title: Quorum sensing signaling molecules produced by reference and emerging soft-rot bacteria (Dickeya and Pectobacterium spp.).
abstract: BACKGROUND
  Several small diffusible molecules are involved in bacterial quorum sensing and virulence. The production of autoinducers-1 and -2, quinolone, indole and γ-amino butyrate signaling molecules was investigated in a set of soft-rot bacteria belonging to six Dickeya or Pectobacterium species including recent or emerging potato isolates.
  
  
  RESULTS
  Using bacterial biosensors, immunoassay, and chromatographic analysis, we showed that soft-rot bacteria have the common ability to produce transiently during their exponential phase of growth the N-3-oxo-hexanoyl- or the N-3-oxo-octanoyl-l-homoserine lactones and a molecule of the autoinducer-2 family. Dickeya spp. produced in addition the indole-3-acetic acid in tryptophan-rich conditions. All these signaling molecules have been identified for the first time in the novel Dickeya solani species. In contrast, quinolone and γ-amino butyrate signals were not identified and the corresponding synthases are not present in the available genomes of soft-rot bacteria. To determine if the variations of signal production according to growth phase could result from expression modifications of the corresponding synthase gene, the respective mRNA levels were estimated by reverse transcriptase-PCR. While the N-acyl-homoserine lactone production is systematically correlated to the synthase expression, that of the autoinducer-2 follows the expression of an enzyme upstream in the activated methyl cycle and providing its precursor, rather than the expression of its own synthase.
  
  
  CONCLUSIONS
  Despite sharing the S-adenosylmethionine precursor, no strong link was detected between the production kinetics or metabolic pathways of autoinducers-1 and -2. In contrast, the signaling pathway of autoinducer-2 seems to be switched off by the indole-3-acetic acid pathway under tryptophan control. It therefore appears that the two genera of soft-rot bacteria have similarities but also differences in the mechanisms of communication via the diffusible molecules. Our results designate autoinducer-1 lactones as the main targets for a global biocontrol of soft-rot bacteria communications, including those of emerging isolates.
authors.affiliation: Laboratoire de Microbiologie Signaux et Microenvironnement, Normandie Université, Université de Rouen EA 4312, IUT, Evreux, Evreux, France.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Crépin
authors.forename: Corinne
authors.initials: C
authors.lastname: Barbey
authors.forename: Amélie
authors.initials: A
authors.lastname: Beury-Cirou
authors.forename: Valérie
authors.initials: V
authors.lastname: Hélias
authors.forename: Laure
authors.initials: L
authors.lastname: Taupin
authors.forename: Sylvie
authors.initials: S
authors.lastname: Reverchon
authors.forename: William
authors.initials: W
authors.lastname: Nasser
authors.forename: Denis
authors.initials: D
authors.lastname: Faure
authors.forename: Alain
authors.initials: A
authors.lastname: Dufour
authors.forename: Nicole
authors.initials: N
authors.lastname: Orange
authors.forename: Marc
authors.initials: M
authors.lastname: Feuilloley
authors.forename: Karin
authors.initials: K
authors.lastname: Heurlier
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Burini
authors.forename: Xavier
authors.initials: X
authors.lastname: Latour
mesh_terms: D015107:4-Butyrolactone / Q000031:analogs & derivatives / Q000378:metabolism; D054742:Acyl-Butyrolactones / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D004755:Enterobacteriaceae / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D006714:Homoserine / Q000031:analogs & derivatives / Q000378:metabolism; D007210:Indoleacetic Acids / Q000378:metabolism; D007700:Kinetics; D007783:Lactones / Q000378:metabolism; D009097:Multienzyme Complexes / Q000235:genetics / Q000378:metabolism; D044043:Pectobacterium / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D015363:Quinolones / Q000378:metabolism; D053038:Quorum Sensing; D012333:RNA, Messenger / Q000378:metabolism; D015398:Signal Transduction; D011198:Solanum tuberosum / Q000382:microbiology; D014364:Tryptophan / Q000494:pharmacology; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
chemical_list: D054742:Acyl-Butyrolactones; D001426:Bacterial Proteins; D007210:Indoleacetic Acids; D007783:Lactones; D009097:Multienzyme Complexes; C091088:N-octanoylhomoserine lactone; D015363:Quinolones; D012333:RNA, Messenger; C421912:indole-3-acetic acid synthase; D005680:gamma-Aminobutyric Acid; D006714:Homoserine; C030737:indoleacetic acid; C030654:N-(3-oxohexanoyl)-3-aminodihydro-2(3H)-furanone; D014364:Tryptophan; D015107:4-Butyrolactone