Antisense expression of polyphenol oxidase genes inhibits enzymatic browning in potato tubers

Spoilage caused by post-harvest enzymatic browning is a problem of considerable importance to food growers, processors and retailers. Here we show that antisense inhibition of polyphenol oxidase (PPO) gene expression abolishes discoloration after bruising of potato tubers in individual transgenic lines grown under field conditions. Using appropriate promoters to express antisense PPO RNA, melanin formation can be specifically inhibited in the potato tuber. This lack of bruising sensitivity in transgenic potatoes, and the absence of any apparent detrimental side effects open the possibility of preventing enzymatic browning in a wide variety of food crops without resorting to treatments such as heating or the application of antioxidants.