Abstract
A genomic DNA clone, DC-ACO1, encoding ACC oxidase was cloned from carnation (Dianthus caryophyllus L. cv. Nora) plants. DC-ACO1 encodes an amino acid sequence which, except for one amino acid, is identical to that of pSR120 obtained previously as a senescencerelated ACC oxidase cDNA from carnation petals (Wang and Woodson, 1991). DC-ACO1 contains 3 exons which are interrupted with 2 introns. Promoter activity of the 5′-flanking region up to -1170 bp, relative to the A (+1) of the translation start codon ATG, of DC-ACO1 was analyzed by transient expression of the 5′-flanking sequence-β-glucuronidase (GUS) gene fusion after delivery by particle bombardment into carnation petals. Expression of the chimeric gene increased depending on the progress of senescence of petals, which was measured by their ethylene production rates. Truncation of the 5′-upstream sequence of -1170 bp to -247 bp increased the promoter activity by 6.5 fold, indicating that the -247 bp-long 5′-flanking sequence was sufficient for promoter activity.
