De Novo Assembly, Characterization and Comparative Transcriptome Analysis of the Gonads of Jade Perch (Scortum barcoo)

SIMPLE SUMMARY: Jade perch (Scortum barcoo) has been affirmed as an economically important species for aquaculture. However, research on its sex and reproductive regulation is still lacking. Herein, the first gonad transcriptomes of juvenile jade perch were identified through Illumina Novaseq technology. According to the comparative transcriptome data of ovaries and testis, a large number of differential expression genes (DEGs) mainly involved in the steroidogenesis pathway, gonad development and differentiation, gametogenesis and gamete maturation were identified. As predicted, the expression patterns of these DEGs in jade perch were similar to well-known sex-related genes in other species. These results will provide valuable information for further studies on sex determination and gonadal development in teleost fish. ABSTRACT: Due to the high meat yield and rich nutritional content, jade perch (Scortum barcoo) has become an important commercial aquaculture species in China. Jade perch has a slow growth rate, taking 3–4 years to reach sexual maturity, and has almost no difference in body size between males and females. However, the study of its gonad development and reproduction regulation is still blank, which limited the yield increase. Herein, the gonad transcriptomes of juvenile males and females of S. barcoo were identified for the first time. A total of 107,060 unigenes were successfully annotated. By comparing male and female gonad transcriptomes, a total of 23,849 differentially expressed genes (DEGs) were identified, of which 9517 were downregulated, and 14,332 were upregulated in the testis. In addition, a large number of DEGs involved in sex differentiation, gonadal development and differentiation and gametogenesis were identified, and the differential expression patterns of some genes were further verified using real-time fluorescence quantitative PCR. The results of this study will provide a valuable resource for further studies on sex determination and gonadal development of S. barcoo.