Salt and genotype impact on antioxidative enzymes and lipid peroxidation in two rice cultivars during de-etiolation

Abstract

Crop yield is severely affected by soil salinity, as salt levels that are harmful to plant growth occur in large terrestrial areas of the world. The present investigation describes the studies of enzymatic activities, in-gel assays, gene expression of some of the major antioxidative enzymes, tocopherol accumulation, lipid peroxidation, ascorbate and dehydroascorbate contents in a salt-sensitive rice genotype PB1, and a relatively salt-tolerant cultivar CSR10 in response to 200 mM NaCl. Salt solution was added to the roots of hydroponically grown 5-day-old etiolated rice seedlings, 12 h prior to transfer to cool white fluorescent + incandescent light (100 μmol photons m(-2) s(-1)). Total tocopherol and ascorbate contents declined in salt-stressed rice seedlings. Among antioxidative enzymes, an increase in the activities of superoxide dismutase (EC 1.15.1.1), catalase (EC 1.11.1.6), ascorbate peroxidase (EC 1.11.1.11), glutathione reductase (EC 1.6.4.2), and their gene expression was observed in both cultivars in response to salt stress. The salt-tolerant cultivar CSR10 resisted stress due to its early preparedness to combat oxidative stress via upregulation of gene expression and enzymatic activities of antioxidative enzymes and a higher redox status of the antioxidant ascorbate even in a non-stressed environment.

Propyl gallate promotes salt stress tolerance in green microalga Dunaliella salina by reducing free radical oxidants and enhancing β-carotene production

“…5d). Salt tolerance in Dunaliella and higher plants can be associated with maintenance of elevated levels of reduced ascorbate (Jahnke and White 2003;Moradi and Ismail 2007;Turan and Tripathy 2013). It can explain the high potential of Dunaliella for scavenging ROS to tolerate salinity as well as PG effects on promoting salt stress tolerance, even in control conditions.…”

Exogenous salicylic acid improves photosynthesis and growth through increase in ascorbate-glutathione metabolism and S assimilation in mustard under salt stress

“…3 Salt stress induces oxidative stress through the over production of reactive oxygen species (ROS) that trigger lipid peroxidation, damage to photosynthetic pigments and disturbance in mineral nutrient status. 4,5 The inhibitory effect of salt stress on photosynthetic rate may involve stomatal or non-stomatal limitations and inhibition of photochemical processes 6 by disturbing the water balance in plants, homeostasis of Na C and Cl ¡ ions and nutrient uptake. 7 In order to cope with the excess ROS and maintain redox homeostasis, plants have evolved several adaptive mechanisms including highly efficient antioxidant enzymes, such as superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione reductase (GR) and dehydroascorbate reductase (DHAR) and also nonenzymatic antioxidants, such as ascorbate (AsA) and glutathione (GSH).…”

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“…The improved salt tolerance were highly correlated with increased activation of antioxidant enzymes in Arabidopsis, rice [30], wheat, tomato [24], soybean, maize [31], which is in accordance with our observations. Even many previous reports on genotype dependent accumulation of H2O2 content and differential response of antioxidative enzymes in salinity have been done in rice cultivars [32,33]. We have extended their work in a tissue specific manner to further elucidate the contribution of root or shoot towards enhancement of plant defense system in salinity.…”