宿主-细菌共生普遍存在，阐明它们之间的关系与协同进化是生态学与进化生物学的重要研究问题。但是，现有研究共生的模式系统存在着共生菌组成复杂、难以分离，而且无法与宿主重新组合研究协同进化机制等问题。本课题将建立一种相对简化且可控的新共生模式系统（社会性阿米巴盘基网柄菌-共生菌）来回答以上问题。申请人将以前期分离的盘基网柄菌作为宿主，与前期分离并命名的伯克氏菌（Burkholderia agricolaris & Burkholderia hayleyella）作为共生菌，系统地研究盘基网柄菌-伯克氏菌共生系统的形成和维持机制、以及二者协同适应的分子与进化机制。结合微流控芯片、宿主重组实验、基因组进化分析以及多组学手段，本课题可以详细地揭示每一种共生菌与宿主的关系。这不仅能阐明此共生系统的运作机制，也有助回答宿主-细菌共生领域亟待解决的有关共生系统的形成、维持机制以及协同进化等关键科学问题。

A key question in ecology and evolutionary biology is to disentangle the relationship and coevolution between host and its associated bacteria. However, it is very difficult to separate, mix, and match host with its bacteria using existing model systems, which limits our ability to understand the interaction and coevolution between them. In this project, we propose a simple model system (Dictyostelium discoideum and its associated bacteria) to address these issues. Using previously isolated D. discoideum and two symbiotic bacteria Burkholderia agricolaris and Burkholderia hayleyella, we will investigate how this symbiotic system forms and maintains, and study the molecular and evolutionary mechanisms of coevolution between them. By combining microfluidics, host recombination experiment, genome evolution analysis and multi-omics approaches, we can explicitly demonstrate how each clone interacts and impacts host growth and fitness. This project will help us understand how the amoeba-bacteria system works, and how symbiosis is formed and maintained in general. This project will also present empirical evidence of interaction and coevolution between the host and its symbiotic bacteria.