PCBs降解红球菌运动和趋化机制研究

The bioremediation of organic pollutants is regarded as a safe, economical and efficient strategy. Nevertheless, biodegradation efficiency is not only associated with the degrading capability of bacteria, but also depends on the bioavailability of pollutants. The chemotactic motility of bacteria could increase pollutants bioavailability, which plays a key role in bioremediation. However, most of the reported degrading bacteria with chemotactic capability are flagella bacteria. There are few studies about the chemotaxis of degrading bacteria such as Rhodococcus sp., which is flagella-free and widely distributes in the environment. Studying the chemotactic mechanism of Rhodococcus is important for the exploration of environmental pollution controlling techniques based on chemotactic functional microorganism.. In this project, polychlorinated biphenyls degrading strain Rhodococcus sp. will be studied, focusing on the movement behavior and extracellular secretion of strain TG9 during chemotaxis by microscopic tracking. At the same time, the key chemotactic genes contained in TG9 genome will be knocked out and functionally complemented, and the transcriptome analysis will be performed by high-throughput sequencing, and the chemotaxis mechanism of strain TG9 would be initially explored.

有机污染的微生物治理被认为是一种安全、有效和经济的治理方式，其生物可利用性是影响生物降解效率的主要限制因子之一。趋化性可以使细菌与污染物紧密接触，提高有机污染物的生物可利用性，从而提高降解效率。然而，目前的研究主要集中在鞭毛介导的趋化行为，关于红球菌等无鞭毛而又在环境中广泛分布的降解菌趋化性研究较少。研究红球菌的运动和趋化机制，对探索基于趋化功能微生物精准调控的环境污染治理技术有重要意义。. 本项目拟以PCBs降解红球菌TG9为研究对象，应用显微追踪技术和分子生物学技术，研究菌株TG9在趋化过程中的运动行为及胞外分泌物的产生情况；对TG9基因组含有的关键趋化基因进行敲除和功能互补验证，并结合高通量转录组测序分析，探索菌株TG9的运动和趋化机制。

本项目以PCBs降解红球菌为研究对象，主要研究菌株的运动和趋化行为，对菌株运动和趋化基因进行相关分析，构建趋化基因突变株，菌株趋化过程中，对其运动和趋化基因的表达情况进行研究，探索菌株的运动和趋化机制。主要研究结果如下：（1）菌株可能通过固体表面的蹭行运动（twitching motility）实现趋化功能；（2）采用同源重组法对菌株TG9的趋化基因mcp和cheR进行敲除研究，暂未获得趋化基因突变株；（3）对菌株趋化过程中相关运动和趋化基因表达情况进行分析，发现与菌株运动和趋化相关的基因Cpaf、BcsQ、mcp、cheR、cheY和Tfp的表达量均显著上调，说明Cpaf、BcsQ、MCP、cheR、cheY和Tfp基因可能参与菌株的运动和趋化调控。因菌株涉及的运动和趋化的基因较多，且未成功构建突变株，结果有一定的不确定性，我们将要在后续的工作中不断完善，进一步明确菌株TG9的运动和趋化机制。