AUTHOR=Zhu Miao , Zhao Jingru , Kang Huaping , Kong Weina , Zhao Yuanyu , Wu Min , Liang Haihua 

TITLE=Modulation of Type III Secretion System in Pseudomonas aeruginosa: Involvement of the PA4857 Gene Product

JOURNAL=Frontiers in Microbiology

VOLUME=7

YEAR=2016

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2016.00007

DOI=10.3389/fmicb.2016.00007

ISSN=1664-302X

ABSTRACT=<p><italic>Pseudomonas aeruginosa</italic> is an opportunistic pathogen that causes serious acute or chronic infections in humans. Acute infections typically involve the type III secretion systems (T3SSs) and bacterial motility, whereas chronic infections are often associated with biofilm formation and the type VI secretion system. To identify new genes required for pathogenesis, a transposon mutagenesis library was constructed and the gene PA4857, named <italic>tspR</italic>, was found to modulate T3SS gene expression. Deletion of <italic>P. aeruginosa tspR</italic> reduced the virulence in a mouse acute lung infection model and diminished cytotoxicity. Suppression of T3SS gene expression in the <italic>tspR</italic> mutant resulted from compromised translation of the T3SS master regulator ExsA. TspR negatively regulated two small RNAs, RsmY and RsmZ, which control RsmA. Our data demonstrated that defects in T3SS expression and biofilm formation in <italic>retS</italic> mutant could be partially restored by overexpression of <italic>tspR</italic>. Taken together, our results demonstrated that the newly identified <italic>retS-tspR</italic> pathway is coordinated with the <italic>retS-gacS</italic> system, which regulates the genes associated with acute and chronic infections and controls the lifestyle choice of <italic>P. aeruginosa</italic>.</p>