Studying the role of Vibrio-Amoeba interactions in the emergence of pathogens in marine environments

Ec2co INSU-CNRS VIBRAM (2017-2018)
Project leader: Guillaume Charrière
Since 2008, oyster farms have been experiencing summer mortalities with around 60% losses every years. Pathogens such as viruses and various vibrio bacteria have been described for their involvement in these mortalities. Intriguingly, several strains of pathogenic vibrios against oysters possess the ability to inhibit and/or resist the phagocytosis activity of hemocytes, the immune cells of the oyster. We therefore study the potential role of environmental phagocytes, such as amoebae, in the selection of phagocytosis resistance traits in marine vibrios. We carry out an interdisciplinary study of amoebic diversity in the marine environment and the role of vibrios-amoeba interactions in the emergence of pathogens. During the first year of the project, we carried out a sampling of amoebae in the Thau and Banyuls pond areas. We have already collected over 64 points of culturable amoebic diversity, and we clonally isolated nearly 130 marine amoebae. In parallel, we identified different populations of vibrios that have different resistance abilities to amoebae. By analyzing the genomes of the vibrios of interest, we identified factors of resistance and virulence involved in both amoeba resistance and oyster pathogenesis. Knowledge of the amoebic biodiversity and its impact on vibrio population dynamics will allow a better understanding of the role of these interactions in the emergence of pathogens and the development of indicators of the quality of the environments and risk factors to support the development of sustainable aquaculture.


Virulent Vibrio strain (in green) surviving inside the marine amoeba Vannella sp. AP14-11 isolated in the oyster environment of the Thau lagoon © E. Robino
Partner 1 – UMR 5244 IHPE: Guillaume Charrière, Etienne Robino, Angélique Perret
Partner 2 – UMR 9190 MARBEC: Marion Richard, Jean-Christophe Auguet
Partner 3 – LBBM/OOB, Banyuls : Philippe Lebaron, Laurent Intertaglia