Functional characterization of terpene synthases and chemotypic variation in three lavender species of section Stoechas |
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| Authors: | Tarek Benabdelkader Yann Guitton Bernard Pasquier Jean Louis Magnard Frédéric Jullien Abdelkrim Kameli Laurent Legendre |
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| Institution: | 1. Département de Biologie, Faculté des Sciences, Université M'hamed Bougara, Boumerdes, Algeria;2. Université de Nantes, UFR des Sciences Pharmaceutiques et Biologiques, Nantes cedex 1, France;3. Conservatoire National des plantes à Parfum, Médicinales, Aromatiques et Industrielles (CNPMAI), Milly la Forêt, France;4. Université de Lyon, Saint Etienne, France;5. Université de Saint Etienne, Saint Etienne, France;6. Laboratoire de Biotechnologie Végétale Appliquée aux Plantes Aromatiques et Médicinales, Faculté des Sciences et Techniques, Saint Etienne, France;7. Ecole Normale Supérieure, Laboratoire d'Ecophysiologie Végétale, Kouba, Algeria;8. Université de Lyon, Lyon, France;9. Université Lyon 1, Villeurbanne, France;10. CNRS, UMR5557, Ecologie Microbienne, Villeurbanne, France |
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| 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. |
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