Cloning the mRNA encoding 1-aminocyclopropane-1-carboxylate synthase, the key enzyme for ethylene biosynthesis in plants.

Ethylene is the plant hormone that controls several features of plant growth and development. The rate-limiting step in its synthesis is the formation of the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC) from S-adenosylmethionine (AdoMet), catalyzed by ACC synthase. We have isolated a complementary DNA sequence encoding ACC synthase from zucchini (Cucurbita) fruits. The biological activity of the clone was confirmed by the ability of the cloned sequence to direct ACC synthase activity in Escherichia coli and yeast. In vivo studies using the ACC cDNA as probe showed that the ACC synthase gene is induced by a diverse group of inducers, including wounding, Li+ ions, and the plant hormone auxin.