JXB Advance Access originally published online on June 18, 2004
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Journal of Experimental Botany, Vol. 55, No. 402, pp. 1519-1528, July 2004
Journal of Experimental Botany, Vol. 55, No. 402, © Society for Experimental Biology 2004; all rights reserved
RESEARCH PAPER |
Developmental regulation of peach ACC oxidase promoterGUS fusions in transgenic tomato fruits

USDA-ARS Appalachian Fruit Research Station, 2217 Wiltshire Road, Kearneysville, WV 25430, USA
To whom correspondence should be addressed. Fax: +1 304 728 2340. E-mail: acallaha{at}afrs.ars.usda.gov
A genomic DNA sequence (PpACO1) encoding 1-aminocyclopropane-1-carboxylic acid oxidase (ACO) from peach (Prunus persica L. Batsch cv. Loring) was isolated. It has four exons interrupted by three introns and 2.9 kb of flanking region 5' of the translational start codon. Previous work with the cDNA demonstrated that accumulation of the peach ACO message correlated with increasing amounts of ethylene synthesized by the fruit as they ripened. To identify regulatory elements in the peach ACC oxidase gene, chimeric fusions between 403, 610, 901, 1319, 2141, and 2919 bp of the 5' flanking region of the PpACO1 sequence and the ß-glucuronidase (GUS) coding sequence were constructed and used to transform tomato (Lycopersicon esculentum [Mill] cv. Pixie). Fruits from the various promoter lines were analysed for GUS expression by histochemical GUS staining, GUS quantitative enzyme activity determination, and measuring the relative amounts of GUS mRNA. Constructs with the smallest promoter of 403 bp had significant GUS expression in fruit, but not in other tissues, indicating the presence of a region that affects tissue-specific expression. An increase in GUS expression was observed with promoters longer than 901 bp, indicating an enhancer region between 1319 and 901. The full-length promoter of 2919 bp directed GUS expression in the green stage of fruit development, and increased GUS expression as fruit matured, indicating a regulatory region between 2919 and 2141 that controls the temporal expression of the gene in fruit. Only the full-length promoter sequence demonstrated responsiveness to ethylene.
Key words: Peach ACC oxidase, promoter analysis, promoterGUS fusions, transgenic tomato