Fig. 1

The biosynthetic pathway of MIA in C. roseus leaves. Simplified representation of the MIA biosynthesis in C. roseus highlighting the subcellular organization of the central steps of the pathway. Known single enzymatic steps in each cell type are indicated by grey arrows and abbreviation of enzyme names. Broken grey arrows and broken pink arrows indicate unknown enzymatic steps and metabolite translocation, respectively. DXS, 1-deoxy-D-xylulose-5-phosphate (DXP) synthase; DXR, DXP reductoisomerase; CMS, 4-(cytidine 5′-diphospho)-2C-methyl-D-erythritol (CM) synthase; CMK, CM kinase; MECS, 2C-methyl-D-erythritol-2,4-cyclodiphosphate (MEC) synthase; HDS, hydroxymethylbutenyl 4-diphosphate (HD) synthase; HDR, HD reductase; IDI, isopentenyl diphosphate isomerase; GPPS, geranyl diphosphate synthase; GES, geraniol synthase; G10H (CYP76B6), geraniol 10-hydroxylase; CPR, cytochrome P450-reductase; 10HGO, 10-hydroxygeraniol oxidoreductase; IO, iridoid oxidase; IS, iridoid synthase; 7DLGT, 7-deoxyloganetic acid glucosyltransferase; 7DLH, 7-deoxyloganic acid 7-hydroxylase; LAMT, loganic acid O-methyltransferase; SLS (CYP72A1), secologanin synthase; TDC, tryptophan decarboxylase; STR, strictosidine synthase; SGD, strictosidine β-glucosidase; T16H2 (CYP71D351), tabersonine 16-hydroxylase 2; 16OMT, 16-hydroxytabersonine O-methyltransferase; NMT, 16-methoxy-2,3-dihydrotabersonine N-methyltransferase; D4H, desacetoxyvindoline 4-hydroxylase; DAT, deacetylvindoline 4-O-acetyltransferase. DMAPP, dimethylallyl diphosphate; GAP, glyceraldehyde 3-phosphate; IPP, isopentenyl diphosphate