title: Root jasmonic acid synthesis and perception regulate folivore-induced shoot metabolites and increase Nicotiana attenuata resistance.
abstract: While jasmonic acid (JA) signaling is widely accepted as mediating plant resistance to herbivores, and the importance of the roots in plant defenses is recently being recognized, the role of root JA in the defense of above-ground parts remains unstudied. To restrict JA impairment to the roots, we micrografted wildtype Nicotiana attenuata shoots to the roots of transgenic plants impaired in JA signaling and evaluated ecologically relevant traits in the glasshouse and in nature. Root JA synthesis and perception are involved in regulating nicotine production in roots. Strikingly, systemic root JA regulated local leaf JA and abscisic acid (ABA) concentrations, which were associated with differences in nicotine transport from roots to leaves via the transpiration stream. Root JA signaling also regulated the accumulation of other shoot metabolites; together these account for differences in resistance against a generalist, Spodoptera littoralis, and a specialist herbivore, Manduca sexta. In N. attenuata's native habitat, silencing root JA synthesis increased the shoot damage inflicted by Empoasca leafhoppers, which are able to select natural jasmonate mutants. Silencing JA perception in roots also increased damage by Tupiocoris notatus. We conclude that attack from above-ground herbivores recruits root JA signaling to launch the full complement of plant defense responses.
authors.affiliation: Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, 07745, Jena, Germany.
authors.forename: Variluska
authors.initials: V
authors.lastname: Fragoso
authors.affiliation: Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, 07745, Jena, Germany.
authors.forename: Eva
authors.initials: E
authors.lastname: Rothe
authors.affiliation: Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, 07745, Jena, Germany.
authors.forename: Ian T
authors.initials: IT
authors.lastname: Baldwin
authors.affiliation: Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, 07745, Jena, Germany.
authors.forename: Sang-Gyu
authors.initials: SG
authors.lastname: Kim
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism*; D000818:Animals; D001692:Biological Transport; D003517:Cyclopentanes / Q000378:metabolism*; D060434:Herbivory; D018402:Manduca / Q000502:physiology; D009154:Mutation; D009538:Nicotine / Q000378:metabolism; D054883:Oxylipins / Q000378:metabolism*; D010937:Plant Growth Regulators / Q000378:metabolism*; D018515:Plant Leaves / Q000276:immunology / Q000469:parasitology / Q000502:physiology; D018517:Plant Roots / Q000276:immunology / Q000469:parasitology / Q000502:physiology; D018520:Plant Shoots; D030821:Plants, Genetically Modified; D015398:Signal Transduction; D018411:Spodoptera / Q000502:physiology; D014026:Nicotiana / Q000235:genetics / Q000276:immunology / Q000469:parasitology / Q000502:physiology*
chemical_list: D003517:Cyclopentanes; D054883:Oxylipins; D010937:Plant Growth Regulators; D009538:Nicotine; C011006:jasmonic acid; D000040:Abscisic Acid
keywords: above-ground herbivores; jasmonates; leaf wounding; nicotine; plant defense; plant tolerance; roots