( lengthening by reducing the levels of K...)New success in engineering plant oils

Their hypothesis was supported by the fact that scientists had previously identified a plant with a mutated KASII that showed reduced enzyme activity, and these plants were able to accumulate more saturated fats than was normal. So the Brookhaven team set out to reduce KASII activity with the use of RNA-interference (RNAi) to see if they could further increase the level of saturation in plant seed oils.

The Brookhaven scientists performed their experiments on Arabidopsis, a plant commonly used in research. Like other plants from temperate climates (e.g., canola, soybean, and sunflower), Arabidopsis contains predominantly 18-carbon unsaturated fatty acids in its seed oil. Tropical plants, in contrast (e.g. palm), contain higher proportions (approximately 50 percent) of 16-carbon saturated fatty acids.

The results were surprising. The genetic manipulations that reduced KASII activity resulted in a seven-fold increase in 16-carbon unsaturated fatty acids ?up to an unprecedented 53 percent ?in the temperate Arabidopsis plant seed oils.

"These results demonstrate that manipulation of a single enzyme's activity is sufficient to convert the seed oil composition of Arabidopsis from that of a typical temperate pant to that of a tropical palm-like oil," Shanklin said. "It is fascinating ?and potentially very useful ?to know that we can change the oil composition so drastically by simple specific changes in seed oil metabolism, and that this process can occur independently from the adaptation to either tropical or temperate climates."

For example, such a technique could lead to the engineering of temperate crop plants to produce saturated oils as renewable feedstocks for industrial processes. Such renewable resources could help reduce dependence on petroleum.

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Source:DOE/Brookhaven National Laboratory