title: Evolutionary patterns of volatile terpene emissions across 202 tropical tree species.
abstract: Plant responses to natural enemies include formation of secondary metabolites acting as direct or indirect defenses. Volatile terpenes represent one of the most diverse groups of secondary metabolites. We aimed to explore evolutionary patterns of volatile terpene emission. We measured the composition of damage-induced volatile terpenes from 202 Amazonian tree species, spanning the angiosperm phylogeny. Volatile terpenes were extracted with solid-phase micro extraction and desorbed in a gas chromatography-mass spectrometry for compound identification. The chemical diversity of the terpene blend showed a strong phylogenetic signal as closely related species emitted a similar number of compounds. Closely related species also tended to have compositionally similar blends, although this relationship was weak. Meanwhile, the ability to emit a given compound showed no significant phylogenetic signal for 200 of 286 compounds, indicating a high rate of diversification in terpene synthesis and/or great variability in their expression. Three lineages (Magnoliales, Laurales, and Sapindales) showed exceptionally high rates of terpene diversification. Of the 70 compounds found in >10% of their species, 69 displayed significant correlated evolution with at least one other compound. These results provide insights into the complex evolutionary history of volatile terpenes in angiosperms, while highlighting the need for further research into this important class of compounds.
authors.affiliation: CNRS Guyane USR 34562, Avenue Gustave Charlery 97300 Cayenne France; Laboratoire Evolution et Diversité Biologique UMR 5174 CNRS/Université Paul Sabatier 118, route de Narbonne 31062 Toulouse France; CNRS, UMR Ecofog Université Antilles Guyane BP 70997387 Kourou Cedex France.
authors.forename: Elodie A
authors.initials: EA
authors.lastname: Courtois
authors.affiliation: Laboratoire Evolution et Diversité Biologique UMR 5174 CNRS/Université Paul Sabatier 118, route de Narbonne 31062 Toulouse France; School of GeoSciences University of Edinburgh Edinburgh EH9 3FFUK; Royal Botanic Garden Edinburgh 20a Inverleith Row Edinburgh EH3 5LR UK.
authors.forename: Kyle G
authors.initials: KG
authors.lastname: Dexter
authors.affiliation: Biological and Environmental Sciences University of Stirling Stirling FK9 4LA UK.
authors.forename: Charles Eliot Timothy
authors.initials: CE
authors.lastname: Paine
authors.affiliation: CNRS, UMR Ecofog Université Antilles Guyane BP 70997387 Kourou Cedex France; Laboratoire de Biodiversité et Biotechnologies Microbiennes (LBBM) Observatoire Océanologique Sorbonne Universités, UPMC Univ Paris 06, CNRS 66650 Banyuls-sur-mer France.
authors.forename: Didier
authors.initials: D
authors.lastname: Stien
authors.affiliation: INRA UMR Ecofog BP 701 97387 Kourou Cedex France.
authors.forename: Julien
authors.initials: J
authors.lastname: Engel
authors.affiliation: INRAUMR Ecofog BP 70197387 Kourou Cedex France; International Center for Tropical Botany Department of Biological Sciences Florida International University Miami Florida 33199.
authors.forename: Christopher
authors.initials: C
authors.lastname: Baraloto
authors.affiliation: Laboratoire Evolution et Diversité Biologique UMR 5174 CNRS/Université Paul Sabatier 118, route de Narbonne 31062 Toulouse France.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Chave
keywords: Chemical defense; French Guiana; herbivory; secondary metabolites; tropical forest