Figure 3.

Peroxidase- and NADPH oxidase-dependent oxidative burst and HRs in pepper plants. A, DAB and trypan blue staining of the primary and secondary pepper leaves at different times after inoculation of primary leaves with the avirulent strain Bv5-4a (10⁸ cfu mL⁻¹) of Xcv. Secondary leaves were also simultaneously infiltrated with either 1 mm KCN (peroxidase inhibitor) or 2.5 μm DPI (NADPH oxidase complex inhibitor) immediately after Xcv inoculation. Xcv-infected local leaves were harvested for DAB and trypan blue staining 1 and 24 h after inoculation, respectively; however, uninoculated systemic leaves were stained with both agents 24 h after inoculation. Bars = 200 μm. B, RNA gel-blot analysis of expression of CaPO2 and CaBPR1 in primary and secondary pepper leaves 24 h after inoculation with the Xcv avirulent strain Bv5-4a at the six-leaf stage. The membrane was successively hybridized with ³²P-dCTP-labeled CaPO2 and CaBPR1 probes. Local, Xcv-inoculated leaves; Systemic, uninoculated leaves distant from the Xcv infection site.