科研之友
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摘要
SPINDLY (SPY) gene encodes a putative O-linked N-acetyl-glucosamine transferase, and yeast two-hybrid assay identified GIGANTEA (GI) as a SPY-interacting partner in Arabidopsis. GIGANTEA gene was previously shown to be involved in the regulation of oxidative stress response; however, it is unclear whether SPY gene is also involved in oxidative stress response. Here we showed that SPY plays a role in the regulation of the oxidative stress response. The spy-1 mutant was more tolerant to paraquat (PQ)- or hydrogen peroxide (H2O2)-mediated oxidative stress than wild-type plants. Analyses of endogenous H2O2 and superoxide anion radicals as well as lipid peroxidation revealed that enhanced tolerance of the spy-1 mutant to PQ-stress was not due to defects in the PQ uptake or the PQ sequestration from its site of action but rather the spy-1 mutation alleviated oxidative damage of plant cells upon PQ stress. Higher constitutive activities of superoxide dismutase (SOD) and ascorbate peroxidase (APX) in spy-1 are more likely to be due to activation of both CSD2 gene encoding chloroplast Cu/Zn SOD and APX1 gene. Taken together, these results suggest that enhanced tolerance of the spy-1 mutant to oxidative stress is associated, at least in part, with constitutive activation of CSD2 and APX1.
