UPTON, NY -- Using genetic manipulation to modify the activity of a plant enzyme, researchers at the U.S. Department of Energy's Brookhaven National Laboratory have converted an unsaturated oil in the seeds of a temperate plant to the more saturated kind usually found in tropical plants. The research will be published online by the Proceedings of the National Academy of Sciences (PNAS) the week of March 5, 2007.
While conversion of an unsaturated oil to an oil with increased saturated fatty acid levels may not sound like a boon to those conscious about consuming unsaturated fats, "the development of new plant seed oils has several potential biotechnological applications," said Brookhaven biochemist John Shanklin, lead author on the paper.
For one thing, the new tropical-like oil has properties more like margarine than do temperate oils, but without the trans fatty acids commonly found in margarine products. Furthermore, engineered oils could be used to produce feedstocks for industrial processes in place of those currently obtained from petrochemicals. Shanklin also suggests that the genetic manipulation could work in the reverse to allow scientists to engineer more heart-healthy food oils.
"Scientists have known for a long time that the ratio of saturated to unsaturated fatty acids plays a key role in plants' ability to adapt to different climates, but to change this ratio specifically in seed oils without changing the climate is an interesting challenge," remarked Shanklin. "Our group sought to gain a better understanding of the enzymes and metabolic pathways that produce these oils to find ways to manipulate the accumulation of fats using genetic techniques."
The researchers focused on an enzyme known as KASII that normally elongates fatty acid chains by adding two carbon atoms. The longer 18-carbon chains are more likely to be acted on by enzymes that desaturate the fat. So the scientists hypothesized that if they could
Contact: Karen McNulty Walsh
DOE/Brookhaven National Laboratory