Arabidopsis Glutathione Peroxidase Functions as Both a Redox Transducer and a Scavenger in Abscisic Acid and Drought Stress Responses

We isolated two T-DNA insertion mutants of Arabidopsis thaliana GLUTATHIONE PEROXIDASE3 (ATGPX3) that exhibited a higher rate of water loss under drought stress, higher sensitivity to H₂O₂ treatment during seed germination and seedling development, and enhanced production of H₂O₂ in guard cells. By...

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Bibliographic Details
Published in:The Plant cell 2006-10, Vol.18 (10), p.2749-2766
Main Authors: Miao, Yuchen, Lv, Dong, Wang, Pengcheng, Wang, Xue-Chen, Chen, Jia, Miao, Chen, Song, Chun-Peng
Format: Article
Language:English
Subjects:
Abscisic Acid - metabolism
Arabidopsis - enzymology
Arabidopsis - genetics
Arabidopsis - metabolism
Arabidopsis thaliana
Base Sequence
Calcium Channels - metabolism
Cell Membrane - metabolism
Disasters
DNA Primers
DNA, Bacterial - genetics
Drought
Gene expression regulation
Genes
Glutathione Peroxidase - genetics
Glutathione Peroxidase - metabolism
Guard cells
Hydrogen Peroxide - metabolism
Leaves
Mutagenesis, Insertional
Oxidation-Reduction
Oxidative stress
Phosphatases
Plant cells
Plants, Genetically Modified
RNA
Signal Transduction
Thioredoxin
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Summary:We isolated two T-DNA insertion mutants of Arabidopsis thaliana GLUTATHIONE PEROXIDASE3 (ATGPX3) that exhibited a higher rate of water loss under drought stress, higher sensitivity to H₂O₂ treatment during seed germination and seedling development, and enhanced production of H₂O₂ in guard cells. By contrast, lines engineered to overexpress ATGPX3 were less sensitive to drought stress than the wild type and displayed less transpirational water loss, which resulted in higher leaf surface temperature. The atgpx3 mutation also disrupted abscisic acid (ABA) activation of calcium channels and the expression of ABA- and stress-responsive genes. ATGPX3 physically interacted with the 2C-type protein phosphatase ABA INSENSITIVE2 (ABI2) and, to a lesser extent, with ABI1. In addition, the redox states of both ATGPX3 and ABI2 were found to be regulated by H₂O₂. The phosphatase activity of ABI2, measured in vitro, was reduced approximately fivefold by the addition of oxidized ATGPX3. The reduced form of ABI2 was converted to the oxidized form by the addition of oxidized ATGPX3 in vitro, which might mediate ABA and oxidative signaling. These results suggest that ATGPX3 might play dual and distinctive roles in H₂O₂ homeostasis, acting as a general scavenger and specifically relaying the H₂O₂ signal as an oxidative signal transducer in ABA and drought stress signaling.
ISSN:1040-4651
1532-298X
1532-298X
DOI:10.1105/tpc.106.044230