Explore the gene regulation mechanism under high temperature and hypoxia stress in the sea cucumber Apostichopus japonicus by high-throughput RNA-seq technology

Temperature and dissolved oxygen (DO) are important biological environmental factors for aquatic animal. The sea cucumber Apostichopus japonicus was an important aquaculture species in China, which was highly impacted by temperature and DO. In the present study, the transcriptomics expression profiles under high temperature (HT), hypoxia (LO), and these combined stressors (HL) were investigated by RNA-seq technique. Compared with the control group, 275, 409 and 434 differential expressed genes (DEGs) were detected in HT, LO and HL groups respectively. Further analysis of KEGG pathways revealed that “protein processing in endoplasmic reticulum” pathway was significantly enriched in both HT vs C and HL vs C comparisons. Protein folding-related genes in this pathway, such as HSPs, were up-regulated in the two comparisons. In LO vs C comparison, “fatty acid metabolism” pathway was significantly enriched, and genes related to de novo biogenesis of fatty acids was significantly down-regulated. Some genes related to anti-apoptosis, such as BCL-2 and BAG3, were up-regulated in HL vs C comparison, which revealed that the combined stress threatened the survival of cells. The present research provided new insights for the response to different stressful environments in A. japonicus.