Characterizing a novel vibriosis associated to oyster juvenile mass mortalities in the Thau Lagoon, South of France

Project leader: Delphine Destoumieux-Garzόn
This project focuses on the Pacific Oyster Mortality syndrome, which dramatically affects the production of juvenile oysters over all of France’s coastlines during the summer in the Atlantic and during spring and autumn in the Mediterranean, when water temperatures enter the range of ~ 16-24°C. While the pathogens present on the Atlantic coasts are now well characterized (OsHV-1 μvar virus and V. crassostreae bacteria), our recent work in the Mediterranean shellfish growing areas shows the presence of OsHV-1 μvar virus but a very low prevalence of V. crassostreae in diseased oysters. Conversely, mortalities are characterized by an abundance of vibrios of the Harveyi clade during spring and fall mortalities. These vibrios have only rarely been isolated during the mortality of juveniles in the Atlantic. Vibrios related to V. harveyi have been associated with many diseases in aquaculture. It therefore appears that there may be a variety of pathogenic associations involved in juvenile oyster mortalities that affect our coasts. Thus, we propose in this research project to answer the following questions. Does the syndrome of Pacific Oyster Mortality has the same etiology along the French coast? What are the characteristics of vibriosis associated with this syndrome in the Mediterranean? Finally, what are the mechanisms by which strains of V. harveyi colonize oysters and express their virulence thus inducing juvenile mortality?
Partner 1 – Interactions Hôtes-Pathogènes-Environnements (UMR 5244 – Ifremer, CNRS, Université de Perpignan Via Domitia, Université de Montpellier) : Arnaud Lagorce, Philippe Haffner, Julien de Lorgeril, Guillaume Charrière, Caroline Montagnani, Jean-Luc Rolland, Etienne Robino, Léa-Lou Pamparé, Abi-Gail Delort,  Daniel Oyanedel-Trigo, Delphine Destoumieux-Garzón.
Partner2 – Laboratoire De Biologie Intégrative Des Modèles Marins (UMR 8227). Unité Ifremer PFOM. Frédérique Le Roux, Maxime Bruto.
Partner 3 – Observatoire Océanologique de Banyuls (USR 3579 UPMC-CNRS, Laboratoire de Biodiversité et Biotechnologies Microbiennes). Raphael Lami, Didier Stien, Julia Baudart, Marion Soree.
Partner 4 – Institut des Biomolécules Max Mousseron (UMR 5247 Université de Montpellier, CNRS, ENSCM). Hervé Cottet
Partner 5 – Unité Ifremer SG2M/ LGPMM, La Tremblade : Marie-Agnès Travers
Partner 6 – Unité Ifremer PFOM/ UMR LEMAR, Brest : Bruno Petton