Unable to connect to database - 08:34:13 Unable to connect to database - 08:34:13 SQL Statement is null or not a SELECT - 08:34:13 SQL Statement is null or not a DELETE - 08:34:13 Botany & Plant Biology 2007 - Abstract Search
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Abstract Detail

Secondary Metabolism

Long, Michael [1], Kaminaga, Yasuhisa [2], Nagegowda, Dinesh A. [2], Ho, Kwok Ki [3], Weiner, Henry [3], Kish, Christine [2], Dudareva, Natalia [2].

Involvement of benzaldehyde dehydrogenase in benzoic acid biosynthesis in snapdragon flowers.

Biosynthesis of benzoic acid (BA) from phenylalanine requires the shortening of the carbon skeleton side chain by a C2 unit, which can occur via either β-oxidative or non-β-oxidative pathways. The non-β-oxidative pathway requires benzaldehyde dehydrogenase (BALDH) to convert benzaldehyde, a key intermediate, to BA. Using a functional genomic approach we have identified an aldehyde dehydrogenase (ALDH), which exhibited high sequence similarity (78-81%) to described ALDHs from tobacco, maize, and rice and 40% identity to BALDH from the bacteria Sphingomonas aromaticivorans. In contrast to known plant ALDHs, BALDH is expressed predominantly in upper and lower petal lobes, the parts of the flower that are primarily responsible for scent production in snapdragon flowers. Its expression is developmentally regulated and correlated with emission of methylbenzoate for which BA is the immediate precursor. Moreover, rhythmic oscillations were found in BALDH transcript levels during the daily light/dark cycle, which correlated strongly with the level of BA. Biochemical characterization of the purified recombinant protein revealed that, although BALDH has broad substrate specificity, benzaldehyde is the preferred physiological substrate. The product formed from benzaldehyde was BA as was confirmed by HPLC analysis. Since BALDH contains a putative mitochondrial targeting sequence, its subcellular localization was confirmed experimentally by green fluorescent protein localization studies and immunogold labeling with antibodies generated against the BALDH protein. Substantial immunogold labeling with BALDH antibodies within the mitochondria of the conical epidermal cells of snapdragon petals suggests that the conversion of benzaldehyde to BA catalyzed by BALDH occurs in mitochondria.

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1 - Purdue University, Horticulture & Landscape Architecture, 625 Agriculture Mall Dr., West Lafayette, IN, 47907, USA
2 - Purdue University, Horticulture & Landscape Architecture
3 - Purdue University, Biochemistry

secondary metabolism
Aldehyde dehydrogenase
Floral scent.

Presentation Type: Plant Biology Abstract
Session: P
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM
Number: P20023
Abstract ID:519

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