Review on nitric oxide at the forefront of rapid systemic signaling in mitigation of salinity stress in plants: Crosstalk with calcium and hydrogen peroxide

Abstract

Soil salinity is a global issue that limits plant growth in agricultural fields and contributes to food crisis. Salt stressors impede plant's ionic, osmotic, and oxidative balance, as well as a variety of physiological functions. Exposure to salinity stress manifest considerable ROS clustering, entailing modification in performance of various organelles. To deal with salinity, plants use a variety of coping strategies, such as osmoregulation, ion-homeostasis, increased antioxidant synthesis, and so on. Nitric oxide (NO) is a pivotal signalling molecule that helps facilitate salt stress-induced physiological plant responses. A variety of evidences point to NO being produced under similar stress conditions and with similar kinetics as hydrogen peroxide (H₂O₂). The interplay between H₂O₂ and NO has important functional implications for modulating plant transduction processes. Besides, NO and calcium (Ca²⁺)-dependent pathways also have some connection in salt stress response mechanisms. Extensive crosstalk between NO and Ca²⁺ signalling pathways is investigated, and it suggests that almost every type of Ca²⁺ channel is under the tight control of NO, and NO acts as a Ca²⁺ mobilising compound and aids in signal reliance. The review provides insights into understanding recent advances regarding NO's, Ca²⁺ and H₂O₂ role in salt stress reduction with entwine signaling mechanisms.

Keywords: Adventitious rooting; Apoptosis; Calmodulin; Floral development; MAPKs; Nitration; Nitric oxide donors; Osmoregulation; S-nitrosylation; SOS pathway; Seed germination index; Sodium nitroprusside.