title: Isolation and functional characterization of a methyl jasmonate-responsive 3-carene synthase from Lavandula x intermedia.
abstract: A methyl jasmonate responsive 3-carene synthase (Li3CARS) gene was isolated from Lavandula x intermedia and functionally characterized in vitro. Lavenders produce essential oils consisting mainly of monoterpenes, including the potent antimicrobial and insecticidal monoterpene 3-carene. In this study we isolated and functionally characterized a leaf-specific, methyl jasmonate (MeJA)-responsive monoterpene synthase (Li3CARS) from Lavandula x intermedia. The ORF excluding transit peptides encoded a 64.9 kDa protein that was expressed in E. coli, and purified with Ni-NTA agarose affinity chromatography. The recombinant Li3CARS converted GPP into 3-carene as the major product, with Kmand kcatof 3.69 ± 1.17 µM and 2.01 s-1respectively. Li3CARS also accepted NPP as a substrate to produce multiple products including a small amount of 3-carene. The catalytic efficiency of Li3CARS to produce 3-carene was over ten fold higher for GPP (kcat/Km= 0.56 µM-1s-1) than NPP (kcat/Km= 0.044 µM-1s-1). Production of distinct end product profiles from different substrates (GPP versus NPP) by Li3CARS indicates that monoterpene metabolism may be controlled in part through substrate availability. Li3CARS transcripts were found to be highly abundant in leaves (16-fold) as compared to flower tissues. The transcriptional activity of Li3CARS correlated with 3-carene production, and was up-regulated (1.18- to 3.8-fold) with MeJA 8-72 h post-treatment. The results suggest that Li3CARS may have a defensive role in Lavandula.
authors.affiliation: Department of Biology, University of British Columbia, 1177 Research Rd, Kelowna, BC. V1V 1V7, Canada.
authors.forename: Ayelign M
authors.initials: AM
authors.lastname: Adal
authors.affiliation: Department of Biology, University of British Columbia, 1177 Research Rd, Kelowna, BC. V1V 1V7, Canada.
authors.forename: Lukman S
authors.initials: LS
authors.lastname: Sarker
authors.affiliation: Department of Biology, University of British Columbia, 1177 Research Rd, Kelowna, BC. V1V 1V7, Canada.
authors.forename: Ashley D
authors.initials: AD
authors.lastname: Lemke
authors.affiliation: Department of Biology, University of British Columbia, 1177 Research Rd, Kelowna, BC. V1V 1V7, Canada. soheil.mahmoud@ubc.ca.
authors.forename: Soheil S
authors.initials: SS
authors.lastname: Mahmoud
mesh_terms: D000085:Acetates / Q000378:metabolism*; D019883:Alkyl and Aryl Transferases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D020134:Catalytic Domain; D003001:Cloning, Molecular; D003517:Cyclopentanes / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D027523:Lavandula / Q000201:enzymology / Q000235:genetics*; D039821:Monoterpenes / Q000378:metabolism; D054883:Oxylipins / Q000378:metabolism*; D010802:Phylogeny; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D011487:Protein Conformation; D040681:Structural Homology, Protein
chemical_list: D000085:Acetates; D003517:Cyclopentanes; D039821:Monoterpenes; D054883:Oxylipins; D010940:Plant Proteins; C072239:methyl jasmonate; D019883:Alkyl and Aryl Transferases
keywords: 3-Carene synthase; Lavandula; Lavandula x intermedia; Methyl jasmonate; Monoterpene synthase; Transcriptional regulation