Influence of a toxic microalgae Alexandrium pacificum (catenella) on the virulence of a oyster pathogenic bacteria strain, Vibrio tasmaniensis LGP 32


Leader project : Jean-Luc Rolland
Different species of vibrios are known for their particular interactions with many planktonic microorganisms. These interactions range from predation to the acquisition of nutrients essential for their growth. Among the species that can represent a source of nutrients, micro-algae are a source of useful nutrients useful or even necessary for their growth, especially during the decomposition of these algae at the time of decline of the bloom of micro-algae. While some oyster pathogenic bacterial strains, Vibrio tasmaniensis and Vibrio aesturianus have been shown to be associated with massive oyster mortalities, no studies exist on the ecological consequences of their interaction with microalgae blooms. In particular, the effects of toxic microalgae (HAB) on their virulence have, to our knowledge, never been studied before.
The results of this project showed for the first time that the toxic micro-algae Alexandrium pacificum, which produces recurrent efflorescence in the Thau lagoon, promotes the growth and increases the virulence of the oyster pathogen V. tasmaniensis LGP32 (Rolland et al, in prep). This is a significant advance in the understanding of the phenomena of massive mortality of oysters which we know is of multifactorial origin. The characterization of this virulence is currently underway through the EN3VI project (2018-2019).
Team 1 – Interactions Hôtes-Pathogènes-Environnements (IHPE, Université de Montpellier, CNRS, Ifremer, UPVD, Montpellier, France). Rolland Jean-Luc, Destoumieux-Garzon Delphine, Gourbal Benjamin, Tetreau Guillaume, Leroy Marc
Team 2 – MARine Biodiversity, Exploitation and Conservation (MARBEC, Université de Montpellier, CNRS, Ifremer, IRD, Montpellier, France). Laabir Mohamed, Masseret Estelle, Abadie Eric