A chromosome-level genome assembly of the yellowfin seabream (Acanthopagrus latus) (Hottuyn, 1782) provides insights into its osmoregulation and sex reversal

Abstract

The yellowfin seabream Acanthopagrus latus is the economically most important Sparidae fish species in the northern South China Sea. As euryhaline fish, they are perfect model for investigating osmoregulatory mechanisms in teleosts. Moreover, the reproductive biology of hermaphrodites has long been intriguing; however, very little is known about the molecular pathways underlying their sex change. To elucidate genetic mechanisms of osmoregulation and sex reversal in this fish, a high-quality reference genome of the yellowfin seabream was generated by a combination of Illumina and PacBio technologies. The draft genome of yellowfin seabream was 806 Mb, with 732 Mb scaffolds anchored on 24 chromosomes. The contig N50 and scaffold N50 were 2.6 Mb and 30.17 Mb, respectively. The assembly is of high integrity and includes 92.23% universal single-copy orthologues based on benchmarking universal single-copy orthologs (BUSCO) analysis. Moreover, among the 19,631 protein-coding genes, we found that the ARRDC3 and GSTA gene families related to osmoregulation underwent an extensive expansion in two euryhaline Sparidae fish genomes compared to other teleost genomes. Moreover, integrating sex-specific transcriptome analyses, several genes related to the transforming growth factor beta (TGF-{beta}) signalling pathway involved in sex differentiation and development. This genomic resource will not only be valuable for studying the osmoregulatory mechanisms in estuarine fish and sex determination in hermaphrodite vertebrate species, but also provide useful genomic tools for facilitating breeding of the yellowfin seabream.