title: The plant pathogen Pseudomonas fuscovaginae contains two conserved quorum sensing systems involved in virulence and negatively regulated by RsaL and the novel regulator RsaM.
abstract: Pseudomonas fuscovaginae is a Gram-negative fluorescent pseudomonad pathogenic towards several plant species. Despite its importance as a plant pathogen, no molecular studies of virulence have thus far been reported. In this study we show that P. fuscovaginae possesses two conserved N-acyl homoserine lactone (AHL) quorum sensing (QS) systems which we designated PfsI/R and PfvI/R. The PfsI/R system is homologous to the BviI/R system of Burkholderia vietnamiensis and produces and responds to C10-HSL and C12-HSL whereas PfvI/R is homologous to the LasI/R system of Pseudomonas aeruginosa and produces several long-chain 3-oxo-HSLs and responds to 3-oxo-C10-HSL and 3-oxo-C12-HSL and at high AHL concentrations can also respond to structurally different long-chain AHLs. Both systems were found to be negatively regulated by a repressor protein which was encoded by a gene located intergenically between the AHL synthase and LuxR-family response regulator. The pfsI/R system was regulated by a novel repressor designated RsaM while the pfvI/R system was regulated by both the RsaL repressor and by RsaM. The two systems are not transcriptionally hierarchically organized but share a common AHL response and both are required for plant virulence. Pseudomonas fuscovaginae has therefore a unique complex regulatory network composed of at least two different repressors which directly regulate the AHL QS systems and pathogenicity.
authors.affiliation: International Centre for Genetic Engineering & Biotechnology, Trieste, ItalyInternational Centre for Genetic Engineering & Biotechnology, Biosafety Outstation, Ca'Tron, Treviso, ItalyUnité de Phytopathologie, Université catholique de Louvain, Louvain-la-Neuve, Belgium.
authors.forename: Maura
authors.initials: M
authors.lastname: Mattiuzzo
authors.affiliation: International Centre for Genetic Engineering & Biotechnology, Trieste, ItalyInternational Centre for Genetic Engineering & Biotechnology, Biosafety Outstation, Ca'Tron, Treviso, ItalyUnité de Phytopathologie, Université catholique de Louvain, Louvain-la-Neuve, Belgium.
authors.forename: Iris
authors.initials: I
authors.lastname: Bertani
authors.affiliation: International Centre for Genetic Engineering & Biotechnology, Trieste, ItalyInternational Centre for Genetic Engineering & Biotechnology, Biosafety Outstation, Ca'Tron, Treviso, ItalyUnité de Phytopathologie, Université catholique de Louvain, Louvain-la-Neuve, Belgium.
authors.forename: Sara
authors.initials: S
authors.lastname: Ferluga
authors.affiliation: International Centre for Genetic Engineering & Biotechnology, Trieste, ItalyInternational Centre for Genetic Engineering & Biotechnology, Biosafety Outstation, Ca'Tron, Treviso, ItalyUnité de Phytopathologie, Université catholique de Louvain, Louvain-la-Neuve, Belgium.
authors.forename: Laura
authors.initials: L
authors.lastname: Cabrio
authors.affiliation: International Centre for Genetic Engineering & Biotechnology, Trieste, ItalyInternational Centre for Genetic Engineering & Biotechnology, Biosafety Outstation, Ca'Tron, Treviso, ItalyUnité de Phytopathologie, Université catholique de Louvain, Louvain-la-Neuve, Belgium.
authors.forename: Joseph
authors.initials: J
authors.lastname: Bigirimana
authors.affiliation: International Centre for Genetic Engineering & Biotechnology, Trieste, ItalyInternational Centre for Genetic Engineering & Biotechnology, Biosafety Outstation, Ca'Tron, Treviso, ItalyUnité de Phytopathologie, Université catholique de Louvain, Louvain-la-Neuve, Belgium.
authors.forename: Corrado
authors.initials: C
authors.lastname: Guarnaccia
authors.affiliation: International Centre for Genetic Engineering & Biotechnology, Trieste, ItalyInternational Centre for Genetic Engineering & Biotechnology, Biosafety Outstation, Ca'Tron, Treviso, ItalyUnité de Phytopathologie, Université catholique de Louvain, Louvain-la-Neuve, Belgium.
authors.forename: Sandor
authors.initials: S
authors.lastname: Pongor
authors.affiliation: International Centre for Genetic Engineering & Biotechnology, Trieste, ItalyInternational Centre for Genetic Engineering & Biotechnology, Biosafety Outstation, Ca'Tron, Treviso, ItalyUnité de Phytopathologie, Université catholique de Louvain, Louvain-la-Neuve, Belgium.
authors.forename: Henri
authors.initials: H
authors.lastname: Maraite
authors.affiliation: International Centre for Genetic Engineering & Biotechnology, Trieste, ItalyInternational Centre for Genetic Engineering & Biotechnology, Biosafety Outstation, Ca'Tron, Treviso, ItalyUnité de Phytopathologie, Université catholique de Louvain, Louvain-la-Neuve, Belgium.
authors.forename: Vittorio
authors.initials: V
authors.lastname: Venturi
mesh_terms: D015107:4-Butyrolactone / Q000031:analogs & derivatives / Q000378:metabolism; D054742:Acyl-Butyrolactones / Q000378:metabolism*; D003001:Cloning, Molecular; D015964:Gene Expression Regulation, Bacterial; D055786:Gene Knockout Techniques; D006714:Homoserine / Q000031:analogs & derivatives / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D012275:Oryza / Q000382:microbiology; D010935:Plant Diseases / Q000382:microbiology; D011549:Pseudomonas / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity*; D053038:Quorum Sensing; D012097:Repressor Proteins / Q000378:metabolism; D013379:Substrate Specificity; D014774:Virulence
chemical_list: D054742:Acyl-Butyrolactones; C109860:N-(3-oxododecanoyl)homoserine lactone; D012097:Repressor Proteins; D006714:Homoserine; D015107:4-Butyrolactone