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First published online 23 January 2007
doi: 10.1242/jcs.001362

This Article Figures Only Full Text Full Text (PDF) Supplementary Material All Versions of this Article: jcs.001362v1 120/4/596    most recent Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Liu, G. Articles by Wei, Y. Search for Related Content PubMed PubMed Citation Articles by Liu, G. Articles by Wei, Y.

Targeted alterations in iron homeostasis underlie plant defense responses

Guosheng Liu^1,*, David L. Greenshields^1,*, Ramaswami Sammynaiken², Rozina N. Hirji³, Gopalan Selvaraj³ and Yangdou Wei^1,

¹ Department of Biology, University of Saskatchewan, 112 Science Place, Saskatoon, SK S7N 5E2, Canada
² Saskatchewan Structural Sciences Center, University of Saskatchewan, 110 Science Place, Saskatoon, SK S7N 5C9, Canada
³ Plant Biotechnology Institute, National Research Council of Canada, 110 Gymnasium Place, Saskatoon, SK S7N 0W9, Canada

Author for correspondence (e-mail: yangdou.wei{at}usask.ca)

Accepted 26 November 2006

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.

Key words: Iron homeostasis, Reactive oxygen species, Plant defense, Cell wall apposition, Wheat powdery mildew, Prussian Blue staining

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