CHARACTERIZATION OF A PCR FRAGMENT ENCODING 1-AMINOCYCLOPROPANE-1-CARBOXYLATE SYNTHASE IN PEPPER (CAPSICUM-ANNUUM)

Degenerate oligonucleotides corresponding to conserved domains found a mong diverse 1-aminocyclopropane-1-carboxylate (ACC) synthases (EC 4.4 .1.14) were used with cDNA prepared from pepper fruit (pericarp) to is olate PCR fragments encoding ACC synthase in pepper. The clones isolat ed from green, turning and red pericarp were identical fragments of 10 90 bp having a predicted 83% amino acid sequence similarity with the f ruit-specific genes from tomato. Genomic hybridization suggests that t he PCR fragment corresponds to a single gene, which we call CA-ACC1. E xpression of the CA-ACC1 gene occurs at low levels in a range of organ s. The levels of expression of CA-ACC1 measured in ripening fruit are coincident with the low levels of ethylene evolved by the fruit.