APP and infection: In combination with analysis by mass spectrometry (MS), ABPP‐MS has been applied to study dynamic changes in the activities of serine hydrolases (SHs) in tomato upon infection with C. fulvum and Ralstonia solanacearum, as well as in Arabidopsis thaliana (Arabidopsis) upon infection with Botrytis cinerea (Kaschani et al., 2009; Sueldo et al., 2014; Planas‐Marquès et al., 2018).