Nitric Oxide Mitigates Salt Stress by Regulating Levels of Osmolytes and Antioxidant Enzymes in Chickpea

Abstract

This work was designed to evaluate whether external application of nitric oxide (NO) in the form of its donor S-nitroso-N-acetylpenicillamine (SNAP) could mitigate the deleterious effects of NaCl stress on chickpea (Cicer arietinum L.) plants. SNAP (50 μM) was applied to chickpea plants grown under non-saline and saline conditions (50 and 100 mM NaCl). Salt stress inhibited growth and biomass yield, leaf relative water content (LRWC) and chlorophyll content of chickpea plants. High salinity increased electrolyte leakage, carotenoid content and the levels of osmolytes (proline, glycine betaine, soluble proteins and soluble sugars), hydrogen peroxide (H2O2) and malondialdehyde (MDA), as well as the activities of antioxidant enzymes, such as superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and glutathione reductase in chickpea plants. Expression of the representative SOD, CAT and APX genes examined was also up-regulated in chickpea plants by salt stress. On the other hand, exogenous application of NO to salinized plants enhanced the growth parameters, LRWC, photosynthetic pigment production and levels of osmolytes, as well as the activities of examined antioxidant enzymes which is correlated with up-regulation of the examined SOD, CAT and APX genes, in comparison with plants treated with NaCl only. Furthermore, electrolyte leakage, H2O2 and MDA contents showed decline in salt-stressed plants supplemented with NO as compared with those in NaCl-treated plants alone. Thus, the exogenous application of NO protected chickpea plants against salt stress-induced oxidative damage by enhancing the biosyntheses of antioxidant enzymes, thereby improving plant growth under saline stress. Taken together, our results demonstrate that NO has capability to mitigate the adverse effects of high salinity on chickpea plants by improving LRWC, photosynthetic pigment biosyntheses, osmolyte accumulation and antioxidative defense system.

Zinc application mitigates the adverse effects of NaCl stress on mustard [Brassica juncea (L.) Czern & Coss] through modulating compatible organic solutes, antioxidant enzymes, and flavonoid content

“…Salt stress enhances ROS generation, thereby increasing antioxidant enzyme activity (Tavallali et al 2009;Ahmad et al 2016b;Weisany et al 2014). In the present study, salt stress up-regulated the activities of SOD, APX, GR, and GST.…”

“…However, poor irrigation practices are further aggravating the problem (Gupta and Huang 2014). Salinity stress hampers plant growth via diminishing cell division and expansion, reducing photosynthetic efficiency, modifying metabolic processes, as well as causing ion toxicity, osmotic stress, oxidative stress, genotoxicity, and other physiological disorders (Ibrahim et al 2012;Wani et al 2013;Yan et al 2013;Ahmad et al 2016b;Anjum et al 2015;Hussein et al 2017). Cumulatively, these adverse effects perturb growth and alter normal metabolism in plants (Wani et al 2013;Rasool et al 2013;Ahmad et al 2014;Iqbal et al 2015;Tang et al 2015;Hussein et al 2017).…”

Hydrogen sulfide: a new endogenous player in an old mechanism of plant tolerance to high salinity

“…Similar results were observed in salt-stressed cotton seedlings wherein application of 100 µM SNP to leaves improved plants photosynthetic performance . The treatment of chickpea (Cicer arietinum) plants with 100 mM NaCl and 50 µM of S-nitroso-N-acetylpenicillamine (SNAP; an NO donor) provided higher amounts of chlorophylls a and b and carotenoids in plant leaves in comparison with those solely treated with NaCl (Ahmad et al 2016). Aspersion of salt-stressed cotton plants with SNP delayed leaf senescence …”

“…Avicennia marina (Chen et al 2010) Cucumis sativus (Shi et al 2007) Cynodon dactylon (Liu et al 2016) Gossypium hirsutum (Liu et al 2013;Kong et al 2016) Kandelia obovata (Lang et al 2014) Aegiceras corniculatum (Lang et al 2014) Limonium bicolor (Ding et al 2013) Populus euphratica Triticum aestivum (Tian et al 2015) Induction of osmoregulators accumulation Brassica juncea (Zeng et al 2011;Khan et al 2012) Cicer arietinum (Ahmad et al 2016) Cucumis sativus (Fan et al 2013) Gossypium hirsutum (Liu et al 2013) Lycopersicom esculentum ) Solanum lycopersicum (Hayat et al 2012) Triticum aestivum (Tian et al 2015) Induction of polyamines accumulation Cucumis sativus (Fan et al 2013) Protection of photosynthetic apparatus Brassica juncea (Fatma et al 2016) Cicer arietinum (Ahmad et al 2016) Fragaria × ananassa (Christou et al 2014) Gossypium hirsutum (Kong et al 2016) Medicago truncatula (Jian et al 2016) Stimulation of seed germination Arabidopisis thaliana (Zhao et al 2007) Triticum aestivum (Zheng et al 2008) Zea mays (Bai et al 2011) Stimulation of plant growth Arabidopisis thaliana ) Glycine max (Egbichi et al 2014;Vaishnav et al 2016) Gossypium hirsutum and increased chlorophylls content and photosynthetic rate (Kong et al 2016). The NO and sulfur nutrition were found to prevent chloroplasts damage in salt-exposed mustard (B. juncea) plants (Fatma et al 2016).…”

“…Since then, NO has been shown to influence plant response to salt stress by improving seed vigor and germination (Hayat et al 2012) and controlling the cellular levels of reactive oxygen species (ROS) (Keyster et al 2012;Ahmad et al 2016), nutrient (Kong et al 2016;Liu et al 2016) and osmoprotectants Tian et al 2015). The NO biosynthesis in plant cells can occur by non-enzymatic and enzymatic means.…”