Improved control of postharvest blue mold rot in pear fruit by a combination of Cryptococcus laurentii and gibberellic acid

Gibberellic acid (GA3) is associated with fruit ripening and senescence. In this study, we investigated the feasibility of GA3 to improve the efficacy of Cryptococcus laurentii in controlling postharvest blue mold rot caused by Penicillium expansum in pear fruit. Although GA3 alone was not found to have any influence on P. expansum or C. laurentii in vivo and in vitro, the combination of C. laurentii and GA3 at 2000 μg per ml resulted in a more efficient control of blue mold rot in pear wounds C. laurentii alone, with the associated rapid increase in peroxidase and polyphenol oxidase activities and with an inhibition of lipoxygenase activity and lipid peroxidation. In addition, no phytotoxic injury was observed in fruit tissue treated with GA3 at 2000 μg per ml. The results from this investigation enabled us to find a new way to improve the performance of C. laurentii.