二、三倍体牙鲆肌肉组织对高温胁迫的转录响应特征研究OA

High temperature has been a severe challenge to the aquaculture.In recent years,with the continuous rise of water temperatures and prolonged duration of high-temperature periods in summer,the impact of heat stress on fish has become increasingly apparent.Triploid fishes exhibit advantages in growth performance,stress resistance and quality traits due to low or complete sterility,and have been widely applied in aquaculture.However,research on their heat tolerance and molecular responses to heat stress remains limited.Olive flounder(Paralichthys olivaceus)is a commercially important marine fish species in China.The present study evaluated the heat tolerance of triploid flounder,analyzed its molecular response to heat stress in muscle via transcriptome sequencing,and compared with those of diploids.The results demonstrated that triploid flounder exhibited significantly enhanced heat tolerance compared to diploids,with both the higher high temperature threshold and longer survival time under high temperature than those of diploids(P＜0.01).Under heat stress at 31℃for 24 h,diploid fish displayed adaptive changes in gene expression,a total of 847 genes were differentially expressed,including 618 up-regulated and 229 down-regulated genes,among which genes related to apoptosis and metabolic regulation were significantly upregulated.In contrast,high temperature exerted a relatively minor effect on gene expression in triploid fish,with only 19 genes differentially expressed(16 up-regulated and 3 down-regulated).Among these,genes involved in carbohydrate,fatty acid,amino acid metabolism,apoptosis and FoxO signaling pathway were downregulated.These findings enrich the theoretical foundation for research on fish stress resistance,and provide critical insights for the development of heat-tolerant germplasm.