title: Cytosolic and Chloroplastic DHARs Cooperate in Oxidative Stress-Driven Activation of the Salicylic Acid Pathway.
abstract: The complexity of plant antioxidative systems gives rise to many unresolved questions. One relates to the functional importance of dehydroascorbate reductases (DHARs) in interactions between ascorbate and glutathione. To investigate this issue, we produced a complete set of loss-of-function mutants for the three annotated Arabidopsis (Arabidopsis thaliana) DHARs. The combined loss ofDHAR1andDHAR3expression decreased extractable activity to very low levels but had little effect on phenotype or ascorbate and glutathione pools in standard conditions. An analysis of the subcellular localization of the DHARs in Arabidopsis lines stably transformed with GFP fusion proteins revealed that DHAR1 and DHAR2 are cytosolic while DHAR3 is chloroplastic, with no evidence for peroxisomal or mitochondrial localizations. When the mutations were introduced into an oxidative stress genetic background (cat2), thedhar1 dhar2combination decreased glutathione oxidation and inhibitedcat2-triggered induction of the salicylic acid pathway. These effects were reversed incat2 dhar1 dhar2 dhar3complemented with any of the three DHARs. The data suggest that (1) DHAR can be decreased to negligible levels without marked effects on ascorbate pools, (2) the cytosolic isoforms are particularly important in coupling intracellular hydrogen peroxide metabolism to glutathione oxidation, and (3) DHAR-dependent glutathione oxidation influences redox-driven salicylic acid accumulation.
authors.affiliation: Institute of Plant Sciences Paris-Saclay, Unité Mixte de Recherche 9213/Unité Mixte de Recherche 1403, Université Paris-Sud, Centre National de la Recherche Scientifique, Institut National de la Recherche Agronomique, Université d'Evry, Université Paris-Diderot, Sorbonne Paris-Cité, 91405 Orsay, France (M.-S.R., S.L., G.C.-I., E.I.-B., A.M., G.N.); and.|Unité Mixte de Recherche ECOSYS/Pôle BIOCLIMATOLOGIE, Institut National de la Recherche Agronomique-AgroParisTech, F-78850 Thiverval-Grignon, France (A.T.).
authors.forename: Marie-Sylviane
authors.identifier: http://orcid.org/0000-0002-1758-866X
authors.initials: MS
authors.lastname: Rahantaniaina
authors.affiliation: Institute of Plant Sciences Paris-Saclay, Unité Mixte de Recherche 9213/Unité Mixte de Recherche 1403, Université Paris-Sud, Centre National de la Recherche Scientifique, Institut National de la Recherche Agronomique, Université d'Evry, Université Paris-Diderot, Sorbonne Paris-Cité, 91405 Orsay, France (M.-S.R., S.L., G.C.-I., E.I.-B., A.M., G.N.); and.|Unité Mixte de Recherche ECOSYS/Pôle BIOCLIMATOLOGIE, Institut National de la Recherche Agronomique-AgroParisTech, F-78850 Thiverval-Grignon, France (A.T.).
authors.forename: Shengchun
authors.initials: S
authors.lastname: Li
authors.affiliation: Institute of Plant Sciences Paris-Saclay, Unité Mixte de Recherche 9213/Unité Mixte de Recherche 1403, Université Paris-Sud, Centre National de la Recherche Scientifique, Institut National de la Recherche Agronomique, Université d'Evry, Université Paris-Diderot, Sorbonne Paris-Cité, 91405 Orsay, France (M.-S.R., S.L., G.C.-I., E.I.-B., A.M., G.N.); and.|Unité Mixte de Recherche ECOSYS/Pôle BIOCLIMATOLOGIE, Institut National de la Recherche Agronomique-AgroParisTech, F-78850 Thiverval-Grignon, France (A.T.).
authors.forename: Gilles
authors.initials: G
authors.lastname: Chatel-Innocenti
authors.affiliation: Institute of Plant Sciences Paris-Saclay, Unité Mixte de Recherche 9213/Unité Mixte de Recherche 1403, Université Paris-Sud, Centre National de la Recherche Scientifique, Institut National de la Recherche Agronomique, Université d'Evry, Université Paris-Diderot, Sorbonne Paris-Cité, 91405 Orsay, France (M.-S.R., S.L., G.C.-I., E.I.-B., A.M., G.N.); and.|Unité Mixte de Recherche ECOSYS/Pôle BIOCLIMATOLOGIE, Institut National de la Recherche Agronomique-AgroParisTech, F-78850 Thiverval-Grignon, France (A.T.).
authors.forename: Andrée
authors.identifier: http://orcid.org/0000-0003-3617-4195
authors.initials: A
authors.lastname: Tuzet
authors.affiliation: Institute of Plant Sciences Paris-Saclay, Unité Mixte de Recherche 9213/Unité Mixte de Recherche 1403, Université Paris-Sud, Centre National de la Recherche Scientifique, Institut National de la Recherche Agronomique, Université d'Evry, Université Paris-Diderot, Sorbonne Paris-Cité, 91405 Orsay, France (M.-S.R., S.L., G.C.-I., E.I.-B., A.M., G.N.); and.|Unité Mixte de Recherche ECOSYS/Pôle BIOCLIMATOLOGIE, Institut National de la Recherche Agronomique-AgroParisTech, F-78850 Thiverval-Grignon, France (A.T.).
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Issakidis-Bourguet
authors.affiliation: Institute of Plant Sciences Paris-Saclay, Unité Mixte de Recherche 9213/Unité Mixte de Recherche 1403, Université Paris-Sud, Centre National de la Recherche Scientifique, Institut National de la Recherche Agronomique, Université d'Evry, Université Paris-Diderot, Sorbonne Paris-Cité, 91405 Orsay, France (M.-S.R., S.L., G.C.-I., E.I.-B., A.M., G.N.); and.|Unité Mixte de Recherche ECOSYS/Pôle BIOCLIMATOLOGIE, Institut National de la Recherche Agronomique-AgroParisTech, F-78850 Thiverval-Grignon, France (A.T.).
authors.forename: Amna
authors.identifier: http://orcid.org/0000-0001-9959-1362
authors.initials: A
authors.lastname: Mhamdi
authors.affiliation: Institute of Plant Sciences Paris-Saclay, Unité Mixte de Recherche 9213/Unité Mixte de Recherche 1403, Université Paris-Sud, Centre National de la Recherche Scientifique, Institut National de la Recherche Agronomique, Université d'Evry, Université Paris-Diderot, Sorbonne Paris-Cité, 91405 Orsay, France (M.-S.R., S.L., G.C.-I., E.I.-B., A.M., G.N.); and graham.noctor@u-psud.fr.|Unité Mixte de Recherche ECOSYS/Pôle BIOCLIMATOLOGIE, Institut National de la Recherche Agronomique-AgroParisTech, F-78850 Thiverval-Grignon, France (A.T.) graham.noctor@u-psud.fr.
authors.forename: Graham
authors.identifier: http://orcid.org/0000-0003-1980-4554
authors.initials: G
authors.lastname: Noctor
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D017360:Arabidopsis / Q000201:enzymology* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000378:metabolism*; D001205:Ascorbic Acid / Q000378:metabolism; D016923:Cell Death; D002736:Chloroplasts / Q000201:enzymology*; D003600:Cytosol / Q000201:enzymology*; D004269:DNA, Bacterial / Q000235:genetics; D005816:Genetic Complementation Test; D005978:Glutathione / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000378:metabolism; D016254:Mutagenesis, Insertional / Q000235:genetics; D009154:Mutation / Q000235:genetics; D018384:Oxidative Stress; D010088:Oxidoreductases / Q000378:metabolism*; D010641:Phenotype; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D020156:Salicylic Acid / Q000378:metabolism*; D013347:Subcellular Fractions / Q000378:metabolism
chemical_list: D000975:Antioxidants; D029681:Arabidopsis Proteins; D004269:DNA, Bacterial; D011993:Recombinant Fusion Proteins; C036483:T-DNA; D049452:Green Fluorescent Proteins; D010088:Oxidoreductases; C020666:glutathione dehydrogenase (ascorbate); D005978:Glutathione; D020156:Salicylic Acid; D001205:Ascorbic Acid