The GntR family regulators are widely distributed in bacteria and play critical roles in metabolic processes and bacterial pathogenicity. In this study, we describe a GntR family protein encoded by PA4132 that we named MpaR (M vfR-mediated P QS and a nthranilate r egulator) for its regulation of
Pseudomonas quinolone signal (PQS) production and anthranilate metabolism in
Pseudomonas aeruginosa. The deletion of
mpaR increased biofilm formation and reduced pyocyanin production. RNA sequencing analysis revealed that the mRNA levels of
antABC encoding enzymes for the synthesis of catechol from anthranilate, a precursor of the PQS, were most affected by
mpaR deletion. Data showed that MpaR directly activates the expression of
mvfR, a master regulator of
pqs system, and subsequently promotes PQS production. Accordingly, deletion of
mpaR activates the expression of
antABC genes, and thus, increases catechol production. We also demonstrated that MpaR represses the
rhl quorum-sensing (QS) system, which has been shown to control
antABC activity. These results suggested that MpaR function is integrated into the QS regulatory network. Moreover, mutation of
mpaR promotes bacterial survival in a mouse model of acute pneumonia infection. Collectively, this study identified a novel regulator of
pqs system, which coordinately controls anthranilate metabolism and bacterial virulence in
P.
aeruginosa.
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