Fig. 1.

The crocin biosynthetic pathways in C. sativus and G. jasminoides. The precursors of carotenoids are generated via the 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway. The enzymes marked in green are known enzymes from the upstream carotenoid biosynthetic pathway, and those in red and purple are identified from C. sativus and G. jasminoides, respectively. GGPPS, geranylgeranyl diphosphate synthase; PSY, phytoene synthase; PDS, phytoene desaturase; Z-ISO, ζ-carotene isomerase; ZDS, ζ-carotene desaturase; CRTISO, carotenoid isomerase; LCYB, lycopene β-cyclase; BHY, β-carotene hydrolase; CCD, carotenoid cleavage dioxygenase; ALDH, aldehyde dehydrogenase; UGT, UDP-glucosyltransferase. Information on these enzymes can be found in Table 1. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)