title: Transcriptome analysis revealed that a quorum sensing system regulates the transfer of the pAt megaplasmid in Agrobacterium tumefaciens.
abstract: Agrobacterium tumefaciens strain P4 is atypical, as the strain is not pathogenic and produces a for this species unusual quorum sensing signal, identified as N-(3-hydroxy-octanoyl)-homoserine lactone (3OH,C8-HSL).
  
  
  
  By sequence analysis and cloning, a functional luxI-like gene, named cinI, has been identified on the At plasmid of A. tumefaciens strain P4. Insertion mutagenesis in the cinI gene and transcriptome analyses permitted the identification of 32 cinI-regulated genes in this strain, most of them encoding proteins responsible for the conjugative transfer of pAtP4. Among these genes were the avhB genes that encode a type 4 secretion system (T4SS) involved in the formation of the conjugation apparatus, the tra genes that encode the DNA transfer and replication (Dtr) machinery and cinI and two luxR orthologs. These last two genes, cinR and cinX, exhibit an unusual organization, with the cinI gene surrounded by the two luxR orthologs. Conjugation experiments confirmed that the conjugative transfer of pAtP4 is regulated by 3OH,C8-HSL. Root colonization experiments indicated that the quorum sensing regulation of the conjugation of the pAtP4 does not confer a gain or a loss of fitness to the bacterial host in the tomato plant rhizosphere.
  
  
  
  This work is the first identification of the occurrence of a quorum sensing regulation of the pAt conjugation phenomenon in Agrobacterium.
authors.affiliation: Institut for integrative biology of the cell, CEA, CNRS, Université Paris-sud, Université Paris-Saclay, 91198, Gif sur Yvette, CEDEX, France.
authors.forename: Nadia
authors.initials: N
authors.lastname: Mhedbi-Hajri
authors.affiliation: Institut for integrative biology of the cell, CEA, CNRS, Université Paris-sud, Université Paris-Saclay, 91198, Gif sur Yvette, CEDEX, France.|Present address: CIRAD, 7 chemin de l'IRAT, ligne Paradis, 97410, Saint Pierre de la Réunion, France.
authors.forename: Noura
authors.initials: N
authors.lastname: Yahiaoui
authors.affiliation: Institut for integrative biology of the cell, CEA, CNRS, Université Paris-sud, Université Paris-Saclay, 91198, Gif sur Yvette, CEDEX, France.|Present address: UMR1347 Agroécologie, INRA, Centre de Dijon, 17 rue Sully, BP 86510, 21065, Dijon, CEDEX, France.
authors.forename: Samuel
authors.initials: S
authors.lastname: Mondy
authors.affiliation: Institut de chimie des substances naturelles, CNRS, Avenue de la terrasse, 91198, Gif sur Yvette, France.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Hue
authors.affiliation: Institut de chimie des substances naturelles, CNRS, Avenue de la terrasse, 91198, Gif sur Yvette, France.
authors.forename: Franck
authors.initials: F
authors.lastname: Pélissier
authors.affiliation: Institut for integrative biology of the cell, CEA, CNRS, Université Paris-sud, Université Paris-Saclay, 91198, Gif sur Yvette, CEDEX, France.
authors.forename: Denis
authors.initials: D
authors.lastname: Faure
authors.affiliation: Institut for integrative biology of the cell, CEA, CNRS, Université Paris-sud, Université Paris-Saclay, 91198, Gif sur Yvette, CEDEX, France. yves.dessaux@i2bc.paris-saclay.fr.
authors.forename: Yves
authors.initials: Y
authors.lastname: Dessaux
mesh_terms: D016960:Agrobacterium tumefaciens / Q000235:genetics / Q000502:physiology*; D001426:Bacterial Proteins / Q000235:genetics; D003001:Cloning, Molecular; D003227:Conjugation, Genetic; D020869:Gene Expression Profiling / Q000379:methods*; D015964:Gene Expression Regulation, Bacterial; D056084:Genetic Fitness; D018551:Solanum lycopersicum / Q000382:microbiology; D010802:Phylogeny; D018517:Plant Roots / Q000382:microbiology; D010957:Plasmids / Q000235:genetics*; D053038:Quorum Sensing; D017423:Sequence Analysis, RNA / Q000379:methods*
chemical_list: D001426:Bacterial Proteins
keywords: Acylhomoserine lactone; Agrobacterium; At plasmid; Conjugation; Dtr system; Quorum sensing; T4SS; Transcriptomics