title: Pleiotropic role of quorum-sensing autoinducer 2 in Photorhabdus luminescens.
abstract: Bacterial virulence is an integrative process that may involve quorum sensing. In this work, we compared by global expression profiling the wild-type entomopathogenic Photorhabdus luminescens subsp. laumondii TT01 to a luxS-deficient mutant unable to synthesize the type 2 quorum-sensing inducer AI-2. AI-2 was shown to regulate more than 300 targets involved in most compartments and metabolic pathways of the cell. AI-2 is located high in the hierarchy, as it controls the expression of several transcriptional regulators. The regulatory effect of AI-2 appeared to be dose dependent. The luxS-deficient strain exhibited decreased biofilm formation and increased type IV/V pilus-dependent twitching motility. AI-2 activated its own synthesis and transport. It also modulated bioluminescence by regulating the synthesis of spermidine. AI-2 was further shown to increase oxidative stress resistance, which is necessary to overcome part of the innate immune response of the host insect involving reactive oxygen species. Finally, we showed that the luxS-deficient strain had attenuated virulence against the lepidopteran Spodoptera littoralis. We concluded that AI-2 is involved mainly in early steps of insect invasion in P. luminescens.
authors.affiliation: Unité de Génétique des Génomes Bactériens (URA2171), Institut Pasteur, 28 rue du Docteur Roux, 75724 Paris Cedex 15, France. ekrin@pasteur.fr
authors.forename: Evelyne
authors.initials: E
authors.lastname: Krin
authors.forename: Nesrine
authors.initials: N
authors.lastname: Chakroun
authors.forename: Evelyne
authors.initials: E
authors.lastname: Turlin
authors.forename: Alain
authors.initials: A
authors.lastname: Givaudan
authors.forename: François
authors.initials: F
authors.lastname: Gaboriau
authors.forename: Isabelle
authors.initials: I
authors.lastname: Bonne
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Rousselle
authors.forename: Lionel
authors.initials: L
authors.lastname: Frangeul
authors.forename: Céline
authors.initials: C
authors.lastname: Lacroix
authors.forename: Marie-Françoise
authors.initials: MF
authors.lastname: Hullo
authors.forename: Laetitia
authors.initials: L
authors.lastname: Marisa
authors.forename: Antoine
authors.initials: A
authors.lastname: Danchin
authors.forename: Sylviane
authors.initials: S
authors.lastname: Derzelle
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D018441:Biofilms; D013437:Carbon-Sulfur Lyases / Q000172:deficiency / Q000235:genetics / Q000378:metabolism; D020869:Gene Expression Profiling; D006714:Homoserine / Q000031:analogs & derivatives* / Q000502:physiology; D007783:Lactones; D018384:Oxidative Stress / Q000502:physiology; D020637:Photorhabdus / Q000737:chemistry* / Q000472:pathogenicity / Q000502:physiology; D011073:Polyamines / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D014774:Virulence / Q000502:physiology
chemical_list: D001426:Bacterial Proteins; D007783:Lactones; C091088:N-octanoylhomoserine lactone; D011073:Polyamines; D006714:Homoserine; D013437:Carbon-Sulfur Lyases; C117753:LuxS protein, Bacteria