Figure 2.

Macroscopical and microscopical analysis of Bgh inoculated barley leaves after BSMV-IGS of the Mlo gene. Third leaves of barley cv. Morex (control Mlo), Grannenlose Zweizeilige (mlo11), Morex infected with unmodified BSMV (BSMV-γMCS) and Morex infected with BSMV carrying a Mlo silencing construct (BSMV-γMlo), respectively, were inoculated with Bgh. (A) Powdery mildew disease symptoms 8 days after inoculation. (B) For quantitative cytological analysis leaves were harvested at 48 h p.i., cleared and stained with blue ink. Only sites with a non-penetrated papilla beneath the appressorium were counted. The micrograph shows an example of these interaction sites (sp = spore, gt = germ tube, pap = papilla). Results presented in the bar chart are means and standard errors from 4 leaves with 100 interaction sites inspected per leaf. Significant differences (α = 5%) were determined using OneWayAnova and indicated by different letters. The experiment was repeated twice with similar results.