鹿儿岛被毛孢蜕皮激素失活酶Hsegt和Hseck的功能及调控机制研究

虫生真菌与寄主昆虫的互作机理一直是真菌杀虫剂研究的重要内容，真菌在寄主血体腔中的定殖会受到昆虫激素的影响。前期研究发现，虫生真菌鹿儿岛被毛孢对昆虫蜕皮激素有系统性应答作用，首次发现该菌中存在昆虫蜕皮激素失活酶，但其具体作用机制尚不明晰。为阐明这类酶的功能及作用机制，本项目拟开展如下研究：1）探究虫生真菌中蜕皮激素失活酶可能的起源与进化关系，通过基因组学、分子系统学及分化时间估算等方法对其进行种类和功能分化分析；2）解析鹿儿岛被毛孢中Hsegt和Hseck两类蜕皮激素失活酶的生物学功能，明确其对虫生真菌发育分化、逆境胁迫反应、菌株毒力及昆虫免疫反应的影响；3）阐明这两种失活酶调控寄主蜕皮激素活性反应机制，通过鉴定两种酶的上游调控转录因子或下游相关靶向基因，并研究它们之间的相互作用关系来揭示调控网络。项目对于理解虫生真菌在适应寄主内环境过程调节寄主蜕皮激素滴度和应答昆虫免疫反应有重要科学意义。

The interaction mechanism between entomogenous fungi and host insects has always been an important part of the research on fungal insecticides. The colonization of fungi in the host's haemocoele is affected by insect hormones. We recently found that the entomopathogenic fungus Hirsutella satumaensis has a systematic response to hydroxyecdysone. It is the first time to find that ecdysteroid-inactivating enzyme exists in this fungus, but its biological function and mechanism are still unclear. In order to reveal the role of ecdysteroid-inactivating enzyme in entomopathogenic fungi and their relationship with fungal infection and pathogenesis, this project is planned to 1) explore the possible origin and evolution of ecdysteroid-inactivating enzyme in entomogenous fungi and analyze its species and functional differentiation by means of genomics molecular phylogeny and divergence times estimation; 2) analyze the biological functions of Hsegt and Hseck, two different types of ecdysteroid-inactivating enzymes, and their effects on fungal development and differentiation, stress response, strain virulence and insect immune response; 3) explore the mechanism by which these two ecdysteroid-inactivating enzymes regulate the active reaction of the hydroxyecdysone and reveal the regulatory network by identifying the upstream regulatory transcription factors or downstream targeted genes of Hsegt and Hseck. The goal of our project is to expect to achieve a new breakthrough on understanding the mechanisms of entomopathogenic fungi in adapting to the internal environment of insect haemocoele and exploring the mechanism of entomopathogenic fungi in response to insect hormones.