Exposure to the Paralytic Shellfish Toxin Producer Alexandrium catenella Increases the Susceptibility of the Oyster Crassostrea gigas to Pathogenic Vibrios
Celina Abi-Khalil,
Carmen Lopez-Joven,
Eric Abadie,
Veronique Savar,
Zouher Amzil,
Mohamed Laabir,
Jean-Luc Rolland
Affiliations
Celina Abi-Khalil
Institut Français de Recherche pour l’Exploitation de la Mer (IFREMER), Interactions-Hôtes-Pathogènes-Environnements (IHPE UMR 5244), University of Perpignan Via Domitia, Centre National de la Recherche Scientifique (CNRS), University of Montpellier, Montpellier F-34095, France
Carmen Lopez-Joven
Institut Français de Recherche pour l’Exploitation de la Mer (IFREMER), Interactions-Hôtes-Pathogènes-Environnements (IHPE UMR 5244), University of Perpignan Via Domitia, Centre National de la Recherche Scientifique (CNRS), University of Montpellier, Montpellier F-34095, France
Eric Abadie
Center for MARine Biodiversity, Exploitation and Conservation (MARBEC, UMR 9190), University of Montpellier, Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD), Institut Français de Recherche pour l’Exploitation de la Mer (IFREMER), Montpellier F-34095, France
Veronique Savar
Institut Français de Recherche pour l’Exploitation de la Mer (IFREMER), Phycotoxines Laboratory, l’Iled’Yeu street BP 21105, Nantes Cedex 3 F-44311, France
Zouher Amzil
Institut Français de Recherche pour l’Exploitation de la Mer (IFREMER), Phycotoxines Laboratory, l’Iled’Yeu street BP 21105, Nantes Cedex 3 F-44311, France
Mohamed Laabir
Center for MARine Biodiversity, Exploitation and Conservation (MARBEC, UMR 9190), University of Montpellier, Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD), Institut Français de Recherche pour l’Exploitation de la Mer (IFREMER), Montpellier F-34095, France
Jean-Luc Rolland
Institut Français de Recherche pour l’Exploitation de la Mer (IFREMER), Interactions-Hôtes-Pathogènes-Environnements (IHPE UMR 5244), University of Perpignan Via Domitia, Centre National de la Recherche Scientifique (CNRS), University of Montpellier, Montpellier F-34095, France
The multifactorial etiology of massive Crassostrea gigas summer mortalities results from complex interactions between oysters, opportunistic pathogens and environmental factors. In a field survey conducted in 2014 in the Mediterranean Thau Lagoon (France), we evidenced that the development of the toxic dinoflagellate Alexandrium catenella, which produces paralytic shellfish toxins (PSTs), was concomitant with the accumulation of PSTs in oyster flesh and the occurrence of C. gigas mortalities. In order to investigate the possible role of toxic algae in this complex disease, we experimentally infected C. gigas oyster juveniles with Vibrio tasmaniensis strain LGP32, a strain associated with oyster summer mortalities, after oysters were exposed to Alexandrium catenella. Exposure of oysters to A. catenella significantly increased the susceptibility of oysters to V. tasmaniensis LGP32. On the contrary, exposure to the non-toxic dinoflagellate Alexandrium tamarense or to the haptophyte Tisochrysis lutea used as a foraging alga did not increase susceptibility to V. tasmaniensis LGP32. This study shows for the first time that A. catenella increases the susceptibility of Crassostrea gigas to pathogenic vibrios. Therefore, in addition to complex environmental factors explaining the mass mortalities of bivalve mollusks, feeding on neurotoxic dinoflagellates should now be considered as an environmental factor that potentially increases the severity of oyster mortality events.
