Characterization of a Type VI Secretion System Gene in the Pathogenicity of BPM.

is a clinically underestimated conditional pathogen in the genus , the pathogenicity of the infection caused by remains poorly understood. According to previous studies, Type-VI secretion system (T6SS) is a protein secreting device widely existing in Gram-negative bacilli. Valine-glycine repeat protein G (VgrG) is not only an important component of T6SS, but also a virulence factor of many Gram-negative bacilli. In one of our previous studies, a unique T6SS gene ( gene) was present in a virulent strain BPM (BPM), but not in the relatively avirulent strain E264 (E264). Meanwhile, transcriptome analysis of BPM and E264 showed that the gene was strongly expressed in BPM, but not in E264. Therefore, we identified the function of the gene by constructing the mutant and complemented strains in this study. , the gene was observed to be involved in the interactions with host cells. The animal model experiment showed that the deletion of gene significantly led to the decrease in the lethality of BPM and impaired its ability to trigger host immune response. In conclusion, our study provides a new perspective for studying the pathogenicity of and lays the foundation for discovering the potential T6SS effectors.