Sodium nitroprusside modulates gene expression involved in glutathione synthesis in Zea mays leaves

Abstract

To investigate a possible involvement of nitric oxide in gene regulation of glutathione and flavonoid synthesis pathways, maize seedlings were treated with sodium nitroprusside (SNP), a NO donor, and apocynin (APO), an inducer of NO production. After 12-h treatment, the transcripts of γ-glutamylcysteine synthetase (γ-ecs) , glutathione synthetase (gsh-s), chalcone synthase (chs), phenylalanine ammonia lyase (pal.1), myb-related protein P (P1) and actin 1 (act) genes were quantified in maize leaves by real time PCR, using α-tubulin as standard transcript. The level of γ-ecs and gsh-s transcripts in maize leaves were increased 9-fold and 12-fold, respectively, following SNP treatment, while after APO treatment, those transcripts were not significantly different from control plants. SNP-treated maize leaves did not show significant changes in pal.1 and chs expression. NO content in maize leaves was increased in SNP and APO treated plants in comparison to control plants. In conclusion, our experiments suggested that genes involved in glutathione synthesis could be modulated by SNP in maize leaves. On the other hand, APO had no effect on γ-ecs and gshs gene expression.

ROS-Mediated Inhibition of S-nitrosoglutathione Reductase Contributes to the Activation of Anti-oxidative Mechanisms

“…Both, loss of GSNOR function and fumigation with NO enhanced GSH level ( Figures 3A,C ) assuming that NO/SNO is able to stimulate the GSH biosynthesis pathway. These measurements coincide with previous reports demonstrating a higher amount of GSH in roots of Medicago truncatula (Innocenti et al, 2007) and maize leaves (Mello et al, 2012) after GSNO and SNP treatment, respectively. In both cases, an enhanced expression of the γ-glutamylcysteine synthetase and GSH synthetase gene was detectable suggesting a NO-dependent transcriptional regulation of GSH production.…”

Nitric oxide enhances selenium concentration by promoting selenite uptake by rice roots

“…Although the mechanism of SeO 3 2− assimilation in roots remains unclear, some studies have demonstrated that GSH can greatly facilitate SeO 3 2− uptake by non‐enzymatically reduction of SeO 3 2− to SeCys in plant roots ( Xu et al, ; Mello et al, ). Hence, we focused on the effect of NO on GSH biosynthesis.…”

“…Molecular analysis suggests that NO is a potential regulator of gene expression (Besson-Bard et al, 2009). Numerous putative NO-responsive genes related to stress, plant defense and hormonal responses have been identified (Polverari et al, 2003;Parani et al, 2004;Moreau et al, 2010;Mello et al, 2012). In addition, Innocenti et al (2007) reported that the NO donor sodium nitroprusside (SNP) mediated GSH synthesis by up-regulating the gene expression of two enzymes of GSH synthesis, including γ-glutamylcysteine synthetase (γ-ECS) and glutathione synthetase (GS) in Medicago truncatula roots.…”