Skip to main content
PMC home page
Proceedings of the National Academy of Sciences of the United States of America logoLink to Proceedings of the National Academy of Sciences of the United States of America
. 1995 Jul 3;92(14):6424–6428. doi: 10.1073/pnas.92.14.6424

Autoinducer-mediated regulation of rhamnolipid biosurfactant synthesis in Pseudomonas aeruginosa.

U A Ochsner 1, J Reiser 1
PMCID: PMC41530  PMID: 7604006

Abstract

The opportunistic human pathogen Pseudomonas aeruginosa produces a variety of virulence factors, including exotoxin A, elastase, alkaline protease, alginate, phospholipases, and extracellular rhamnolipids. The previously characterized rhlABR gene cluster encodes a regulatory protein (RhlR) and a rhamnosyltransferase (RhlAB), both of which are required for rhamnolipid synthesis. Another gene, rhII, has now been identified downstream of the rhlABR gene cluster. The putative RhlI protein shares significant sequence similarity with bacterial autoinducer synthetases of the LuxI type. A P. aeruginosa rhlI mutant strain carrying a disrupted rhlI gene was unable to produce rhamnolipids and lacked rhamnosyltransferase activity. Rhamnolipid synthesis was restored by introducing a wild-type rhlI gene into such strains or, alternatively, by adding either the cell-free spent supernatant from a P. aeruginosa wild-type strain or synthetic N-acylhomoserine lactones. Half-maximal induction of rhamnolipid synthesis in the rhlI mutant strain required 0.5 microM N-butyrylhomoserine lactone or 10 microM N-(3-oxohexanoyl)homoserine lactone. The P. aeruginosa rhlA promoter was active in the heterologous host Pseudomonas putida when both the rhlR and rhlI genes were present or when the rhlR gene alone was supplied together with synthetic N-acylhomoserine lactones. The RhlR-RhlI regulatory system was found to be essential for the production of elastase as well, and cross-communication between the RhlR-RhlI rhamnolipid regulatory system and the LasR-LasI elastase regulatory system was demonstrated.

Full text

PDF
6424

Images in this article

6425Fig. 1
on p.6425
6427Fig. 6
on p.6427

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Bainton N. J., Bycroft B. W., Chhabra S. R., Stead P., Gledhill L., Hill P. J., Rees C. E., Winson M. K., Salmond G. P., Stewart G. S. A general role for the lux autoinducer in bacterial cell signalling: control of antibiotic biosynthesis in Erwinia. Gene. 1992 Jul 1;116(1):87–91. doi: 10.1016/0378-1119(92)90633-z. [DOI] [PubMed] [Google Scholar]
  2. Bainton N. J., Stead P., Chhabra S. R., Bycroft B. W., Salmond G. P., Stewart G. S., Williams P. N-(3-oxohexanoyl)-L-homoserine lactone regulates carbapenem antibiotic production in Erwinia carotovora. Biochem J. 1992 Dec 15;288(Pt 3):997–1004. doi: 10.1042/bj2880997. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Bjorn M. J., Sokol P. A., Iglewski B. H. Influence of iron on yields of extracellular products in Pseudomonas aeruginosa cultures. J Bacteriol. 1979 Apr;138(1):193–200. doi: 10.1128/jb.138.1.193-200.1979. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Davison J., Heusterspreute M., Chevalier N., Ha-Thi V., Brunel F. Vectors with restriction site banks. V. pJRD215, a wide-host-range cosmid vector with multiple cloning sites. Gene. 1987;51(2-3):275–280. doi: 10.1016/0378-1119(87)90316-7. [DOI] [PubMed] [Google Scholar]
  5. Engebrecht J., Silverman M. Nucleotide sequence of the regulatory locus controlling expression of bacterial genes for bioluminescence. Nucleic Acids Res. 1987 Dec 23;15(24):10455–10467. doi: 10.1093/nar/15.24.10455. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Fuqua W. C., Winans S. C. A LuxR-LuxI type regulatory system activates Agrobacterium Ti plasmid conjugal transfer in the presence of a plant tumor metabolite. J Bacteriol. 1994 May;176(10):2796–2806. doi: 10.1128/jb.176.10.2796-2806.1994. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Fuqua W. C., Winans S. C., Greenberg E. P. Quorum sensing in bacteria: the LuxR-LuxI family of cell density-responsive transcriptional regulators. J Bacteriol. 1994 Jan;176(2):269–275. doi: 10.1128/jb.176.2.269-275.1994. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Gambello M. J., Iglewski B. H. Cloning and characterization of the Pseudomonas aeruginosa lasR gene, a transcriptional activator of elastase expression. J Bacteriol. 1991 May;173(9):3000–3009. doi: 10.1128/jb.173.9.3000-3009.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Gray K. M., Passador L., Iglewski B. H., Greenberg E. P. Interchangeability and specificity of components from the quorum-sensing regulatory systems of Vibrio fischeri and Pseudomonas aeruginosa. J Bacteriol. 1994 May;176(10):3076–3080. doi: 10.1128/jb.176.10.3076-3080.1994. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Huijberts G. N., Eggink G., de Waard P., Huisman G. W., Witholt B. Pseudomonas putida KT2442 cultivated on glucose accumulates poly(3-hydroxyalkanoates) consisting of saturated and unsaturated monomers. Appl Environ Microbiol. 1992 Feb;58(2):536–544. doi: 10.1128/aem.58.2.536-544.1992. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Jones S., Yu B., Bainton N. J., Birdsall M., Bycroft B. W., Chhabra S. R., Cox A. J., Golby P., Reeves P. J., Stephens S. The lux autoinducer regulates the production of exoenzyme virulence determinants in Erwinia carotovora and Pseudomonas aeruginosa. EMBO J. 1993 Jun;12(6):2477–2482. doi: 10.1002/j.1460-2075.1993.tb05902.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Kuo A., Blough N. V., Dunlap P. V. Multiple N-acyl-L-homoserine lactone autoinducers of luminescence in the marine symbiotic bacterium Vibrio fischeri. J Bacteriol. 1994 Dec;176(24):7558–7565. doi: 10.1128/jb.176.24.7558-7565.1994. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Ochsner U. A., Fiechter A., Reiser J. Isolation, characterization, and expression in Escherichia coli of the Pseudomonas aeruginosa rhlAB genes encoding a rhamnosyltransferase involved in rhamnolipid biosurfactant synthesis. J Biol Chem. 1994 Aug 5;269(31):19787–19795. [PubMed] [Google Scholar]
  14. Ochsner U. A., Koch A. K., Fiechter A., Reiser J. Isolation and characterization of a regulatory gene affecting rhamnolipid biosurfactant synthesis in Pseudomonas aeruginosa. J Bacteriol. 1994 Apr;176(7):2044–2054. doi: 10.1128/jb.176.7.2044-2054.1994. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Ohman D. E., Cryz S. J., Iglewski B. H. Isolation and characterization of Pseudomonas aeruginosa PAO mutant that produces altered elastase. J Bacteriol. 1980 Jun;142(3):836–842. doi: 10.1128/jb.142.3.836-842.1980. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Passador L., Cook J. M., Gambello M. J., Rust L., Iglewski B. H. Expression of Pseudomonas aeruginosa virulence genes requires cell-to-cell communication. Science. 1993 May 21;260(5111):1127–1130. doi: 10.1126/science.8493556. [DOI] [PubMed] [Google Scholar]
  17. Pearson J. P., Gray K. M., Passador L., Tucker K. D., Eberhard A., Iglewski B. H., Greenberg E. P. Structure of the autoinducer required for expression of Pseudomonas aeruginosa virulence genes. Proc Natl Acad Sci U S A. 1994 Jan 4;91(1):197–201. doi: 10.1073/pnas.91.1.197. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Pearson J. P., Passador L., Iglewski B. H., Greenberg E. P. A second N-acylhomoserine lactone signal produced by Pseudomonas aeruginosa. Proc Natl Acad Sci U S A. 1995 Feb 28;92(5):1490–1494. doi: 10.1073/pnas.92.5.1490. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Piper K. R., Beck von Bodman S., Farrand S. K. Conjugation factor of Agrobacterium tumefaciens regulates Ti plasmid transfer by autoinduction. Nature. 1993 Apr 1;362(6419):448–450. doi: 10.1038/362448a0. [DOI] [PubMed] [Google Scholar]
  20. Pirhonen M., Flego D., Heikinheimo R., Palva E. T. A small diffusible signal molecule is responsible for the global control of virulence and exoenzyme production in the plant pathogen Erwinia carotovora. EMBO J. 1993 Jun;12(6):2467–2476. doi: 10.1002/j.1460-2075.1993.tb05901.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Seed P. C., Passador L., Iglewski B. H. Activation of the Pseudomonas aeruginosa lasI gene by LasR and the Pseudomonas autoinducer PAI: an autoinduction regulatory hierarchy. J Bacteriol. 1995 Feb;177(3):654–659. doi: 10.1128/jb.177.3.654-659.1995. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Swift S., Bainton N. J., Winson M. K. Gram-negative bacterial communication by N-acyl homoserine lactones: a universal language? Trends Microbiol. 1994 Jun;2(6):193–198. doi: 10.1016/0966-842x(94)90110-q. [DOI] [PubMed] [Google Scholar]
  23. Swift S., Winson M. K., Chan P. F., Bainton N. J., Birdsall M., Reeves P. J., Rees C. E., Chhabra S. R., Hill P. J., Throup J. P. A novel strategy for the isolation of luxI homologues: evidence for the widespread distribution of a LuxR:LuxI superfamily in enteric bacteria. Mol Microbiol. 1993 Nov;10(3):511–520. doi: 10.1111/j.1365-2958.1993.tb00923.x. [DOI] [PubMed] [Google Scholar]
  24. Toder D. S., Ferrell S. J., Nezezon J. L., Rust L., Iglewski B. H. lasA and lasB genes of Pseudomonas aeruginosa: analysis of transcription and gene product activity. Infect Immun. 1994 Apr;62(4):1320–1327. doi: 10.1128/iai.62.4.1320-1327.1994. [DOI] [PMC free article] [PubMed] [Google Scholar]
  25. Zhang L., Murphy P. J., Kerr A., Tate M. E. Agrobacterium conjugation and gene regulation by N-acyl-L-homoserine lactones. Nature. 1993 Apr 1;362(6419):446–448. doi: 10.1038/362446a0. [DOI] [PubMed] [Google Scholar]

Articles from Proceedings of the National Academy of Sciences of the United States of America are provided here courtesy of National Academy of Sciences

RESOURCES