Wolf Prize Laureate in Agriculture 1991
Affiliation at the time of the award:
University of California, USA
“for remarkable contributions to the understanding of the mechanism of biosynthesis, mode of action and applications of the plant hormone, Ethylene”.
Professor Shang-Fa Yang has studied the pathway of ethylene biosynthesis and proved unequivocally the central role of methionine as a precursor of ethylene. Ethylene represents one of the five major hormones affecting plant development and maturation.
Yang was the first to report S-adenosylmethionine as an intermediate in methionine conversion to ethylene. Later in 1979, he discovered aminocylopropane-1-carboxylic acid (ACC) as an intermediate. The discovery of ACC-synthase opened the way to the understanding of the regulating process of ethylene biosynthesis. Moreover, the finding of malonyl-ACC was followed by the understanding of the mechanism of autocatalytic production and suppression of this hormone in the plant tissues.
This research has also opened up further investigations leading to the understanding of ethylene action. At the same time these studies have emphasized the important role played by ethylene in plant growth, development and senescence. This enhanced the application of ethylene in agriculture mainly for optimization of fruit ripening and inhibition of abscission of leaves and flowers. These findings have significantly contributed to economic benefits by prolonging shelf life of fruits, flowers and vegetables after harvest.
Since ethylene has such profound effects, genetic modification of the ACC synthase will now permit scientists to regulate the production of ethylene for prolonging the life span of plants and the modification of flower and fruit development, thus leading to even greater economic advantages for food production.