，并同时产生大量的适合该pH条件的蛋白来增强病原菌的致病力。苹果树腐烂病菌就属于这类产酸的真菌。因此，研究其在致病过程中产生的酸调控蛋白及其致病作用机制，具有十分重要的意义。本项目拟通过转录组学和蛋白质组学联合分析来鉴定苹果树腐烂病菌中酸调控蛋白，预测其中的致病相关蛋白；构建苹果树腐烂病致病过程中酸调控的基因响应全景图；并通过基因敲除等方法验证候选致病相关蛋白的功能及其在致病过程中的作用机制。本项目通过深入解析苹果树腐烂病菌致病过程中酸调控的分子机制，为开发特异靶标新农药、创制新抗病材料或发现新的防治枝干病害途径提供新的思路和理论依据。

由真菌黑腐皮壳 (Valsa mali) 引起的苹果树腐烂病是我国苹果产区危害较严重的病害之一。目前研究表明，自然界中有许多真菌在致病过程中需要产生大量酸或者氨来调节周围环境的pH，同时产生大量的适合该pH条件的蛋白和小分子物质，来增强病原菌的致病力。许多植物病原菌中存在pH调节转录因子PacC，该基因对病原真菌的致病性具有调控作用。本项目组在前期通过基因敲除技术构建了苹果树腐烂病菌PacC基因的敲除突变体，其致病力与野生型相比明显下降，此外该突变体在液体培养基中培养3d后，其发酵液pH值为4.2，而野生型的发酵液pH值为3.5。由此推测苹果树腐烂病菌PacC缺失突变体致病力的减弱，其部分原因是可能由于产酸能力下降，导致受酸调控的蛋白酶活下降，从而使病原菌的致病力下降。因此，在前期的研究基础上，本项目利用高通量的转录组学和蛋白质组学联合分析，鉴定苹果腐烂病菌受酸调控的蛋白；利用生物信息学分析预测苹果腐烂病菌中酸调控致病相关蛋白；借助于这两种组学结果之间的互补性，探索其转录后调节机制，构建了早期腐烂病菌响应环境pH调控机制网络和苹果树腐烂病菌酸调控机制网络；通过对关键致病基因进行功能研究，发现VmSpm1与苹果MdPYL4蛋白互作同时激发植物的免疫反应；VmPma1具有葡萄糖转运功能并且降解ATP为其提供所需的能量；VmAGP1与烟草NbSRLK蛋白互作激发植物的免疫反应。本项目以苹果树腐烂病菌PacC基因研究为出发点，系统而全方位地研究苹果腐烂病菌的酸调控蛋白在致病过程中的分子机制，为新型农药潜在分子物靶标的寻找提供方向，为加快该重大病害防控理论研究提供新的思路和策略。