THE HYPERSENSITIVE RESPONSE AND THE INDUCTION OF CELL-DEATH IN PLANTS

The hypersensitive response, or HR, is a form of cell death often asso ciated with plant resistance to pathogen infection. Reactive oxygen in termediates and ion fluxes are proximal responses probably required fo r the HR. Apoptosis as defined in animal systems is, thus far, not a s trict paradigm for the HR. The diversity observed in plant cell death morphologies suggests that there may be multiple pathways through whic h the HR can be triggered. Signals from pathogens appear to interfere with these pathways. HR may play in plants the same role as certain pr ogrammed cell deaths in animals with respect to restricting pathogen g rowth. In addition, the HR could regulate the defense responses of the plant in both local and distant tissues.