Metabolic profile and morphological characteristics of leaf tips among different sweet potato (Ipomoea batatas Lam.) varieties

Sweet potato leaf tips have high nutritional values, and exploring the differences in metabolic profile of leaf tips among different sweet potato varieties can provide information to improve their qualities. In this study, a UPLC-Q-Exactive Orbitrap/MS-based untargeted metabolomics method was used to evaluate the metabolites in leaf tips of 32 sweet potato varieties. Three varieties, A01, A02, and A03, with distinct overall metabolic profiles, two varieties, A20 and A18, with distinct profiles of phenolic acids, and three varieties, A05, A12, and A16, with distinct profiles of flavonoids were identified. In addition, a total of 163 and 29 differentially expressed metabolites correlated with the color and leaf shape of sweet potato leaf tips were identified through morphological characterization. Group comparison analysis of the phenotypic traits and metabolite–phenotypic trait correlation analysis indicated that the color differences of sweet potato leaf tips were markedly associated with flavonoids. Also, the level of polyphenols was correlated with the leaf shape of sweet potato leaf tips, lobed leaf types had more higher levels of polyphenols than the entire types. The findings on the metabolic profile and differentially expressed metabolites associated with the morphology of sweet potato leaf tips would provide useful information for breeding sweet potato varieties with higher nutritional values.1