Effects of benzothiadiazole on disease resistance and related defense enzyme activity of harvested mango fruits

The effects of benzothiadiazole (BTH) on induction of disease resistance in harvested mango (Mangifera indica Linn. cv. Hongmang No.6)fruits and the activities of several defense-related enzymes were investigated. Harvested mango fruits were sprayed with 50 mg·L-1 of BTH solution before being stored at (20±1) ℃ with the relative humidity of 80%. The disease incidence and five defense-related enzymes were monitored during the storage. The results showed that, compared with the control, BTH treatment significantly reduced the disease indices of mango fruits. Moreover, BTH treatment enhanced the activities of the defense-related enzymes, i.e., peroxidase (POD), catalase (CAT), polyphenol oxidase (PPO), phenylalanine ammonia lyase (PAL) and β-1,3-glucanase (GUN). In addition, BTH treatment increased the contents of hydrogen peroxide (H2O2) and total phenolics, and decreased content of malondialdehyde (MDA). Therefore, the results suggested that the enhanced disease resistance in harvested mango by BTH treatment could result from the activation of the disease-related defense system.