Gonadal Transcriptome Analysis of Sex-Related Genes in the Protandrous Yellowfin Seabream ().

Yellowfin seabream (), a protandrous hermaphroditic fish, is a good model for studying the mechanism of sex reversal. However, limited knowledge is known about the genetic information related to reproduction and sex differentiation in this species. Here, we performed transcriptome sequencing analysis of the testis, ovotestis, and ovary to identify sex-related genes in yellowfin seabream. The results assembled 71,765 unigenes in which 16,126 and 17,560 unigenes were differentially expressed in the ovotestis and ovary compared to the testis, respectively. The most differentially expressed gene (DEG)-enriched Kyoto Encyclopedia of Genes and Genomes and GO pathways were closely associated with the synthesis of sex steroid hormones. Functional analyses identified 55 important sex-related DEGs, including 32 testis-biased DEGs (, , and , etc.), 20 ovary-biased DEGs (, , and , etc.), and 3 ovotestis-biased DEGs (, , and ). Furthermore, the testis-specific expression of and the brain-pituitary-ovary axis expression of were characterized, suggesting that they might play important roles in sex differentiation in yellowfin seabream. Our present work provided an important molecular basis for elucidating the mechanisms underlying sexual transition and reproductional regulation in yellowfin seabream.