Redox regulation in plant programmed cell death

Programmed cell death (PCD) is a genetically controlledprocess described both in eukaryotic and prokaryoticorganisms. Even if it is clear that PCD occurs in plants, inresponse to various developmental and environmentalstimuli, the signalling pathways involved in the triggering ofthis cell suicide remain to be characterized. In this review,the main similarities and differences in the players involvedin plant and animal PCD are outlined. Particular attentionis paid to the role of reactive oxygen species (ROS) as keyinducers of PCD in plants. The involvement of differentkinds of ROS, different sites of ROS production, as well astheir interaction with other molecules, is crucial in activatingPCD in response to specific stimuli. Moreover, theimportance is stressed on the balance between ROS productionand scavenging, in various cell compartments, forthe activation of specific steps in the signalling pathwaystriggering this cell suicide process. The review focuses onthe complexity of the interplay between ROS and antioxidantmolecules and enzymes in determining the most suitableredox environment required for the occurrence ofdifferent forms of PCD