Die and let live - programmed cell death in plants

Cysteine and serine proteases are prominent players in the control of devel opmental and pathogen-activated cell deaths in plants. Ethylene, salicylic acid, the small G-protein Rac, calcium and reactive oxygen species are recu rring mediators of death signaling. Lastly, the mitochondrion has emerged i n both plant and animal systems as a 'central depot' that interprets multip le signals and in some instances determines the fate of the cell.