病原细菌与线虫互作的感知信号通路

Investigation to the interactions between pathogenic microorganisms and hosts is always the focus in microbiology. It has been shown in our previous study that the nematode pathogenic baterium Bacillus nematocida strain B16 employs a "Trojan horse" strategy to infect its hosts, in which the bacterium lures nematodes by emitting potent volatile pheromone compounds. Though the recognization of those signal molecules by nematodes is the precondition of successful infection, how the nematodes recognize those signal molecules in the interaction between pathogens and hosts still remains unknown. Thus, here using the worms Caenorhabditis elegans that have a well-defined neural system and a suit of well-established genetic tools as a model, we design to invesigate the signal transduction pathway of nematodes to olfactoryly sense the different types of attractive odorant. Focus on the signal transduction of G-protein-coupled receptor that is known widely existed in the olfactory signal pathway of nematodes or even humans, we shall determine the category of neurons, the detailed molecules used in the signal transduction pathway, such as the recepors,G alpha subunits as well as the other effector in the cascade. It will be also confirmed if the same or a novel olfactory pathway has been employed in sensing the volatile odorant produced by the nematode pathogenic bacteria as in pursue of food. These unresolved questions will help us to understand the relationship between pathogens and hosts in a new view-point, and also lay a theoretical foundation for the application of pheromone compounds in nematode biocontrol.

阐明病原微生物与宿主的互作关系是微生物研究领域的热点。申请人在前期研究中发现，线虫病原细菌Bacillus nematocida strain B16可通过"特洛伊木马"模式侵染线虫，即病原细菌所产生吸引性信息化合物强烈引诱线虫是侵染宿主的前提条件。但这些信号分子在病原与宿主互作中如何被感知的信号途径迄今无相关报道。因此，本项目将以神经系解剖结构、遗传背景清楚的秀丽隐杆线虫作为模式生物，围绕嗅觉产生的G蛋白信号传导途径，研究宿主线虫怎样感知不同类型的信息化合物，揭示其感知的神经元种类和信号传递中的具体分子途径，包括信号途径中的受体GPCRs、G蛋白和下游信号级联反应中的效应分子；证实感知病原细菌信号分子的途径和线虫觅食行为中的趋化感知途径是否相同，或者为新的嗅觉感知途径。该研究的完成将有助于从全新角度探讨该病原微生物与宿主之间相互作用的分子机制，并对信息化合物在线虫生物防治方面的应用奠定理论基础。

阐明病原微生物与宿主的互作关系是微生物研究领域的热点。申请人在前期研究中发现，线虫病原细菌Bacillus nematocida B16可通过“特洛伊木马”模式侵染线虫，即病原细菌所产生吸引性信息化合物强烈引诱线虫是侵染宿主的前提条件。但这些信号分子在病原与宿主互作中如何被感知的信号途径迄今无相关报道。因此，本项目将以神经系解剖结构、遗传背景清楚的秀丽隐杆线虫作为模式生物，围绕嗅觉产生的G蛋白信号传导途径，解析了线虫如何感知信息化合物2-庚酮、吲哚和2-乙基己醇的信号通路，揭示其感知的神经元种类和信号传递中的具体分子途径。通过该项目的实施，首次在C. elegans的AWC嗅觉神经元中鉴定出一条新的、且独立于食物感知的嗅觉信号转导途径。该研究的完成将有助于从全新角度探讨该病原微生物与宿主之间相互作用的分子机制，并对信息化合物在线虫生物防治方面的应用奠定理论基础。本项目已发表SCI论文5篇，受邀请参编撰写由SPRINGER出版社出版专著“Principles of plant-microbe interactions”中有关线虫生物防治的章节，相关研究成果也获得2015年云南省自然科学特等奖1项。