Cloning the Candidate Genes for Benedenia Disease Resistance in Japanese Yellowtail (Seriola quinqueradiata)

The production of cultured Japanese yellowtail approximately accounts for 60% of marine finfish aquaculture in Japan. Benedenia disease caused by infected with Benedenia seriolae is a serious parasitic disease for yellowtail in aquaculture, and it is very hard to remove parasites from their bodies. Therefore, as a drastic resolution, we have been trying to establish benedenia disease resistant strains and identify the genes associated with benedenia disease resistant (BD-R). In the previous study, QTL analysis against BD-R F1 families was shown the most significant BD-R QTLs on linkage group Squ2. This QTL region was covered with 7 BAC clones. The sequence of this region was obtained by next generation sequencing using BAC clones and assembled into 22 contigs. In this study, we determined approximately 520 kbps complete sequence of this QTL region by closing the gaps between the contigs. Candidate genes were predicted by GENSCAN and Augustus software in this region. Then those sequences of the predicted genes were searched against the database of NCBI by using BLAST search and characterized protein. And we tested the gene expression of those characterized proteins in skin by RT-PCR. We have performed RACE (Rapid amplification of cDNA ends) method in order to obtain the full-length cDNA sequence on some of the expressed genes.