Gene encoding polygalacturonase inhibitor in apple fruit is developmentally regulated and activated by wounding and fungal infection. Decay caused by postharvest pathogens can result in a substantial loss of apple fruit in storage. Many of these diseases can be effectively controlled by fungicides, but public concerns about health and environmental impact may limit the future applications of these chemicals. Many pathogens are also becoming resistant to the effects of these pesticides. To reduce storage losses and provide a continued source of abundant food for the consumer, alternative methods of postharvest disease control must be investigated.
Postharvest pathogens produce polygalacturonase, a cell wall degrading protein, to decay fruit.
The results of this research indicate that a naturally occurring protein that inhibits polygalacturonase activity is present in apple fruit. Since this polygalacturonase inhibiting protein has proven to be a plant defense mechanism against pathogen infection, it could be used as an alternate method to control postharvest diseases. Apple packing and storage facilities may then be able to reduce the amount of fungicides used to maintain fruit quality in storage.