Mario Serrano’s research line is the characterization of plant innate immunity to the necrotrophic fungus Botrytis cinerea (grey mold), which has been classified as the second most important plant pathogen. The first interaction between the plant and the fungal organism takes place at the epidermis. Here, not only does the plant have the first physical barrier, which includes the plant cuticle in aerial organs, but the organisms are recognized, and the plant immune responses are potentially triggered. The objective of this project is to identify and characterize molecular elements that link the degradation of the cuticle and the induction of plant innate immunity, using the plant–pathogen system Arabidopsis thaliana–Botrytis cinerea and traditional and chemical genetics.