玫瑰杆菌类群代表菌株中DMSP合成的生理作用及调控

Dimethylsulfoniopropionate (DMSP) is an important organosulfur compound in marine environment, and many marine bacteria have been reported to be capable of DMSP biosynthesis. However, the physiological functions and regulation of DMSP biosynthesis in bacteria remain largely unknown. In this project, representative DMSP biosynthesis Roseobacter strain J526 and La6 are chosen as model organisms, and we will perform transcriptome and proteome sequencing and analysis on their wildtype and ΔdsyB mutant strains which were constructed in our previous work, trying to identify and confirm the different phenotypes between wildtype and ΔdsyB mutant strains. A comprehensive comparation on the metabolism and biochemical characteristics will be carried out to get a thorough understanding of the influence and physiological role of DMSP biosynthesis in these bacteria. Besides, we will try to clarify the mechanisms which causes the previously observed difference in biofilm formation of La6 wildtype strain and ΔdsyB mutant. Furthermore, quorum sensing signal molecules will be tested for their possible regulation role on DMSP biosynthesis in J526 and La6. These studies will help to illuminate the importance of DMSP biosynthesis in bacteria and lead to a better understanding of DMSP metabolism process.

二甲基巯基丙酸内盐（DMSP）是海洋中重要的有机硫化合物，目前已发现众多海洋细菌具有合成DMSP的能力，然而对于DMSP在细菌中的生理功能及调控目前尚未有深入研究。本项目拟选择玫瑰杆菌中DMSP合成代表菌株J526和La6为研究对象，在已获得其DMSP合成关键基因dsyB框内缺失突变株的基础上，利用转录组及蛋白质组测序对野生株及dsyB突变株间的差异表达进行分析，确定存在差异的表型并进行验证，同时对野生株和突变株的代谢及各种生理生化特征进行全面比较，以深入了解DMSP合成对细菌的影响及生理作用。此外，基于前期研究中La6野生株和dsyB缺失突变株在生物被膜形成方面表现出的差异，阐明DMSP合成影响La6生物被膜的具体机制。最后，验证外源密度感应信号分子是否能够调控J526及La6中DMSP的合成。本研究有助于了解细菌中DMSP合成重要生理意义，加深对海洋细菌DMSP代谢过程的认识。

二甲基巯基丙酸内盐（DMSP）是海洋中重要的有机硫化合物，在气候调节和全球硫循环中扮演重要的角色。目前已发现众多海洋细菌具有合成DMSP的能力，然而对于DMSP在细菌中的生理功能及调控目前尚未有深入研究。本项目以玫瑰杆菌中DMSP合成代表菌株J526和La6为研究对象，在已获得其DMSP合成关键基因dsyB框内缺失突变株的基础上，揭示了DMSP合成缺陷对细菌在基因转录水平和代谢水平上的差异，验证了DMSP对于海洋细菌具有抗氧化、渗透压保护、压力保护等重要功能，同时证实DMSP合成过程对于细菌的膜转运、碳源利用等代谢过程具有重要的影响。在此基础上，本项目发现海洋细菌的DMSP合成过程受到启动子水平的调控，并鉴定了影响DMSP合成与渗透压调节的关键因子RpoN。以上结果证实了细菌中DMSP合成的重要生理意义，拓展了对海洋细菌DMSP代谢及相关调控过程的认识。本项目开展过程中在本领域主流期刊发表SCI论文3篇，协助培养硕士研究生3名。