Multi-omics integration of metabolome and transcriptome identifies candidate gene associated with differential anthocyanins accumulation in sorghum

Background Anthocyanins are important plant secondary metabolites with significant antioxidant activities and health benefits. However, compared with deoxyanthocyanidins, the composition of anthocyanins in sorghum grains remains largely unclear. Results Metabolomics and transcriptomics were integrated to analyze anthocyanin accumulation in three sorghum cultivars, the high-anthocyanin varieties BYQ and HYZ versus the low-anthocyanin variety P898012. Total anthocyanin content and antioxidant capacity were significantly higher in the darker grains. Targeted metabolomics identified 35 anthocyanin compounds, with cyanidin-derived anthocyanins—particularly cyanidin-3-O-glucoside—being the predominant compounds in the high-anthocyanin cultivars. Transcriptomics revealed 4,039 differentially expressed genes (DEGs) in BYQ versus P898012 and 6,092 in HYZ versus P898012, which were enriched in phenylalanine metabolism and secondary metabolite biosynthesis pathways. Correlation analysis of the differentially expressed genes and metabolites identified a UDP-glycosyltransferase (UGT), SbUGT1, that was significantly upregulated in the high-anthocyanin cultivars and strongly correlated with cyanidin-3-O-glucoside levels. Conclusions These findings systematically characterize the anthocyanins in sorghum grains and identify a candidate enzyme SbUGT1 for cyanidin 3-O-glucosyltransferase, providing an important foundation for elucidating the anthocyanin accumulation in sorghum and facilitating future metabolic engineering of grain color and nutritional quality.