Reactive Oxygen and Nitrogen Species in Stress-Induced Programmed Death of Plant Cultured Cells

Programmed cell death (PCD) is a genetically controlled process present in all living organisms aimed to eliminate unwanted or detrimental cells. PCD is a fundamental part of the plant lifestyle and it is present in various developmental (senescence, sex determination, formation of tracheary elements) and pathological contexts (response to stresses and to pathogen attack). In contrast to the well‐described forms of PCD present in animals (for example apoptosis), characteristics of plant PCD are still poorly understood and the term PCD is widely used to describe most instances of cell death observed in plants. In fact, correct dissection of the mechanism of PCD in whole plants can often be difficult as this process generally occurs in a small group of cells surrounded by a large number of uninvolved cells. In this perspective, cell cultures appear an attractive model to several scientists as they present several advantages respect to entire tissues or organs. From these studies, a relevant role for reactive oxygen species (ROS) and reactive nitrogen species (RNS) in the transduction of the death signal and in the activation of the death machinery has rapidly emerged. In this chapter, we reviewed papers dealing with the role of ROS and NOS in the induction of PCD process of plant cultured cells.