外源生物胁迫对棉铃虫免疫的动态调控

Cotton bollworm Helicoverpa armigera (Hübner) is a polyphagous pest that causes serious damage to cultivated crops in China. The application of biological control will reduce the usage of chemical insecticides. In this study, through high-throughput sequencing technique, we will use different entopathogenic agents or biopesticide, fungi (Beauveria bassiana), and endoparasitic wasp (Microplitis mediator) to infect H. armigera. The dynamics of immunity-related pathways and other physiological pathways in H. armigera modulated by biological agents will be investigated. We will identify differential expressed gene repertoire in response to distinct biological agents. Entomopathogenic agents will produce distinct virulence factors to modulate host’s defense systems. The key molecules interacted with virulent factors will be screened using yeast two hybrid systems and other approaches. In previous study, we have identify the critical role of CTL14、serpin-5，serpin-9，cSP4，cSP6 in immune responses of H. armigera against the invasion of fungus and virus. Novel immunity-related protein will be revealed using biochemical and molecular biology techniques. Their interaction with foreign virulent factors will be investigated. And their involvement in pathogen recognition, melanization reaction, and Toll immune pathway will be revealed. Finally, it is postulated that infection of biological agents will also cause the activation of cellular immunity. Taken together, we aim to decipher the key players of systemic immune response, including immune modulators, cell receptors in this study. It will improve our understanding of molecular aspect of pathogen-host interaction and also provide valuable information to design highly specific guided prevention and control methods for future green agriculture.

棉铃虫是重要农业害虫，对其进行生物防治是未来发展方向。本研究拟利用不同的外源生物因子，真菌、核型多角体病毒侵染棉铃虫，实现对棉铃虫免疫通路的动态调控。解析棉铃虫免疫和其他生理信号传递过程和调控网络，并根据相关免疫通路的差异反应，推测与其互作的外源生物的毒力因子，通过酵母双杂交等技术明确分子互作关系。在已知CTL14、serpin-5，serpin-9，cSP4，cSP6等免疫功能蛋白基础上，利用生化和分子生物学技术进一步筛选新的调控蛋白。明确其与毒力因子互作并参与免疫识别，黑化反应、Toll通路。最后，利用免疫荧光显微镜等技术研究外源生物因子对棉铃虫血细胞数目和细胞免疫反应的影响。在鉴定到重要免疫因子和细胞受体的基础上，揭示受外源生物调控的免疫机制，对其进行遗传改造，使得外源生物的调控更为有效。以此为突破口，开发更为高效、精准、环保的新方法，对病虫害的防治提供导向性可持续的调控措施。

棉铃虫是世界范围内的重要农业害虫，而对其进行生物防治是未来发展方向。本项目研究解析了核型多角体病毒和中红侧沟茧蜂等外源生物因子对棉铃虫免疫通路的动态调控。根据相关免疫通路的差异反应，通过酵母双杂交等分子生物学技术明确互作的毒力因子。首先，利用转录组与蛋白质组相结合的方法，鉴定了中红侧沟茧蜂的毒液蛋白组分，并解析了寄生前后棉铃虫血淋巴蛋白差异的动态变化，对多种毒液蛋白进行了功能研究。首先，发现金属蛋白酶MmVRF1能够影响宿主血细胞的包被反应，同时也能抑制Toll免疫通路。而MmGAP通过与宿主小G蛋白互作以破坏细胞骨架，从而调节细胞免疫。此外。本项目通过研究和棉铃虫核多角体病毒与棉铃虫互作，揭示了棉铃虫肠道微生物群可通过调节免疫反应影响口服杆状病毒的感染。本项目的研究结果在鉴定到重要免疫因子和细胞内靶标的基础上，探索了受外源生物因子调控的免疫机制，明确了外源生物因子与棉铃虫的互作关系，为更好地应用生物防治提供可靠的理论基础。