Unlocking the Mysteries of Soybean Seed Composition

March 24th, 2002

AMES, Iowa — Mark Westgate knows his research won't earn him a spot on the "Amazing Discoveries" television program. It doesn't have flash and pizzazz. But the way he sees it, slow and steady wins the race.

"Sometimes it's a tough sell," says Westgate, a plant physiologist in Iowa State University's agronomy department. "Sometimes it's difficult to see the short-term benefits that can accrue from the long-term, basic research we are doing."

But Westgate is a firm believer his basic research will pay dividends to soybean growers.

The term "basic research" refers to studies aimed at understanding mechanisms and underlying causes, rather than prescribing a quick solution to a problem. To the non-scientist, however, Westgate's work seems anything but basic. He uses sophisticated scientific equipment and state-of-the-art technologies to gain a greater understanding of the factors that determine the composition of soybean seeds.

"Soybean seed composition is important because it affects the market price paid to producers," Westgate says. "And it will become even more important as the soybean market evolves into a system based on seed component values."

Westgate says an integrated effort on several fronts is the key to increasing the value of soybeans by modifying seed composition. To that end, he has several research projects underway, with the largest funded the past two years by the Iowa Soybean Promotion Board (ISPB).

The project has three objectives, and progress has been made on all three.

The first focuses on determining how seed protein, oil and starch content respond to changing environmental conditions. "We have learned that the response to temperature and nitrogen supply are primarily seed-determined characteristics - that is, controlled by gene activity within the seeds," Westgate says.

The second objective is identifying important genes that control variation in seed composition. This involves profiling the expression of seed genes during seed development. Westgate and his colleagues at Iowa State expect to have gathered this key information by mid-summer.

The third objective is aimed at modifying the genes in soybeans. "This involves adding unique genes from another plant, animal or microbe," Westgate says. "Our research team has selected a group of genes involved in protein and oil synthesis and inserted them into soybean plants at ISU's Plant Transformation Facility. Now we're watching to see if the plants accept these genes and if they work in their new genetic environment."

Westgate's other research projects on soybean seed composition complement the ISPB-funded project. One is a collaborative breeding project with the University of Minnesota. "We've developed soybean lines that share 94 percent of the same genes, but differ in seed protein by about 10 percent," Westgate says. "Because the genetic differences have been narrowed that much, they are ideal for identifying the genes that control composition."

A project funded by ISU's Plant Sciences Institute is applying chemical engineering technology to map the process by which sugar is transformed into protein in the soybean seed. Additional funding for this and other projects comes from Iowa State's agronomy department.

Historically, increasing yields has been the biggest concern of soybean growers. And Westgate's research doesn't leave yields out of the picture.

He's involved in the Yields Project, a multistate research program funded by Iowa and Illinois checkoff dollars through the Soybean Research and Development Council. The Yields Project is one of the largest soybean research projects ever undertaken to understand factors that limit soybean yields.

"The accumulation of proteins, oil and carbohydrates within the seed ultimately determines grain yield. We're collecting composition data on all the Yields Project plots," Westgate says. "This database will help us sort out how various stresses affect yield and seed composition."

Westgate is confident his research will someday uncover what genes are responsible for different seed components, and that these genes will be bred into new varieties. But until then, producers who want to capture some of the price benefits of specialty soybeans must pay attention to these traits in varieties currently available.

"We know variation in seed composition is primarily a genetically-determined characteristic. So variety selection is important if a grower contracts to deliver soybeans with a special component," Westgate says.


Mark Westgate, Agronomy, (515) 294-9654

Susan Thompson, Agriculture Communications, (515) 294-0705