群体感应信号介导下弧菌对珊瑚白化的诱发机制研究

海洋弧菌引发的白化事件对珊瑚礁生态健康造成了巨大的冲击。前期的研究证实群体感应(quorum sensing, QS)信号调控着弧菌的增殖及其与珊瑚共附生细菌的互作，有望成为珊瑚白化的诱因。然而目前对于QS信号影响下的弧菌行为和白化机制尚不清楚，对共附生细菌群落的稳态干扰更是鲜有涉足。为此，本课题在前期工作基础上聚焦QS信号，结合原位调查与室内控制实验，拟开展三方面的研究。首先，采用宏基因组方法比较自然环境下健康与白化状态珊瑚的共附生弧菌群落结构与功能差异；其次，高通量筛选共附生弧菌并鉴定其QS信号产物；最后，构建弧菌QS分子突变株，并搭建弧菌-珊瑚互作模型，比较突变型与野生型在菌群行为和侵染能力上的差异，验证QS效应介导下的因果关系，并获得基于宏转录组学的分子调控机制。课题旨在揭示群体感应信号调节下的弧菌行为对白化的诱导效应，为珊瑚的白化成因和共生体稳态维护探寻微生物化学生态学的新理论。

Coral bleaching caused by marine Vibrio has damaged tremendously on the ecological health of coral reefs. Previous studies have confirmed quorum sensing (QS) signal regulates Vibrio proliferation and interaction with coral symbiotic bacteria, which expected to be the inducement of coral bleaching. However, the Vibrio behavior and bleaching mechanism under the effect of QS signal are still unclear. Further all, the interference of Vibrio to steady-state coral symbiotic bacterial community is rarely involved. Therefore, based on the previous work, this project will focus on QS signal, combining in-situ investigation and indoor control experiment, and carry out three research aspects. Firstly, the comparison of Vibrio community structural and functional differences between healthy and bleached coral under natural environment by metagenomics. Secondly, high-throughput screening of symbiotic Vibrio and identification of its QS signal products. Finally, construction of the QS knockout mutations of Vibrio. The Vibrio-coral interaction model will be established to compare the differences between wild-type and mutation in bacterial behavior and infection ability, verify the causality mediated by QS effect, as well as obtain the regulatory mechanism based on meta-transcriptomics. This project aims to reveal the process of coral bleaching caused by Vibrio under the regulation of QS signals, and establish microbial chemical ecological novel theory for the cause of coral bleaching and the maintenance of symbiont homeostasis.