Researchers from the U.S. Department of Energy's Brookhaven National Laboratory revealed the biomolecules that can put brakes on oil production of plants. When these biomolecular brakes are disabled, oil production could be boosted which may lead to more biofuels and plant-derived bioproducts. The results of the study are published in 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. But we also discovered that the brakes on oil production are partially on even under normal conditions, which was a big surprise," said John Shanklin, a biochemist and leader of the study. "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," he said.

The study puts the spotlight on the enzyme that determines the rate of oil production. The enzyme, known as ACCase, is a protein made of four subunits, all of which are necessary for the enzyme to function. The researchers suspected that disabling the genes that code for the inactive subunits would turn off the off-switch for oil production, allowing the plant cells to make more oil. When they tested this idea by feeding the plant cells excess fatty acids, that's exactly what happened: Cells with combinations of the disabled genes didn't turn off oil production the way cells with the normal genes did. This implies that, even under normal conditions, inactive subunits are putting the brakes on ACCase, reducing its activity and limiting oil production.

"Disabling the genes for those inactive subunits is like taking the brakes off the car, revealing the motor's true potential," Shanklin said.

Read the media release from Brookhaven National Laboratory.

Figure: Using biochemical genetic techniques in plant cell cultures, this Brookhaven Lab team evaluates the effects of releasing the biochemical "brakes" on plant oil production. Pictured are: Group leader and Biology Department Chair John Shanklin (standing), Jan Keereetaweep (front right), Hui Liu (front left), and Zhiyang Zhai.