板栗疫病菌基因组DNA甲基化与毒力调节的关系

项目名称： 板栗疫病菌基因组DNA甲基化与毒力调节的关系

项目编号： No.31260027

项目类型： 地区科学基金项目

立项/批准年度： 2013

项目学科： 生物科学

项目作者： 李茹

作者单位： 广西大学

项目金额： 50万元

中文摘要： 低毒病毒侵染可导致板栗疫病菌（Cp）表型发生改变并显著降低真菌的毒力，因而该系统被视为解析病原真菌致病机理的一个优秀模型。我们的前期研究发现，受病毒侵染后，Cp有两种甲基转移酶表达量上升；敲除S-腺苷高半胱氨酸水解酶的Cp突变株，多个甲基转移酶基因转录水平显著上升，但三联体G-蛋白途径的多个关键基因以及一个致病相关基因cyp1的转录水平则显著下调，同时真菌毒力也显著下降。由于DNA甲基化是基因表达调控中一种重要的机制，参与多个生命过程，我们提出假说，病毒可能通过调控宿主DNA的甲基化水平而影响毒力基因的表达。本课题拟以Cp野生强毒菌株和受病毒侵染的弱毒菌株为实验材料，分析真菌基因组中受病毒调控的DNA甲基化谱，确定DNA甲基化与转录水平的关系，阐明受病毒调控的基因组选择性甲基化的机制，明确关键基因甲基化在真菌毒力和重要生理性状表达上的作用，从而进一步揭示Cp毒力调节的机制。

中文关键词： DNA甲基化；板栗疫病菌；毒力；；

英文摘要： Hypovirus/Cryphonectria parasitica (Cp) system is regarded as an excellent experimental system to dissect the virulence regulation mechanism, since infection by a hypovirus can profoundly reduce the virulence and result in persistent changes in multiple traits of this pathogenic fungus. Our preliminary work had shown that the expression of two DNA methyltransferases were up-regulated in the hypovirus-infected strain EP713 compared to its isogenic wild-type strain EP155 and deletion of ahcy, a gene that encodes an hydrogenase to S-adenosylhomocysteine, resulted in an increased intracellular concentration of S-adenosylmethionine, a methyl donor, and up-regulated accumulation of transcripts of genes functioned in DNA methylation pathway, but suppressed transcript accumulation of genes of the trimeric G-protein pathway, and remarkably reduced the virulence of Cp. As one of the major epigenetic mechanisms, DNA methylation plays an important role in many biological processes. We hypothesize that a hypovirus regulates the gene expression by pertubing the DNA methylation of the fungal genome. In this proposal, the sprectrum of DNA methylation from the EP155 and the EP713 strains will be identified, the relation bewteen DNA methylation and gene transcription will be analysed, the mechanism of differential methylation by

英文关键词： DNA methylation；Cryphonectria parasitica；virulence；；