Multi-omics reveals Leiocassis longirostris testis developmental dynamics

The Chinese longsnout catfish (Leiocassis longirostris) is an important commercial freshwater fish in China. A comprehensive understanding of the mechanisms underlying testis development and spermatozoan ejaculation of L. longirostris could serve as a foundation for enhancing its seed quality and breeding. However, current research on its testis development is limited to the morphological level. To enhance the molecular regulatory mechanisms underlying the testis development of L. longirostris, we performed the integrated transcriptome and proteome sequencing of the five stages of L. longirostris testes (stage I to stage V). Transcriptome analysis revealed that differentially expressed genes (DEGs) involved in the TGF-beta signing pathway, MAPK signaling pathway, Wnt signaling pathway, ECM-receptor interaction, PI3K/Akt, etc. were enriched. The specific roles of these DEGs in key biological processes such as germ cell proliferation, differentiation, meiosis, and spermatogenesis were also elucidated by Gene Ontology (GO) enrichment analysis. Moreover, proteomics unveiled the dynamic alterations of differentially expressed proteins (DEPs) were enriched in the TGF-beta signaling pathway, cell cycle, ubiquitin-mediated proteolysis, and ECM-receptor interaction. The GO enrichment analysis of DEPs supported that in DEGs. Through integrated analyses, potential regulatory factors like LysC were identified. Additionally, genes specifically and highly expressed in the testes at different developmental stages, including wnt7a, pax6, and kiss1r, were also discovered. These results could provide the basis for the investigation of the testicular development in L. longirostris and pivotal clues for elucidating the molecular mechanisms that govern the development of reproductive systems in fishes.