Figure 3. Microscopic analysis of hypersensitive response (HR). Trypan blue staining performed on Desiree, SW93-1015 and Sarpo Mira. (A) Trypan blue staining did not show any HR in uninfected leaves of the three genotypes. (B) Phytophthora zoospores at 6 hpi in Desiree (left), SW93-1015 (middle) and Sarpo Mira (right). (C) Phytophthora zoospore germination in Desiree (left), scattered HR in SW93-1015 (middle) and Sarpo Mira (right) indicated by blue coloration at 24 hpi. (D) Intense hyphal growth in Desiree (left), scattered HR in SW93-1015 (middle) and increased cell death in Sarpo Mira (right) at 3 dpi. Size bars represent 100 µm.