GANESH (2016-2018)

Functional study of the genes involved in embryo-larval abnormalities in the cupped oyster Crassostrea gigas in the context of exposure to pesticides

Ifremer Coordination

Type of project

Financing

 Project duration

 Link

R. Sussarellu (LEX)

Ecodyn

EC2CO

2016-2018

The main objective of this study was to identify the molecular mechanisms leading to the developmental abnormalities observed in oysters using the embryo-larval test during exposure to pesticides. The long-term goal is to develop early molecular markers of embryotoxicity.

Ifremer staff
Academic partners 

F. Akcha (LEX), J. Rouxel (LEX), M. Lebreton (LEX)

BOREA Univ Caen Normandie : G. Rivière

Principle results :

The analysis of modulations of the expression of target genes involved in embryogenesis and shell formation was studied following exposure to pesticides. The target gene analysis focused mainly on 3 functional classes of genes (homeotic genes, biomineralization genes and DNA methylation genes). The pesticides chosen were copper (used in many natural and synthetic antifungals) and diuron (herbicide). The expression profiles of these different genes were examined by RT-qPCR at different stages of development. Furthermore, the harmful effects of exposure to pesticides on the oyster embryo have been assessed in terms of (i) embryotoxicity via the observation of developmental anomalies at the D larva stage and (ii) genotoxicity via the comet test. Epigenetic alterations associated with embryotoxicity and modulation of candidate gene expression were studied in parallel. Global DNA methylation was measured by HPLC in gastrula stage embryos. Specific methylation of target genes was evaluated by immuno-precipitation of methylated DNA followed by qPCR (MeDIP-qPCR) at different stages of development and at the level of coding sequences (exons).

The results of the GANEsH project led to a better understanding of the molecular mechanisms involved in the embryotoxicity associated with certain pesticides in the cupped oyster. The results obtained during the project laid the foundations for the development of early molecular markers of embryotoxicity in cupped oysters.

Publications:

Sussarellu, R., Lebreton, M., Rouxel, J., Akcha, F., & Rivière, G. (2018). Copper induces expression and methylation changes of early development genes in Crassostrea gigas embryos. Aquatic Toxicology, 196. https://doi.org/10.1016/j.aquatox.2018.01.001