Comparative transcriptome preliminary reveals the molecular mechanism of the growth rate of Procambarus clarkii

The red swamp crayfish (Procambarus clarkii) is a well-known invasive species. It has become one of the most important freshwater aquaculture resources in China. In this study, we reported the karyotype and whole mitochondrial genome of Procambarus clarkii. In addition, we performed transcriptome analysis of Procambarus clarkii from two different body size populations. The three large individuals, namely, the LS group, were randomly chosen, with body lengths and weights of 16.24–18.85 ​cm and 38.96–45.36 ​g, respectively. The three small individuals, namely, the SS group, were randomly chosen, with body lengths and weights of 10.50–12.70 ​cm and 19.56–25.95 ​g, respectively. Comparative transcriptomic analysis of Procambarus clarkii characterized 36 differentially expressed genes (DEGs), comprising 20 upregulated genes and 16 downregulated genes in the SS group. Functional analyses revealed that four genes (metalloreductase STEAP4-like (Steap4), myosin heavy chain fast skeletal muscle, muscle-like (MH), vitelline membrane outer layer protein I-like protein (VMO-I), and secreted protein acidic and rich in cysteine (SPARC)) were involved in the regulation of cell proliferation, muscle growth and energy metabolism, suggesting that four genes were related to growth in P. clarkii. We validated the expression levels of these four differentially expressed genes in LS and SS using Quantitative real-time PCR. These results provide insights into the regulatory mechanisms underlying the difference in P. clarkii growth.