Salicylic acid increases the contents of glutathione and ascorbate and temporally regulates the related gene expression in salt-stressed wheat seedlings

Exogenous salicylic acid (SA) significantly improved abiotic tolerance in higher plants, and ascorbate (ASA) and glutathione (GSH) play important roles in abiotic tolerance. In this study, SA (0.5 mM) markedly increased the contents of ASA and GSH in SA-treated plants during salt stress (250 mM NaCl). The transcript levels of the genes encoding ASA and GSH cycle enzymes were measured using quantitative real-time PCR. The results indicated that, during salt stress, exogenous SA significantly enhanced the transcripts of glutathione peroxidase (GPX1), phospholipid hydroperoxide glutathione peroxidase (GPX2) and dehydroascorbate reductase (DHAR) genes at 12 h, glutathione reductase (GR) at 24 h, 48 h and 72 h, glutathione-S-transferase 1 (GST1), 2 (GST2), monodehydroascorbate reductase (MDHAR) and glutathione synthetase (GS) at the 48 h and 72 h after salt stress, respectively. The results implied that SA temporally regulated the transcript levels of the genes encoding ASA-GSH cycle enzymes, resulting in the increased contents of GSH and ASA and enhanced salt tolerance. (C) 2013 Elsevier B.V. All rights reserved.