Coordinate induction of antioxidant defense and glyoxalase system by exogenous proline and glycinebetaine is correlated with salt tolerance in mung bean

Abstract

The purpose of this study was to assess the synergistic effects of exogenously applied proline and glycinebetaine (betaine) in antioxidant defense and methylglyoxal (MG) detoxification system in mung bean seedlings subjected to salt stress (200 mmol$L -1 NaCl, 48 h). Seven-day-old mung bean seedlings were exposed to salt stress after pre-treatment with proline or betaine. Salt stress caused a sharp increase in reduced glutathione (GSH) and oxidized glutathione (GSSG) content in leaves, while the GSH/GSSG ratio and ascorbate (AsA) content decreased significantly. The glutathione reductase (GR), glutathione peroxidase (GPX), glutathione S-transferase (GST) and glyoxalase II (Gly II) activities were increased in response to salt stress, while the monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), catalase (CAT) and glyoxalase I (Gly I) activities sharply decreased with an associated increase in hydrogen peroxide (H 2 O 2 ) and lipid peroxidation level (MDA). Proline or betaine pre-treatment had little influence on nonenzymatic and enzymatic components as compared to those of the untreated control. However, proline or betaine pre-treated salt-stressed seedlings showed an increase in AsA, GSH content, GSH/GSSG ratio and maintained higher activities of APX, DHAR, GR, GST, GPX, CAT, Gly I and Gly II involved in ROS and MG detoxification system as compared to those of the untreated control and mostly also salt-stressed plants with a simultaneous decrease in GSSG content, H 2 O 2 and MDA level. These results together with our previous results suggest that coordinate induction of antioxidant defense and glyoxalase system by proline and betaine rendered the plants tolerant to salinity-induced oxidative stress in a synergistic fashion.

Effect of Salicylic Acid on the Growth, Photosynthetic Efficiency and Enzyme Activities of Leguminous Plant under Cadmium Stress

“…Moreover, proline plays vital role in wide range of protective responses including osmotic adjustment, stabilizer for cellular structure and reducing damage to photosynthetic apparatus (Nounjan et al, 2012). Hossain et al (2011) demonstrated that exogenous proline provided a protective action against abiotic stress-induced oxidative damage by reducing H2O2 and lipid peroxidation level and by enhancing antioxidant defense and methylglyoxal detoxification systems. In addition to this, exogenous proline also prevents protein aggregation and stabilization of M4 lactate dehydrogenase during extreme temperatures, protection of nitrate reductase during heavy metal and osmotic stress (Szabados and Savouré, 2010).…”

Influence of Strigolactone (GR24) as a Seed Treatment on Growth, Gas Exchange and Chlorophyll Fluorescence of Wheat under Saline Conditions

“…Excess Na + in root cells competes with K + for uptake causing ionic imbalance (Bavei et al, 2011). Uptake of K + is reduced due to having similar physiochemical properties of Na + under high salinity (Hossain et al, 2011). Salt stress induces disturbance in various metabolic processes such as photosynthesis, stomatal regulation and protein synthesis (Nusrat et al, 2014).…”

NaCl protects against Cd and Cu-induced toxicity in the halophyte Atriplex halimus

“…GSH, a non-enzymatic antioxidant, is a low-molecular-weight thiol involved in various metabolic processes that acts as an important plant defense molecule against environmental stresses, including trace elements (Hossain et al, 2011). It is one of the major antioxidant and redox buffers in plants, abundantly found in all cell compartments.…”