Significant mortalities have been regularly occurring in the Pacific oyster, Crassostrea gigas, associated with the incidence of OsHV-1 and impacting the aquaculture production at a global level. Long-term solutions such as the selection of resistant strains and the identification of molecular markers have been postulated as prioritizing strategies by the scientific community. In this context, the information gathered by novel sequencing methodologies offers new perspectives for the study of non-model species. RNA-seq data previously carried out for comparison of C. gigas spat with different susceptibility was further analysed for potential molecular markers examination. For that, read mappings corresponding to differently expressed transcripts were manually checked for variant localization. Validation of potential polymorphisms was carried out in oyster families produced by single pair matting of adult animals with different susceptibility to OsHV-1. Families were naturally exposed to OsHV-1 in a culturing raft and after a mortality outbreak; survivors were collected and compared to initial samples. A total of 461 animals were genotyped by sequencing using individual barcoding identification for multiplex amplification. Twelve transcripts containing 30 nucleotide variants were analysed. Among them, 18 variants were real single nucleotide polymorphisms (SNPs). The allele frequencies significantly varied in 10 loci on resistant families and 5 loci on susceptible families. Moreover, two linked SNPs were also significantly different attending to the disease susceptibility features of the broodstock. These results showed the identification of two linked molecular markers that can be used in selective breeding programmes.

Póster.-- 113th Annual Meeting National Shellfisheries Association, Virtual Conference, March 22 – 25, 2021

No