6533b833fe1ef96bd129c3db

RESEARCH PRODUCT

The transcriptional activator rfiA is quorum-sensing regulated by cotranscription with the luxI homolog pcol and is essential for plant virulence in Pseudomonas corrugata

Iris BertaniVittorio VenturiGrazia LicciardelloVittoria CataraLaura SteindlerPatrizia Bella

subject

OperonTranscription FactorPhysiologyMutantMolecular Sequence DataPlant DiseaseVirulenceBacterial ProteinPseudomonaMicrobiologyBacterial ProteinsSolanum lycopersicumPseudomonasLycopersicon esculentumBacillus megateriumPlant DiseasesbiologyVirulencefood and beveragesQuorum SensingSettore AGR/12 - Patologia VegetaleGeneral MedicineGene Expression Regulation Bacterialbiology.organism_classificationPseudomonas corrugataQuorum sensingPseudomonadalesMutationAgronomy and Crop SciencePseudomonadaceaeTranscription Factors

description

The gram-negative phytopathogen Pseudomonas corrugata has an acyl-homoserine lactone (AHL) quorum-sensing (QS) system called PcoI/PcoR that is involved in virulence on tomato. This work identifies, downstream of pcol, a gene designated rfiA, which we demonstrate is directly linked to QS by cotranscription with pcol. The deduced RfiA protein contains a DNA-binding domain characteristic of the LuxR family but lacks the autoinducer-binding terminus characteristic of the QS LuxR-family proteins. We also identified, downstream of rfiA, an operon designated pcoABC, encoding for the three components of a tripartite resistance nodulation-cell-division (RND) transporter system. The expression of pcoABC is regulated by RfiA. We found that lipodep-sipeptide (LDP) production is cell density dependent and mutants of pcol, pcoR, and rfiA are unable to inhibit the growth of the LDP-sensitive microorganisms Rhodotorula pilimanae and Bacillus megaterium. P. corrugata rfiA mutants were significantly reduced in their ability to cause necrosis development in tomato pith. In addition, it was established that PcoR in the absence of AHL also played a role in virulence on tomato. A model for the role of PcoI, PcoR, and RfiA in tomato pith necrosis is presented. © 2009 The American Phytopathological Society.

10.1094/mpmi-22-12-1514http://hdl.handle.net/10447/247636