Differential expression miRNAs in the gonad of sea cucumber Holothuria leucospilota

MicroRNAs are defined as a class of short noncoding RNAs, which play important function in cell differentiation, developmental process and gender determination. The sea cucumber Holothuria leucospilota is a member of the Echinodermata, known for its excellent nutritional and economic value. Breeding efficiency of sea cucumbers is low due to the difficulty in distinguishing between male and female individuals. Discovering molecular markers that distinguish between genders will provide a robust strategy for elucidating the genetic mechanisms governing gender determination and differentiation. In this investigation, high-throughput sequencing was utilized to compare miRNA expression patterns in the gonadal tissues of male and female specimens of H. leucospilota. A total of 584 known miRNAs and 404 novel miRNAs were identified, of which 97 miRNAs were identified as significantly differentially expressed miRNAs (DEMs) between male and female sea cucumbers. These findings enabled the construction of a miRNA-mRNA regulatory network. Pathway analysis of target genes highlighted the potential roles of neuroactive ligand-receptor interactions, calcium signaling, Salmonella infection, endocytosis, and MAPK signaling in governing gender differentiation processes. The expression results of high-throughput sequencing were validated in sc-miR121, sc-miR41, sc-miR67, sc-miR90, sc-miR104 and sc-miR189 by quantitative real-time quantity polymerase chain reaction (RT-qPCR). In summary, our results will provide a foundation for future studies of miRNA regulation in gender differentiation of sea cucumber H. leucospilota.