Fatty-Acid Factories
Engineered seeds produce healthful oils

Results: Canadian researchers have engineered mustard seeds to make very-long-chain polyunsaturated fatty acids such as omega-3 fatty acids that are known to reduce the risk of death from heart attacks and strokes. By transplanting genes from six sources, including marine fungi and marigolds, into the mustard plant, the researchers built new metabolic pathways that enabled the plants' seeds to convert two fatty acids they ordinarily make into two omega-3 fatty acids they don't normally make: eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The seeds produced a commercially viable amount of EPA, which topped out at 15 percent of the total fatty acids in the seed oil, and a detectable but not commercially viable amount of DHA, at 1.5 percent.

Why It Matters: Omega-3 acids are found primarily in fish oils, and food manufacturers have recently been extracting them and adding them to eggs, milk, juice, butter, breads, and other foods. But while these acids are good for people's health, their source, fish oil, can contain high levels of toxic chemicals such as mercury. By turning mustard seeds--chosen because they normally produce large amounts of oils and can easily incorporate new genes--into fatty-acid factories, the researchers hope to produce a safe source of omega-3 acids not limited by the supply of fish. Previously engineered plants produced low levels of EPA and no DHA. Here, an engineered mustard seed produced DHA for the first time and high enough levels of EPA to make it a potential commercial source.