Isolation and Cloning of 1-Aminocyclopropane-1-Carboxylate Oxidases from Carica papaya var. Eksotika I and Eksotika II

Sequence analysis was carried out on 1-aminocyclopropane-1-carboxylate oxidase (ACO)cDNAs from different papaya varieties available in the public databases and showed two divergent groups of ACO gene that differ significantly in the 5' and 3' untranslated regions (UTR). Two ACO cDNAs previously isolated from Eksotika I and Eksotika II papaya variety namely CAPACO1 and CP-ACO1 respectively are in the same group of ACO gene. In order to isolate another version of ACO gene from Eksotika varieties, we designed specific primers based on 5' and 3' UTR. RT-PCR method was used for Eksotika I ripe fruit while PCR screening was done on Eksotika II papaya unripe and ripe fruit cDNA libraries constructed earlier. The amplified ACO gene fragments from both Eksotika varieties had the same size of approximately 1400 bp. The putative ACO DNA fragments were then subcloned and sequenced. Homology search showed that these clones were the full-length cDNA of the other version of ACO genes. Therefore, the Eksotika I and II papaya varieties contain ACO genes from the two groups.