Removing the Brakes on Plant Oil Production

(Brookhaven National Laboratory/Biodiesel Magazine) Scientists studying plant biochemistry at the U.S. DOE’s Brookhaven National Laboratory have discovered new details about biomolecules that put the brakes on oil production. The findings suggest that disabling these biomolecular brakes could push oil production into high gear—a possible pathway toward generating abundant biofuels and plant-derived bioproducts. The study appears in in the journal Plant Physiology.

“It’s normal for plant cells to down-regulate oil production when we feed them excess fatty acids, and this study confirms our hypothesis about how they do that,” said Brookhaven Lab biochemist John Shanklin, who led the research. “But we also discovered that the brakes on oil production are partially on even under normal conditions, which was a big surprise. It would be like driving a car for several years and finding out one day that a parking brake you didn’t know about had been on all along. When you remove that brake, the car has much more power; that’s what we’ve just discovered for plant oil production.”

The biomolecule central to this study is the enzyme that determines the rate of oil production. That enzyme, known as ACCase, is a protein made of four subunits, all of which are necessary for the enzyme to function. With all four subunits in place, the enzyme drives the first step in the synthesis of fatty acids, key components of oils.

But the big surprise came when Keereetaweep measured fatty acid synthesis in the plant cells with disabled inactive subunits without artificially feeding them excess fatty acids and compared the results with those for wild-type plant cells under the same conditions. Under those normal conditions, where you wouldn’t expect to see oil production inhibited, the enzyme driving oil production was significantly more active in plant cells with the disabled genes than in normal plant cells.

“That means that, even under normal conditions, inactive subunits are putting the brakes on ACCase, reducing its activity and limiting oil production,” Shanklin said. “Disabling the genes for those inactive subunits is like taking the brakes off the car, revealing the motor’s true potential.”

“This project was an excellent collaboration among Keereetaweep, Liu and Zhiyang Zhai to answer some basic scientific questions about plant metabolism,” Shanklin noted. “Now, the knowledge they generated can potentially underpin strategies to increase oil accumulation in plant species grown for applications such as biofuels or bioproducts.”

This research was funded by the DOE Office of Science and the National Science Foundation. READ MORE