title: Isolation and Characterization of Three New Monoterpene Synthases from Artemisia annua.
abstract: Artemisia annua, an annual herb used in traditional Chinese medicine, produces a wealth of monoterpenes and sesquiterpenes, including the well-known sesquiterpene lactone artemisinin, an active ingredient in the treatment for malaria. Here we report three new monoterpene synthases of A. annua. From a glandular trichome cDNA library, monoterpene synthases of AaTPS2, AaTPS5, and AaTPS6, were isolated and characterized. The recombinant proteins of AaTPS5 and AaTPS6 produced multiple products with camphene and 1,8-cineole as major products, respectively, and AaTPS2 produced a single product, β-myrcene. Although both Mg(2+) and Mn(2+) were able to support their catalytic activities, altered product spectrum was observed in the presence of Mn(2+) for AaTPS2 and AaTPS5. Analysis of extracts of aerial tissues and root of A. annua with gas chromatography-mass spectrometry detected more than 20 monoterpenes, of which the three enzymes constituted more than 1/3 of the total. Mechanical wounding induced the expression of all three monoterpene synthase genes, and transcript levels of AaTPS5 and AaTPS6 were also elevated after treatments with phytohormones of methyl jasmonate, salicylic acid, and gibberellin, suggesting a role of these monoterpene synthases in plant-environment interactions. The three new monoterpene synthases reported here further our understanding of molecular basis of monoterpene biosynthesis and regulation in plant.
authors.affiliation: National Key Laboratory of Plant Molecular Genetics and National Plant Gene Research Center (Shanghai), CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai China.
authors.forename: Ju-Xin
authors.initials: JX
authors.lastname: Ruan
authors.affiliation: National Key Laboratory of Plant Molecular Genetics and National Plant Gene Research Center (Shanghai), CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai China.
authors.forename: Jian-Xu
authors.initials: JX
authors.lastname: Li
authors.affiliation: National Key Laboratory of Plant Molecular Genetics and National Plant Gene Research Center (Shanghai), CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai China.
authors.forename: Xin
authors.initials: X
authors.lastname: Fang
authors.affiliation: National Key Laboratory of Plant Molecular Genetics and National Plant Gene Research Center (Shanghai), CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai China.
authors.forename: Ling-Jian
authors.initials: LJ
authors.lastname: Wang
authors.affiliation: National Key Laboratory of Plant Molecular Genetics and National Plant Gene Research Center (Shanghai), CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai China.
authors.forename: Wen-Li
authors.initials: WL
authors.lastname: Hu
authors.affiliation: National Key Laboratory of Plant Molecular Genetics and National Plant Gene Research Center (Shanghai), CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, ShanghaiChina; Shanghai Key Laboratory of Plant Functional Genomics and Resources, Shanghai Chenshan Plant Science Research Center, Chinese Academy of Sciences, ShanghaiChina.
authors.forename: Xiao-Ya
authors.initials: XY
authors.lastname: Chen
authors.affiliation: National Key Laboratory of Plant Molecular Genetics and National Plant Gene Research Center (Shanghai), CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai China.
authors.forename: Chang-Qing
authors.initials: CQ
authors.lastname: Yang
keywords: 1; 8-cineole; Artemisia annua; camphene; monoterpene synthase; β-myrcene