Liver transcriptome analysis revealing response to high-temperature stress in Glyptosternum maculatum (Sisoridae: Siluriformes)

Glyptosternum maculatum (G. maculatum) is a species of endemic fish to the aquatic ecosystem of Tibetan Plateau and has been listed as a critically endangered species in the Red List of China's Vertebrates. The change in water temperature due to global warming may induce plasticity in G. maculatum to adapt to temperature stress. In this study, we performed transcriptome analysis to characterize the genes and pathways involved in temperature stress response in the liver of G. maculatum. Compared with group A (habitat temperature = 12 degrees C), changes in expression profiles were more significant in C (habitat temperature = 24 degrees C) group than that in B (habitat temperature = 4 degrees C) group. These results suggest the possible lack of reponse to cold stress in G. maculatum. A total of 1247 annotated differentially expressed genes (DEGs) were identified between groups A and C. Based on enrichment analysis, 17 candidate genes with potential roles in heat stress were identified. Additionally, eight important heat-stress-reducing pathways were identified and classified into folding, sorting and degradation, endocrine system, signal transduction, translation, infectious diseases (bacterial), glycan biosynthesis and metabolism, and digestive system. This study also showed that heat stress-regulated DEGs are not only related to intracellular biochemical reactions, metabolism, immune response, and protein folding, but also to the response to heat stress in the liver of G. maculatum. In conclusion, our present results revealed the response of G. maculatum to heat stress at the transcriptional level, which is beneficial for further research and conservation of G. maculatum.