多重共生菌协同调控截形叶螨生殖及适合度的分子机制研究

Symbiotic bacteria are widespread in arthropods and alter their hosts’ reproduction and fitness. Multiple infections, a variety of symbiotic bacteria infecting the same host individual, are common. These symbiotic bacteria will synergistically manipulate their hosts’ reproduction and fitness, while the underlying mechanism is unclear. Our laboratory has established the Tetranychus truncatus line that was infected with Wolbachia, Cardinium and Spiroplsma, and found that the hosts’ reproduction and fitness were significantly manipulated by symbiotic bacteria. By using the methods of genetics, biology, high-throughput sequencing and gene function analyses, the project will investigate the effects of symbiotic bacteria on spider mite’s reproduction and fitness, study the titers and tissue distribution of these bacteria to reveal cooperative or competitive relationship between them, verify the related genes regulating the biology of the spider mite and construct the mutual network of spider mite and symbionts proteins. The results will help to clarify the multiple symbiotic bacterial infection stability and their effect on host ecology and evolution and lay foundation of understanding the genetics and damage of the spider mite.

共生菌在节肢动物中普遍感染且能够引起宿主生殖及适合度的改变。多重感染，即多种共生菌感染同一宿主个体的现象普遍发生。多重共生菌对宿主生殖及适合度产生协同调控，然而其机制尚不清楚。项目组前期已获得同时感染Wolbachia、Cardinium和Spiroplasma3种共生菌的截形叶螨品系，并发现共生菌感染显著调控叶螨的生殖方式及适合度。本项目拟采用遗传学、生物学、高通量测序及基因功能分析等手段，调查多重共生菌感染对叶螨生殖及适合度指标的影响；研究共生菌在叶螨中的滴度及组织分布，明确共生菌间的协作或竞争关系；验证参与调控截形叶螨生物学相关基因；构建叶螨与共生菌蛋白相互作用网络。研究结果有助于揭示多重共生菌感染的稳定发生及对宿主生态及进化的影响机理，为了解该螨遗传和灾变机理奠定基础。

本项目深入探究多重共生菌（Wolbachia和Spiroplasma等）对我国重要经济害虫截形叶螨生殖及适合度的协同调控作用及其分子机制。研究发现宿主环境因子影响野外截形叶螨体内3种共生菌（Wolbachia、Cardinium和Spiroplasma）的分布与发生；感染共生菌Wolbachia和Spiroplasma降低叶螨的产卵量、影响宿主细菌微生物组成，Wolbachia诱导叶螨杀雌性胞质不亲和（CI）；Wolbachia和Spiroplasma主要分布在叶螨颚体与卵巢中，且在同一个体内Wolbachia滴度大于Spiroplasma，说明Wolbachia是更具竞争性的优势内共生菌；比较转录组揭示共生菌感染诱导宿主解毒代谢、生殖代谢、免疫应答和脂质蛋白等相关基因的差异表达，其中，感染与未感染共生菌截形叶螨间差异表达基因chorion protein S38-like 和 Rop可能参与调控宿主的生殖，此外，在Wolbachia全基因组中注释到CI调控关键基因CifA和CifB，表明宿主与共生菌的相关基因可能形成互作网络，共同参与调控宿主叶螨的生殖。本项目明确了截形叶螨体内多重共生菌的稳定发生规律，阐明了Wolbachia和Spiroplasma的共生关系，揭示了共生菌调控宿主生殖和适合度的作用及分子机制。研究成果发表了12篇研究论文。研究结果有助于解析多重共生菌感染对宿主生态及进化的影响机理，为开发害螨绿色防控技术及保障农业生产安全奠定基础。