Reactive Nitrogen Species in Plant Metabolism

Reactive nitrogen species are a set of highly reactive molecules that derive from nitric oxide and oxidative metabolism, such as nitrogen dioxide, peroxynitrite, nitroxyl anion, nitrate, among others. The role of reactive nitrogen species in plants has become an area of much scientific interest in recent years. In particular, nitric oxide and peroxynitrite are the main reactive nitrogen species best known for their important interactions with different cellular metabolic processes related to seed germination, plant growth and development, root development, stomatal movements, interaction with phytohormones, reproduction, pollen tube development and fruit ripening. It is also relevant to highlight the important role of nitric oxide as a signalling molecule involved in alleviating toxic effects caused by various biotic and abiotic stresses via intense cellular metabolic reprogramming. Thus, nitric oxide is able to modulate oxidative, antioxidant and phytohormonal metabolisms, among others, as well as ion homeostasis, metal transport and transcriptional factors. With such a background, this chapter summarises recent advances in the metabolic pathways in generating reactive nitrogen species, their bioactivity to react with different cellular molecules, like proteins, nucleic acids and fatty acids, and finally, their role in plant metabolism under physiological and stress conditions.