title: LasI/R and RhlI/R quorum sensing in a strain of Pseudomonas aeruginosa beneficial to plants.
abstract: Pseudomonas aeruginosa possesses three quorum-sensing (QS) systems which are key in the expression of a large number of genes, including many virulence factors. Most studies of QS in P. aeruginosa have been performed in clinical isolates and have therefore focused on its role in pathogenicity. P. aeruginosa, however, is regarded as a ubiquitous organism capable of colonizing many different environments and also of establishing beneficial associations with plants. In this study we examined the role of the two N-acyl homoserine lactone systems known as RhlI/R and LasI/R in the environmental rice rhizosphere isolate P. aeruginosa PUPa3. Both the Rhl and Las systems are involved in the regulation of plant growth-promoting traits. The environmental P. aeruginosa PUPa3 is pathogenic in two nonmammalian infection models, and only the double las rhl mutants are attenuated for virulence. In fact it was established that the two QS systems are not hierarchically organized and that they are both important for the colonization of the rice rhizosphere. This is an in-depth genetic and molecular study of QS in an environmental P. aeruginosa strain and highlights several differences with QS regulation in the clinical isolate PAO1.
authors.affiliation: International Centre for Genetic Engineering & Biotechnology, Trieste, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Steindler
authors.forename: Iris
authors.initials: I
authors.lastname: Bertani
authors.forename: Luisa
authors.initials: L
authors.lastname: De Sordi
authors.forename: Stephan
authors.initials: S
authors.lastname: Schwager
authors.forename: Leo
authors.initials: L
authors.lastname: Eberl
authors.forename: Vittorio
authors.initials: V
authors.lastname: Venturi
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000502:physiology*; D017173:Caenorhabditis elegans / Q000382:microbiology; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D008025:Ligases / Q000235:genetics / Q000502:physiology*; D008969:Molecular Sequence Data; D009036:Moths / Q000382:microbiology; D012275:Oryza / Q000382:microbiology; D018517:Plant Roots / Q000382:microbiology; D011552:Pseudomonas Infections / Q000382:microbiology; D011550:Pseudomonas aeruginosa / Q000235:genetics / Q000472:pathogenicity / Q000502:physiology*; D053038:Quorum Sensing; D017422:Sequence Analysis, DNA; D016019:Survival Analysis; D015534:Trans-Activators / Q000235:genetics / Q000502:physiology*; D014157:Transcription Factors / Q000235:genetics / Q000502:physiology*; D014774:Virulence
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; C081237:LasI protein, Pseudomonas aeruginosa; C080365:LasR protein, Pseudomonas aeruginosa; C086515:RhlR protein, Pseudomonas aeruginosa; D015534:Trans-Activators; D014157:Transcription Factors; D008025:Ligases; C096955:RHLI protein, Pseudomonas aeruginosa