Submitted to: International Biotechnology Congress
Publication Type: Abstract Only
Publication Acceptance Date: 3/1/2002
Publication Date: 6/23/2002
Citation: Moon, H., Callahan, A.M. 2002. Developmental regulation of peach ACC oxidase-GUS fusions in transgenic tomato fruits. International Biotechnology Congress. 10th International Association of Plant & Tissue Culture Biotechnology Congress Proceedings; P-1077, pg S2. Interpretive Summary:
Technical Abstract: Fruit ripening involves changes in the expression of a large number of genes including the well-characterized 1-Aminocyclopropane-1-caboxylic acid oxidase which catalyzes the conversion of 1-aminocyclopropane-1-caboxylate to ethylene. We isolated a genomic DNA sequence encoding ACC oxidase from peach that has three introns and 2.9 kb of 5' flanking region to the start codon. Previous work with the related cDNA had shown that the accumulatio of the mRNA occurred during the softening stage of fruit ripening and that phenomenon was associated with increases in the amount of ethylene synthesized by fruit. To investigate the regulation and tissue specificity of the peach ACC oxidase gene expression, chimeric fusions betwen 403, 610, 901, 1319, 2141 and 2913 bp, of 5' flanking region of the PpACOI sequence sequence and the B-glucuronidase coding sequence were constructed and used used to transform tomato. Tomato plants transformed with pB1121 and pB1101 1were positive and negative controls, respectively. Histochemical GUS analysis of the transgenic tomato fruits indicated that the 403 bp of the 5' UTR is sufficient to confer significant GUS activity. The 2913 bp of PpACOI upstream sequence directed GUS expression in the early green stage of fruit development, and increased GUS activity as fruit matured, reaching maximum at 'pink' or 'light red' stage. There was little or no GUS staining in leaves or stems. The 2141 bp promoter drove GUS expression from the early green stage as the 2913 bp promoter did but the GUS activity decreased at late stages of fruit development indicating a regulatory region between -2913 and -2141. There appear to be at least one positive and one negative regulatory regions between -2913 bp and -403 bp of PpACOI that influence GUS expression at different fruit development stages.