Induction of defensive enzymes (isozymes) during defense against two different fungal pathogens in pear calli

摘要

Activities of defensive enzymes?peroxidase?(POD), superoxide dismutase?(SOD), catalase?(CAT), polyphenol oxidase?(PPO)?and esterase?(EST) and their isozymes in pear calli were studied to reveal their role in the defensive response to different fungal infections and to find some clues to enhance their antimicrobial properties. The results confirm the fact that the activities and isozymes of these five enzymes showed differences in response to different fungal infections. After?the?inoculation of two different fungi for the same calli, its defensive enzymes’ activities changed relatively when compared with those of?the?control and in?Botryosphaeria berengrianaf.sp.?piricola?(BBP)-infected calli,?the enzymes’ activities changed more significantly than those of?Monilinia fructigena Honcy?(MFH). Meanwhile, more new isozymes were induced by BBP infection. These are in agreement with the fact?that?the BBP-infected calli decay?was?slower than that of the MFH.?These results suggest that enhancing defensive enzymes’ activities and inducing new isozymes may be related to mitigating pathogen-induced oxidative damage which result in?the?decrease of calli decay, and this implies that antioxidant defense response may be involved in the mechanisms of plant against fungal pathogen.