Arabidopsis GLUTATHIONE REDUCTASE1 Plays a Crucial Role in Leaf Responses to Intracellular Hydrogen Peroxide and in Ensuring Appropriate Gene Expression through Both Salicylic Acid and Jasmonic Acid Signaling Pathways
Glutathione is a major cellular thiol that is maintained in the reduced state by glutathione reductase (GR), which is encoded by two genes in Arabidopsis (Arabidopsis thaliana; GR1 and GR2). This study addressed the role of GR1 in hydrogen peroxide (H₂O₂) responses through a combined genetic, transc...
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Published in | Plant physiology (Bethesda) Vol. 153; no. 3; pp. 1144 - 1160 |
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Main Authors | , , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
Rockville, MD
American Society of Plant Biologists
01.07.2010
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Subjects | |
Online Access | Get full text |
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Summary: | Glutathione is a major cellular thiol that is maintained in the reduced state by glutathione reductase (GR), which is encoded by two genes in Arabidopsis (Arabidopsis thaliana; GR1 and GR2). This study addressed the role of GR1 in hydrogen peroxide (H₂O₂) responses through a combined genetic, transcriptomic, and redox profiling approach. To identify the potential role of changes in glutathione status in H₂O₂ signaling, gr1 mutants, which show a constitutive increase in oxidized glutathione (GSSG), were compared with a catalase-deficient background (cat2), in which GSSG accumulation is conditionally driven by H₂O₂. Parallel transcriptomics analysis of gr1 and cat2 identified overlapping gene expression profiles that in both lines were dependent on growth daylength. Overlapping genes included phytohormone-associated genes, in particular implicating glutathione oxidation state in the regulation of jasmonic acid signaling. Direct analysis of H₂O₂-glutathione interactions in cat2 gr1 double mutants established that GR1-dependent glutathione status is required for multiple responses to increased H₂O₂ availability, including limitation of lesion formation, accumulation of salicylic acid, induction of pathogenesis-related genes, and signaling through jasmonic acid pathways. Modulation of these responses in cat2 gr1 was linked to dramatic GSSG accumulation and modified expression of specific glutaredoxins and glutathione S-transferases, but there is little or no evidence of generalized oxidative stress or changes in thioredoxin-associated gene expression. We conclude that GR1 plays a crucial role in daylength-dependent redox signaling and that this function cannot be replaced by the second Arabidopsis GR gene or by thiol systems such as the thioredoxin system. |
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ISSN: | 0032-0889 1532-2548 1532-2548 |
DOI: | 10.1104/pp.110.153767 |