Abstract

As much as the definition of life may be controversial, the definition of death also may prove problematic. In recent years ii became apparent that the death of a living eel may follow more than one possible scenario: it may result from an externally applied physical injury (an accidental death), or it may be the outcome of activating on internal pathway for cell suicide (a programmed death). That cells can participate in their own execution may indicate that certain types of cell deaths that were previously considered io be caused by foreign agents such as pathogens or drugs may actually result from the activation of a programmed cell death pathway that is normally latent in cells. Here, we describe the activation of such a cell suicide pathway in plant cells upon the recognition of on invading gen. We discuss the possible use of this pathway as a defense mechanism against infection and the possibility thai in many ways the use of this type of eel death in plants is functionally analogous io that used by mammalian cells in response to infection by pathogens. (C) 1997 Wiley-Liss, Inc.