Genetic engineering breakthrough ups oil content of seeds by 18%

Vegetable oils have wide-ranging uses, playing a role in everything from food processing, to perfume production to the manufacture of biofuels. With demand only expected to increase, a team of scientists in Singapore has demonstrated a way of increasing the yield of oil from plants through genetic engineering, which could increase their output by as much as 18%.

The work was carried out by scientists at Singapore’s Nanyang Technological University (NTU) and builds on existing knowledge around the way oil builds up in plant seeds and edible nuts. A protein called Wrinkled1 (WRI1) has been known for decades to play an important role in the accumulation of oils in this context, but the NTU team managed to image the molecular structure of this protein for the first time.

With this new, detailed understanding of the protein and the way it binds to a plant’s DNA to regulate the accumulation of oil in its seeds, the team was able to make some tweaks. The team’s genetic modifications were aimed at improving the protein's ability to bind to DNA, and the versions they produced were able to increase this ability tenfold, in turn boosting the oil content of the seeds.

“Being able to see exactly what WRI1 looks like and how it binds to DNA that is responsible for oil production in the plant was the key to understanding the entire process,” said study author Associate Professor Gao Yonggui. “WRI1 is an essential regulator that informs the plant how much oil to store in its seeds. Once we were able to visualize the ‘lock’, we then engineered the ‘key’ that can unlock the potential of WRI1.”

The experiments involved injecting modified WRI1 proteins into the leaves of Nicotiana benthamiana plants, which increased levels of a dietary lipid called triacylglycerol. Follow-up experiments saw a model plant called Arabidopsis thaliana receive the same treatment, which boosted the oil content in its seeds by 15 to 18% compared to controls. The scientists say the offspring of this modified plant would feature the same modified WRI1 protein and produce more oil as a result.

“We know that WRI1 is a protein that binds to a plant’s DNA sequence and sets off a specific chain of instructions that regulates the accumulation of oils in the seeds,” explained study author Assistant Professor Ma Wei. “The stronger the binding – the more oil the plant will concentrate in its seeds. Therefore, we chose to improve this portion of WRI1 that binds to its target DNA, which is highly conserved across many seed-bearing plants. Being highly conserved means many species of plants will have the exact same mechanism that can be modified, so we should be able to translate our oil-yielding modification easily to many different types of crops in future.”

Crops that produce large amounts of vegetable oil, such as soybean, sunflower and rapeseed, already boast a high percentage of oil in their seeds, so the types of gains demonstrated in the scientists’ experiments are significant. The breakthrough is one that could help shore up food security by increasing the nutritional value of certain foods, while also lessening the strain on agriculture.

“When we can increase the fat content in edible seeds and nuts, a person can eat a lesser amount but still feel full, due to the increase in calories consumed,” said Professor William Chen, Director of Food Science & Technology Programme at NTU, who was not involved in the study. “So instead of growing more crops to feed more people, we should also look at methods where the crops grown have more calories and nutrition, so that the same amount of food can feed more people.”

The research was published in the journal Science Advances.

Source: Nanyang Technological University