The shade-requiring plant of Amomum tsao-ko adapts to sunlit environment by promoting the flavonoids biosynthesis

The growth, development, and quality of Shade-requiring plants are inhibited by sunlit stress. However, the molecular mechanism underlying the response to sunlit stress in A. tsao-ko is remains unknown. Here, we therefore performed a multi-omics investigation of A. tsao-ko under sunlit stress to determine the mechanisms underlying A. tsao-ko adaptability to sunlit stress. Compared to the control, light conditions increase the density of secretory glands but decrease the content of chlorophyll, total flavonoids, and total terpene. The multiomics data shown that the volatile in fruits decreased and the flavonoids in leaves increased significantly to defend the strong sunlit. In addition, The RNA sequencing showed that sunlit stress influenced the secondary metabolism, especially the flavonoid pathway, is strongly enhanced in A. tsao-ko under sunlit stress. Pearson correlation coefficient analysis identified the key regulatory gene chalcone synthase 1 (AmTCHI1), which is key enzyme gene in the phenylpropane pathway. Moreover, luciferase assays indicated that the AmTbHLH1 and AmTMYB1 transcription factor binds to the AmTCHS1 promoter to enhance its transcription in sunlit environment. These results clarify the role of the phenylpropane pathway, especially flavonoid metabolism, in the response to sunlit stress in A. tsao-ko .