Functional Role of Nitric Oxide Under Abiotic Stress Conditions

Abstract

Nitric oxide (NO), a free radical in living organisms, is considered a phytohormone and a key signalling molecule functioning in various physiological processes of plants. These physiological processes include germination, growth, senescence, and photosynthesis as well as response mechanisms to specific environmental stresses. Plants under abiotic stress conditions experience oxidative and nitrosative stress; the latter mainly elicited by regulation of NO production. Nitrosative stress describes the molecular or cellular damage promoted by imbalance in NO homeostasis and other reactive nitrogen species. Additionally, depending on its concentration and location in plant cells or tissues, NO might function as an antioxidant and scavenge some other reactive intermediates. Direct or indirect involvement of NO in response mechanisms under water stress, drought, salinity, heavy metal stress, high or low temperature extremities, and ultraviolet radiation has been reported. In this work, the recent findings and current knowledge on the function of NO in plants under abiotic stress conditions are reviewed briefly.

Insights into Nitric Oxide-Mediated Water Balance, Antioxidant Defence and Mineral Homeostasis in Rice (<em>Oryza sativa L.</em>) under Chilling Stress

“…Exogenous application of some signaling molecules have enormous potentiality to reduce the deleterious effects of abiotic stresses such as chilling stresses from both theoretical and practical perspectives [52,53]. Nitric oxide (NO), a signaling molecule and secondary messenger, has been shown that to counteract with excessive ROS-induced toxicity and positively regulate many physiological processes under different stress conditions [18,54,55]. Therefore, NO could potentially be used to reduce the adverse effects of chilling stress.…”

“…In this context, chemical priming has been considered as an alternative strategy for improving abiotic stress resistance of plants [15].Augmenting the defensive responses of plants can minimize the chilling-induced damage, which can be attained by applying exogenous signalling molecules [16]. Nitric oxide (NO), an enormously diffusible and a versatile bioactive inter-and intra-cellular signalling compound, found to be involved in seed germination, water balance, mineral adjustment, gene regulation, and upregulation of antioxidant enzyme activities in plants [17,18,19]. NO networks with other hormones (abscisic acid, auxins, brassinosteroids, cytokinins, ethylene, gibberellins, jasmonates, and salicylic acid, etc.)…”

Insights Into the Nitric Oxide Mediated Stress Tolerance in Plants

“…Although initial discoveries in plants recognized NO as an atmospheric toxic pollutant for plant foliage, it was eventually considered as a modulator of plant defense during pathogen attacks. The increasing number of reports demonstrated the role of NO in a plethora of plant development processes including seed germination (Arc et al, 2013), root formation, different stages of the seed development, gravitropism, stomatal movements, photosynthesis, mitochondrial functionality, senescence, plant maturation (Sun et al, 2017;Patel et al, 2017;Hasanuzzaman et al, 2018;Locato et al, 2016;Mostofa et al, 2015;Asgher et al, 2017), multiple abiotic (Fancy et al, 2017;Santisree et al, 2015;Parankusam et al, 2017;Adimulam et al, 2017;Tossi et al, 2012;Sehrawat et al, 2013;Ziogas et al, 2013) and biotic stress responses in plants (Vaishnav et al, 2018). In addition, a number of studies focused on describing the crucial role of NO in moderating various plant hormone-mediated development and stress responses (Asgher et al, 2017).…”

“…These studies concluded AtNOS1 as a regulator of NO levels rather than the molecule of synthesis. Eventually it was renamed as Arabidopsis thaliana nitric oxide associated (atnos1) mutant (Parankusam et al, 2017). Even though a few other recent pharmacological studies in various plant species also suggested the existence of NOS-like enzyme in plants, the attempts of purifying the gene or protein are still underway (Negi et al, 2010;Fröhlich and Durner, 2011).…”

Dealing with abiotic stresses: an integrative view of how phytohormones control abiotic stress-induced oxidative stress

“…Abscisic acid (ABA) acts on several non-stressful and stressful situations during plant life, and drought stress is the most known adverse situation that is able to induce ABA production, consequently triggering its responses (Huang et al 2012). It is already known that the main effect of ABA during drought stress is the induction of stomatal closure (Daszkowska-Golec and Szarejko 2013), and some researchers have demonstrated that it is signaled by ROS under ABA induction (Huang et al 2008;Xu 2010) as well as by Reactive Nitrogen Species (RNS) (Oz et al 2015).…”