title: Ferripyochelin uptake genes are involved in pyochelin-mediated signalling in Pseudomonas aeruginosa.
abstract: In response to iron starvation, Pseudomonas aeruginosa produces the siderophore pyochelin. When secreted to the extracellular environment, pyochelin chelates iron and transports it to the bacterial cytoplasm via its specific outer-membrane receptor FptA and the inner-membrane permease FptX. Exogenously added pyochelin also acts as a signal which induces the expression of the pyochelin biosynthesis and uptake genes by activating PchR, a cytoplasmic regulatory protein of the AraC/XylS family. The importance of ferripyochelin uptake genes in this regulation was evaluated. The fptA and fptX genes were shown to be part of the fptABCX ferripyochelin transport operon, which is conserved in Burkholderia sp. and Rhodospirillum rubrum. The fptB and fptC genes were found to be dispensable for utilization of pyochelin as an iron source, for signalling and for pyochelin production. By contrast, mutations in fptA and fptX not only interfered with pyochelin utilization, but also affected signalling and diminished siderophore production. It is concluded from this that pyochelin-mediated signalling operates to a large extent via the ferripyochelin transport system.
authors.affiliation: Département de Microbiologie Fondamentale, Université de Lausanne, CH-1015 Lausanne, Switzerland.
authors.forename: Laurent
authors.initials: L
authors.lastname: Michel
authors.affiliation: Département de Microbiologie Fondamentale, Université de Lausanne, CH-1015 Lausanne, Switzerland.
authors.forename: Aude
authors.initials: A
authors.lastname: Bachelard
authors.affiliation: Département de Microbiologie Fondamentale, Université de Lausanne, CH-1015 Lausanne, Switzerland.
authors.forename: Cornelia
authors.initials: C
authors.lastname: Reimmann
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000502:physiology*; D001426:Bacterial Proteins / Q000096:biosynthesis*; D017124:Conserved Sequence; D004268:DNA-Binding Proteins / Q000096:biosynthesis*; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology*; D005798:Genes, Bacterial; D026901:Membrane Transport Proteins / Q000235:genetics / Q000502:physiology*; D009876:Operon; D010636:Phenols / Q000378:metabolism*; D011550:Pseudomonas aeruginosa / Q000235:genetics / Q000502:physiology*; D011956:Receptors, Cell Surface / Q000235:genetics / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*; D014157:Transcription Factors / Q000096:biosynthesis*
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C075523:FPTA protein, Pseudomonas; D026901:Membrane Transport Proteins; D010636:Phenols; D011956:Receptors, Cell Surface; D014157:Transcription Factors; C025315:ferripyochelin; C083187:pchR protein, Pseudomonas aeruginosa