Figure 4. Appressorium induction. Conidia of the wild-type (WT), Mratg8Δ and Comp mutant harvested after 20 d on CM plates were subjected to appressorial induction for 16 h either on a hydrophobic surface (A–C; sterile plastic Petri dishes in six cm diameter containing 3 ml of 0.0125% yeast extract) or on locust hind wings (D–F). In contrast to the WT (A and D) and Comp (C and F), appressorium production by Mratg8Δ (B and E) were significantly impaired on the surfaces of either plastic Petri dishes (G) or locust hind wings (H). The same letter labeled within (G or H) means that no statistical difference was detected between the samples at a level of p < 0.01. AP, appressorium. CO, conidium. Scale bar: 5 μm.