Damaged plants are susceptible to microbial attack. In response to physical damage, plants proactively generate signal peptides to activate their immune systems. Researchers based in Ghent, Belgium (VIB-UGent Center for Plant Systems Biology) and Basel, Switzerland (University of Basel) have found a link between a class of enzymes and immune signals that is rapidly triggered upon physical damage in plants. This new discovery extends understanding of the plant immune system that can be exploited to improve crop health and yield in the future.