Ancestral gene acquisition as the key to virulence potential in environmental Vibrio populations

• Published in: The ISME Journal
• Main Authors: Bruto, Maxime, Labreuche, Yannick, James, Adèle, Piel, Damien, Chenivesse, Sabine, Petton, Bruno, Polz, Martin, F, Le Roux, Frédérique
• Other Authors: Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Station biologique de Roscoff = Roscoff Marine Station (SBR), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), MIT Parsons Laboratory, Massachusetts Institute of Technology (MIT), ANR-16-CE32-0008,REVENGE,L'huître comme niche de l'évolution et l'émergence de vibrios pathogènes(2016)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2018
• Subjects: ACL; Functional genomics; Microbial ecology; Molecular evolution; [SDV.MP.BAC]Life Sciences [q-bio]/Microbiology and Parasitology/Bacteriology; [SDV.GEN.GPO]Life Sciences [q-bio]/Genetics/Populations and Evolution [q-bio.PE]; [SDE.BE]Environmental Sciences/Biodiversity and Ecology; Crassostrea gigas
• Online Access: https://hal.science/hal-01936591; https://hal.science/hal-01936591/document; https://hal.science/hal-01936591/file/s41396-018-0245-3.pdf; https://doi.org/10.1038/s41396-018-0245-3

International audience Diseases of marine animals caused by bacteria of the genus Vibrio are on the rise worldwide. Understanding the eco-evolutionary dynamics of these infectious agents is important for predicting and managing these diseases. Yet, compared to Vibrio infecting humans, knowledge of their role as animal pathogens is scarce. Here we ask how widespread is virulence among ecologically differentiated Vibrio populations, and what is the nature and frequency of virulence genes within these populations? We use a combination of population genomics and molecular genetics to assay hundreds of Vibrio strains for their virulence in the oyster Crassostrea gigas, a unique animal model that allows high-throughput infection assays. We show that within the diverse Splendidus clade, virulence represents an ancestral trait but has been lost from several populations. Two loci are necessary for virulence, the first being widely distributed across the Splendidus clade and consisting of an exported conserved protein (R5.7). The second is a MARTX toxin cluster, which only occurs within V. splendidus and is for the first time associated with virulence in marine invertebrates. Varying frequencies of both loci among populations indicate different selective pressures and alternative ecological roles, based on which we suggest strategies for epidemiological surveys.