ABSTRACT
Reactive nitrogen species (RNS) molecules are formed incessantly in plant cells as by-products of metabolism and are ubiquitous. RNS production is also the first response of plants under stress. They are both free radicals and non-radicals. Nitric oxide (NO) radical and molecules derived from it are collectively referred to as RNS. Plants interact closely with their surrounding environment; therefore, RNS intensely affect their biochemistry. RNS functions rely on their actual level (the “nitrosative door” concept) and exposure period of the plant. In plants, RNS play a dual role acting as both beneficial and deleterious. RNS (nitric oxide, nitrogen dioxide, nitrous acid, peroxynitrite, and dinitrogen tetroxide) are regulatory molecules of different physiological processes concerning plant growth and development. RNS have gained significant attention in recent decades as they are found to be involved in the nitration of nucleic and fatty acids, post-translational protein modifications, and reactive oxygen species metabolism modulation. On the contrary, RNS also cause oxidative damage and tissue dysfunction when produced in a certain amount, leading to plant death.
