褐飞虱内共生菌参与调控宿主生长繁殖以及环境适应性，是褐飞虱生物学特性的重要调控因子。绿僵菌是一种经典的丝孢类生防真菌，具有广谱高毒力和良好的环境相容性，两者均在褐飞虱的微生物防治中具有广阔的应用前景。本项目围绕褐飞虱生物防治新技术的开发为主题，以“共生菌-褐飞虱-绿僵菌”为模型，首先通过宏基因组技术系统分析褐飞虱体内共生菌的多样性，探明共生菌种群结构在褐飞虱不同生长发育时期的动态变化规律；其次运用杂交，数字基因表达谱等遗传学和分子生物学技术全面解析褐飞虱内共生细菌Arsenophonus的生物学功能，阐明其在介导褐飞虱抵御黄绿绿僵菌侵染过程中的作用及其分子机制，并筛选能够提高黄绿绿僵菌致病褐飞虱的关键靶标基因，进而构建毒力显著增强的重组工程菌株。项目的实施和完成不仅为研究褐飞虱与共生菌协同进化，互利共生关系奠定理论基础，也为开发具有强针对性和高毒力的真菌杀虫剂产品提供新的策略。

The endosymbionts in the brown planthopper (Nilaparvata lugens Stål) is one of key regulators that involved in the regulation of host biological characters, such as growth, reproduction and environmental adaptability. Metarhizium flavoviride, a classic entomopathogenic hyphomycete, has broad spectrum, high virulence and environmental safety. Both of them possess broad application prospects in microbial control of N. lugens. The study sought to explore new biocontrol technology for the brown planthopper using "Endosymbiont–N. lugens–M. flavoviride " system as a model. Firstly, the diversity and dynamics of the endosymbionts in N. lugens was assessed by metagenomic sequencing approach. Secondly, the biological functions of an endosymbiotic bacterium Arsenophonus were elucidated through the genetic methods and molecular biotechnologies. Digital gene expression analysis of the downstream genes that respond to infection by M. flavoviride were detected in Arsenophonus-harboring and Arsenophonus-lacking N. lugens populations. From this analysis, we can summarize the possible molecular mechanism of symbiont-mediated resistence to a fungal entomopathogen in N. lugens and find the suits of genes that directly regulated the fungal virulence. Finally, the recombinant fungal strain with higher virulence was constructed by genetic manipulating the key genes that selected as above. Implementation and completion of this project not only to lay the theoretical basis for the study of the coevolution or mutualism relationship between N. lugens and its endosymbiontes, but also to provide new strategy for developing a strong targeted microbial pesticide products.