Objective As an important fish species for aquaculture, the growth and survival of hybrid snakehead (Channa maculata♀ × Channa argus♂) are greatly affected by low-temperature stress. This study aims to reveal the molecular mechanisms of cold response by analyzing the transcriptomic changes in the muscle tissue of hybrid snakehead under low-temperature stress, providing a theoretical basis for the breeding of cold-resistant varieties and healthy aquaculture.

Method Using muscle tissues of hybrid snakehead under normal temperature (control group) and low-temperature stress as materials, transcriptome sequencing and comparative analysis were conducted, transcription factors were predicted and identified, differentially expressed genes (DEGs) were screened, and some DEGs were validated by qRT-PCR.

Result When the water temperature dropped to 7 ℃, the hybrid snakehead exhibited loss of equilibrium. Transcriptome analysis identified a total of 1857 DEGs, of which 750 were upregulated and 1107 were downregulated. Transcription factor analysis identified a total of 126 transcription factors, among which C2H2, bHLH and bZIP were the relatively large transcription factor families. Expression of most genes of the bHLH family was upregulated, while the expression of TCF12 and MyoD1 was downregulated. GO and KEGG functional enrichment analyses indicated that these DEGs were significantly enriched in pathways such as the FOXO signaling pathway and actin cytoskeleton regulation. The expression of key cold stress-related genes (such as VEGF, B-AR, HSP90, Metrnl, and FOXO1) was significantly upregulated. Eleven DEGs were randomly selected for qPCR validation, and the results were highly consistent with the transcriptome data, indicating that the RNA-seq data were reliable.

Conclusion The expression of muscle growth-related transcription factors in hybrid snakehead is inhibited under low-temperature stress, suggesting that hybrid snakehead may cope with low-temperature stress by adjusting energy metabolism. In addition, hybrid snakehead may enhance cold resistance by regulating the expression of cold stress-related genes in muscle tissue (such as HSP90 and FOXO1), activating the FOXO signaling pathway, and engaging in physiological processes such as actin cytoskeleton remodeling. The research results provide an important reference for in-depth analysis of the low-temperature response mechanism of hybrid snakehead and for the breeding of cold-resistant varieties.