Genetic parameters characterization of the resistance to certain infectious agents in cupped oyster, Crassostrea gigas, in the context of mass mortalities

• Main Author: Azema, Patrick
• Other Authors: Unité Santé, Génétique et Microbiologie des Mollusques (SGMM), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), AgroParisTech, Institut agronomique, vétérinaire et forestier de France, Tristan Renault, Pierre Boudry
• Format: Doctoral or Postdoctoral Thesis
• Language: French
• Published: HAL CCSD 2018
• Subjects: Crassostrea gigas; Herpesvirus; Vibrios; Disease resistance; Challenge; Selection; Vibrions; Résistance aux maladies; Épreuves pathologiques; Sélection; [SDV.GEN.GA]Life Sciences [q-bio]/Genetics/Animal genetics; Pacific; Pacific oyster
• Online Access: https://pastel.hal.science/tel-03392362; https://pastel.hal.science/tel-03392362/document; https://pastel.hal.science/tel-03392362/file/52124_AZEMA_2018_archivage.pdf

The aim of the thesis is the characterization of genetic basis of resistance to certain infectious agents in the Pacific oyster, Crassostrea gigas, in the context of mass mortalities of spat. Previous work at Ifremer highlighted a genetic component to the survival of oyster spat in the field rearing conditions or experimental conditions. Characterization of selected lines having contrasted survival rates in rearing conditions ('resistant' or 'sensitive') clarified the physiological basis of this genetic component or of their resistance/susceptibility to certain pathogens coming after mortalities experienced in the environment. Since 2008, mortality outbreaks of oysters worsened, in particular with a wider geographical distribution, and the involvement of infectious agents (viruses and bacteria) has been identified. In addition, with protocols developed in experimental pathology, it is now possible to assess specifically the level of resistance or susceptibility to certain infectious agents (OsHv-1 and vibrios). Thus, in the framework of the European project Bivalife (FP7, 2011-2013), two-parent families were produced (with factorial crosses, generating full-sib and half-sib families) in the Laboratory of Genetics and Pathology (Ifremer, Tremblade) and the behavior of these families, especially in terms of survival and sensitivity to various infectious agents (OsHv-1 and vibrios) was studied through pathological challenges. Once this biological material characterized, families with extreme behavior for induced mortality by infectious agents were stored (protected from mortality) for a selected generation production in 2013. On the other hand, in the SCORE project, funded following the call for proposals “selection and resource improvement program in oyster' launched by the Maritime Directorate of Fisheries and Aquaculture (DPMA) in June 2011, two-parent families are and will be produced in 2012 and 2013 in the facilities of the Regional Innovation Platform (PRI) in Bouin (Vendée). This project is coordinated by ...