Fig. 1.
Simplified schematic representation of the biosynthetic pathway of scopoletin, umbelliferone and their corresponding glycosides, scopolin and skimmin respectively, along with monolignols in Arabidopsis thaliana. The step of umbelliferone synthesis was hypothesized to occur via the same pathway as scopoletin synthesis. Genes whose expression was studied are highlighted: HCT, Hydroxycinnamoyl CoenzymeA shikimate: quinate hydroxycinnamoyltransferase; C3’H, Coumarate p-coumaroyl shikimate 3’-hydroxylase; F6’H1, F6’H2, Feruloyl-CoA 6’-Hydroxylase1 and 2; 4CL1, 4CL2, 4CL3, 4-Coumarate CoenzymeA ligase 1–3; CCoAOMT, Caffeoyl CoenzymeA 3-o-methyltransferase; CCR1, CCR2, Cinnamoyl CoA reductase 1 and 2. Other enzymes shown in the diagram are: COSY, coumarin synthesis; putative UGT, UDP-glucosyltransferase.