Fig. 1.

Schematic representation of MVA and MEP pathways with different upstream and common downstream steps, and different classes of terpenoids with their structure generated from IPP/DMAPP pool. Upstream pathway abbreviations RuBP ribulose-1,5-bisphosphate, 3-PGA 3-phosphoglyceric acid, Ac-CoA acetyl-CoA, AcAc-CoA acetoacetyl-CoA, HMG-CoA 3-hydroxy-3-methylglutaryl-CoA, MVA mevalonate, MVAP mevalonate-5-phosphate, MVAPP mevalonate-5-pyrophosphate, G3P glyceraldehyde 3-phosphate, DXP 1-deoxy-d-xylulose 5-phosphate, MEP methylerythritol-4-phosphate, CDP-ME 4-(cytidine 5′-diphospho)-2-C-methyl-d-erythritol, CDP-MEP 2-phospho-4-(cytidine 5′-diphospho)-2-C-methyl-d-erythritol, MEcPP 2-C-methyl-d-erythritol 2,4-cyclodiphosphate, HMB-PP 4-hydroxy-3-methylbut-2-enyldiphosphate, AtoB acetoacetyl-CoA thiolase, HMGS HMG-CoA synthase, HMGR HMG-CoA reductase, MK mevalonate kinase, PMK MVAP kinase, PMD MVAPP decarboxylase, DXS DXP synthase, DXR DXP reductoisomerase: IspD: CDP-ME cytidylyltransferase, IspE CDP-ME kinase, IspF MEC synthase, IspG HMBPP synthase, IspH HMBPP reductase. Downstream pathway abbreviations DMAPP dimethylallyl diphosphate, IPP isopentenyl diphosphate, GPP geranyl diphosphate, FPP farnesyl diphosphate, GGPP geranylgeranyl diphosphate, IDI isopentenyl diphosphate isomerase, GPPS GPP synthase, FPPS FPP synthase, GGPPS GGPP synthase, TPS Terpene synthase. *Downstream pathway is common to MVA and MEP pathways and is functional in cytosol and plastid. Besides that, it operates in mitochondria to generate ubiquinone