Programmed Cell Death in Plants.

Abstract

There is increasing evidence for occurrence of programmed cell death (PCD) in plant development, plant-microbe interaction and cells under a variety of stresses. Recent studies on PCD in plants indicate that various features of apoptosis in mammals are shared with plant PCD: there is evidence for DNA fragmentation, oligonucleosomal DNA laddering, morphological changes in plant cells. These studies suggest that PCD plays an important role in the life of plants as in animals. Despite the wide occurrence of PCD in plants, signaling and components of the machinery for PCD are largely unknown. We recently identified the Rac family of the small GTP-binding protein as a key regulator of PCD in plants. Also, the analysis of lesion mimic mutants of rice indicates that some mutants have biochemical alterations in early steps of signaling in disease resistance. The major challenge in the study of plant PCD in the near future is the identification of signaling molecules and components of machinery involved in plant PCD. This will enable us to better understand this important cellular process of plants.