Nitric oxide strengthens defense system in plants

The world is facing huge misfortune in the production of crops due to a stressful environment that is also not sufficient to fulfill the needs of the growing population. To overcome such problems, plants employ the use of a gaseous, bioactive molecule named nitric oxide (NO). NO is considered a small, reactive, lipid-soluble, and highly diffusive secondary messenger that is involved in various intracellular and physiological processes and brings about overall growth in plants. NO has the ability to freely roam inside the cell and interact with various biological entities and signaling molecules because of its high reactivity and short lifecycle. The two key methods for protection in plants shown by NO are either it can act as antioxidants or it signals different biomolecules that regulate several cascades of events to strengthen the defense system in combating various stresses. NO-related events help one to understand how plants adapt, function, and respond to stressful conditions. This chapter emphasizes the current knowledge about NO being a crucial multifunctional molecule that has a tendency to alter several metabolic and molecular processes in plants. The goal is to provide a comprehensive overview of its potential to work under abiotic stresses in plants that would help confer strategies in the development of climate-resilient crops of better quality and yield.