Antisense gene that inhibits synthesis of the hormone ethylene in transgenic plants

Abstract

ETHYLENE controls many physiological and developmental processes in higher plants, including ripening of fruit, abscission, senescence and responses to wounding¹. Although the accumulation of messenger RNAs in ripening fruit and senescing leaves has been correlated with ethylene production and perception^2–4, the regulatory mechanisms governing ethylene synthesis and the stimulation of gene expression by ethylene are not understood. We have previously shown that the complementary DNA, pTOM13, corresponds to an mRNA whose synthesis is correlated with that of ethylene in ripening fruit and wounded leaves^5,6,8. The pTOM13 mRNA encodes a protein of relative molecular mass 35,000⁶. The cDNA and three related genomic clones have been sequenced, but the function of the protein is unknown^7–9. We show here that antisense RNA, which has previously been used only to reduce the expression of genes of known function^10–12, when applied to pTOM13, reduces ethylene synthesis in a gene dosage-dependent manner. Analysis of these novel mutants suggests that pTOM13 encodes a polypeptide involved in the conversion of 1-amino-cyclopropane-1-carboxylic acid to ethylene by the ethylene-forming enzyme (ACC-oxidase).