Induction and mechanism of cucumber resistance to anthracnose induced by Pieris rapae extract

Abstract

Pieris rapae extract was sprayed on the surface of cucumber leaf to determine the induction of resistance to anthracnose. The enzyme activities of peroxidase (POD) and polyphenoloxidase (PPO) were detected on cucumber leaves after P. rapae extract induction and pathogen challenge. The results showed that the disease index of cucumber anthracnose was significantly decreased after the cucumber was induced with the P. rapae extract at a concentration of 5.0 mg·mL−1. The POD and PPO activities in foliar-applied P. rapae extract without pathogen inoculation (PETO) or with pathogen inoculation (PETI) were relatively higher than those with no-P. rapae extract treatment and without pathogen inoculation (CONO) or with pathogen inoculation (CONI), respectively. The results suggested that the increased levels of POD and PPO activities in PETO and PETI play an important role in the induction of resistance to cucumber anthracnose.