Programmed Cell Death in Plants: Orchestrating an Intrinsic Suicide Program Within Walls

Abstract

Plants are remarkable organisms in that they constantly adjust their growth and developmental patterns in response to changes in their environment. Part of this repertoire of dynamic readjustment of its body plan is the induction of programmed cell death in order to remove unwanted or unneeded cells and/or tissues. In addition, the programmed demise of specific cells can also be used to create specialized cell types, such as tracheary elements. In spite of its importance in the life of plants, the mechanistic understanding of how cell death is orchestrated remains poorly defined at the molecular and biochemical levels. In recent years, genetic and molecular studies are beginning to generate a growing list of good candidates for the central core of a possible cell death “engine”. These include the metacaspase protease family and the highly conserved plant orthologues to mammalian Bax Inhibitor-1. However, further characterization of the biochemical functions for these proteins and the resolution of the pathways that they work in would be necessary to achieve a comprehensive understanding of how cellular suicide is carried out in plants. In addition, critical definition of different plant cell death morphotypes via biochemical, molecular and genetic approaches will be important to delineate the complex interplay between different suicide pathways that appear to coexist and thus complicate their analysis.

Keywords:

• programmed cell death
• disease resistance
• metacaspase
• Bax Inhibitor-1
• differentiation
• mitochondria
• plastids
• vacuoles
• autophagy
• chromatin
• ER stress

ACKNOWLEDGMENT

The work on plant PCD in my lab is supported by NSF (award # 0744709) and the Biotechnology Center for Agriculture and the Environment of Rutgers University.

Referee: Dr. Kimberly Gwinn, 2431 Joe Johnson Drive, Room 205, Department of Entomology and Plant Pathology The University of Tennessee Knoxville, TN 37996-4560