Figure 1.

HR cell death defect in dnd1 mutant. Leaves of wild-type parent (Col) and dnd1 mutant (dnd1) plants were inoculated with a high dose (2 × 10⁸ cfu/ml) of avirulent, HR-stimulating P. syringae pv. glycinea Race 4 pV288 (Psg avrRpt2⁺) or the isogenic, nonavirulent control strain P. syringae pv. glycinea Race 4 pVSP61 (Psg). At 24 h postinoculation, leaves were harvested, fixed, and examined for autofluorescent dead cells by using a fluorescence microscope. (Upper Right) The edge of an inoculated zone, revealing confluent cell death in response to bacteria only on the left (inoculated) side.