Metabolomic and transcriptomic reveal flavonoid biosynthesis and regulation mechanism in Phlomoides rotata from different habitats

Phlomoides rotata is a traditional medical plant at 3100-5200 m altitude in the Tibet Plateau. In this study, flavonoid metabolites were investigated in P. rotata from Henan County (HN), Guoluo County (GL), Yushu County (YS), and Chengduo County (CD) habitats in Qinghai. The level of kaempferol 3-neohesperidoside, sakuranetin, and biochanin A was high in HN. The content of limocitrin and isoquercetin was high in YS. The levels of ikarisoside A and chrysosplenol D in GL were high. Schaftoside, miquelianin, malvidin chloride, and glabrene in CD exhibited high levels. The results showed a significant correlation between 59 flavonoids and 29 DEGs. Eleven flavonoids increased with altitude. PAL2, UFGT6, COMT1, HCT2, 4CL4, and HCT3 genes were crucial in regulating flavonoid biosynthesis. Three enzymes CHS, 4CL, and UFGT, were crucial in regulating flavonoid biosynthesis. This study provided biological and chemical evidence for the different uses of various regional plants of P. rotata.