| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
|
First published online July 9, 2004; 10.1104/pp.104.044354 Plant Physiology 135:1324-1335 (2004) © 2004 American Society of Plant Biologists Cloning and Functional Characterization of a Phospholipid:Diacylglycerol Acyltransferase from Arabidopsis1 Department of Crop Science, Swedish University of Agricultural Sciences, S–230 53 Alnarp, Sweden (A.S.C., A.B., S.S.); Department of Plant Biology and Forest Genetics, Uppsala Genetic Centre, Swedish University of Agricultural Sciences, S–750 07 Uppsala, Sweden (U.S.); Scandinavian Biotechnology Research (ScanBi) AB, S–230 53 Alnarp, Sweden (M.L., A.D.); Institute of Biology, University of Podlasie, 08–110, Siedlce, Poland (W.B); and College of Life Science, Hubei University, Wuhan, 430062, P.R. China (B.H.)
A new pathway for triacylglycerol biosynthesis involving a phospholipid:diacylglycerol acyltransferase (PDAT) was recently described (Dahlqvist A, Stahl U, Lenman M, Banas A, Lee M, Sandager L, Ronne H, Stymne S, [2000] Proc Natl Acad Sci USA 97: 6487–6492). The LRO1 gene that encodes the PDAT was identified in yeast (Saccharomyces cerevisiae) and shown to have homology with animal lecithin:cholesterol acyltransferase. A search of the Arabidopsis genome database identified the protein encoded by the At5g13640 gene as the closest homolog to the yeast PDAT (28% amino acid identity). The cDNA of At5g13640 (AtPDAT gene) was overexpressed in Arabidopsis behind the cauliflower mosaic virus promoter. Microsomal preparations of roots and leaves from overexpressers had PDAT activities that correlated with expression levels of the gene, thus demonstrating that this gene encoded PDAT (AtPDAT). The AtPDAT utilized different phospholipids as acyl donor and accepted acyl groups ranging from C10 to C22. The rate of activity was highly dependent on acyl composition with highest activities for acyl groups containing several double bonds, epoxy, or hydroxy groups. The enzyme utilized both sn-positions of phosphatidylcholine but had a 3-fold preference for the sn-2 position. The fatty acid and lipid composition as well as the amounts of lipids per fresh weight in Arabidopsis plants overexpressing AtPDAT were not significantly different from the wild type. Microsomal preparations of roots from a T-DNA insertion mutant in the AtPDAT gene had barely detectable capacity to transfer acyl groups from phospholipids to added diacylglycerols. However, these microsomes were still able to carry out triacylglycerol synthesis by a diacylglycerol:diacylglycerol acyltransferase reaction at the same rate as microsomal preparations from wild type.
1 This work was supported by the Swedish University of Agricultural Science's strategic research grants (The Biological Factory and AgriFunGen), ScanBi AB, Stiftelsen Svensk Ojeväxtforskning, the Swedish Farmers Foundation for Agricultural Research, Stiftelsen Västsvenska Lantmännen Odal, and the European Commissions (grant no. QLRT1999–00213). 2 These authors contributed equally to the paper. Article, publication date, and citation information can be found at www.plantphysiol.org/cgi/doi/10.1104/pp.104.044354. * Corresponding author; e-mail anders.carlsson{at}vv.slu.se; fax 46–40–415519. Received April 9, 2004; returned for revision May 21, 2004; accepted May 22, 2004. This article has been cited by other articles:
|
|||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| ASPB Publications | PLANT PHYSIOLOGY | THE PLANT CELL | |
|---|---|---|---|
