The soybean is an extremely complex plant.
Kristin Bilyeu knows this all too well.
Bilyeu, a research molecular biologist for the United States Department of Agriculture’s Agricultural Research Service and an adjunct associate professor at the University of Missouri, has been researching soybean seed composition since 2003.
Her research can best be described as detective work. Bilyeu’s main objective has been to improve soybean oil quality, to make it healthier for consumers. It’s a goal that she’s been able to achieve.
To hit that objective, Bilyeu dives deep into the soybean genome. She researches every soybean pathway, looking for the right combination to give favorable results.
“When I started my job with the USDA, I was given a mission to go after the challenges of seed composition,” Bilyeu said. “At that time, there had been ongoing efforts to improve the oil quality. There were impending changes that the federal government was looking at, from a regulatory standpoint, which put a timeclock on finding answers.”
Bilyeu started researching linolenic acid first. She was able to find varieties that lowered linolenic acid, however, there was still work to be done.
“I first went after changing the oil in a way that improved the most unstable component – linolenic acid,” Bilyeu said. “It’s one of the five principal fatty acids in soybean oil. It is unstable when the oil is heated or exposed to air. It interferes with the shelf life and the flavor as well. When oil goes bad, that’s the reason. I made some progress there.
“I identified the genes responsible for controlling this, and that allowed breeders to more efficiently capture the trait in new varieties. That research went along very well. We developed new varieties that were low in linoleic acid. They did not solve the functional properties of the oil, however. They were launched, but they didn’t solve the main problem. The oil wasn’t at its top function.”
To make the oil more functional, Bilyeu shifted her focus away from the unstable components, such as linolenic and linoleic acids, to oleic acid. More oleic acid leads to a more healthy oil.
After more sleuthing, Bilyeu was able to find the correct pathways to increase the oleic acid in soybean oil from 20 percent to 80 percent. It was a huge breakthrough, considering soybean oil research has been going on since the 1960s.
“People had been looking for this for a long time,” Bilyeu said. “To see that kind of change, everyone gets excited. It’s one thing to make an incremental change, going from 10 percent to 11 percent. You could get excited if that was statistically significant. It’s a different thing to make a four-fold change, from 20 percent to 80 percent.”
Why high oleic?
Health regulations and codes continually change. That was a big part of why soybean oil quality has been researched over the years.
“The goal is to create an oil that has a stability and a functionality and allows the flavor of the food to predominate when the oil is used as a cooking or frying oil,” Bilyeu said.
Bilyeu said that one way to make soybean oil more stable and functional was hydrogenation or partial hydrogenation. However, those processes lead to trans fats, which are not good for human health. Some companies use palm oil, which is an inexpensive alternative. However, palm oil is high in saturated fats.
That led to Bilyeu and others researching the oleic acid in soybean oil.
“Oil is not something that everyone thinks about in terms of their diet,” Bilyeu said. “It’s very, very calorie-dense. Americans get a lot of calories from oil that they don’t realize.
“High oleic oil gives people an opportunity to enhance the nutritional component of their diet without doing anything consciously. If you’re buying tortilla chips for your chips and dip, and you get a chip that’s been fried in high oleic oil, that chip is going to have a better profile for your health than if it’s fried in palm oil for instance.”
Bilyeu’s research on oleic acid began around 2004.
The big breakthrough
Bilyeu came in contact with several people during her research, including Grover Shannon at the Fisher Delta Research Center in Portageville, Mo. Bilyeu and Shannon had similar objectives – but were attacking them in different ways. Bilyeu was focused on the molecular side, while Shannon was exploring the breeding approach to increasing oleic acid.
Several people combined their efforts for the project.
“Many people had the same goals,” Bilyeu said. “We had enough of the same goals that we kept in contact. I sampled some of the lines that Grover was working with.
“In general, it was a helpful environment. We didn’t line out specific projects, but we were aware of what each other was doing.”
Shannon had some early findings that pointed to an increase in oleic acid in soybean oil.
“He had some preliminary data from our winter nursery that seemed to indicate he had found a way to make the high oleic acid in soybean oil,” Bilyeu said. “The problem was, anytime we got results from our winter nursery, they were not the same as the results we would get from a Missouri producer. He had some pretty good hints, though.
“I then started exploring the genes that might be responsible. We found the two genes that control the trait. It is a real trait. Since Grover came on so early, we were able to enable breeding for that trait very, very efficiently. We were able to explore other sources as well.”
The breakthrough came around 2008. Bilyeu’s next job was to figure out why the increase in oleic acid happened.
“The key for us was that we took sources of variant genes from two separate soybean lines that had never gotten together before on their own,” she said. “We made some educated guesses about which combinations we should make that might have a chance for success.
“We go through the whole genome of soybean, just looking. We know enough about the genes in soybeans that we were able to take a solid approach. It’s called a candidate-gene approach. We had candidate genes and sequenced those and identified single base changes. Soybeans have a billion-base genome and we know that one single change in one base is responsible in one gene. But it takes two. There is another gene in the genome that has its own single base change. If we know those single-base changes, we can create a molecular marker so we can distinguish any sample. We can use that in breeding to put those together.”
The findings resulted in two patents, both of which relate to the method of joining the two separate variants together.
“We feel pretty good about paving the way,” Bilyeu said. “We feel like it’s going to be really useful as a solution.”
Much like medical research, there are several steps in place before a product like this can reach consumers.
While high oleic is extremely desirable, the breeding done to make that possible leads to a soybean that is very different.
“The soybean line that contributed these two genes are not very good on their own,” Bilyeu said. “They did not come from breeding material that is in a program creating high-yielding materials with disease resistance and other traits that farmers want. They either came out of a mutant population or out of land races. They are not adapted to our environment.
“The breeding work that you have to do is pretty intense. You have to create new populations breeding with good materials that are adapted and high yielding. Then, you have to worry that the big change in the seed affects things farmers care about. Farmers care about yield. It’s hard to test yield in an unadapted variety. You have to go through and do the work.”
Current studies are being done to look at the yield of the new soybean line. So far, Bilyeu said, things look promising.
“When we saw the trait come about, it was in the winter nursery,” she said. “We see a lot of high numbers coming from the winter nursery, and when we bring them here, they go right back down. We worried about growing it in different places. We call that an environmental stability test. No one is going to pick a variety that they know will give them a 20-percent yield loss.
“We have to breed the trait into soybean lines that are adapted to other areas, such as Iowa, Minnesota and Georgia. We’re in the process now of deploying the trait in different maturities. We are just getting data back. It looks pretty good so far.”
There’s also the fact that high oleic is not enough on its own.
“We still need to have low-lin,” Bilyeu said. “We’re using four genes to breed, using conventional genetics, to put those genes together to give an oil profile where over 80 percent of the oil is oleic acid. We’ve reduced the saturates by about 20 to 25 percent. We don’t really have to do anything special. That is just a consequence of the other breeding. We keep the linolenic acid at the lowest level that we can. Three percent is what the industry says. We don’t want our fried potatoes to taste like fish. We want them to taste like potatoes.”
Bilyeu said they want the soybean to be something farmers are a fan of as well.
“Our farmers are interested in sustainability, conservation and land management that are beneficial,” she said. “They are very progressive minded.
“I would like to see that food use go back to soybean oil. It’s a great domestic product. If high oleic is the way to do that, then we have to convert some portion of the soybean crop to high oleic so that the food companies have those options.”
For now, Bilyeu is focused on making progress each day.
“Plant breeding is a challenge that will probably never completely be overcome. It’s an art and a science,” she said. “That’s the nature of research. You have to investigate many avenues to find a major challenge – and hope that at least one of them is going to be appropriate.
“Some days it’s frustrating and some days it’s really interesting.”
This research was partially funded by the Missouri Soybean Merchandising Council and the soybean checkoff.