Figure 1.

Isoprenoid biosynthetic pathways and enzymes in Arabidopsis. Solid arrows indicate single enzymatic steps, and dashed arrows represent multiple steps. Mevalonic acid (MVA) pathway: HMG-CoA, hydroxymethylglutaryl-CoA. Methylerythritol 4-phosphate (MEP) pathway: GAP, glyceraldehyde 3-phosphate; DXP, deoxyxylulose 5-phosphate. Prenyl diphosphates: IPP, isopentenyl diphosphate; DMAPP, dimethylallyl diphosphate; GPP, geranyl diphosphate; FPP, farnesyl diphosphate; GGPP, geranylgeranyl diphosphate; PPP, polyprenyl diphosphate. Hormones: CKs, cytokinins; BRs, brassinosteroids; GAs, gibberellins; SLs, strigolactones; ABA, abscisic acid. Enzymes: HMGR, HMG-CoA reductase; DXS, DXP synthase; IDI, IPP/DMAPP isomerase; FPPS, FPP synthase; GGPPS, GGPP synthase. *GGPPS activity unclear. **Isoforms reported in this work.