Figure 6.

3,3′-Diaminobenzidine (DAB) staining of bean leaf disks 48 h after treatment with PD-L1 2 µg/mL (a) or PD-L4 2 µg/mL (b) or water as control (c); no staining is present in the tissues, except for veins (arrows) that are stained in brown as they contain H₂O₂ for cell wall lignification. (d) Leaf disk from a non-treated leaf inoculated with 40 µg/mL of TNV, at 48 h after infection: a developing virus lesion, densely stained for the presence of H₂O₂ due to the oxidative stress induced by the virus, is shown. (e) Leaf inoculated with a mixture of 2 µg/mL PD-L4 and 40 µg/mL TNV (1:1), no staining is present except for the veins (arrow). (f) Leaf treated with 2 µg/mL PD-L4 in the abaxial surface and inoculated soon after with 40 µg/mL of TNV in the adaxial surface: some DAB staining is present at 48 h in walls of cells possibly involved in an early formation of a small lesion (arrows), as the one showed in Figure 5f. All bars = 50 µm.