ANTISENSE EXPRESSION OF POLYPHENOL OXIDASE GENES INHIBITS ENZYMATIC BROWNING IN POTATO-TUBERS

Spoilage caused by post-harvest enzymatic browning is a problem of con siderable importance to food growers, processors and retailers. Here w e show that antisense inhibition of polyphenol oxidase (PPO) gene expr ession abolishes discoloration after bruising of potato tubers in indi vidual transgenic lines grown under field conditions. Using appropriat e promoters to express antisense PPO RNA, melanin formation can be spe cifically inhibited in the potato tuber. This lack of bruising sensiti vity in transgenic potatoes, and the absence of any apparent detriment al side effects open the possibility of preventing enzymatic browning in a wide variety of food crops without resorting to treatments such a s heating or the application of antioxidants.