The phenazine pyocyanin is a terminal signalling factor in the quorum sensing network of Pseudomonas aeruginosa
Abstract
Certain members of the fluorescent pseudomonads produce and secrete phenazines. These heterocyclic, redox-active compounds are toxic to competing organisms, and the cause of these antibiotic effects has been the focus of intense research efforts. It is largely unknown, however, how pseudomonads themselves respond to – and survive in the presence of – these compounds. Using Pseudomonas aeruginosa DNA microarrays and quantitative RT-PCR, we demonstrate that the phenazine pyocyanin elicits the upregulation of genes/operons that function in transport [such as the resistance-nodulation-cell division (RND) efflux pump MexGHI-OpmD] and possibly in redox control (such as PA2274, a putative flavin-dependant monooxygenase), and downregulates genes involved in ferric iron acquisition. Strikingly, mexGHI-opmD and PA2274 were previously shown to be regulated by the PA14 quorum sensing network that controls the production of virulence factors (including phenazines). Through mutational analysis, we show that pyocyanin is the physiological signal for the upregulation of these quorum sensing-controlled genes during stationary phase and that the response is mediated by the transcription factor SoxR. Our results implicate phenazines as signalling molecules in both P. aeruginosa PA14 and PAO1.
Additional Information
© 2006 The Authors Accepted 26 June, 2006. We are grateful to Pierre Cornelis for sending us a phzM mutant of PA14. We thank members of the Newman lab and Tracy J. LaGrassa for helpful discussions. This work was supported by grants from the Luce Foundation, Packard Foundation, and Howard Hughes Medical Institute to D.K.N. L.E.P.D. is supported by a postdoctoral EMBO Long Term Fellowship, and A.M.P-W. by an N.I.H. training grant.Files
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Additional details
- Eprint ID
- 4816
- Resolver ID
- CaltechAUTHORS:DIEmm06
- Created
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2006-09-08Created from EPrint's datestamp field
- Updated
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2021-11-08Created from EPrint's last_modified field
- Caltech groups
- Division of Geological and Planetary Sciences