Expression of PPO and POD genes and contents of polyphenolic compounds in harvested mango fruits in relation to Benzothiadiazole-induced defense against anthracnose

Abstract

Mango is susceptible to decay caused by pathogen infection during storage and transport. Chemical fungicides have been the major weapons against postharvest fungal diseases, but they have caused increasing public resistance. BTH does not have anti-microbial properties, but it induces systemic acquired resistance in plants. Here the relationship between BTH-induced disease resistance in harvested mango fruits and expression of PPO and POD genes, together with contents of total phenolic compounds (TPC), were investigated. BTH treatment reduced disease indices and lesion diameter. Compared with the control, BTH increased TPC, up-regulated gene expression and enhanced enzymes activities of PPO and POD during the latter period of storage life, suggesting that enhanced gene expression of PPO and POD played an important role in BTH-activated defense response of mango fruits and that the up-regulation of the two genes were related to the accumulation of TPC. This study also showed that BTH-induced resistance in harvested mango fruits could differ with varieties.