Dissection of ToxR-dependent and ToxR-independent stress-regulated pathways in Vibrio parahaemolyticus

In this study, we demonstrated that ToxR is essential for V. parahaemolyticus to tolerate acid stress by constructing a ToxR deletion mutant (ΔtoxR) and its complemented strain (toxR+). Quantitative PCR showed that the expression of toxR was up regulated under acid stress condition. RNA-seq analysis showed that ompU encoding one of outer membrane proteins was dramatically down regulated in ΔtoxR. Furthermore, the mutation of ompU also led to a significant reduction in tolerating acid stress indicating that ToxR mediated acid stress through regulating ompU expression. RNA-seq results further confirmed that acid stress condition could alter multiple signaling pathways either depending on ToxR (e.g., quorum sensing, fatty acid metabolism) or independent of ToxR (e.g., biosynthesis of secondary metabolites, microbial metabolism in diverse environment, biosynthesis of antibiotics, biosynthesis of amino acids and carbon metabolism pathways). We also for the first time demonstrated that ToxR positively regulated the expression of T6SS2 gene and the interbacteria killing activity. Our study provides comprehensive understanding of signaling pathways which are regulated by both acid stress and ToxR.
Source: Microbiological Research - Category: Infectious Diseases Source Type: research