Metabolomic variation associated with coloration in purple-fleshed sweet potato storage roots under different substrate conditions.

UNLABELLED: Purple-fleshed sweet potato storage roots grown under three substrates (LS, VM, and SS) showed distinct biochemical and metabolic characteristics, accompanied by differences in flesh coloration. To characterize metabolic variation associated with these phenotypes, physiological measurements were integrated with untargeted metabolomic analysis. Among 14 putatively annotated anthocyanin-related metabolites, five differed significantly among substrate treatments, revealing substrate-associated variation in anthocyanin-related metabolic profiles. Total anthocyanin content followed the order LS ≥ VM > SS, whereas individual anthocyanin derivatives displayed substrate-specific accumulation patterns. Keracyanin and delphinidin-related derivatives accumulated at higher levels in LS, while peonidin-derived anthocyanins were enriched in SS. Significant differences were also observed in total phenolics, total flavonoids, soluble carbohydrates, and starch among treatments. Correlation analysis revealed significant associations between substrate pH, Fe3+ content, and phenolic- and carbohydrate-related traits. These findings suggest that substrate environments are associated with visual flesh coloration and anthocyanin-related metabolic variation in purple-fleshed sweet potato storage roots.

LIST OF COMPOUNDS: Peonidin-3-O-α-arabinopyranoside (PubChem CID: 74315894); Peonidin-3-O-β-galactopyranoside (PubChem CID: 11454027); Leucodelphinidin (PubChem CID: 3081374); Keracyanin (PubChem CID: 29231).