Regulation of Quorum Sensing by RpoS in
            <i>Pseudomonas aeruginosa</i>

Whiteley, Marvin; Parsek, Matthew R.; Greenberg, E. Peter

doi:10.1128/jb.182.15.4356-4360.2000

Cited by 210 publications

(189 citation statements)

References 29 publications

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“…A role of rpoS in antibiotic production has been reported (Sarniguet et al, 1995;Suh et al, 1999), but not for regulating PCN production. The inhibitory effect of RpoS on quorum sensing and pyocyanin in P. aeruginosa (Whiteley et al, 2000) or of PsrA and RpoS on quorum sensing in P. putida WCS358 (Bertani & Venturi, 2004) is the opposite of what we observed for strain PCL1391. Surprisingly, RpoS was previously shown not to be involved in homoserine lactone production by P. putida WCS358 (Kojic et al, 1999).…”

Section: Discussioncontrasting

confidence: 49%

Regulatory roles of psrA and rpoS in phenazine-1-carboxamide synthesis by Pseudomonas chlororaphis PCL1391

et al. 2006

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Production of the secondary metabolite phenazine-1-carboxamide (PCN) by Pseudomonas chlororaphis PCL1391 is crucial for biocontrol activity against the phytopathogen Fusarium oxysporum f. sp. radicis lycopersici on tomato. Regulation of PCN production involves the two-component signalling system GacS/GacA, the quorum-sensing system PhzI/PhzR and the regulator PsrA. This paper reports that a functional rpoS is required for optimal PCN and N-hexanoyl-l-homoserine lactone (C6-HSL) production. Constitutive expression of rpoS is able to complement partially the defect of a psrA mutant for PCN and N-acylhomoserine lactone production. Western blotting shows that rpoS is regulated by gacS. Altogether, these results suggest the existence of a cascade consisting of gacS/gacA upstream of psrA and rpoS, which influence expression of phzI/phzR. Overproduction of phzR complements the effects on PCN and C6-HSL production of all mutations tested in the regulatory cascade, which shows that a functional quorum-sensing system is essential and sufficient for PCN synthesis. In addition, the relative amounts of PCN, phenazine-1-carboxylic acid and C6-HSL produced by rpoS and psrA mutants harbouring a constitutively expressed phzR indicate an even more complex network of interactions, probably involving other genes. Preliminary microarray analyses of the transcriptomics of the rpoS and psrA mutants support the model of regulation described in this study and allow identification of new genes that might be involved in secondary metabolism.

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Section: Discussioncontrasting

confidence: 49%

Regulatory roles of psrA and rpoS in phenazine-1-carboxamide synthesis by Pseudomonas chlororaphis PCL1391

et al. 2006

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“…Cultures of this qscR mutant grew at the same rate as the parent strain PAO1 (data not shown); however, they were noticeably different from the parent in that they were blue. This is a characteristic of strains that overproduce the phenazine pigment pyocyanin (15). Direct measurements confirmed that the qscR mutant produced more pyocyanin than the parent.…”

Section: A Qscr Mutant Overexpresses Quorum-sensing-controlled Virulencementioning

confidence: 60%

QscR, a modulator of quorum-sensing signal synthesis and virulence in Pseudomonas aeruginosa

Chugani

Whiteley

Lee

et al. 2001

Proc. Natl. Acad. Sci. U.S.A.

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The opportunistic pathogenic bacterium Pseudomonas aeruginosa uses quorum-sensing signaling systems as global regulators of virulence genes. There are two quorum-sensing signal receptor and signal generator pairs, LasR-LasI and RhlR-RhlI. The recently completed P. aeruginosa genome-sequencing project revealed a gene coding for a homolog of the signal receptors, LasR and RhlR. Here we describe a role for this gene, which we call qscR. The qscR gene product governs the timing of quorum-sensing-controlled gene expression and it dampens virulence in an insect model. We present evidence that suggests the primary role of QscR is repression of lasI. A qscR mutant produces the LasI-generated signal prematurely, and this results in premature transcription of a number of quorum-sensing-regulated genes. When fed to Drosophila melanogaster, the qscR mutant kills the animals more rapidly than the parental P. aeruginosa. The repression of lasI by QscR could serve to ensure that quorum-sensing-controlled genes are not activated in environments where they are not useful.

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“…Previous reports have suggested that genes under the control of QS may also be regulated by other factors, including the alternative sigma factors RpoS (Van Delden & Iglewski, 1998) and PvdS (Ochsner et al, 1996). RpoS may regulate QS itself via repression of rhlI transcription post-stress (Whiteley et al, 2000). PA4944 may be another protein in this family of regulators.…”

Section: Discussionmentioning

confidence: 99%

Proteome analysis of extracellular proteins regulated by the las and rhl quorum sensing systems in Pseudomonas aeruginosa PAO1

et al. 2003

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The las and rhl quorum sensing (QS) systems regulate the expression of several genes in response to cell density changes in Pseudomonas aeruginosa. Many of these genes encode surfaceassociated or secreted virulence factors. Proteins from stationary phase culture supernatants were collected from wild-type and P. aeruginosa PAO1 mutants deficient in one or more of the lasRI, rhlRI and vfr genes and analysed using two-dimensional gel electrophoresis. All mutants released significantly lower amounts of protein than the wild-type. Protein spot patterns from each strain were compared using image analysis and visible spot differences were identified using mass spectrometry. Several previously unknown QS-regulated proteins were characterized, including an aminopeptidase (PA2939), an endoproteinase (PrpL) and a unique 'hypothetical' protein (PA0572), which could not be detected in the culture supernatants of Dlas mutants, although they were unaffected in Drhl mutants. Chitin-binding protein (CbpD) and a hypothetical protein (PA4944) with similarity to host factor I (HF-I) could not be detected when any of the lasRI or rhlRI genes were disrupted. Fourteen proteins were present at significantly greater levels in the culture supernatants of QS mutants, suggesting that QS may also negatively control the expression of some genes. Increased levels of two-partner secretion exoproteins (PA0041 and PA4625) were observed and may be linked to increased stability of their cognate transporters in a QS-defective background. Known QS-regulated extracellular proteins, including elastase (lasB), LasA protease (lasA) and alkaline metalloproteinase (aprA) were also detected.

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Regulation of Quorum Sensing by RpoS in Pseudomonas aeruginosa

Cited by 210 publications

References 29 publications

Regulatory roles of psrA and rpoS in phenazine-1-carboxamide synthesis by Pseudomonas chlororaphis PCL1391

Regulatory roles of psrA and rpoS in phenazine-1-carboxamide synthesis by Pseudomonas chlororaphis PCL1391

QscR, a modulator of quorum-sensing signal synthesis and virulence in Pseudomonas aeruginosa

Proteome analysis of extracellular proteins regulated by the las and rhl quorum sensing systems in Pseudomonas aeruginosa PAO1

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