Molecular cloning and expression of a cDNA encoding 1‐aminocyclopropane‐1‐carboxylate (ACC) oxidase from apricot fruit (Prunus armeniaca)

Little is known on gene expression during ripening of apricot fruit (Prunus armeniaca cv. Bergeron), in particular for the enzymes involved in ethylene biosynthesis. ACC oxidase (EC 1.4.3) catalyses the last step of the ethylene biosynthesis pathway in higher plants. Based on sequence conservation of ACC oxidases, a reverse transcriptase‐polymerase chain reaction (RT‐PCR) experiment was carried out to synthesize a homologous ACC oxidase probe from apricot fruit. This probe was further used to isolate a full length ACC oxidase cDNA, Pa‐ACO, from a ripe fruit cDNA library. Pa‐ACO is 1 236 bp long and contains a single open reading frame encoding a mature peptide of 319 amino acids with a calculated molecular mass of 36.17 kDa and a pI of 5.07. Immunoblot analysis allowed us to associate a 40 kDa protein to apricot fruit ACC oxidase. Pa‐ACO belongs to a multi‐gene family, is fruit specific and is transcriptionally regulated during ripening of apricot fruit.