The oomycete Phytophthora infestans, the causal agent of late blight disease, is a devastating pathogen of potato. Without appropriate control measures, potato fields can be destroyed within a couple of weeks. Both cost of yield loss and of control measures are reported to be more than 6 billion dollars annually (http://usablight.org/), making late blight economically the most important foliar disease. Our group is interested in plant defense mechanisms against this oomycete. Therefore, we are studying plants that can defend themselves successfully against P. infestans. We concentrate on the nonhost pathogen interaction of Arabidopsis thaliana and P. infestans, as well as on induced resistance in potato.