| Abstract Detail
Secondary Metabolism Modolo, L. V. [1], Blount, J. W. [1], Wang, X. [1], Dixon, R. A. [1]. Expression profile of eight (iso)flavonoid-glycosyltransferase from Medicago truncatula and biochemical characterization of UGT78G1. Glycosyltransferases (GTs) are ubiquitous in living organisms. They catalyze the transfer of a sugar residue from a specific donor to an acceptor (metabolites, xenobiotics, macromolecules etc). The glycosylation of hydrophobic aglycones is important to increase stability, to reduce toxic properties and to facilitate compartmentalization, transport and storage. The understanding of how glycosyltransferases are involved in such processes will be helpful for generating plants with altered profiles of natural products. Here we present the tissue-specific expression patterns of eight (iso)flavonoid GTs identified from Medicago truncatula, and the biochemical characterization of UGT78G1. His-tagged fusion proteins were tested for activity in the presence of UDP-glucose and a large number of individual flavonoid acceptors. All (iso)flavonoid GTs were active, at different extents, against chalcone, coumestan, flavanone, flavone, flavonol, isoflavone, and pterocarpan acceptors. UGT78G1 was the only enzyme to show activity toward anthocyanidins. UGT78G1 catalyzed glucosylation at the 7-O-position unless the flavonoid had a hydroxyl group at C3, in which case this position was substituted. The tissue-specific expression patterns of these Medicago UGTs, together with in vitro enzyme activity data, suggest in vivo functions of at least four of the enzymes.
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1 - The Samuel Roberts Noble Foundation, Plant Biology Division, 2510 Sam Noble Parkway, Ardmore, OK, 73401, USA
Keywords:
glycosyltransferase
flavonoids
gene expression
Medicago truncatula.
Presentation Type: Plant Biology Abstract
Session: P
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM
Number: P20009
Abstract ID:197 |
