Characterization of a PCR fragment encoding 1-aminocyclopropane-1-carboxylate synthase in pepper (Capsicum annuum)

Degenerate oligonucleotides corresponding to conserved domains found among diverse 1-aminocyclopropane-1-carboxylate (ACC) synthases (EC 4.4.1.14) were used with cDNA prepared from pepper fruit (pericarp) to isolate PCR fragments encoding ACC synthase in pepper. The clones isolated from green, turning and red pericarp were identical fragments of 1090 bp having a predicted 83% amino acid sequence similarity with the fruit-specific genes from tomato. Genomic hybridization suggests that the PCR fragment corresponds to a single gene, which we call CA-ACC1. Expression of the CA-ACC1 gene occurs at low levels in a range of organs. The levels of expression of CA-ACC1 measured in ripening fruit are coincident with the low levels of ethylene evolved by the fruit.