Transcriptome analysis and weighted gene co-expression network reveals potential genes responses to heat stress in turbot Scophthalmus maximus.

Turbot (Scophthalmus maximus) is an economically important marine fish cultured in China. In this study, we performed transcriptome gene expression profiling of kidney tissue in turbot exposed to heat stress (20, 23, 25 and 28 °C); control fish were maintained at 14 °C. We investigated gene relationships based on weighted gene co-expression network analysis (WGCNA). Accordingly, enrichment analyses of GO terms and KEGG pathways showed that several pathways (e.g., fat metabolism, cell apoptosis, immune system, and insulin signaling) may be involved in the response of turbot to heat stress. Moreover, via WGCNA, we identified 19 modules: the dark grey module was mainly enriched in pathways associated with fat metabolism and the FOXO and Jak-STAT signaling pathways. The ivory module was significantly enriched in the P53 signaling pathway. Furthermore, the key hub genes CBP, AKT3, CCND2, PIK3r2, SCOS3, mdm2, cyc-B, and p48 were enriched in the FOXO, Jak-STAT and P53 signaling pathways. This is the first study reporting co-expression patterns of a gene network after heat stress in marine fish. Our results may contribute to our understanding of the underlying molecular mechanism of thermal tolerance.