title: Targeted alterations in iron homeostasis underlie plant defense responses.
abstract: Iron (Fe) is a ubiquitous redox-active element essential for most life. The formation of localized cell wall appositions, the oxidative burst and the production of pathogenesis-related proteins are hallmarks of plant defense responses. Here, we report that iron is a central mediator linking these three phenomena. We show that in response to pathogen attack, reactive Fe3+, but not Fe2+, is deposited at cell wall appositions where it accumulates and mediates the oxidative burst. We provide evidence that the bulk secretion of Fe3+ provoked by pathogen attack leads to intracellular iron depletion, and that H2O2 itself induces ATP-dependent intracellular iron efflux. Finally, we demonstrate that this intracellular iron depletion promotes the transcription of pathogenesis-related genes in concert with H2O2. This work identifies iron as an underlying factor associated with the oxidative burst and regulating cereal defenses, and establishes links between disease-related iron homeostasis in plants and animals.
authors.affiliation: Department of Biology, University of Saskatchewan, 112 Science Place, Saskatoon, SK S7N 5E2, Canada.
authors.forename: Guosheng
authors.initials: G
authors.lastname: Liu
authors.forename: David L
authors.initials: DL
authors.lastname: Greenshields
authors.forename: Ramaswami
authors.initials: R
authors.lastname: Sammynaiken
authors.forename: Rozina N
authors.initials: RN
authors.lastname: Hirji
authors.forename: Gopalan
authors.initials: G
authors.lastname: Selvaraj
authors.forename: Yangdou
authors.initials: Y
authors.lastname: Wei
mesh_terms: D001203:Ascomycota / Q000472:pathogenicity; D015870:Gene Expression; D006706:Homeostasis; D006861:Hydrogen Peroxide / Q000378:metabolism; D007501:Iron / Q000378:metabolism*; D019190:Iron Overload / Q000378:metabolism; D008954:Models, Biological; D008969:Molecular Sequence Data; D018515:Plant Leaves / Q000382:microbiology; D018521:Plant Physiological Phenomena; D017382:Reactive Oxygen Species / Q000378:metabolism; D014908:Triticum / Q000382:microbiology
chemical_list: D017382:Reactive Oxygen Species; D006861:Hydrogen Peroxide; D007501:Iron