葱地种蝇幼虫伴生细菌对球孢白僵菌侵染阻遏研究

“Insect-microbe” has been a hotspot in ecology study. This theory revealed the necessity of regarding the insect and the microbial associate as one holobiont. However, the majority of researchers only take insect hosts as their research objects in current pest biocontrol practices, and they did not take the effect of microbial symbionts on control efficiency of microbial control agents into consideration. Preliminary researches have revealed that bacterial associates of onion maggots could protect the insect from Beauveria bassiana infection. Thus, basing on the close symbiosis system formed by the onion maggot Delia antiqua and its associated bacteria, and with integration of technologies such as microbial ecology, insect ecology and high throughput sequencing, we try to illustrate the microbial species composition basis and the biochemical basis for bacterial protection of onion maggots from B. bassiana infection in 3 aspects: 1) which bacterial associates could protect the insect from infection, 2) how bacterial associates protect the insect from infection, 3) what bacterial metabolites are responding for inhibition of B. bassiana infection. Furthermore, we aim to illustrate the multitrophic interaction participated by insects, bacteria, and biocontrol agents, which would provide theoretical basis for screening assit microbes for biocontrol agents in breaking the microbial protection of pests and developing novel and effective antibiological inoculants.

“虫菌共生”在生态学领域受到广泛关注，它揭示了伴生微生物对昆虫的重要生态学功能，指明了将昆虫和微生物视作共生体的必要性。然而，在蝇类害虫生防实践中，多数研究者将害虫作为孤立的研究对象，少有研究者考虑伴生菌对生防菌防治效果的影响。本项目前期研究发现，蝇类幼虫伴生细菌能够抵御生防菌球孢白僵菌对幼虫的侵染。因此，本项目以我国重要农业害虫葱地种蝇及其伴生细菌组成的共生体为研究对象，在前期研究基础上，结合微生物生态学、昆虫生态学以及高通量测序技术，预期从幼虫哪些伴生细菌能够抵御球孢白僵菌的侵染、伴生细菌如何抵御球孢白僵菌的侵染、伴生细菌产生哪些代谢物抵御球孢白僵菌的侵染3个方面揭示伴生细菌抵御球孢白僵菌侵染幼虫的物种组成基础、作用方式和生化机制。在此基础上阐明虫菌共生框架下昆虫、伴生菌、生防菌参与的多物种互作过程，为以后寻找协助生防菌突破害虫伴生菌防御屏障的微生物、研发新型高效生防菌剂提供理论基础。

葱地种蝇是我国危害百合科蔬菜例如大蒜、洋葱等作物的重要地下害虫，其生物防治效果较差的机制一直缺乏深入研究。本项目以此害虫为研究对象，关注目前日益凸显的蝇类伴生细菌的生态学功能，以葱地种蝇幼虫伴生细菌为中心，开展相关就工作，明确了葱地种蝇幼虫伴生细菌抵御球孢白僵菌侵染的物种组成基础、作用方式和生化基础，回答了“（1）葱地种蝇幼虫哪些伴生细菌抵御球孢白僵菌侵染、（2）伴生细菌如何抵御球孢白僵菌侵染、（3）伴生细菌产生哪些代谢物抵御球孢白僵菌侵染”三个科学问题，揭示了葱地种蝇幼虫伴生细菌抵御球孢白僵菌侵染的微生态机制，在此基础上，阐明了虫菌共生框架下昆虫、伴生菌、生防菌参与的多物种互作过程，相关成果可以为以后寻找协助生防菌突破害虫伴生微生物防御屏障的微生物、研发新型复合高效生防菌剂提供理论基础。