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September 14, 2001

Goal: Corn that acts like wheat

by Skip Derra
Paul Scott says his corn research is growing, like a tree branching out into new directions that he finds more tantalizing than his initial goal. Scott, a USDA collaborator and plant geneticist at Iowa State, started out to produce corn that included the wheat gene that makes glutenin. He wants to develop a plant that has all the characteristics of corn, such as the taste and ability to grow in various climates, but also includes specific properties of wheat, like its "doughiness" and flexibility when used as a flour.
Paul Scott standing among his corn
Paul Scott's conventional corn breeding research has
branched into the not-so-conventional. Photo by Bob Elbert.

Scott originally wanted to develop grains that could be grown economically and would be easy to process into flat breads, such as tortillas. If he put the right wheat gene into a corn plant, Scott thought, it could result in products that help feed developing nations. It also could lead to the world's first foldable all-corn tortilla.

"Some people mix wheat and corn flour together to get the taste of corn and the flexibility of wheat," Scott explained. "The problem is, wheat is harder to grow in some places and it's more expensive than corn. So it would be nice to do it all with corn."

But the project funded by the Iowa Corn Promotion Board and the U.S. Department of Agriculture has taken different directions in the four years since it began. Those directions have kept Scott from sending samples of the glutenous corn to the "tortilla testing lab" at Texas A&M.

Convenient and nutritious
Scott still plans to do that, but first he wants to nail down a few other interesting properties of the glutenous corn. For example, Scott and his students have found that not only does this glutenous-corn exhibit interesting physical properties, but it also has enhanced nutritional properties. One line has 40 percent more protein in transgenic kernels, a substantial jump.

It also has a significant increase in tryptophan, a "limiting" amino acid. Such an amino acid can increase the ability of people and animals to use the corn protein, further enhancing its nutritional value.

Scott now is concentrating on the corn's "strange inheritance trait."

The transgene researchers use seems to be transmitted normally from the female parent through the ear, but very inefficiently from the male parent through pollen. Most corn genes are transmitted with equal efficiency from either parent.

"We've shown this is not specific to just this transgene, but we think it is a general mechanism that can be applied to any transgenic plants," Scott said. "Now we want to figure out exactly what turns this on and off."

Turning off the pollination of a corn plant could be good news to those concerned with "pollen drift" from fields of genetically modified corn to non-modified cornfields. It may also allay the fear of those alarmed over the recent Starlink corn episode.

"We've shown we can prevent a herbicide resistance gene from getting transmitted through pollen," he said. "Now we are trying to pin down the genetic feature that controls this unusual trait."

Plants are in his genes
Trying to prevent the pollination of plants through genetics is a bit of a twist for Scott, whose own interest in plant genetics is a cross pollination of several sources. His grandparents were Iowa corn farmers. While growing up in Ames, Scott used the resident expertise of Iowa State to help solve problems he encountered with a boyhood hobby a hydroponic garden in the basement of his parents' house. Attending the same church as Griffith Buck, Iowa State's noted rose breeder, helped solidify his interest in plants, and a growing interest in genetics was forged when he bred guppies in high school.

Scott's interest in plants is not limited to his lab. His home, once owned by Bethel Pickett, head of horticulture and forestry from 1923 to 1947, includes a backyard greenhouse where he propagates his own seed.

Scott said he doesn't grow many plants annually, around 5,000, because his work requires analysis of many of the kernels from each ear. With 400 kernels on average per ear, the analysis alone could keep students in Scott's group up to their ears in work.

"We're making new variations of that gene and in these versions we make small changes and ask, 'What does the inheritance of this gene look like?'" Scott said. "Is it inherited through pollen or not? We want to know what part of the gene is responsible. We want to narrow it down to a smaller piece of the DNA so we can figure out exactly what causes this."

All of which means the world's first foldable all-corn tortilla will be on the back burner a little longer as Scott and his students pin down the inheritance trait, or until a new branch of their research sprouts.

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