title: Systemic and intracellular responses to photooxidative stress in Arabidopsis.
abstract: As the sun tracks daily through the sky from east to west, different parts of the canopy are exposed to high light (HL). The extent of and mechanisms by which a systemic acquired acclimation (SAA) response might preacclimate shaded leaves that will be subsequently exposed to full sunlight is largely undefined. We investigated the role of an Arabidopsis thaliana zinc finger transcription factor, ZAT10, in SAA. ZAT10 overexpression resulted in enhanced tolerance to photoinhibitory light and exogenous H2O2, increased expression of antioxidative genes whose products are targeted to multiple subcellular compartments. Partial HL exposure of a leaf or leaves rapidly induced ZAT10 mRNA in distal, shaded photosynthetic tissues, including the floral stem, cauline leaves, and rosette, but not in roots. Fully 86% of fivefold HL-upregulated and 71% of HL-downregulated genes were induced and repressed, respectively, in distal, shaded leaves. Between 15 and 23% of genes whose expression changed in the HL and/or distal tissues were coexpressed in the ZAT10 overexpression plants, implicating ZAT10 in modulating the expression of SAA-regulated genes. The SAA response was detectable in plants with mutations in abscisic acid, methyl jasmonate, or salicylic acid synthesis or perception, and systemic H2O2 diffusion was not detected. Hence, SAA is distinct from pathogen-stimulated systemic acquired resistance and apparently involves a novel signal or combination of signals that preacclimate photosynthetic tissues to HL.
authors.affiliation: Australian Research Council Centre of Excellence in Plant Energy Biology, School of Biochemistry and Molecular Biology, Australian National University, Canberra, ACT 0200, Australia.
authors.forename: Jan Bart
authors.initials: JB
authors.lastname: Rossel
authors.forename: Pip B
authors.initials: PB
authors.lastname: Wilson
authors.forename: Dawar
authors.initials: D
authors.lastname: Hussain
authors.forename: Nick S
authors.initials: NS
authors.lastname: Woo
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Gordon
authors.forename: Osman P
authors.initials: OP
authors.lastname: Mewett
authors.forename: Katharine A
authors.initials: KA
authors.lastname: Howell
authors.forename: Jim
authors.initials: J
authors.lastname: Whelan
authors.forename: Kemal
authors.initials: K
authors.lastname: Kazan
authors.forename: Barry J
authors.initials: BJ
authors.lastname: Pogson
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism / Q000494:pharmacology; D000085:Acetates / Q000378:metabolism / Q000494:pharmacology; D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D003517:Cyclopentanes / Q000378:metabolism / Q000494:pharmacology; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000528:radiation effects*; D006861:Hydrogen Peroxide / Q000378:metabolism / Q000494:pharmacology; D008027:Light; D020411:Oligonucleotide Array Sequence Analysis; D018384:Oxidative Stress / Q000187:drug effects / Q000528:radiation effects; D054883:Oxylipins / Q000378:metabolism / Q000494:pharmacology; D010788:Photosynthesis / Q000187:drug effects / Q000528:radiation effects; D018515:Plant Leaves / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D030821:Plants, Genetically Modified; D017382:Reactive Oxygen Species / Q000378:metabolism; D020156:Salicylic Acid / Q000378:metabolism / Q000494:pharmacology
chemical_list: D000040:Abscisic Acid; D000085:Acetates; D029681:Arabidopsis Proteins; D003517:Cyclopentanes; D006861:Hydrogen Peroxide; D054883:Oxylipins; D017382:Reactive Oxygen Species; D020156:Salicylic Acid; C516241:STZ protein, Arabidopsis; C072239:methyl jasmonate