Transcriptomic study of muscle in response to heat in Triplophysa yarkandensis.

Triplophysa yarkandensis is an economically important fish species native to the Tarim River of Xinjiang, China. Amid ongoing climate warming and rising temperatures in the Tarim River, T. yarkandensis has demonstrated a degree of physiological adaptation to heat stress. However, the underlying mechanisms of this thermal adaptation and the impact of high-temperature stress on gene expression profiles remain poorly understood. Investigating its heat tolerance genes can aid in protecting wild populations from the threat of endangerment due to ecological damage. Based on the optimal growth temperature and maximum heat tolerance of T. yarkandensis, 20°C was used as the normal temperature control group (NT20), while 27 and 34°C served as the heat treatment groups (HT27 and HT34). In this study, 9544 differentially expressed genes (DEGs) were identified, comprising 4823 upregulated and 4861 downregulated genes in muscle tissue. Several heat-related genes, such as hspa5, hsp70, hyou1, hsp40, atp2a and cacna1a, were identified. These genes were primarily enriched in pathways such as spinocerebellar ataxia, protein processing in endoplasmic reticulum and the legionellosis signalling pathway. Quantitative real-time PCR analysis was employed to verify the significantly expressed DEGs, and the results aligned with the trends observed in transcriptome analysis. Key genes including ire1, traf2, map3k5, map2k7, jnk, bax, bcl2 and capn1 enriched in protein processing in endoplasmic reticulum were quantitatively analysed. In this study, we employed transcriptomic analysis combined with bioinformatics approaches to explore the molecular responses of T. yarkandensis under heat stress. The findings contribute to the conservation of its germplasm resources, support the breeding of heat-tolerant strains, and provide a scientific basis for artificial propagation and stock enhancement efforts.