In:
Frontiers in Microbiology, Frontiers Media SA, Vol. 15 ( 2024-6-26)
Abstract:
The transcription factor PsrA regulates fatty acid metabolism, the type III secretion system, and quinolone signaling quorum sensing system in Pseudomonas aeruginosa . To explore additional roles of PsrA in P. aeruginosa , this study engineered a P. aeruginosa PAO1 strain to carry a recombinant plasmid with the psrA gene (pMMB psrA ) and examined the impact of elevated psrA expression to the bacterium. Transcriptomic analysis revealed that PsrA significantly downregulated genes encoding the master quorum-sensing regulators, RhlR and LasR, and influenced many quorum-sensing-associated genes. The role of PsrA in quorum sensing was further corroborated by testing autoinducer synthesis in PAO1 [pMMB psrA ] using two reporter bacteria strains Chromobacterium violaceum CV026 and Escherichia coli [pSB1075], which respond to short- and long-chain acyl homoserine lactones, respectively. Phenotypic comparisons of isogenic Δ psrA , Δ lasR , and Δ psrA Δ lasR mutants revealed that the reduced elastase, caseinase, and swarming activity in PAO1 [pMMB psrA ] were likely mediated through LasR. Additionally, electrophoretic mobility shift assays demonstrated that recombinant PsrA could bind to the lasR promoter at a 5’-AAACGTTTGCTT-3′ sequence, which displays moderate similarity to the previously reported consensus PsrA binding motif. Furthermore, the PsrA effector molecule oleic acid inhibited PsrA binding to the lasR promoter and restored several quorum sensing-related phenotypes to wild-type levels. These findings suggest that PsrA regulates certain quorum-sensing phenotypes by negatively regulating lasR expression, with oleic acid acting as a crucial signaling molecule.
Type of Medium:
Online Resource
ISSN:
1664-302X
DOI:
10.3389/fmicb.2024.1424330
DOI:
10.3389/fmicb.2024.1424330.s001
DOI:
10.3389/fmicb.2024.1424330.s002
DOI:
10.3389/fmicb.2024.1424330.s003
DOI:
10.3389/fmicb.2024.1424330.s004
Language:
Unknown
Publisher:
Frontiers Media SA
Publication Date:
2024
detail.hit.zdb_id:
2587354-4
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