Figure 6.

Enhancement or suppression of HR cell death by alterations in ROI metabolism. (A) Enhanced HR cell death in tobacco plants infected with bacteria at high oxygen pressure. Leaves of wild-type Bel-W3 plants were infiltrated with bacteria and treated with high oxygen pressure. Twelve hours after inoculation, leaves were sampled and analyzed for cell death. (B) Suppression of pathogen-induced PCD by pretreatment of leaves with high oxygen pressure. Leaves of wild-type Bel-W3 plants were treated with high oxygen pressure for 5 h. After treatment, leaves were taken out of the chambers, incubated for 30 min at ambient conditions, and challenged with different concentrations of bacteria. Twelve hours after inoculation, leaves were sampled and analyzed for cell death. (C) RNA gel blot showing that treatment of leaves with high oxygen pressure for 5 h results in the induction of cAPX mRNA. An OD₆₀₀ of 1.0 is the equivalent of 500,000 cfu/ml.