Nitric Oxide Alleviates Salt Stress Inhibited Photosynthetic Performance by Interacting with Sulfur Assimilation in Mustard

Abstract

The role of nitric oxide (NO) and sulfur (S) on stomatal responses and photosynthetic performance was studied in mustard (Brassica juncea L.) in presence or absence of salt stress. The combined application of 100 μM NO (as sodium nitroprusside) and 200 mg S kg−1 soil (S) more prominently influenced stomatal behavior, photosynthetic and growth performance both in the absence and presence of salt stress. The chloroplasts from salt-stressed plants had disorganized chloroplast thylakoids, but combined application of NO and S resulted in well-developed chloroplast thylakoids and properly stacked grana. The leaves from plants receiving NO plus S exhibited lower superoxide ion accumulation under salt stress than the plants receiving NO or S. These plants also exhibited increased activity of ATP-sulfurylase (ATPS), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR) and optimized NO generation that helped in minimizing oxidative stress. The enhanced S-assimilation of these plants receiving NO plus S resulted in increased production of cysteine (Cys) and reduced glutathione (GSH). These findings indicated that NO influenced photosynthesis under salt stress by regulating oxidative stress and its effects on S-assimilation, an antioxidant system and NO generation. The results suggest that NO improves photosynthetic performance of plants grown under salt stress more effectively when plants received S.

Cross Talk between Nitric Oxide and Phytohormones Regulate Plant Development during Abiotic Stresses

“…Evidence suggests that NO promotes S-assimilation, which is linked to ET production through Cys synthesis [86]. Hence, it may be speculated that NO and S interact to modulate ABA and ET levels in guard cells that may inluence the stomatal and photosynthetic response under salt stress conditions.…”

“…However, recent studies indicate ET as a stress-signaling hormone that interacts with signaling cascades of other phytohormones to enhance tolerance against various biotic/abiotic stresses [70,86]. Studies involving tobacco seedlings showed that transcriptional activation of ethylene response factor (ERF) in ethylene-signaling process improved salt stress tolerance by decreasing ROS accumulation [89].…”

“…Phytohormones play a key role in enhancing the tolerance and adaptability of plants against salinity stress. Some recent studies suggest that NO acts in concert with signaling pathways of phytohormones to induce tolerance against salt stress [85,86]. Presumably, plant hormones such as ABA, ET, and AUX are transported from salt-treated roots to leaves to trigger NO synthesis or transport throughout the plant [87].…”

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

“…The NO and sulfur nutrition were found to prevent chloroplasts damage in salt-exposed mustard (B. juncea) plants (Fatma et al 2016). The SNP stimulated the expression of AOX, a component of plant mitochondrial electron transport, in barrelclover (M. truncatula) under high salinity thus, alleviating oxidative stress and photosynthetic damages (Jian et al 2016).…”

“…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).…”