Genome Wide Identification of Terpenoid Metabolism Pathway Genes in Chili and Screening of Key Regulatory Genes for Fruit Terenoid Aroma Components  
[PERSON]  
1 School of Breeding and Multiplication (Sanya Institute of Breeding and Multiplication), Hainan University, Sanya 572025, China; [EMAIL_ADDRESS] (M.Y. ); [EMAIL_ADDRESS] (G.F.); [EMAIL_ADDRESS] (X.L. ); [EMAIL_ADDRESS] (H.F.)  
[PERSON]  
1 School of Breeding and Multiplication (Sanya Institute of Breeding and Multiplication), Hainan University, Sanya 572025, China; [EMAIL_ADDRESS] (M.Y. ); [EMAIL_ADDRESS] (G.F.); [EMAIL_ADDRESS] (X.L. ); [EMAIL_ADDRESS] (H.F.)  
[PERSON]  
1 School of Breeding and Multiplication (Sanya Institute of Breeding and Multiplication), Hainan University, Sanya 572025, China; [EMAIL_ADDRESS] (M.Y. ); [EMAIL_ADDRESS] (G.F.); [EMAIL_ADDRESS] (X.L. ); [EMAIL_ADDRESS] (H.F.)  
[PERSON]  
1 School of Breeding and Multiplication (Sanya Institute of Breeding and Multiplication), Hainan University, Sanya 572025, China; [EMAIL_ADDRESS] (M.Y. ); [EMAIL_ADDRESS] (G.F.); [EMAIL_ADDRESS] (X.L. ); [EMAIL_ADDRESS] (H.F.)  
[PERSON]  
1 School of Breeding and Multiplication (Sanya Institute of Breeding and Multiplication), Hainan University, Sanya 572025, China; [EMAIL_ADDRESS] (M.Y. ); [EMAIL_ADDRESS] (G.F.); [EMAIL_ADDRESS] (X.L. ); [EMAIL_ADDRESS] (H.F.)  
[PERSON]  
1 School of Breeding and Multiplication (Sanya Institute of Breeding and Multiplication), Hainan University, Sanya 572025, China; [EMAIL_ADDRESS] (M.Y. ); [EMAIL_ADDRESS] (G.F.); [EMAIL_ADDRESS] (X.L. ); [EMAIL_ADDRESS] (H.F.)  
[PERSON]  
1 School of Breeding and Multiplication (Sanya Institute of Breeding and Multiplication), Hainan University, Sanya 572025, China; [EMAIL_ADDRESS] (M.Y. ); [EMAIL_ADDRESS] (G.F.); [EMAIL_ADDRESS] (X.L. ); [EMAIL_ADDRESS] (H.F.)  
[PERSON]  
1 School of Breeding and Multiplication (Sanya Institute of Breeding and Multiplication), Hainan University, Sanya 572025, China; [EMAIL_ADDRESS] (M.Y. ); [EMAIL_ADDRESS] (G.F.); [EMAIL_ADDRESS] (X.L. ); [EMAIL_ADDRESS] (H.F.)  
[PERSON]  
2 Key Laboratory for Quality Regulation of Tropical Horizontal Crops of Hainan Province, School of Tropical Agriculture and Forestry, Hainan University, Haikou 570228, China  
So far, at least three pathways for the biosynthesis of VACs have been found in plants, including phenylpropanol, alkaloid, and terpene metabolic pathways [4]. The terpene metabolism pathway, also known as the isoprene metabolism pathway, includes the mevalonate pathway (MVA pathway) in eukaryotic cytoplasm and the methylerythitol 4-phosphate pathway (MEP pathway) in plant chloroplasts or other plastids. In the MVA pathway, acetyl CoA produced by the breakdown of sugars and fatty acids are condensed into acetyl CoA carboxylase (AcAc CoA) under the action of acetyl CoA C-acetyl transferase (AACT). AcAc CoA is catalyzed by 3-hydroxy-3-methylglutaryl-CoA synthase (HMGS) to form HMG CoA, which is then reacted by 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR) to form mevalonate. Mevalonate is further phosphorylated and decarboxylated under the action of mevalonate kinase (MVK), 5-phosphate mevalonate enzyme (MPK), and mevalonate pyrophosphate decarboxylase (MVD), forming isopentenyl diphosphate (IPP). Under the catalysis of isopentenyl diphosphate isomerase (IDI), IPP isomerizes to form dimethylallyl diphosphate (DMAPP). IPP and DMAPP undergo a series of addition reactions under the action of geranylgeranyl pyrophosphate synthase (GGPPS) and farnesyl pyrophosphate synthase (FPPS) to form geranylgeranyl diphosphate (GGPP) and farnesyl diphosphate (FPP), respectively, and further produce diterpenes and sesquiterpenes under terpene synthase (TPS) catalysis. In the MEP pathway, 1-deoxy-D-xylulose-5-phosphate synthase (DXS) catalyzes the condensation of glyceraldehyde-3-phosphate dehydrogenase (G3P) produced by photosynthesis with pyruvate acid to form 1-deoxy-D/xylulose-5-phosphate (DXP), which is reduced to MEP under the action of 1-deoxy-D-xylulose-5-phosphate reductase (DXR).