Article describes how kudzu produces both O- and C-glycosylated isoflavones, with puerarin (C-glucosyl daidzein) as an important bioactive compound. The authors go on to explain how expression of recombinant UGTs in Escherichia coli and candidate C-glycosyltransferases in Medicago truncatula were used to explore substrate specificities, and gene silencing of UGT and key isoflavone biosynthetic genes in kudzu hairy roots employed to test hypotheses concerning the substrate(s) for C-glycosylation.