title: Wounding of Arabidopsis halleri leaves enhances cadmium accumulation that acts as a defense against herbivory.
abstract: Approximately 0.2% of all angiosperms are classified as metal hyperaccumulators based on their extraordinarily high leaf metal contents, for example >1% zinc, >0.1% nickel or >0.01% cadmium (Cd) in dry biomass. So far, metal hyperaccumulation has been considered to be a taxon-wide, constitutively expressed trait, the extent of which depends solely on available metal concentrations in the soil. Here we show that in the facultative metallophyte Arabidopsis halleri, both insect herbivory and mechanical wounding of leaves trigger an increase specifically in leaf Cd accumulation. Moreover, the Cd concentrations accumulated in leaves can serve as an elemental defense against herbivory by larvae of the Brassicaceae specialist small white (Pieris rapae), thus allowing the plant to take advantage of this non-essential trace element and toxin. Metal homeostasis genes are overrepresented in the systemic transcriptional response of roots to the wounding of leaves in A. halleri, supporting that leaf Cd accumulation is preceded by systemic signaling events. A similar, but quantitatively less pronounced transcriptional response was observed in A. thaliana, suggesting that the systemically regulated modulation of metal homeostasis in response to leaf wounding also occurs in non-hyperaccumulator plants. This is the first report of an environmental stimulus influencing metal hyperaccumulation.
authors.affiliation: Institute of Plant Biology, University of Zurich, 8008, Zurich, Switzerland.
authors.forename: Sonia
authors.initials: S
authors.lastname: Plaza
authors.forename: Johann
authors.initials: J
authors.lastname: Weber
authors.forename: Simone
authors.initials: S
authors.lastname: Pajonk
authors.forename: Jérôme
authors.initials: J
authors.lastname: Thomas
authors.forename: Ina N
authors.initials: IN
authors.lastname: Talke
authors.forename: Maja
authors.initials: M
authors.lastname: Schellenberg
authors.forename: Sylvain
authors.initials: S
authors.lastname: Pradervand
authors.forename: Bo
authors.initials: B
authors.lastname: Burla
authors.forename: Markus
authors.initials: M
authors.lastname: Geisler
authors.forename: Enrico
authors.initials: E
authors.lastname: Martinoia
authors.forename: Ute
authors.initials: U
authors.lastname: Krämer
mesh_terms: D000818:Animals; D017360:Arabidopsis / Q000378:metabolism* / Q000469:parasitology*; D002080:Butterflies / Q000472:pathogenicity; D002104:Cadmium / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D060434:Herbivory; D007814:Larva / Q000472:pathogenicity; D018515:Plant Leaves / Q000378:metabolism* / Q000469:parasitology*
chemical_list: D002104:Cadmium