Abstract:In order to understand the molecular response mechanism of Thamnaconus septentrionalis muscle tissue under chronic density stress,and explore the related signaling pathways and differentially expressed genes under density stress,two culturing density groups (i.e.,a middle-density group of 100 individuals/m3 and a high-density group of 500 individuals/m3) were set up in this study.The muscle tissues of T. septentrionalis under the two densities were obtained on the 25th and 50th day,respectively,and the Illumina sequencing platform was used to perform transcriptome sequencing of the muscle tissue samples.A 103.3 Gb of high-quality sequencing data was obtained.Compared with the control group,a large number of differentially expressed genes were screened in each experimental group.Through GO(Gene Ontology) functional annotation and KEGG(Kyoto Encyclopedia of Genes and Genomes) functional enrichment analysis,the osteoclast differentiation,MAPK signaling pathway,focal adhesion,PI3K-Akt signaling pathway and other signaling pathways were screened,and the key genes such as nfatc1,tgfbr2,map3k14,pparg,fos,flna,flnc,fn1,tln1,and thbs1,were differentially expressed in the muscle tissue of T. septentrionalis.These differentially express genes may play a key role in regulating the cell growth,differentiation and immune ability of T. septentrionalis,which can lay a foundation for studying the regulation of muscle tissue-related gene expression in this fish under density stress.