A novel plant ferredoxin-like protein and the regulator Hor are quorum-sensing targets in the plant pathogen Erwinia carotovora.
Quorum sensing (QS), a population-density-sensing mechanism, controls the production of the main virulence determinants, the plant cell-wall-degrading enzymes (PCWDEs) of the soft-rot phytopathogen Erwinia carotovora subsp. carotovora. In this study, we used random transposon mutagenesis with a gusA reporter construct to identify two new QS-controlled genes encoding the regulator Hor and a plant ferredoxin-like protein, FerE. The QS control of the identified genes was executed by the QS regulators ExpR1 and ExpR2 and mediated by the global repressor RsmA. Hor was shown to contribute to bacterial virulence at least partly through its control of PCWDE production. Our results showed that FerE contributes to oxidative stress tolerance and in planta fitness of the bacteria and suggest that QS could be central to control of oxidative stress tolerance. The presence of the FerE protein appears to be rather unique in heterotrophic bacteria and suggests an acquisition of the corresponding gene from plant host by horizontal gene transfer.
Viikki Biocenter, Faculty of Biosciences, Department of Biological and Environmental Sciences, Division of Genetics, University of Helsinki, P.O.Box 56, FIN-00014, Helsinki, Finland.
Solveig
S
Sjöblom
Heidi
H
Harjunpää
Günter
G
Brader
E Tapio
ET
Palva
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000382:microbiology / Q000502:physiology; D001426:Bacterial Proteins / Q000235:genetics / Q000502:physiology*; D001483:Base Sequence; D017931:DNA Primers / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D018744:DNA, Plant / Q000235:genetics; D005798:Genes, Bacterial; D017343:Genes, Plant; D054884:Host-Pathogen Interactions / Q000235:genetics / Q000502:physiology*; D008954:Models, Biological; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D018384:Oxidative Stress; D016973:Pectobacterium carotovorum / Q000235:genetics / Q000472:pathogenicity* / Q000502:physiology*; D010935:Plant Diseases / Q000382:microbiology; D010940:Plant Proteins / Q000235:genetics / Q000502:physiology*; D030821:Plants, Genetically Modified; D053038:Quorum Sensing / Q000235:genetics / Q000502:physiology; D017386:Sequence Homology, Amino Acid; D011198:Solanum tuberosum / Q000235:genetics / Q000382:microbiology / Q000502:physiology; D015534:Trans-Activators / Q000235:genetics / Q000502:physiology; D014774:Virulence / Q000235:genetics / Q000502:physiology
D001426:Bacterial Proteins; D017931:DNA Primers; D004269:DNA, Bacterial; D018744:DNA, Plant; C115748:ExpR protein, Erwinia; D010940:Plant Proteins; D015534:Trans-Activators; C110353:hor protein, bacteria