IHPE – RONDON Rodolfo english
ACTUAL POSITION : Post-doctoral Fellowship, Laboratory of Biotechnology and Aquicole Genomic (LBGA), Center of Biotechnology, University of Concepcion – Chili (email)
PH.D THESIS IN 2015
THESIS DIRECTORS : Caroline MONTAGNANI & Céline COSSEAU . TEAM : MIMM
SCIENTIFIC SOCIAL NETWORKS : (click on the logo)
Effects of parental exposure to diuron on methylome and transcriptome of the Pacific oyster Crassostrea gigas
KEY WORDS :
Bivalve mollusk ; Crassostrea gigas ; Pesticide ; Transcriptome ; Epigenetic.
The Pacific Oyster Crassostrea gigas is the most cultivated oyster species in the world with a production superior to 4 millions of tons in 2010. In France, C. gigas is cultivated since the end of 1970s. However, this specie suffers from a syndrome of summer mortalities since the 1980s, with amplification since 2008 affecting up to 100% of spats. This syndrome of mortality is a multifactorial phenomenon, based on the interaction of many factors: Environmental factors, genetic and physiologic features of the oysters, and the presence and virulence of pathogens. The Pacific Oyster C. gigas is an estuarine species which is subjected to anthropogenic pressures such as pollution of the coastal environment. These events represent a potencial source of stress in oyster farm areas. However, the knowledge about the effects of pollutants such as pesticides on C. gigas remains fragmented. The herbicide application periods may coincide with the oyster breeding period, reason for which we consider that these chemicals could affect the next generation of oysters. Among pesticides, diuron is the most frequently detected on the French coasts. The direct exposure to herbicides affects the transcriptome of oysters which is the first level of response to the exposure of pollutants. It was shown that parental exposure to diuron has genotoxic effects on C. gigas at the spat stage. Another possible effect of pesticides would be the modification of epigenetic marks. It is known that environmental factors such as pollution by chemical compounds can alter the epigenome and consequently the phenotype of individuals and of their offspring acting at a transgenerational level. These last observations allow us to hypothesize the involvement of epigenetic mechanisms in response to interactions with herbicide products. These mechanisms could modify the phenotype of oysters spat state following a parental exposure. To test this hypothesis we studied the genome-wide DNA methylation (methylome), which is a main epigenetic mark, and the transcriptome of the spat from diuron-exposed genitors. We identified methylome and transcriptome changes that could be related to the phenotype of life history trait of these spats. These results show that an indirect or parental exposure to the diuron is able to modify the methylation and the expression of specific gene functions, potentiallyexplaining the phenotypic variability observed.
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