Transcriptome analysis elucidates mating affects the expression of intra-/extra-ovarian factors, thereby influencing ovarian development in the mud crab Scylla paramamosain

Abstract

Prior to the pubertal molt and mating, the ovarian development of the mud crab Scylla paramamosain was primarily at stage II. However, immediately after mating, female crabs initiate vitellogenesis, and their ovaries quickly develop. The aim of this study was to identify differentially expressed genes associated with ovarian development in the mud crab before and after mating, in order to elucidate the influence of mating on ovarian development using comparative transcriptomics. The KEGG pathway analysis results indicated that ribosome and ribosome-related pathways were highly associated with ovarian development at stage II across both transcriptomes, likely to support the subsequent vitellogenesis by providing the necessary materials. Additionally, the neurodegeneration, MAPK, cAMP and PLD pathways were active in regulating oogonia differentiation, oocyte proliferation and vitellogenesis after mating. Meanwhile, certain intra-ovarian factors, such as the cell cycle-related genes cyclin B and APC, the forkhead box family genes Foxl2 and slp1, the SOX family gene SOX5-like, the hormone-related genes SULT1E1 and Eip74EF-like, the growth factor-related genes VEGFD-like and CUBE1-like, as well as HPS10 and tra1-like, have essential functions in regulating ovarian development after mating. Furthermore, the receptors of extra-ovarian hormones, such as RPCHR, HR4, and ILR1, as well as the neurotransmitter receptor 5-HTR4, were involved in ovarian development. It is believed that ovarian development is controlled by the coordinated action of both intrinsic and extrinsic endocrine factors, and these factors are influenced by mating. Finally, the analysis of epigenic modification-related genes, transcription factors, and target genes revealed the regulation of gene expression. Our study indicated that, those genes work in a coordinated manner to regulate the complex processes of follicle cell development, oogonia differentiation, oocyte proliferation, and vitellogenesis during ovarian development.