An R2R3-MYB transcription factor regulates anthocyanin accumulation in response to temperature signals in Cymbidiumensifolium.

Cymbidium ensifolium, an ornamental plant in China, is prized for its diverse flower colors and high aesthetic value. The flower color of C. ensifolium is significantly affected by temperature. In this research, we examined the impact of temperature on anthocyanin accumulation in the sepals of C. ensifolium ('Shi Zhang Hong') through different temperature treatments (T1, 20/15 °C, T2, 28/23 °C, T3, 36/31 °C), combined with metabolomics, transcriptome analysis and various experimental methods, screening for key temperature-responsive genes. The results indicated that high temperatures suppress both red pigmentation and anthocyanin accumulation in sepals, while low temperatures promote this process. Metabolomic analysis indicated that temperature primarily influences sepal coloration by regulating the abundance of cyanidin-3-O-glucoside. Notably, its abundance significantly increases under low temperatures but decreases at high temperatures. CeMYB52 was found to be a crucial transcription factor (TF) regulating anthocyanin accumulation by transcriptome analysis, with high expression at low temperatures and low expression at high temperatures. Remarkably, the spatio-temporal expression profiles of CeCHS8 and CeGST were aligned with CeMYB52. Through regulating the expression of CeCHS8 and CeGST, CeMYB52 contributes significantly to the promotion of anthocyanin biosynthesis and transport. Our findings offer a molecular basis for breeding temperature-resilient ornamental plants, contributing to agricultural sustainability under climate change.