title: OSC2 and CYP716A14v2 catalyze the biosynthesis of triterpenoids for the cuticle of aerial organs of Artemisia annua.
abstract: Artemisia annua is widely studied for its ability to accumulate the antimalarial sesquiterpenoid artemisinin. In addition to producing a variety of sesquiterpenoids, A. annua also accumulates mono-, di-, and triterpenoids, the majority of which are produced in the glandular trichomes. A. annua also has filamentous trichomes on its aerial parts, but little is known of their biosynthesis potential. Here, through a comparative transcriptome analysis between glandular and filamentous trichomes, we identified two genes, OSC2 and CYP716A14v2, encoding enzymes involved in the biosynthesis of specialized triterpenoids in A. annua. By expressing these genes in Saccharomyces cerevisiae and Nicotiana benthamiana, we characterized the catalytic function of these proteins and could reconstitute the specialized triterpenoid spectrum of A. annua in these heterologous hosts. OSC2 is a multifunctional oxidosqualene cyclase that produces α-amyrin, β-amyrin, and δ-amyrin. CYP716A14v2 is a P450 belonging to the functionally diverse CYP716 family and catalyzes the oxidation of pentacyclic triterpenes, leading to triterpenes with a carbonyl group at position C-3, thereby providing an alternative biosynthesis pathway to 3-oxo triterpenes. Together, these enzymes produce specialized triterpenoids that are constituents of the wax layer of the cuticle covering the aerial parts of A. annua and likely function in the protection of the plant against biotic and abiotic stress.
authors.affiliation: Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB), B-9052 Gent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Gent, Belgium Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, Katholieke Universiteit Leuven, B-3000 Leuven, Belgium Department of Molecular Microbiology, Flanders Institute for Biotechnology (VIB), B-3001 Leuven-Heverlee, Belgium Department of Metabolic Biology, John Innes Centre, Norwich NR4 7UH, United Kingdom.
authors.forename: Tessa
authors.initials: T
authors.lastname: Moses
authors.affiliation: Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB), B-9052 Gent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Gent, Belgium.
authors.forename: Jacob
authors.initials: J
authors.lastname: Pollier
authors.affiliation: Key Laboratory of Urban Agriculture (South) Ministry of Agriculture, Plant Biotechnology Research Center, Fudan-SJTU-Nottingham Plant Biotechnology R&D Center, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Shen
authors.affiliation: Laboratory of Pharmaceutical Biotechnology, Faculty of Pharmaceutical Sciences, Ghent University, 9000 Ghent, Belgium.
authors.forename: Sandra
authors.initials: S
authors.lastname: Soetaert
authors.affiliation: Department of Metabolic Biology, John Innes Centre, Norwich NR4 7UH, United Kingdom.
authors.forename: James
authors.initials: J
authors.lastname: Reed
authors.affiliation: Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB), B-9052 Gent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Gent, Belgium.
authors.forename: Marie-Laure
authors.initials: ML
authors.lastname: Erffelinck
authors.affiliation: Laboratory of Pharmaceutical Biotechnology, Faculty of Pharmaceutical Sciences, Ghent University, 9000 Ghent, Belgium.
authors.forename: Filip C W
authors.initials: FC
authors.lastname: Van Nieuwerburgh
authors.affiliation: Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB), B-9052 Gent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Gent, Belgium.
authors.forename: Robin
authors.initials: R
authors.lastname: Vanden Bossche
authors.affiliation: Department of Metabolic Biology, John Innes Centre, Norwich NR4 7UH, United Kingdom.
authors.forename: Anne
authors.initials: A
authors.lastname: Osbourn
authors.affiliation: Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, Katholieke Universiteit Leuven, B-3000 Leuven, Belgium Department of Molecular Microbiology, Flanders Institute for Biotechnology (VIB), B-3001 Leuven-Heverlee, Belgium.
authors.forename: Johan M
authors.initials: JM
authors.lastname: Thevelein
authors.affiliation: Laboratory of Pharmaceutical Biotechnology, Faculty of Pharmaceutical Sciences, Ghent University, 9000 Ghent, Belgium.
authors.forename: Dieter
authors.initials: D
authors.lastname: Deforce
authors.affiliation: Key Laboratory of Urban Agriculture (South) Ministry of Agriculture, Plant Biotechnology Research Center, Fudan-SJTU-Nottingham Plant Biotechnology R&D Center, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China.
authors.forename: Kexuan
authors.initials: K
authors.lastname: Tang
authors.affiliation: Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB), B-9052 Gent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Gent, Belgium alain.goossens@psb-vib.ugent.be.
authors.forename: Alain
authors.identifier: http://orcid.org/0000-0002-1599-551X
authors.initials: A
authors.lastname: Goossens
mesh_terms: D031172:Artemisia annua / Q000378:metabolism*; D035261:Plant Components, Aerial / Q000378:metabolism; D010940:Plant Proteins / Q000378:metabolism*; D014315:Triterpenes / Q000378:metabolism*
chemical_list: D010940:Plant Proteins; D014315:Triterpenes