Behind the scene: Critical role of reactive oxygen species and reactive nitrogen species in salt stress tolerance

Abstract

Salinity is one of the most important abiotic factors which affects plant growth and development and reduces crop productivity. Plants have stress tolerance ability to respond to a particular type of stress. For salt stress alleviation, plants retain specific mechanisms, such as activation of signalling cascades, ion channels, receptors, hormonal stimulation, ion exchange, osmolytes and antioxidant enzymes which are involved either directly or indirectly in plant protection. In plants, reactive oxygen species (ROS) and reactive nitrogen species (RNS) are produced in different cell compartments and involved in the "oxidative signalling" mechanism. Based on the recent studies in signalling and mechanisms for salt tolerance in plant, we explored the role of the salt overly sensitive system (SOS) related to antiporters of plasma and mitogenactivated protein kinase (MAPK) cascades. Considering the importance of ROS and RNS, the present review has focused on different aspects and mechanisms that play key role in plants cell signalling network in response to salinity stress. In addition, this review highlights the differential expression of ROS, RNS and various antioxidative enzymes in C3, C4 and CAM plants. Moreover, the strategies for alleviation of salt stress such as magnetopriming, nanopriming, biopriming and arbuscular mycorrhizal fungi (AMF) in plants to achieve improved salt tolerance in crops under field conditions and their effects through ROS and RNS is also discussed. We conclude the review with a discussion of unseen issues and suggestions for future researches.

Physiological integration between Bermudagrass ramets improves overall salt resistance under heterogeneous salt stress

“…Here, we detected a higher upregulation of SOS1 , SOS2 , and SOS3 in salt‐stressed ramets with intact stolons than in ramets with severed stolon. Longitudinal long‐distance signal transduction, such as Ca 2+ and ROS, has been involved in salt response and activation of the SOS pathway (Sun et al, 2010; Tomar et al, 2021). It has been proved that Ca 2+ , as a second messenger, participated in rhizome‐mediated physiological integration of Phyllostachys sedulis under heterogeneous water deficiency (Jing et al, 2020).…”

Plant Salinity Sensors: Current Understanding and Future Directions

“…The ions sensed under salt stress are Na + and Cl – . Theoretically, there are intra- and extracellular receptors for Na + and Cl – that regulate ion homeostasis ( Tomar et al, 2021 ). GIPC sphingolipid was the first Na + receptor identified, and it is required for the pulse of cytosolic Ca 2+ induced specifically by NaCl rather than by osmotic stress ( Jiang et al, 2019 ).…”

“…Na + -selective ion channels have not been found in plants ( Hedrich, 2012 ), but there are proteins with Na + binding sites that may act as Na + receptors. The well-known SOS1 protein is a transmembrane transporter with a long amino acid tail, which is likely involved in sensing Na + ( Zhu, 2003 ; Tomar et al, 2021 ). Although the role of the glutamate receptor-like transporter in salt stress perception is not clear, it is known to regulate a variety of physiological functions in abiotic stress ( Cheng et al, 2018 ; Toyota et al, 2018 ), and it also has a cytoplasmic tail in its structure ( Alfieri et al, 2020 ).…”

Arbuscular Mycorrhizal Fungi Induce Tolerance to Salinity Stress in Taro Plantlets (Colocasia esculenta L. Schott) during Acclimatization

“…The symbiosis between AMF and plants under salinity stress could have also induced the synthesis of other compatible osmolytes such as polyamines, sugars, and polyols. These have an important role in osmotic adjustment and protect cells from ROS [54].…”

“…Therefore, the increase in soluble phenol content could be a biochemical indicator of salinity stress tolerance. In addition, under salinity stress, plants synthesize antioxidant enzymes and non-enzymatic antioxidants as tolerance mechanisms [54]. Phenolic compounds are non-enzymatic antioxidants that scavenge free radicals [62].…”