Exogenous proline and glycine betaine mediated upregulation of antioxidant defense and glyoxalase systems provides better protection against salt-induced oxidative stress in two rice (Oryza sativa L.) varieties.

Mirza Hasanuzzaman,Md Mahabub Alam,Md Hasanuzzaman,Anisur Rahman,Masayuki Fujita,Kamrun Nahar

doi:10.1155/2014/757219

Mirza Hasanuzzaman, Md Mahabub Alam + Show 4 more

Open Access

https://doi.org/10.1155/2014/757219

Copy DOI

Abstract

The present study investigates the roles of exogenous proline (Pro, 5 mM) and glycine betaine (GB, 5 mM) in improving salt stress tolerance in salt sensitive (BRRI dhan49) and salt tolerant (BRRI dhan54) rice (Oryza sativa L.) varieties. Salt stresses (150 and 300 mM NaCl for 48 h) significantly reduced leaf relative water (RWC) and chlorophyll (chl) content and increased endogenous Pro and increased lipid peroxidation and H2O2 levels. Ascorbate (AsA), glutathione (GSH) and GSH/GSSG, ascorbate peroxidae (APX), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), glutathione reductase (GR), glutathione peroxidase (GPX), catalase (CAT), and glyoxalase I (Gly I) activities were reduced in sensitive variety and these were increased in tolerant variety due to salt stress. The glyoxalase II (Gly II), glutathione S-transferase (GST), and superoxide dismutase (SOD) activities were increased in both cultivars by salt stress. Exogenous Pro and GB application with salt stress improved physiological parameters and reduced oxidative damage in both cultivars where BRRI dhan54 showed better tolerance. The result suggests that exogenous application of Pro and GB increased rice seedlings' tolerance to salt-induced oxidative damage by upregulating their antioxidant defense system where these protectants rendered better performance to BRRI dhan54 and Pro can be considered as better protectant than GB.

Highlights

Crop plants, as sessile organisms, face a number of environmental adversities termed as abiotic stress which includes soil salinity, water deficit, extremely high or low temperatures, toxic metals, waterlogging, elevated ozone, and ultraviolet radiation, which all create a barrier for proper growth, metabolism, and productivity of crop plants [1,2,3,4,5,6,7,8,9,10]
Decline in Relative water content (RWC) was lower in salt tolerant cultivar Bangladesh Rice Research Institute (BRRI) dhan54 as compared to salt sensitive BRRI dhan49
We examined the performance of salt tolerance and salt sensitive rice cultivars against different salinity levels and we examined how they are protected from salt stress by exogenous Pro or glycine betaine (GB) application

Summary

Introduction

As sessile organisms, face a number of environmental adversities termed as abiotic stress which includes soil salinity, water deficit, extremely high or low temperatures, toxic metals, waterlogging, elevated ozone, and ultraviolet radiation, which all create a barrier for proper growth, metabolism, and productivity of crop plants [1,2,3,4,5,6,7,8,9,10]. Considering the destructive effects of salt-induced oxidative stress in plants it is crucial to keep the ROS level below the toxic limit. The nonenzymatic antioxidants include ascorbic acid (AsA), glutathione (GSH), phenolic compounds, alkaloids, nonprotein amino acids, and α-tocopherols They act together in scavenging or detoxifying ROS and subsequent protection of plant cells from oxidative damage [2, 4]. This system acts differently in different plant species and cultivars and it was observed that the enhancement of the antioxidant defense system is often correlated with salt stress tolerance [4, 7]. It was reported that the coordinated upregulation of both the antioxidant defense and glyoxalase systems is necessary to attain significant tolerance to oxidative stress [2, 6]

Methods

Results

Discussion

Conclusion