蓝细菌Synechococcus elongatus UTEX 3055趋光性信号转导机理研究

趋光性赋予细菌主动寻找生长所需光能并避开强光伤害的能力。对细菌趋光性分子机制的研究大多集中于球形单细胞蓝细菌Synechocystis sp. PCC 6803。然而该菌株的趋光运动受到多个信号通路的调控，增加了对信号转导机制研究的复杂性。并且已有的研究大多集中于光受体的发现及对其所感受光谱的鉴定，而受体接收到光信号之后如何将其传递到运动器官，并调控细菌运动方向的机制尚不清楚。Synechococcus elongatus UTEX 3055是一株新鉴定的短杆状蓝细菌，已有的研究发现该菌株趋光信号通路更直接。因此，本项目将以UTEX 3055为模型，通过对趋光信号转导途径中各蛋白组份进行体内和体外的功能鉴定，细胞定位以及互作关系研究，来揭示其信号转导的分子机制。本研究拟建立一个研究杆状蓝细菌趋光性的模型，帮助我们进一步了解细菌趋光性的分子机理并拓展我们对具有不同形状细菌的趋光性机制的认识。

Phototaxis enables bacteria to search for light energy required for cell growth, while avoiding damages caused by strong light. Current research in bacterial phototaxis is mostly focused on a coccoid unicellular cyanobacterium Synechocystis sp. PCC 6803. However, due to the complexity of multiple pathways affecting phototactic motility, it is difficult to study the mechanism of phototactic signaling in this strain. Moreover, the majority of studies have been focused on identifying the photoreceptors and their responsive light spectra, but the molecular mechanism of signal transduction from photoreceptors to motility apparatus remains elusive. In our previous study, we isolated a wild rod-shaped cyanobacterium S. elongatus UTEX 3055 and found it has a more straightforward mechanism of regulating phototactic motility. Therefore, in this proposal, we will use UTEX 3055 as a model to investigate the mechanism of phototactic signal transduction, mainly through characterizing the function of each pathway proteins, their subcellular localization and protein interactions. This study is aiming to establish a new model for studying rod-shaped cyanobacteria phototaxis, which will help us further dissecting the phototactic signaling mechanism and increase our knowledge of phototaxis in bacteria with different cell shapes.