High temperature poses a major threat to sustainable development of the lettuce industry. Investigation of the mechanisms that regulate heat stress responses has great significance. Four lettuce accessions-two thermotolerant and two thermosensitive cultivars-were selected for comparative analysis. Subsequently, the metabolic changes in lettuce in response to heat treatment were investigated using untargeted metabolomic analysis. Several discriminatory metabolites were identified, including three amino acids, one carbohydrate, eight phenolic compounds, one terpene, one alcohol and one lignin. Transcriptomics analysis was performed in parallel using the same four lettuce accessions. The integrated analysis suggested that a large number of metabolites and genes detected with measurable changes during the heat response are involved in flavonoid biosynthesis. Additionally, 25 of the 31 transcription factors identified, including MYBs, WRKYs, NACs, bHLHs, MADSs, AP2/ERFs and bZIP, were also upregulated. Thus, this study provides a comprehensive understanding of the complex molecular mechanisms underlying the thermal stress responses of lettuce.

高温对生菜产业的可持续发展构成重大威胁。研究调节热应激反应的机制具有重要意义。选择了四个生菜种质——两个耐热品种和两个热敏品种——进行比较分析。随后，使用非靶向代谢组学分析研究了生菜响应热处理的代谢变化。确定了几种有区别的代谢物，包括三种氨基酸、一种碳水化合物、八种酚类化合物、一种萜烯、一种醇和一种木质素。使用相同的四个生菜种质并行进行转录组学分析。综合分析表明，在热反应过程中检测到的大量代谢物和基因发生了可测量的变化，这些代谢物和基因参与了类黄酮的生物合成。此外，确定的 31 个转录因子中有 25 个，包括MYB、WRKY、NAC、bHLH、MADS、AP2/ERF和bZIP也被上调。因此，这项研究提供了对生菜热应激反应背后复杂分子机制的全面理解。