Increasing the oil in tobacco plant leaves may be a step towards using the plants for biofuel, a new study suggests.

Researchers from the Biotechnology Foundation Laboratories (BFL) at Thomas Jefferson University said they have identified a way to increase the oil in tobacco plant leaves, thus paving the way for turning the plants into biofuel.

Their findings were published in the January issue of Plant Biotechnology Journal.

Tobacco can generate biofuel more efficiently than other agricultural crops. However, most of the oil is typically found in the seeds -- tobacco seeds are composed of about 40 percent oil per dry weight.

Although the seed oil has been tested for use as fuel for diesel engines, tobacco plants yield a modest amount of seeds, at only about 600 kg of seeds per acre.

But researchers at BFL sought to find ways to engineer tobacco plants, so that their leaves expressed the oil.

Typical tobacco plant leaves contain 1.7 percent to 4 percent of oil per dry weight.

But the researchers managed to engineer the plants to overexpress one of two genes: the diacyglycerol acytransferase ( DGAT) gene or the LEAFY COTYLEDON 2 (LEC2) gene. The DGAT gene modification led to about 5.8 percent of oil per dry weight in the leaves, which was about two-fold the amount of oil produced normally. The LEC2 gene modification led to 6.8 percent of oil per dry weight.

"Based on these data, tobacco represents an attractive and promising 'energy plant' platform, and could also serve as a model for the utilization of other high-biomass plants for biofuel production," said Vyacheslav Andrianov, Ph.D., assistant professor of Cancer Biology at Jefferson Medical College of Thomas Jefferson University.

"Tobacco is very attractive as a biofuel because the idea is to use plants that aren't used in food production," Dr. Andrianov said. "We have found ways to genetically engineer the plants so that their leaves express more oil. In some instances, the modified plants produced 20-fold more oil in the leaves."

(Xinhua News Agency January 2, 2010)