Objective Targeted flavonoid metabolome detection and analysis were carried out to provide reference for further analysis of color substances and flavonoid metabolism pathway in the tepals of different flower color types of wintersweet using the middle and inner tepals of three cultivars of Rubrum wintersweet, Patens wintersweet, and Concolor wintersweet at early flowering stage.

MethodsUPLC-MS/MS was used to detect the middle and inner tepals of three wintersweet cultivars, and the qualitative and quantitative analysis of metabolites, sample quality control analysis, PCA, HCA, OPLS-DA, KEGG functional annotation and enrichment analysis of differential metabolites were used to explore the differences of flavonoid metabolites in the tepals of different flower color types.

ResultsA total of 82 metabolites were detected in wintersweet tepals, including chalcone, dihydroflavone, flavone, isoflavone, dihydroflavonol, xanthone alcohol, anthocyanin, flavanol; In addition to anthocyanins, the flavonoids in the red tepal of wintersweet also included flavonol compounds, which did not show regular changes in the red and yellow tepals; In the five comparison groups of wintersweet red tepals and yellow tepals, the enrichment of anthocyanin metabolic pathway was the largest and most significant.

Conclusion Besides the main flavonol branch and anthocyanin branch, the flavone branch, isoflavone branch, and procyanidin branch may also be included in the flavonoid biosynthesis pathway of wintersweet tepals; The anthocyanin branch and flavonol branch may not compete for the common substrate in the flavonoid biosynthesis pathway of the red tepals of wintersweet; Cyanidin glycosides are the characteristic metabolites of the red tepals in wintersweet, including cyanidin 3-O-glucoside, cyanidin 3-O-rutinoside, and cyanidin 3-O-galactoside.