title: Tomato-produced 7-epizingiberene and R-curcumene act as repellents to whiteflies.
abstract: How whiteflies (Bemisia tabaci) make the choice for a host plant prior to landing, is not precisely known. Here we investigated whether they respond to specific volatiles of tomato. Zingiberene and curcumene were purified from Solanum habrochaites (PI127826), characterised by NMR and X-ray analysis and identified as 7-epizingiberene and R-curcumene. In contrast, oil from Zingiber officinalis contained the stereoisomers zingiberene and S-curcumene, respectively. Using a combination of free-choice bio-assays and electroantennography, 7-epizingiberene and its dehydrogenated derivative R-curcumene were shown to be active as semiochemicals to B. tabaci adults, whereas the stereoisomers from ginger were not. In addition, R-curcumene elicited the strongest electroantennographic response. Bio-assays showed that a cultivated tomato could be made less attractive to B. tabaci than its neighbouring siblings by the addition of the tomato stereoisomer 7-epizingiberene or its derivative R-curcumene. These sesquiterpenes apparently repel adult whiteflies prior to landing, presumably because it informs them that after landing they, or their offspring, may be exposed to higher and lethal concentrations of the same compounds.
authors.affiliation: University of Amsterdam, Department of Plant Physiology, Amsterdam, The Netherlands. p.m.bleeker@uva.nl
authors.forename: Petra M
authors.initials: PM
authors.lastname: Bleeker
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Diergaarde
authors.forename: Kai
authors.initials: K
authors.lastname: Ament
authors.forename: Stefan
authors.initials: S
authors.lastname: Schütz
authors.forename: Bettina
authors.initials: B
authors.lastname: Johne
authors.forename: Jan
authors.initials: J
authors.lastname: Dijkink
authors.forename: Henk
authors.initials: H
authors.lastname: Hiemstra
authors.forename: René
authors.initials: R
authors.lastname: de Gelder
authors.forename: Michiel T J
authors.initials: MT
authors.lastname: de Both
authors.forename: Maurice W
authors.initials: MW
authors.lastname: Sabelis
authors.forename: Michel A
authors.initials: MA
authors.lastname: Haring
authors.forename: Robert C
authors.initials: RC
authors.lastname: Schuurink
mesh_terms: D000818:Animals; D006430:Hemiptera / Q000187:drug effects / Q000502:physiology*; D006790:Host-Parasite Interactions; D007302:Insect Repellents / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D018551:Solanum lycopersicum / Q000737:chemistry*; D015394:Molecular Structure; D000081222:Monocyclic Sesquiterpenes; D009822:Oils, Volatile; D012717:Sesquiterpenes / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D013237:Stereoisomerism
chemical_list: D007302:Insect Repellents; D000081222:Monocyclic Sesquiterpenes; D009822:Oils, Volatile; D012717:Sesquiterpenes; C477983:zingiberene