The protein kinase MEK1/2 participates in the regulation of ascorbate and glutathione content by jasmonic acid in Agropyron cristatum leaves

This study investigated the role of the protein kinase MEK1/2 in the regulation of ascorbate and glutathione content by jasmonic acid in Agropyron cristatum leaves. The results showed that JA induced increases in the transcript levels and activities of APX, GR, MDHAR, DHAR, GaILDH and gamma-ECS, the contents of AsA, GSH, total ascorbate and total glutathione, and the ratios of AsA/DHA and GSH/GSSG, and reduced the E-GSSG/2GSH. The increases, except for the transcript level and activity of gamma-ECS and the reduction in E-GSSG/2GSH, were all suppressed by pre-treatment with the MEK1/2 inhibitors PD98059 and U0126. The results of western blot analyses showed that JA induced increases in the phosphorylation level of MEK1/2. Our results suggest that JA could induce the activation of MEK1/2 by increasing the phosphorylation level, which, in turn, resulted in the up-regulation of ascorbate and glutathione content in A. cristatum leaves. (C) 2010 Elsevier GmbH. All rights reserved.