扶桑绵粉蚧中分泌2,4-二叔丁基苯酚的肠道细菌多样性与定殖机制

昆虫肠道细菌在宿主消化食物、降解有害物质、防御病原菌等过程中起重要作用。扶桑绵粉蚧可为害多种作物与园林植物，是我国首批重点管理外来入侵物种之一。近期我们从其肠道中分离到了3株可分泌2,4-二叔丁基苯酚（2,4-DTBP）的细菌，鉴于2,4-DTBP具有包括抑菌性在内的诸多生物活性，我们推测此类肠道细菌有助于增强宿主的适应性，来源上则有可能随宿主地理扩张由宿主从环境中获得，但是，迄今尚未见相关报道。为此，本项目拟系统调查不同地区、不同寄主植物上的扶桑绵粉蚧中此类肠道细菌的种类，同时研究其传播方式和植物种类、宿主营养及环境温度对其丰度的影响，并从宿主免疫、microRNA、肠道其他细菌等方面探究影响其定殖的因素，以期明确此类细菌的多样性和定殖过程及机制。研究结果不仅可丰富我们对昆虫肠道细菌种类、多样性及定殖机制的认识，还可为解释粉蚧类昆虫的生态适应性和入侵机制提供一个新视角。

Gut bacteria play several important roles in the life of their host insects, including digesting food, degrading harmful components in food, and defending microbial pathogens. The cotton mealybug, Phenacoccus solenopsis Tinsley, one of important alien invasive species in China to be managed with priority, can damage a range of crops and horticultural plants. Recently, we identified three bacterial strains capacity of secreting 2,4-Di-tert-butylphenol, from the gut of this mealybug. As 2,4-Di-tert-butylphenol has several biological activities, we predict that colonization of such a kind of gut bacteria would contribute to adaptability of their hosts, and possibly they might be attained by the mealybug from environments during invasions. However, no reports are available so far as to such gut bacteria in insects. Therefore, we will investigate the species compositions of 2,4-Di-tert-butylphenol-secreing bacteria in P. solenopsis populations of different regions and plants. Meanwhile, their transition modes, and association of their abundance with environmental factors, including plant species, mealybug nutritional status and ambient temperatures, will be studied. We will also explore the mechanisms underlying in the colonization of these gut bacteria, particularly host immunity, microRNA involved, and effects of native gut bacteria (i.e., Wolbachia). We aim to clarify the diversity of 2,4-Di-tert-butylphenol-secreing bacteria in mealybugs and the major mechanisms underlying in colonization. This project is expected to enrich our knowledge of gut-bacteria diversity and colonization, as well as to offer a new viewpoint over adaption and invasion strategies in mealybugs.