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.