[Cloning of promoter of banana fruit ripening-related ACO1 and primary study on its function]

According to the published sequence of ACC oxidase gene(ACO1) which was shown to express in banana fruits, we cloned its 5'-flanking region by improved adaptor ligation PCR. The 1526 bp fragment contained a putative TATA-box. Sequence alignment of our promoter with two published (934 bp and 1451 bp) revealed 97.3% (López-Gómez et al.) and 88.8% (May and Kipp) similarity in nucleotide sequence, respectively. The 5'-flanking fragments in different length were fused to the coding sequence of GUS gene. These constructs were delivered to leaf, root and fruit cells of banana via particle bombardment. The results of transient gene expression assay showed that the cloned ACO1 promoter was able to direct fruit-specific gene expression, and that the regulatory region for fruit-specificity was probably located in the 0.7 kb 5'-flanking sequence of the gene and some positive regulatory elements may exist within the region of 355 bp from 468 to 822.