Pathogens suppress hydrolases in the plant apoplast to cause disease. Despite the importance of these enzyme-inhibitor interaction to plant diseases, to date only a handful examples have been described. Unravelling new plant targets and their inhibitory mechanisms will identify novel components of the plant immune system and point to molecular coevolution operating in the apoplast. Here, we simultaneously monitor the changes in activity of over 170 extracellular enzymes during bacterial infection.