Plant catalases: Peroxisomal redox guardians

► Catalases are one of several types of H2O2-metabolizing enzymes in plants. ► This review discusses their known or potential roles in redox homeostasis. ► An overview of catalase genes and expression is presented. ► Possible mechanisms of catalase import into peroxisomes are discussed. ► The application of catalase-deficient plants as models to study stress is analyzed.