Analysis of powdery mildew infection by spore counts. G. orontii infected leaves were harvested at 5 dpi from Col-0 wild type (A), eds1 (B), mlo2 (C) and mlo2 mlo6 mlo2 (D) seedlings and stained with Coomassie Brilliant Blue. Arrows indicate conidiospore chains and arrowheads point to the initial spore. (E, F) Brightfield image of isolated spores in the haemocytometer. (F) is a close-up of the indicated area in (E). (G) Spore counts of indicated genotypes at 6 dpi normalized to seedling fresh weight. Bars represent the mean ± standard deviation of three samples (500 mg of seedlings each) from one experiment counting eight fields/sample. Asterisks indicate statistically significant differences to Col-0 in two-tailed Student’s t-test (p <0,05). Scale bars in (A-F) are 100 μm. Data shown are representative of three independent experiments (see Additional file2 for data of a second experiment).