Mu Kexin, He Meina, Chen Haozhe, Liu Tong, Fan Ying, Tao Yongxin, Feng Haoqi, Huang Qiaoyun, Xiao Yujie, Chen Wenli
National Key Laboratory of Agricultural Microbiology, Huazhong Agriculture University, Wuhan, China.
Appl Environ Microbiol. 2025 Jan 31;91(1):e0107124. doi: 10.1128/aem.01071-24. Epub 2024 Nov 26.
The overuse and wanton discharge of antibiotics produces a threat to bacteria in the environment, which, in turn, stimulates the more rapid emergence of antibiotic-resistant bacteria. actively forms biofilms to protect the population under tetracycline stress, but the molecular mechanism remains unclear. This study found that tetracycline at sub-minimal inhibitory concentrations increased cyclic diguanylate (c-di-GMP), a second messenger that positively regulates biofilm formation. Four c-di-GMP-metabolizing proteins were found to be involved in the tetracycline-mediated biofilm promotion, including DibA, WspR, PP_3242, and PP_3319. Among them, the diguanylate cyclase WspR displayed the most significant effect on c-di-GMP level and biofilm formation. belongs to the operon comprising seven genes ( and ). The operon contained six promoters, including one major start promoter (P) and five internal promoters (P, P, P, P, and P), and tetracycline promoted the activity of P. The stress-response sigma factor RpoS directly bound to P and positively regulated its activity under tetracycline stress. Moreover, RpoS was required for tetracycline to induce P activity and promote biofilm formation. Our results enrich the transcriptional regulation of the operon and reveal the mechanism by which tetracycline promotes biofilm formation in .IMPORTANCEThe overuse and wanton discharge of antibiotics produces a threat to bacteria in the environment, which, in turn, stimulates the more rapid emergence of antibiotic-resistant bacteria. The actively forms biofilm against antibiotic threats, but the mechanism remains unclear. Here, our results showed that tetracycline treatment at sub-minimal inhibitory concentrations could induce the expression of the Wsp system via the sigma factor RpoS in , resulting in elevated c-di-GMP levels, which leads to increased biofilm formation. The operon contains one major promoter and five internal promoters, and RpoS directly binds to the major promoter to promote its activity.
抗生素的过度使用和肆意排放对环境中的细菌构成威胁，进而刺激了耐药菌的更快出现。[细菌名称]在四环素胁迫下会积极形成生物膜以保护菌群，但分子机制尚不清楚。本研究发现，亚最小抑菌浓度的四环素会增加环二鸟苷酸（c-di-GMP），这是一种对生物膜形成起正向调节作用的第二信使。研究发现四种参与c-di-GMP代谢的蛋白与四环素介导的生物膜促进作用有关，包括DibA、WspR、PP_3242和PP_3319。其中，双鸟苷酸环化酶WspR对c-di-GMP水平和生物膜形成的影响最为显著。[细菌名称]的Wsp系统属于一个包含七个基因（[基因名称1]和[基因名称2]）的操纵子。该操纵子包含六个启动子，包括一个主要起始启动子（P1）和五个内部启动子（P2、P3、P4、P5和P6），四环素可促进P1的活性。应激反应σ因子RpoS在四环素胁迫下直接结合到P1并正向调节其活性。此外，四环素诱导P1活性和促进生物膜形成需要RpoS。我们的研究结果丰富了[细菌名称]Wsp操纵子的转录调控，并揭示了四环素促进[细菌名称]生物膜形成的机制。重要性抗生素的过度使用和肆意排放对环境中的细菌构成威胁，进而刺激了耐药菌的更快出现。[细菌名称]会积极形成生物膜以应对抗生素威胁，但其机制尚不清楚。在此，我们的研究结果表明，亚最小抑菌浓度的四环素处理可通过σ因子RpoS诱导[细菌名称]中Wsp系统的表达，导致c-di-GMP水平升高，进而导致生物膜形成增加。[细菌名称]的Wsp操纵子包含一个主要启动子和五个内部启动子，RpoS直接结合到主要启动子以促进其活性。
