NaCl-induced expression of glutathione reductase in roots of rice (Oryza sativa L.) seedlings is mediated through hydrogen peroxide but not abscisic acid
Resource
Plant and Soil 320 (1-2): 103-115
Journal
Plant and Soil
Journal Volume
320
Journal Volume
320
Journal Issue
1-2
Journal Issue
1-2
Pages
103-115
Start Page
103
End Page
115
ISSN
0032079X
Date Issued
2009-07
Author(s)
Abstract
Reactive oxygen species (ROS) play an important role in NaCl stress. Plants tolerant to NaCl stress may evolve certain strategies to remove these ROS, thus reducing their toxic effects. Therefore, the expression patterns of the gene family encoding glutathione reductase (GR, EC 1.6.4.2) were analyzed in roots of etiolated rice (Oryza sativa L.) seedlings in response to NaCl stress. Semi-quantitative RT-PCR was applied to quantify the mRNA levels for one cytosolic (OsGR2) and two chloroplastic (OsGR1 and OsGR3) isoforms of glutathione reductase identified in the rice genome. The expression of OsGR2 and OsGR3 but not OsGR1 was increased in rice roots treated with 150 mM NaCl. The Rab16A is an abscisic acid (ABA)-responsive rice gene. Increasing concentrations of ABA, from 1 to 12 μM, progressively increased the expression of OsRab16A in rice roots. In the present study, the ABA level was judged by the expression of OsRab16A in rice roots. Treatment with 150 mM NaCl induced the expression of OsRab16A, and the expression increased with increasing concentrations of ABA, which suggests that ABA may be involved in this response in rice roots. In fact, exogenous application of ABA enhanced the expression of OsGR2 and OsGR3 in rice roots. On inhibiting ABA accumulation with sodium tungstate (Tu), an inhibitor of ABA biosynthesis, the expression of OsGR2 and OsGR3 was still induced by NaCl; therefore, NaCl-triggered expression of OsGR2 and OsGR3 in rice roots is not mediated by accumulation of ABA. However, NaCl treatment could induce H 2O2 production in rice roots, and H2O 2 treatment resulted in enhanced OsGR2 and OsGR3 induction. On inhibiting the NaCl-induced accumulation of H2O2 with diphenylene iodonium, the expression of OsGR2 and OsGR3 was also suppressed. Moreover, the increase in H2O2 level was prior to the induction of OsGR2 and OsGR3 in NaCl-treated rice roots. Thus, H 2O2, but not ABA, is involved in regulation of OsGR2 and OsGR3 expression in NaCl-treated rice roots.
Subjects
Abscisic acid
Glutathione reductase
Hydrogen peroxide
Oryza sativa
Salt stress
Type
journal article
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