Reactive Nitrogen Species and Nitrosative Stress in Plants

Nitric oxide (NO) is a gaseous free radical which can have two opposite physiological roles in higher plants. While a high cellular production of NO can bring about extensive cellular damage, at low levels this compound is involved as a signal molecule in many important physiological processes. NO and a family of related molecules, including peroxynitrite (ONOO), S-nitrosoglutathione (GSNO) and nitrotyrosine (nTyr), among others, are designated with the term reactive nitrogen species (RNS). Under stress conditions, plants can undergo a de-regulated synthesis or overproduction of NO and NO-derived products that can have toxic physiological consequences. This situation is known as nitrosative stress, due to its similarities with animal systems, and can produce important changes in plant cells. In this article the current knowledge of these effects of RNS on the physiology of plants under stress conditions is briefly reviewed. _____________________________________________________________________________________________________________ † This article is dedicated to Mrs. María Luisa Aguirre-Romero and Mr. José Corpas-Martínez with love.