Rho家族GTPase对球孢白僵菌极性生长及抗氧化力的作用研究

球孢白僵菌(Beauveria bassiana)是当前世界上研究和应用最广泛的丝状昆虫病原真菌之一，已被开发成为多种制剂用于农林害虫的生物防治。在实践应用中，真菌的极性生长情况及抵抗氧化胁迫的能力是衡量其生防潜能的重要指标。Rho家族GTPase作为重要且保守的小分子开关，对昆虫病原真菌细胞极性生长及抗氧化力作用的研究罕见报道。本项目拟对球孢白僵菌中6个Rho家族GTPase进行亚细胞定位,并通过构建单基因敲除/回补菌株的方法研究其功能，阐明Rho家族GTPase在球孢白僵菌极性生长及抗氧化力方面的影响；结合细胞隔膜发生和顶体位置的观察、抗氧化酶系相关基因的转录水平分析及总酶活测定分析，探索其在极性生长及抗氧化的作用与功能，以深化球孢白僵菌生防潜能遗传背景及调控机制的科学认识，丰富害虫生物防治的理论基础。

Beauveria bassiana is a classic filamentous entomopathogenic fungus that has been widely applied to biological control of insect pests in agriculture and forestry. Studying the factors involved in biological control potential of filamentous entomopathogenic fungus, including the genetic background and regulation mechanisms, are important not only for understanding the nature of entomopathogenic fungus, but also for developing new fungal agents and optimizing strategy for application of fungal agents. Polar growth and oxidative stress tolerance of filamentous entomopathogenic fungus are two key factors of biological control potential in applying the fungal agents in fields. Functions of Rho GTPases, an family of important and conserved small molecular switches, in polar growth and oxidative stress tolerance in entomopathogenic fungus have not been well investigated. In this application, we aim to study the subcellular localization of 6 Rho GTPases in B. bassiana via eGFP-labelled method and investigate their functions in influencing the biological control potential by constructing and analyzing single Rho-gene deletion/complementary mutants. In addition, we will further confirm the roles of B. bassiana Rho GTPases in regulating the polar growth and oxidative stress tolerance by monitoring hyphal septum formation and Spitzenkörper location in hyphal cells, and by analysis of the transcript levels of 5 sods and 6 cats genes as well as the total enzyme activity of SOD and CAT in hyphal extracts of wild-type strain and single Rho-gene deletion/complementary mutants. The knowledge gained from our work will contribute to a better understanding of the genetic background and regulating mechanism in B. bassiana to biological control potential.