lin Friday? flaxseeds plant biologists designed to contain heart-friendly fats normally only found in fish.
scientists have for the first time GM plants to contain a particularly healthy type of fatty acid in their seeds. The most beneficial of so-called omega-3 fatty acids are found only in fish, so instead of growing omega-3 rich transgenic plants could increase public consumption while relieving the pressure on fishing, the researchers say.
The oil and fats in foods are composed of fatty acids which are chains of carbon atoms and hydrogen. The healthiest variety, poly-unsaturated fatty acids have two or more double bonds between carbon atoms. Of these, omega-3 and omega-6 - for example, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) - confer the greatest benefit, reducing the risk of cardiovascular disease and other ailments
The fish are a good source of DHA and EPA. Plants do not contain, but precursors of these fatty acids are relatively abundant in flaxseed, canola oil, soybeans and nuts. The human body can synthesise DHA from the precursors, but not effectively. Because most people do not eat enough fish to get the recommended amount of EPA and because fishing are already declining, researchers have tried to design plants with enzymes to make the EPA. In June, a group reported success with the model plant Arabidopsis adding three genes, researchers led by Qi Baoxiu of the University of Bath, UK, plants created in which EPA made up 20% of the oils of the plant.
Now, another group led by Ernst Heinz botanist from the University of Hamburg, Germany, has done the same in flax. This plant was a logical starting point, because its seeds have the highest levels of omega-3 precursors. Heinz, biochemist Amine Abbadi, and colleagues added another trio of genes that Qi team used. Genes introduced by the German group encode enzymes that add carbon double bonds precursors and sticky on additional carbon atoms, creating a range of omega-3 fatty acids and other fats.
omega-3 and omega-6 up 3.6% fatty acids in the transgenic seeds, the team reports in the October issue of The Plant Cell . While this is still less than one tenth of what is found in fish oil, Heinz said that a spoonful of transgenic linseed oil (made from crushed flaxseed) provide most of what is recommended for good health. The team also understood that step in reactions limit the amount of omega-3 and omega-6 and works to improve performance.
"It is a good step forward," says Qi, although it notes that the EPA in the seeds are rare. To stimulate this level probably will not be a major obstacle, notes Alan McHughen of University of California, Riverside, who worked on transgenic flax. the biggest challenge, he and Heinz both say, will win public acceptance, especially in Europe. But because this transgenic crop would be a health benefit for consumers more environmental benefit, and Qi they are hopeful.
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