Figure 8.

Increased peroxidase activity and hydrogen peroxide accumulation in rwa2. (A) DAB staining for hydrogen peroxide in untreated (left) and in response to treatment with potato dextrose broth (PDB) (right). Five micro liters of 2% (v/v) PDB was placed on each side of the mid vain for 48 h followed by DAB staining. Chlorophylls were extracted in 96% (v/v) ethanol. (B) Peroxidase activities accumulate at trichome bases in uninfected rwa2 leaves. Leaves were stained with DAB in the presence of 0.1% (v/v) H₂O₂ for 1 h. Chlorophylls were extracted in 96% (v/v) ethanol. (C) Extracellular peroxidase activity in the wild type and rwa2-3 leaves. Detached leaves were treated with mock (PDB) or B. cinerea for 24 and 48 h. To measure peroxidase activity, the leaves were floated with the adaxial side downwards in TMB and H₂O₂. Peroxidase activity was measured as absorbance at 654 nm. The data is average of three samples ± SD. The asterisks indicate significant difference between wild type and rwa2-3 as determined by Two-Way ANOVA test (^*P < 0.05; ^**P < 0.01).