Abstract
When plants recognize invasion by pathogen, various responses such as hypersensitive cell death (HR), accumulation of antimicrobial substances, expression of defense-related genes, and transmission of infection information are activated. However, the temporal and spatial patterns of these responses around infection site are largely unclear. To study this point, we constructed a model system using tobacco BY-2 cultured cells and cryptogein, a proteinaceous elicitor derived from Phytophthora cryptogea. We found that rapid and efficient cell death was induced when BY-2 cells at stationary-phase were adjusted to 105 cells/ml with conditioned medium and treated with cryptogein. Using this system, we found that the fragmentation of cell-nuclear chromatin occurred during cryptogein-induced cell death in BY-2 cells. We also examined the events induced during nicotinamide-induced cell death in BY-2 cells. The results suggest that the processes by which HR-like cell death proceeds are different depending on the stimuli that trigger the cell death.
