Proteomic Analysis of the Protective Effect of Sodium Nitroprusside on Leaves of Barley Stressed by Salinity

Abstract

Objective: The salinization of agricultural soils poses a serious challenge across the world. Although recent studies have shown that exogenous sodium nitroprusside (SNP) application can alleviate the harmful effects of salinity, the roles of SNP in the regulation of proteomic changes remain poorly understood. Materials and Methods: To unravel the protective roles of exogenous SNP in alleviating salt-induced damage in barley (Hordeum vulgare L.), proteomic analysis was carried out on the leaves of seedlings exposed to 100 mM NaCl stress following 200 µM SNP pre-treatment. Results: Our results indicated that SNP pre-treatment restored the seedling growth reduced by salinity stress. Comparing 2-DE gels from the treatments showed that 24 proteins were differentially accumulated under SNP and/or NaCl stress treatments. Among them, 15 proteins were identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Gene ontology analysis demonstrated that several pathways were regulated by SNP and/or NaCl treatments, including photosynthesis, protein metabolism, stress defense, and energy metabolism. Exogenous SNP increased the expression levels of 20 kDa chaperonin, proteasome subunit beta type-2, 2-Cys peroxiredoxin BAS1, ferredoxin-NADP reductase, thiazole biosynthetic enzyme 1-1, S-adenosylmethionine synthetase 3, and elongation factor Tu proteins in the leaves of barley seedlings under NaCl stress. Conclusion: Our results indicate that SNP pre-treatment may induce salinity tolerance through regulation of photosynthesis, activation of stress defence, degradation of damaged proteins, and the promoting of the synthesis of polyamines, proline, and GABA.