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

Abstract

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 (0.5mM) markedly increased the contents of ASA and GSH in SA-treated plants during salt stress (250mM 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 12h, glutathione reductase (GR) at 24h, 48h and 72h, glutathione-S-transferase 1 (GST1), 2 (GST2), monodehydroascorbate reductase (MDHAR) and glutathione synthetase (GS) at the 48h and 72h 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.

Keywords: ASA; Ascorbate; CAT; DHAR; GPX; GR; GS; GSH; GST; Glutathione; MDA; MDHAR; POD; ROS; SA; SOD; Salicylic acid; Salt stress; Wheat; ascorbate; catalase; dehydroascorbate reductase; glutathione; glutathione peroxidase; glutathione reductase; glutathione synthetase; glutathione-S-transferase; malondialdehyde; monodehydroascorbate reductase; peroxidase; qPCR; quantitative real-time PCR; reactive oxygen species; salicylic acid; superoxide dismutases.