Fig. 3
The Genes Involved in Rutin Biosynthesis. a A simplified representation of the flavonoid biosynthetic pathway (adapted from the KEGG PATHWAY Database: http://www.genome.jp/kegg/pathway.html) and the key enzyme-coding genes for each step. The expression value of each gene is indicated by the different colors representing log10(TPM + 1) in six tissues: root, stem, leaf, flower, young fruit, and mature fruit. b Different expression profiles of the gene UGT2 across six tissues of F. tataricum and F. esculentum (significance was tested by paired t test **P-value < 0.01). c Histogram of rutin content in mature fruit of F. tataricum and F. esculentum (significance was tested by paired t test **P-value < 0.01). d LC–ESI–MS/MS analysis of four functional UGT genes. In catalytic reactions, FtUGT1 and FeUGT1 use quercetin and UDP-glucose as substrates, FtUGT2 and FeUGT2 use isoquercitrin and UDP-rhamnose as substrates to generate corresponding flavonoids compounds. The characteristic mass spectrum peaks of products from each reaction are displayed in the dashed box of each track