Light-Induced Flavonoid Biosynthesis in with High-Altitude Adaptation.

is a perennial alpine herb producing the anti-cancer metabolite podophyllotoxin (PPT). Although the adaptation of to high altitudes has been demonstrated and the effects of temperature, precipitation, and UV-B light on plant growth and metabolite accumulation have been studied, knowledge on the role of flavonoid biosynthesis in adapting to high altitudes is limited. In this study, light intensity, amount and type of flavonoids, and differentially expressed proteins (DEPs) and genes (DEGs) at 2300 and 3300 m were analyzed by HPLC, proteomic, transcriptomic, and qRT-PCR analysis. We found that higher light intensity correlated with greater flavonoid, flavonol, and anthocyanin content as well as higher anthocyanin to total flavonoid and flavonol ratios observed at the higher altitude. Based on proteomic and transcriptomic analyses, nine DEPs and 41 DEGs were identified to be involved in flavonoid biosynthesis and light response at 3300 m. The relative expression of nine genes (, , , , , , , , and ) involved in flavonoid biosynthesis and seven genes (, , , , , , and ) involved in light stress were observed to be up-regulated at 3300 m compared with 2300 m. These findings indicate that light intensity may play a regulatory role in enhancing flavonoid accumulation that allows to adapt to elevated-altitude coupled with high light intensity.