AUTHOR=Li Jin , Hu Wei-wei , Qu Guo-xin , Li Xiao-rong , Xiang Yi , Jiang Peng , Luo Jiang-qiao , He Wen-huan , Jin Yu-jia , Shi Qiong 

TITLE=Characterization of a Type VI Secretion System vgrG2 Gene in the Pathogenicity of Burkholderia thailandensis BPM

JOURNAL=Frontiers in Microbiology

VOLUME=12

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2021.811343

DOI=10.3389/fmicb.2021.811343

ISSN=1664-302X

ABSTRACT=<p><italic>Burkholderia thailandensis</italic> is a clinically underestimated conditional pathogen in the genus <italic>Burkholderia</italic>, the pathogenicity of the infection caused by <italic>B. thailandensis</italic> 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 <italic>vgrG</italic> gene (<italic>vgrG2</italic> gene) was present in a virulent <italic>B. thailandensis</italic> strain BPM (BPM), but not in the relatively avirulent <italic>B. thailandensis</italic> strain E264 (E264). Meanwhile, transcriptome analysis of BPM and E264 showed that the <italic>vgrG2</italic> gene was strongly expressed in BPM, but not in E264. Therefore, we identified the function of the <italic>vgrG2</italic> gene by constructing the mutant and complemented strains in this study. <italic>In vitro</italic>, the <italic>vgrG2</italic> gene was observed to be involved in the interactions with host cells. The animal model experiment showed that the deletion of <italic>vgrG2</italic> 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 <italic>B. thailandensis</italic> and lays the foundation for discovering the potential T6SS effectors.</p>