棉铃虫对细菌和真菌感染的免疫应答机制

In China, cotton bollworm Helicoverpa armigera (Hübner) is the most destructive pest of cotton. The use of entomopathogenic agents is an effective alternative biological control method instead of most chemical insecticides. However, few studies have focused on the immunological interactions between them. In this study, through high-throughput sequencing technique, we will analyze the transcriptome of H. armigera infected by different microbial pathogens, gram positive bacteria (Micrococcus luteus), fungi (Beauveria bassiana), and gram negative bacteria (Enterbacter cloacae). The immune genes of Helicoverpa will be analyzed through the method based on sequence similarity to homologues known to participate in immune responses in other insect models, such as Drosophila melanogaster, Bombyx mori, and Aedes aegypti. Likewise, differential expressed gene repertoire will be analyzed as well as the implication of Toll and IMD pathway genes in the defense of pathogens will be revealed. Infection of microbial pathogen will also cause the constitutive activation of melanization, which is indicated by the cleavage of hemolymph prophenoloxidase (PPO), a key enzyme of melanization. Together, we aim to decipher the key players of systemic immune response, including immune modulators, pattern recognition receptors, and immune effectors, which are elicited by distinct virulence factors of entomopahtogenic agents. This study will improve our understanding of molecular aspect of pathogen-host interaction and also provide valuable information to design highly effective and specific scheme of biological control.

棉铃虫是我国广泛分布的重大农业害虫，利用昆虫病原微生物防治棉铃虫是生物防治的重要技术之一。阐明棉铃虫和病原体免疫互作关系是生物防治广泛应用的理论基础。本研究利用不同的病原体：革兰氏阳性菌、真菌和革兰氏阴性菌构建对棉铃虫的感染模型。通过高通量测序和生物信息学方法，对正常棉铃虫免疫基因进行分析，比较不同外源病原体感染后棉铃虫免疫基因的差异表达，揭示Toll，IMD免疫通路在棉铃虫免疫防御中的分子机制，探索棉铃虫在病原体感染条件下体内的酚氧化酶原的激活机理，寻找持续激活黑化反应的方式。该研究在筛选棉铃虫和病原体所特有的相互作用的关键分子、重要免疫调控蛋白、模式受体和效应蛋白基础上，明确二者免疫互作的分子机制。为发展新型、绿色、高效的害虫控制手段、开发破坏昆虫免疫系统的新型生物农药靶标基因提供理论依据和原创性成果，这对于制定切实可行的农业害虫预报模式和生物防治病虫害对策均具有重要应用前景和现实意义

棉铃虫是我国广泛分布的重大农业害虫。利用昆虫病原微生物防治棉铃虫是生物防治的重要技术之一。阐明棉铃虫和病原体免疫互作关系是生物防治广泛应用的理论基础。本研究利用不同的病原体：真菌和革兰氏阴性菌构建对棉铃虫的感染模型。首先采用高通量测序和生物信息学方法对正常棉铃虫免疫基因进行分析，然后比较了不同外源病原体感染后棉铃虫免疫基因的差异表达情况，从而揭示Toll，IMD免疫通路在棉铃虫免疫防御中的区别，探索了棉铃虫在病原体感染条件下体内的酚氧化酶原的激活机理，寻找持续激活黑化反应的方式。该研究在筛选棉铃虫和病原体所特有的相互作用的关键分子、重要免疫调控蛋白、模式受体和效应蛋白基础上，明确了二者免疫互作的分子机制。此外，我们还采用高通量的组学手段对棉铃虫受杆状病毒免疫刺激后基因表达的动态变化进行分析，并展开数据的深度挖掘。为发展新型、绿色、高效的害虫控制手段、开发破坏昆虫免疫系统的新型生物农药靶标基因提供理论依据，并为其他后续重大项目提供原创性的重要结果。