title: Functional genomics of Lactobacillus casei establishment in the gut.
abstract: Although the composition of the gut microbiota and its symbiotic contribution to key host physiological functions are well established, little is known as yet about the bacterial factors that account for this symbiosis. We selected Lactobacillus casei as a model microorganism to proceed to genomewide identification of the functions required for a symbiont to establish colonization in the gut. As a result of our recent development of a transposon-mutagenesis tool that overcomes the barrier that had prevented L. casei random mutagenesis, we developed a signature-tagged mutagenesis approach combining whole-genome reverse genetics using a set of tagged transposons and in vivo screening using the rabbit ligated ileal loop model. After sequencing transposon insertion sites in 9,250 random mutants, we assembled a library of 1,110 independent mutants, all disrupted in a different gene, that provides a representative view of the L. casei genome. By determining the relative quantity of each of the 1,110 mutants before and after the in vivo challenge, we identified a core of 47 L. casei genes necessary for its establishment in the gut. They are involved in housekeeping functions, metabolism (sugar, amino acids), cell wall biogenesis, and adaptation to environment. Hence we provide what is, to our knowledge, the first global functional genomics analysis of L. casei symbiosis.
authors.affiliation: Unité Mixte de Recherche A 02102 Procédés Alimentaires et Microbiologiques, AgroSup Dijon/Université de Bourgogne, 21000 Dijon, France;Unité de Pathogénie Microbienne Moléculaire andInstitut National de la Santé et de la Recherche Médicale U786, Institut Pasteur, 75724 Paris Cedex 15, France; and.
authors.forename: Hélène
authors.initials: H
authors.lastname: Licandro-Seraut
authors.affiliation: Unité Mixte de Recherche A 02102 Procédés Alimentaires et Microbiologiques, AgroSup Dijon/Université de Bourgogne, 21000 Dijon, France;
authors.forename: Hélène
authors.initials: H
authors.lastname: Scornec
authors.affiliation: Unité de Pathogénie Microbienne Moléculaire andInstitut National de la Santé et de la Recherche Médicale U786, Institut Pasteur, 75724 Paris Cedex 15, France; and.
authors.forename: Thierry
authors.initials: T
authors.lastname: Pédron
authors.affiliation: Unité Mixte de Recherche A 02102 Procédés Alimentaires et Microbiologiques, AgroSup Dijon/Université de Bourgogne, 21000 Dijon, France;
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Cavin
authors.affiliation: Unité de Pathogénie Microbienne Moléculaire andInstitut National de la Santé et de la Recherche Médicale U786, Institut Pasteur, 75724 Paris Cedex 15, France; andChaire de Microbiologie et Maladies Infectieuses, Collège de France, 75005 Paris, France philippe.sansonetti@pasteur.fr.
authors.forename: Philippe J
authors.initials: PJ
authors.lastname: Sansonetti
mesh_terms: D000818:Animals; D016680:Genome, Bacterial; D055106:Genome-Wide Association Study; D023281:Genomics; D007082:Ileum / Q000382:microbiology*; D007780:Lacticaseibacillus casei / Q000235:genetics / Q000378:metabolism; D016296:Mutagenesis; D009154:Mutation; D011817:Rabbits
keywords: Lactic acid bacteria; commensalism