Molecular mechanisms of intermuscular bone development in Acrossocheilus wenchowensis

Intermuscular bones (IBs) are little bony spicules found in muscle, which are unsafe for human consumption and detrimental to the processing and export of aquatic products. So, studying the development of IBs in aquaculture species is important. We have learned that the IBs of Acrossocheilus wenchowensis are soft and do not affect its consumption, but its development mechanism is not yet fully understood. In this study, we sequenced the transcriptome of epaxial muscle of A. wenchowensis at three key stages (NIB: IBs not yet emerged, 19 days; LIB: several small IBs starting to appear, 25 days; and CIB: all IBs have appeared and have mature morphology, 1 year), and the results showed that 211 overlapping differentially expressed genes (DEGs) function mainly in Wnt, PI3K-Akt, MAPK and TGF-β signalling pathways. Analysing the transcriptome data, eight genes related to IBs were differentially expressed in the NIB, LIB and CIB groups. To further explore the expression pattern of genes, we analysed the expression of genes on different days (18 days, 19 days, 20 days, 24 days, 25 days, 26 days, 1 year) using quantitative reverse transcription polymerase chain reaction (qRT-PCR). Our results suggested that scx, alpl, bgp and sost genes may play important roles in the formation, ossification and mineralization of IBs. We provide new insights into the development mechanism of IBs of A. wenchowensis.