AUTHOR=Wang Zhuo , Wang Tietao , Cui Rui , Zhang Zhenxing , Chen Keqi , Li Mengyun , Hua Yueyue , Gu Huawei , Xu Lei , Wang Yao , Yang Yantao , Shen Xihui 

TITLE=HpaR, the Repressor of Aromatic Compound Metabolism, Positively Regulates the Expression of T6SS4 to Resist Oxidative Stress in Yersinia pseudotuberculosis

JOURNAL=Frontiers in Microbiology

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2020.00705

DOI=10.3389/fmicb.2020.00705

ISSN=1664-302X

ABSTRACT=<p>HpaR, a MarR family transcriptional regulator, was first identified in <italic>Escherichia coli</italic> W for its regulation of the <italic>hpa-meta</italic> operon. Little else is known regarding its functionality. Here, we report that in <italic>Yersinia pseudotuberculosis</italic>, HpaR negatively regulates the <italic>hpa-meta</italic> operon similar to in <italic>E. coli</italic> W. To investigate additional functions of HpaR, RNA sequencing was performed for both the wild-type and the Δ<italic>hpaR</italic> mutant, which revealed that the type VI secretion system (T6SS) was positively regulated by HpaR. T6SS4 is important for bacteria resisting environmental stress, especially oxidative stress. We demonstrate that HpaR facilitates bacteria resist oxidative stress by upregulating the expression of T6SS4 in <italic>Y</italic>. <italic>pseudotuberculosis</italic>. HpaR is also involved in biofilm formation, antibiotic resistance, adhesion to eukaryotic cells, and virulence in mice. These results greatly expand our knowledge of the functionality of HpaR and reveal a new pathway that regulates T6SS4.</p>