Sheng Qi, Liu Ang, Yang Peiling, Chen Zhuowei, Wang Peng, Sun Haining, Li Chunyang, McMinn Andrew, Chen Yin, Zhang Yuzhong, Su Hainan, Chen Xiulan, Zhang Yuqiang
State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China.
Frontiers Science Center for Deep Ocean Multispheres and Earth System, College of Marine Life Sciences, Ocean University of China, Qingdao 266100, China.
Microorganisms. 2023 Jun 13;11(6):1566. doi: 10.3390/microorganisms11061566.
Swarming regulation is complicated in flagellated bacteria, especially those possessing dual flagellar systems. It remains unclear whether and how the movement of the constitutive polar flagellum is regulated during swarming motility of these bacteria. Here, we report the downregulation of polar flagellar motility by the c-di-GMP effector FilZ in the marine sedimentary bacterium sp. SM9913. Strain SM9913 possesses two flagellar systems, and is located in the lateral flagellar gene cluster. The function of FilZ is negatively controlled by intracellular c-di-GMP. Swarming in strain SM9913 consists of three periods. Deletion and overexpression of revealed that, during the period when strain SM9913 expands quickly, FilZ facilitates swarming. In vitro pull-down and bacterial two-hybrid assays suggested that, in the absence of c-di-GMP, FilZ interacts with the CheW homolog A2230, which may be involved in the chemotactic signal transduction pathway to the polar flagellar motor protein FliM, to interfere with polar flagellar motility. When bound to c-di-GMP, FilZ loses its ability to interact with A2230. Bioinformatic investigation indicated that -like genes are present in many bacteria with dual flagellar systems. Our findings demonstrate a novel mode of regulation of bacterial swarming motility.
群体运动调节在鞭毛细菌中很复杂，尤其是那些拥有双鞭毛系统的细菌。在这些细菌的群体运动过程中，组成型极鞭毛的运动是否以及如何受到调节仍不清楚。在此，我们报道了海洋沉积细菌 sp. SM9913 中 c-di-GMP 效应因子 FilZ 对极鞭毛运动的下调作用。菌株 SM9913 拥有两个鞭毛系统， 位于侧向鞭毛基因簇中。FilZ 的功能受到细胞内 c-di-GMP 的负调控。菌株 SM9913 的群体运动由三个阶段组成。对 的缺失和过表达表明，在菌株 SM9913 快速扩展的阶段，FilZ 促进群体运动。体外下拉实验和细菌双杂交实验表明，在没有 c-di-GMP 的情况下，FilZ 与CheW 同源物 A2230 相互作用，A2230 可能参与向极鞭毛运动蛋白 FliM 的趋化信号转导途径，从而干扰极鞭毛运动。当与 c-di-GMP 结合时，FilZ 失去了与 A2230 相互作用的能力。生物信息学研究表明，类似 的基因存在于许多具有双鞭毛系统的细菌中。我们的研究结果证明了细菌群体运动调节的一种新模式。
