Research Highlights

Researchers working to impact human nutrition through high oleic, low linolenic soybeans

By Carol Brown

A small group of soybean breeders across the country are working to improve the tiny seed and ultimately the health benefits for humans.

Kristin Bilyeu is a research molecular biologist with the United States Department of Agriculture (USDA) Agricultural Research Service and adjunct plant sciences professor at the University of Missouri. She is leading a team of eight plant breeders to develop soybean germplasm with high oleic and low linolenic, or low-lin, fatty acids, both of which can have positive affects on the human diet.

“Linolenic acid is a polyunsaturated fatty acid that is part of a group of fatty acids essential in our diet,” Bilyeu explained. “These fatty acids are important for different functions in human health when we consume them and we must get them from our diet, but we don’t need much.”

But linolenic acid has chemical properties that make the soybean oil susceptible to going rancid, Bilyeu said. Having too much linolenic acid causes food to have off-flavors as the oil is exposed to air or heat. Researchers have developed low-lin soybeans, but just reducing this fatty acid didn’t fix the oil stability problem.

“Oleic acid is another fatty acid, but it’s monounsaturated, which is related to heart health,” said Bilyeu. “Oleic acid is the champion part of oil that we want to have high levels because it allows functionality. People don’t have issues with its flavor and it doesn’t have negative heart consequences.”

Improving oils used for cooking and frying that aren’t detrimental to human health is a complicated process but one that is in demand.  Bilyeu’s research project includes a goal of increasing oleic acid above 70 percent and decreasing the linolenic acid in soybean oil to below 3 percent. Her project is part of a larger effort supported through funding by the United Soybean Board.

“We are creating a nationwide soybean variety development foundation of breeding that has an oil trait to meet the market demand for oil functionality without the need for hydrogenation,” Bilyeu said.

She is working with researchers at six public universities in Arkansas, Georgia, Illinois, Minnesota, Tennessee, and Missouri where she is based. They are targeting all soybean maturity groups (MG 00-VIII), and are including yield, herbicide traits, and non-GMO sources. There isn’t much left out, which makes the project difficult.

“This was not just breeding for one event and one line, we wanted to make sure it spanned all of the U.S. soybean production areas, as well as all pairings including high yield, which has always been a part of our program,” she said.

 Speeding up the process

Achieving the project goal of a high oleic, low-lin soybean takes many cycles of plant crossbreeding for the desired traits. But the soybean can only grow so fast. To accomplish these goals more quickly, the team utilized USDA/ARS nurseries in Puerto Rico to eliminate the gap in cropping seasons.

“In Puerto Rico we ran three cropping seasons per calendar year and across all soybean maturity groups,” Bilyeu said. “It was a very large part of our effort and it was really challenging.”

Because the breeding process was focused on low to high oleic and low-lin traits, it necessitated selection for four separate genes, which, when the math is done, equates to only one of every 256 F2 (second generation cross) seeds containing the traits they wanted. The team used a combination of genetic markers, backcrossing and forward crossing to arrive with soybean lines containing the desired traits.

Being able to carry the breeding process along in Puerto Rico was vital and not without risks. Two hurricanes hit Puerto Rico during the project period.  The island residents had no water, electricity or a way to communicate.  Bilyeu said her contacts were ok and remarked that they are resilient and hard-working people as they got their lives and the project back in order.

After three years of work at all the locations, including three years of three growing cycles in Puerto Rico, soybean lines emerged with the desired oil content traits.

Because of this research, each of the soybean breeders with the project now has high oleic/low-lin genetic breeding programs to work with. This means they can concentrate on creating new soybean varieties using germplasm with these positive traits already developed.

“It is essentially a foundational change in the breeding program,” Bilyeu said.

Published: Apr 16, 2020