A team in the United Sates has identified the genes responsible for increasing the oil content of plant leaves, in a discovery which could lead to great advances in the fields of agriculture and biofuel production.

Scientists at the U.S. Department of Energy's Brookhaven National Laboratory say they have found genes which, when their expression is enhanced, create a significant increase in the oil-content of leaves.

“If we can transfer this strategy to crop plants being used to generate renewable energy or to feed livestock, it would significantly increase their energy content and nutritional values,” said Brookhaven biochemist Changcheng Xu, who led the research.

Typically, plants store a large amount of their oil reserves in seeds to nourish growing plant embryos, and not a great deal within the leaf. The new study hopes to create a way to reprogram the plants so that more oil is kept in the leaves, where it can be more easily extracted and used.

A breakthrough came when researchers found a particular gene which played no role in oil production within seeds, but was a big factor when it came to leaves.

“If you knock out [disable] the gene for an enzyme known as PDAT, it doesn't affect oil synthesis in seeds or cause any problems to plants, but it dramatically decreases oil production and accumulation in leaves,” Xu said.

However, over-expressing the gene for PDAT - getting cells to make a pile of the enzyme - resulted in a 60-fold increase in leaf oil production.

“It was as if many small oil droplets like those found in seeds had fused together to form huge globules,” Xu said.

But that was not immediately a good thing. The large clumps of oil on the leaves were actually more difficult to harvest than when they were found in the seeds. So, the team took the next step of over-expressing a gene which creates a protein to break up the globules into smaller bits.

Over-expressing the two genes together led to a whopping 130-fold increase in production of leaf oil, which was bundled by proteins into a more manageable form.

The encouraging results have of course prompted more research.

The team will now explore the potential effect of over-expressing the same key genes for oil production in dedicated biomass crops such as sugarcane.

Their studies so far have been detailed across two papers, one published in The Plant Journal and another in Plant Cell.