Modification of fruit ripening by suppressing gene expression.

Ethylene is one of the simplest organic molecules with biological activity. Its effects on plant tissue are spectacular and commercially important (1, 2). This hydrocarbon gas is generally considered to be the fruit-ripening hormone (2, 3). Because of its effects on plant senescence, large losses of fruits and vegetables are incurred annually in the United States. The losses are much greater in developing countries because of the lack of sufficient refrigeration and transportation. Consequently, it has always been a goal of plant biologists and of postharvest physiologists, in particular, to be able to prevent or delay fruit ripening in a reversible manner by controlling ethylene action or production. Thus, an understanding of ethylene action and biosynthesis is of fundamental as well as applied significance. This update summarizes the recent advances in manipulating key genes in the ethylene biosynthetic pathway to prevent ethylene production and fruit ripening. Methionine is the biological precursor of ethylene in all higher plants (22) and is converted to ethylene according to the following sequence: