Submitted to: Plant Biology Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 3/6/2004
Publication Date: 3/8/2004
Citation: Shockey, J.M., Chapital, D.C., Kuan, J.W., Mullen, R.T., Dyer, J.M. 2004. Engineering high levels of eleostearic acid content in oilseeds - cloning and functional characterization of triacylglycerol biosynthetic acyltransferase genes from tung (aleurites fordii) (abstract). American Society of Plant Biology.
Technical Abstract: Industrially useful fatty acids have been identified in hundreds of nonagronomic plant species distributed across the globe. Unusual double bond arrangements or other functional groups make these types of fatty acids valuable as feed stocks in the manufacture of nylons, paints, resins, lubricants, and many other products. Attempts to manipulate transgenic organisms to produce novel fatty acids through the introduction of single biosynthetic genes from the novel plant species has met with limited success. The seed oil of the tung tree (Aleurites fordii) contains approximately 80% eleostearic acid, a conjugated trienoic fatty acid. A cDNA clone for the conjugase/desaturase gene FADX was previously isolated and shown to produce low amounts of eleostearic acid in transgenic yeast, Arabidopsis, and tobacco. We seek to enhance the production and accumulation of oils containing high levels of eleostearic acid in transgenic organisms by reconstituting the entire triacylglycerol (TAG) biosynthetic pathway from tung seeds. The long-term goal of this work is to investigate the alterations in TAG content and composition created by co-expression of FADX and multiple other tung genes, especially those encoding the acyltransferases of the Kennedy pathway. To this end, we have cloned cDNAs for one glycerol-3-phosphate acyltransferase (GPAT), two lysophosphatidic acid acyltransferases (LPAAT), two diacylglycerol acyltransferases (DGAT), and one phospholipid:diacylglycerol acyltransferase (PDAT). These clones have been introduced into Saccharomyces cerevisiae and the effects on cellular TAG are currently being investigated. Other characteristics of the enzymes, including their subcellular targeting and in vitro substrate specificities will also be discussed.