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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. maculatumto 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 °C), changes in expression profiles were more significant in C (habitat temperature = 24 °C) group than that in B (habitat temperature = 4 °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. maculatumto heat stress at the transcriptional level, which is beneficial for further research and conservation of G. maculatum.

To identify suitable reference genes for Salmo trutta, real-time fluorescent quantitative PCR (RT–qPCR) technology was used to determine the expression of eight candidate genes in 11 tissues (heart, liver, spleen, head kidney, muscle, brain, gills, ovary, intestine, skin, testis) of S. trutta. Concurrently, expression of these eight reference genes was assessed in 1 d and 30 d S. truttaembryos and muscle tissue of 90 d and 180 d S. trutta. Finally, the eight candidate genes were comprehensively screened using four types of screening software (GeNorm, NormFinder, BestKeeper and RefFinder), and the stability of their expression in different tissues, in response to bacterial stress and during different developmental stages in S. truttatissues was ranked. The results indicated that the eight candidate genes were specifically amplified in each tissue of S. trutta, with band sizes ranging from 73 bp to 150 bp. The stability ranking of the eight candidate genes in different tissues of healthy adult S. truttawas hprt1>β-actin>EF1a>RPL13a>RPS29>β2M>GAPDH>28 S rRNA. The ranking of the stability of expression in different tissues of S. truttaartificially infected with Aeromonas salmonicidawas RPS29>hprt1>β2M>RPL13a>EF1a>β-actin>28 S rRNA>GAPDH. The ranking of the stability of expression in the tissues of S. truttaat different developmental stages was RPS29>GAPDH>hprt1>RPL13a>EF1a>28 S rRNA>β-actin>β2M. Comprehensive analysis revealed that expression of the hprt1gene was relatively stable under different conditions. These results could guide the quantitative analysis of functional gene expression in S. truttaand calibrate the expression of major functional genes of S. trutta, facilitating the acquisition of more accurate, reliable and meaningful results.