Salmonella enterica serovar Typhimurium uses T6SS to promote bacterial adaptability and enhance its survival of niches in broiler chickens
Huimin Chen, Ke Shang, Yanyan Jia, Rongxian Guo, Jing Li, Chengshui Liao, Ke Ding, Songbiao Chen
Abstract
The type VI secretion system (T6SS) is a specialized protein complex in Gram-negative bacteria that delivers toxic effector molecules into target cells. However, the role of ClpV-a critical ATPase involved in T6SS assembly in Salmonella pathogenesis remains poorly understand. In this study, we investigated the contribution of ClpV to environmental stress resistance and virulence in Salmonella enterica serovar Typhimurium ( S . Typhimurium). Our findings demonstrate that ClpV significantly influences the ability of S . Typhimurium strain SL1344 to with stand various stressors, including bile salts, acidic conditions, hydrogen peroxide, and ethanol. Furthermore, ClpV enhances the competitive fitness of S . Typhimurium against commensal gut bacteria. Notably, ClpV appears to play a crucial role in pathogenicity by modulating the gut environment, disrupting microbial homeostasis, and facilitating bacterial persistence in host niches. These results provide a foundation for future studies on the molecular mechanisms by which T6SS mediates gut colonization and chronic infection in S . Typhimurium. Molecular Mechanism of ClpV in S. Typhimurium Pathogenesis. ClpV plays a critical role in S . Typhimurium infection by upregulating its own expression and disrupting the intestinal barrier, thereby facilitating bacterial colonization. Upon invasion, ClpV contributes to microbial dysbiosis-reducing beneficial bacteria while increasing pathogenic bacterial populations—compromising intestinal homeostasis and function. Additionally, ClpV enhances bacterial survival during oral-intestinal transit, providing S. Typhimurium with a competitive advantage for intestinal colonization.