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Biosci Biotechnol Biochem. 2016 May;80(5):870-7. doi: 10.1080/09168451.2015.1135042. Epub 2016 Mar 1.

Redox regulation of ascorbate and glutathione by a chloroplastic dehydroascorbate reductase is required for high-light stress tolerance in Arabidopsis.

Author information

1
a Faculty of Agriculture, Department of Advanced Bioscience , Kinki University , Nara , Japan.
2
b Faculty of Life and Environmental Science, Department of Life Science and Biotechnology , Shimane University , Matsue , Japan.

Abstract

Chloroplasts are a significant site for reactive oxygen species production under illumination and, thus, possess a well-organized antioxidant system involving ascorbate. Ascorbate recycling occurs in different manners in this system, including a dehydroascorbate reductase (DHAR) reaction. We herein investigated the physiological significance of DHAR3 in photo-oxidative stress tolerance in Arabidopsis. GFP-fused DHAR3 protein was targeted to chloroplasts in Arabidopsis leaves. A DHAR3 knockout mutant exhibited sensitivity to high light (HL). Under HL, the ascorbate redox states were similar in mutant and wild-type plants, while total ascorbate content was significantly lower in the mutant, suggesting that DHAR3 contributes, at least to some extent, to ascorbate recycling. Activation of monodehydroascorbate reductase occurred in dhar3 mutant, which might compensate for the lack of DHAR3. Interestingly, glutathione oxidation was consistently inhibited in dhar3 mutant. These findings indicate that DHAR3 regulates both ascorbate and glutathione redox states to acclimate to HL.

KEYWORDS:

Arabidopsis thaliana; ascorbate; dehydroascorbate reductase; photo-oxidative stress; redox regulation

PMID:
26927949
DOI:
10.1080/09168451.2015.1135042
[Indexed for MEDLINE]

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