Salicylic acid alleviated pathogen-induced oxidative stress in harvested sweet cherry fruit

The role of exogenous salicylic acid (SA) in regulating an antioxidative defense response of sweet cherry (Prunus avium L. cv. Hongdeng) fruit inoculated with Penicillium expansum was investigated by immunodetection of carbonylated proteins. After inoculation with P. expansum, carbonylated proteins accumulated to a lesser extent in SA-treated fruit than in control fruit, ranging from molecular mass 29–45 kDa. Higher activities of catalase (CAT), glutathione peroxidase (GPX), chitinase and β-1,3-glucanase were observed in SA-treated fruit. Similarly, the expressions of CAT, GPX and β-1,3-glucanase genes were also stimulated by SA treatment. Moreover, 2 mM SA did not inhibit P. expansum growth in vitro. These results indicate that SA activated antioxidant defense responses of sweet cherry fruit, which may play a role in the resistance against P. expansum.