Nitric oxide mediated mechanisms adopted by plants to cope with salinity

Abstract

Worldwide, a relevant surface of arable lands is facing salt stress, and this surface is increasing continuously due to both natural and anthropogenic activities. Nitric oxide (NO) is a small, gaseous molecule with a plethora of physiological roles in plants. In addition to its normal physiological functions, NO protects plants subjected to different environmental cues including salinity. For example, NO mediates photosynthesis and stomatal conductance, stimulates the activity of Na + /H + antiport in tonoplast, promotes the biosynthesis of osmolytes, and counteracts overaccumulation of reactive oxygen species in plant cells under salt stress. Exogenous NO is also beneficial for plants subjected to salinity, in which it increases salinity tolerance via growth promotion, reversing oxidative damage, and maintaining ion homeostasis. This review provides a comprehensive picture of the NO-mediated mechanisms in plants, resulting in salinity tolerance with a particular focus on the photosynthetic processes, the antioxidant patterns as well as the cross-talk with other regulatory compounds in plant cells.

Coordinated Role of Nitric Oxide, Ethylene, Nitrogen, and Sulfur in Plant Salt Stress Tolerance

“…In plants, enzymatic endogenous NO-generation has been assumed to mainly involve NR [104,105]. Restricted to the cytosol NR has been suggested to catalyze the reduction of NO 3 to NO 2 using NADPH as the main electron donor [103].…”

“…Restricted to the cytosol NR has been suggested to catalyze the reduction of NO 3 to NO 2 using NADPH as the main electron donor [103]. Nevertheless, revealed through in vitro and in vivo experiments, low oxygen concentration and cellular pH were argued as two of the most important requirements for the activity of NR [104]. In Arabidopsis, the NR enzyme encoded redundantly by NIA1 and NIA2 genes is capable of reducing nitrite to NO [106].…”

Magnetopriming Actuates Nitric Oxide Synthesis to Regulate Phytohormones for Improving Germination of Soybean Seeds under Salt Stress

“…Nitric oxide (NO) and reactive oxygen species (ROS) are the apparent signalling molecules that play a crucial role in regulating seed dormancy and germination [ 9 , 12 , 13 , 14 , 15 ]. Apart from various reports on ROS, evidence on NO-based regulation of seed germination, photosynthesis, flowering, senescence, stomatal movement, stress tolerance, ROS scavenging and defence mechanisms in different crop species is also accumulating [ 16 , 19 , 20 , 21 , 22 , 23 , 24 , 25 ]. However, it still remains an intriguing subject for the scientific community, as both NO and ROS serve as secondary messengers to regulate several biological processes.…”

The SlWRKY81 transcription factor inhibits stomatal closure by attenuating nitric oxide accumulation in the guard cells of tomato under drought

“…Nitric oxide (NO) is an important second messenger that aids stomatal functions in a range of plant species (Shi et al ., 2015). NO mediates numerous plant physiological processes as well as responses to abiotic stresses (Hajihashemi et al ., 2020; Sharma et al ., 2020; Sohag et al ., 2020b). NO also acts as an endogenous modulator of plant hormone abscisic acid (ABA) to inhibit water loss by regulating ABA‐induced stomatal closure (Daszkowska‐Golec and Szarejko, 2013; Shi et al ., 2015).…”

“…Notably, NO produced by NR1 acts as an essential signaling molecule in the ABA‐dependent stomatal closure (Neill et al ., 2008). Thus, manipulation of endogenous NO levels and/or exogenous NO application alters plant responses to drought (Sharma et al ., 2020).…”