title: Functional characterization of terpene synthases and chemotypic variation in three lavender species of section Stoechas.
abstract: Lavandula pedunculata (Mill.) Cav. subsp. lusitanica, Lavandula stoechas L. subsp. stoechas and Lavandula viridis l'Hér. are three lavender taxa that belong to the botanical section Stoechas and are widely used as aromatherapy, culinary herb or folk medicine in many Mediterranean regions. The analysis of their bioactive volatile constituents revealed the presence of 124 substances, the most abundant being the bicyclic monoterpenes fenchone, camphor and 1,8-cineole that give these three species their respective chemotypes. Most noteworthy was fenchone which, with its reduced form fenchol, made 48% of the total volatile constituents of L. pedunculata while present at 2.9% in L. stoechas and undetectable in L. viridis. In order to provide a molecular explanation to the differences in volatile compounds of these three species, two monoterpene synthases (monoTPS) and one sesquiterpene synthase (sesquiTPS) were cloned in L. pedunculata and functionally characterized as fenchol synthase (LpFENS), α-pinene synthase (LpPINS) and germacrene A synthase (LpGEAS). The two other lavender species contained a single orthologous gene for each of these three classes of TPS with similar enzyme product specificities. Expression profiles of FENS and PINS genes matched the accumulation profile of the enzyme products unlike GEAS. This study provides one of the rare documented cases of chemotype modification during plant speciation via changes in the level of plant TPS gene expression, and not functionality.
authors.affiliation: Département de Biologie, Faculté des Sciences, Université M'hamed Bougara, Boumerdes, 35000, Algeria.
authors.forename: Tarek
authors.initials: T
authors.lastname: Benabdelkader
authors.forename: Yann
authors.initials: Y
authors.lastname: Guitton
authors.forename: Bernard
authors.initials: B
authors.lastname: Pasquier
authors.forename: Jean Louis
authors.initials: JL
authors.lastname: Magnard
authors.forename: Frédéric
authors.initials: F
authors.lastname: Jullien
authors.forename: Abdelkrim
authors.initials: A
authors.lastname: Kameli
authors.forename: Laurent
authors.initials: L
authors.lastname: Legendre
mesh_terms: D019883:Alkyl and Aryl Transferases / Q000235:genetics* / Q000378:metabolism; D019757:Carbon-Oxygen Lyases; D008401:Gas Chromatography-Mass Spectrometry; D027523:Lavandula / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics; D009822:Oils, Volatile / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D010802:Phylogeny; D018515:Plant Leaves / Q000737:chemistry / Q000201:enzymology / Q000235:genetics; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins; D013045:Species Specificity; D013729:Terpenes / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism
chemical_list: D009822:Oils, Volatile; D010940:Plant Proteins; D011994:Recombinant Proteins; D013729:Terpenes; D019883:Alkyl and Aryl Transferases; C108877:terpene synthase; D019757:Carbon-Oxygen Lyases; C473195:(-)-alpha-pinene synthase