PSENEN and infection: To determine the functional contribution of PEN2 activity to the complete powdery mildew immunity of the mlo2 mlo6 mlo12 triple mutant, we generated the mlo2 mlo6 mlo12 pen2 quadruple mutant as well as the mlo2 mlo6 pen2 and mlo2 mlo12 pen2 triple mutants and assessed their infection phenotypes with the adapted powdery mildew pathogen G. orontii in comparison to a set of informative control plants.