Vindoline Biosynthesis and Its Proposed Localization within the Leaf in C. roseus.
Among ∼30 enzymatic steps involved in vindoline biosynthesis, 17 genes encoding known MIA biosynthesis enzymes and transcription factors and the recently cloned and characterized 16OMT () and LAMT described in this article are represented in the CROLF1NG data set. The leaf epidermal localization of 16OMT and LAMT (highlighted in gray) expands the list of genes and enzymes expressed in this tissue and highlights it as the major site of MIA biosynthesis up to 16-methoxytabersonine. Putative numbers of the enzymatic reactions in each cell type are shown. CPR is believed to be involved in all the reactions catalyzed by cytochrome P450 monooxygenases. DXS, 1-deoxy-d-xylulose 5-phosphate synthase; DXR, 1-deoxy-d-xylulose 5-phosphate reductoisomerase; MECS, 2-C-methyl-d-erythritol-2,4-cyclodiphosphate synthase; G10H, geraniol 10-hydroxylase; LAMT, loganic acid methyltransferase; SGD, strictosidine β-glucosidase; T16H, tabersonine-16-hydroxylase; 16OMT, 16-hydroxytabersonine-O-methyltransferase; BPF1, box P binding factor 1; ZCT2, zinc finger Catharanthus transcription factor 2.