Fig. 4

Cfhos2 regulates appressorium development in a surface-dependent manner. a Quantification of conidial germination rate (Germ), appressorium formation rate (App), and penetration rate (Pen) of selected strains on cellophane membrane. b Conidial germination and appressorium development of selected strains on different membrane surfaces. Note the normal appressorium development phenotype of ∆Cfhos2 (∆hos2-4) on parafilm and apple leaf surface, but not on cellophane. For cellophane, arrowheads in 1104-6 point toward infectious hyphae, and arrowhead in ∆hos2-4 points toward an appressorium. For apple leaf, conidia and germ tubes were stained green by fluorescein isothiocyanate-conjugated wheat germ agglutinin (FITC-WGA) under fluorescent microscope whereas melanized appressoria were not stained. Scale bars represent 50 μm