Nitric oxide donor SNP regulates the ascorbate and glutathione metabolism in Agropyron cristatum leaves through MEK1/2

Abstract

This study investigated the role of the protein kinase MEK1/2 in the regulation of ascorbate and glutathione metabolism by nitric oxide in Agropyron cristatum leaves. The results showed that NO donor, sodium nitroprusside (SNP), induced the increased activities of ascorbate peroxidase, glutathione reductase, monodehydroascorbate reductase, dehydroascorbate reductase, L-galactono-1,4-lactone dehydrogenase, and γ-glutamylcysteine synthetase (γ-ECS), the transcription of respective genes, and the content of reduced ascorbate, reduced glutathione, total ascorbate, and total glutathione. All the above increases, except the activity of γ-ECS, were suppressed by pre-treatment with MEK1/2 inhibitors 2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one and 1,4-diamino-2,3-dicyano-1,4-bis(o-aminophenylmercapto) butadiene. The results of Western blot showed that SNP induced the increase in the phosphorylation of MEK1/2. Our results suggested that SNP induced the phosphorylation of MEK1/2, which, in turn, up-regulated the ascorbate and glutathione metabolism in A. cristatum leaves.

Keywords

• ascorbate peroxidase
• dehydroascorbate reductase
• glutathione reductase
• monodehydroascorbate reductase
• protein kinase