CAT and infection: SOD, CAT, Glutathione peroxidase (GPX), and ascorbate–glutathione (AA-GSH) cycle activities in tomato infected with B. cinerea. It was early noticed increases in SOD, CAT and GPX indicating that initial infection induced their activities and consequently the activation of antioxidant plant defense, which was followed by a progressive inhibition concomitant with disease symptoms development.