title: Petunia hybrida PDR2 is involved in herbivore defense by controlling steroidal contents in trichomes.
abstract: As a first line of defense against insect herbivores many plants store high concentrations of toxic and deterrent secondary metabolites in glandular trichomes. Plant Pleiotropic Drug Resistance (PDR)-type ABC transporters are known secondary metabolite transporters, and several have been implicated in pathogen or herbivore defense. Here, we report on Petunia hybrida PhPDR2 as a major contributor to trichome-related chemical defense. PhPDR2 was found to localize to the plasma membrane and be predominantly expressed in multicellular glandular trichomes of leaves and stems. Down-regulation of PhPDR2 via RNA interference (pdr2) resulted in a markedly higher susceptibility of the transgenic plants to the generalist foliage feeder Spodoptera littoralis. Untargeted screening of pdr2 trichome metabolite contents showed a significant decrease in petuniasterone and petuniolide content, compounds, which had previously been shown to act as potent toxins against various insects. Our findings suggest that PhPDR2 plays a leading role in controlling petuniasterone levels in leaves and trichomes of petunia, thus contributing to herbivory resistance.
authors.affiliation: Institute of Plant Biology, University of Zurich, Zurich, Switzerland.
authors.forename: Joëlle
authors.initials: J
authors.lastname: Sasse
authors.affiliation: Institute of Plant Biology, University of Zurich, Zurich, Switzerland.
authors.forename: Markus
authors.initials: M
authors.lastname: Schlegel
authors.affiliation: Institute of Plant Biology, University of Zurich, Zurich, Switzerland.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Borghi
authors.affiliation: Department of Biochemical and Chemical Engineering, TU Dortmund, Dortmund, Germany.
authors.forename: Friederike
authors.initials: F
authors.lastname: Ullrich
authors.affiliation: Institute of Plant Biology, University of Zurich, Zurich, Switzerland.
authors.forename: Miyoung
authors.initials: M
authors.lastname: Lee
authors.affiliation: Institute of Plant Biology, University of Zurich, Zurich, Switzerland.
authors.forename: Guo-Wei
authors.initials: GW
authors.lastname: Liu
authors.affiliation: Department of Chemistry, SUNY-ESF, Syracuse, NY, USA.
authors.forename: José-Luis
authors.initials: JL
authors.lastname: Giner
authors.affiliation: Department of Biochemical and Chemical Engineering, TU Dortmund, Dortmund, Germany.
authors.forename: Oliver
authors.initials: O
authors.lastname: Kayser
authors.affiliation: Department of Chemistry, University of Zurich, Zürich, 8008, Switzerland.
authors.forename: Laurent
authors.initials: L
authors.lastname: Bigler
authors.affiliation: Institute of Plant Biology, University of Zurich, Zurich, Switzerland.
authors.forename: Enrico
authors.initials: E
authors.lastname: Martinoia
authors.affiliation: Institute of Plant Biology, University of Zurich, Zurich, Switzerland.|International Rice Research Institute, Metro Manila, Philippines.
authors.forename: Tobias
authors.initials: T
authors.lastname: Kretzschmar
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000378:metabolism*; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D004875:Ergosterol / Q000031:analogs & derivatives / Q000378:metabolism; D060434:Herbivory; D032306:Petunia / Q000378:metabolism / Q000502:physiology*; D018515:Plant Leaves / Q000378:metabolism; D010940:Plant Proteins / Q000378:metabolism*; D030821:Plants, Genetically Modified; D018411:Spodoptera; D013256:Steroids / Q000378:metabolism* / Q000502:physiology; D064201:Trichomes / Q000378:metabolism* / Q000502:physiology
chemical_list: D018528:ATP-Binding Cassette Transporters; D010940:Plant Proteins; D013256:Steroids; C061458:petuniasterone A; D004875:Ergosterol
keywords: ABC transporter; Petunia; glandular trichome; herbivory; metabolomics; secondary metabolism