Dataset for: Integrated Multi-Omics Analysis of Physiological and Molecular Responses in Oncidium Orchids under Heat Stress

Hainan Island features a tropical monsoon marine climate with indistinct seasons, characterized by hot summers and mild winters. Prolonged summer high temperatures severely inhibit the growth of Oncidium plants. In this study, we simulated high-temperature conditions using growth chambers to investigate the physiological alterations in Oncidium leaves under heat stress. Key indicators were measured, including leaf color, antioxidant enzyme activities, chlorophyll content, and photosynthetic parameters. Concurrently, the dynamic changes in the transcriptome and metabolome across different treatments were analyzed. By examining differentially expressed genes and metabolites, the molecular regulatory network activated by heat stress was delineated and key responsive molecules were identified. The expression patterns of selected genes were validated by quantitative real-time PCR (qRT-PCR). The results indicated that heat stress induced leaf senescence and yellowing, accompanied by significantly reduced chlorophyll content and impaired photosynthetic capacity. The activities of antioxidant enzymes (such as SOD, POD, CAT) showed a transient increase during the initial stage of the stress but declined remarkably with prolonged exposure, leading to substantial accumulation of malondialdehyde (MDA), a marker of severe oxidative damage. Transcriptomic and metabolomic analyses identified a large number of differentially expressed genes and metabolites involved in the heat stress response. Key pathways, including protein processing in the endoplasmic reticulum, plant hormone signal transduction, MAPK signaling, and flavonoid biosynthesis, were significantly enriched. Several transcription factors (e.g., HSF, WRKY, MYB, GRAS) were consistently upregulated and are likely to play central roles in regulating the heat-responsive network. qRT-PCR validation of selected gene expression patterns confirmed the reliability of the transcriptomic data. This study provided a comprehensive perspective on the heat stress response mechanisms in Oncidium orchids by integrating physiological and multi-omics analyses, thereby offering a theoretical foundation for developing heat-tolerant Oncidium breeding programs and cultivation strategies.