Untargeted metabolomics and functional analyses reveal that the secondary metabolite quinic acid associates with Angelica sinensis flowering.

Flowering is a critical step in the plant life cycle. Angelica sinensis (Oliv.) Diels is a medicinal crop whose root is a well-known herbal medicine used in Asia. Early flowering causes changes in secondary metabolic flow and results in the loss of medicinal quality. Based on untargeted metabolomics studies, quinic acid was identified as a metabolite present in significantly higher concentrations during the early-flowering stage in A. sinensis leaves. This metabolite was subsequently investigated as a potential marker for early bolting in A. sinensis under field conditions. Moreover, quinic acid was found to accelerate flowering in the model plant Arabidopsis thaliana. Importantly, the flowering time was delayed in the quinate dehydrogenase At mutant, and this delay was reversed by quinic acid. Quinic acid upregulated the expression of the GA20OX and GID1 receptors and downregulated the expression of the inhibitor DELLA, thereby affecting the levels of FT and LFY and accelerating plant flowering. Quinic acid also significantly changed the expression of genes such as LOX, JAZ1, MYC2 and MYC3 in the jasmonic acid pathway. The trends of GID1, DELLA (GAI) and LOX2 protein expression were essentially consistent with those at the transcription level. These results suggest that quinic acid may promote plant flowering primarily by regulating the expression of genes and proteins in the gibberellin and jasmonic acid pathways.