Des Moines Register
07-16-06
Plant science grows at ISU
Research spans academic disciplines and spurs advances in technology
ANNE FITZGERALD
REGISTER STAFF WRITER
Ames, Ia. — Technology is speeding developments in plant science, and many
of those developments are occurring here, at Iowa State University.
For example, a decade ago, it took a week or more to assess certain
characteristics of a single corn gene. Today, thousands can be analyzed in just a
few hours, thanks to robotics and other high-technology tools.
Iowa State University researchers are capitalizing on such advances in
technology.
Patrick Schnable, a plant geneticist, and others working in his laboratory at
ISU’s Plant Sciences Institute have used gene chip technology to measure
particular genes’ ability to express proteins — information that plant breeders can
use to develop improved corn hybrids.
Increasingly, such research spans academic disciplines, with plant geneticists,
statisticians, engineers, molecular biologists, chemists and other scientists
collaborating on the Ames campus.
KAN WANG
Perfecting 'pharma corn’
Corn that contains pharmaceutical ingredients has been touted as a triumph of
modern plant breeding. One developed at Iowa State University contains
therapeutic protein that has shown promise for treating bacterial diarrhea in pigs.
Producing so-called pharma corn has proved problematic, because of the
possibility that its pollen could contaminate conventional corn.
Now, ISU researchers may have developed a solution: A male sterile corn that
produces therapeutic proteins but no pollen.
Kan Wang, an ISU professor of agronomy and director of the ISU Center for
Plant Transformation, developed the approach using traditional plant breeding
techniques. She is teaming with Kendall Lamkey, interim chairman of ISU’s
agronomy department and director of the Raymond F. Baker Center for Plant
Breeding. Both centers are part of ISU’s Plant Sciences Institute.
The researchers began developing their sterile-pollen pharma corn last winter,
using the institute’s new biosecure greenhouse on the campus in Ames. This
summer, they are conducting a federally-approved field trial in Marshall County.
They take steps to make sure that none of the transgenic material contaminates
other crops. Seed produced last winter was planted in a remote location,
enclosed by fence, a month later than the nearest field of commercial corn. The
transgenic corn will be detasseled, and conventional corn surrounding it will
pollinate the plants.
PATRICK SCHNABLE
Understanding hybrid vigor
Corn hybrids are developed by crossing two inbred parent lines, but plant
breeders routinely discard many of the crosses because they lack heterosis, or
hybrid vigor, a key to plant growth.
For decades, researchers have sought to unlock the genetic triggers of heterosis.
Patrick Schnable, an Iowa State University professor of plant genetics and
director of ISU’s Center for Plant Genetics, believes he has discovered part of
the key.
Schnable and his team of researchers crossed inbred parent seed corn to create
hybrid corn. They used gene chip technology to measure expression levels in
both the parent and hybrid seeds, observing heterosis at the molecular level in
thousands of genes.
Their research showed that various molecular mechanisms contribute to
heterosis. The scientists also were able to sort genes by the degree of heterosis.
Of the 14,000 genes they started with, they identified about 1,000 that were
especially promising.
The work could mean significant savings of time and expense for researchers in
both the public and private sectors, by speeding the process of elimination.
“If we can get rid of the bottom half, we can eliminate half of the testing,”
Schnable said. “Speed is everything in this.”
Heterosis is “a huge thing” in corn, as well as in wheat and rice, he said. It’s also
important in vegetables, affecting yields, plant height and other factors.
“I think if we understand heterosis, really understand the fundamentals of it, we
will find ways to use it that we hadn’t thought of before,” Schnable said.
WALTER FEHR
Building yet a better bean
In the 1960s, Iowa State University agronomists Walter Fehr and Earl
Hammond developed a soybean with oil containing 1 percent linolenic acid. The
soybean’s oil did not require partial hydrogenation, a chemical process that
makes oil more stable but also produces trans fats, which is considered a no-no
in human health.
The so-called low-lin, or “trans-free,” oil has won favor among food
manufacturers, which since Jan. 1 have been required by the federal government
to specify the trans fat content on food product labeling.
Now, Fehr has developed a soybean variety that also contains elevated levels of
oleic acid, the same monounsaturated fatty acid that is found in olive oil. He
hopes that it, too, will become a hit among food manufacturers.
Fehr tapped soybeans in Japan that had about 50 percent oleic acid content,
compared to 28 percent in conventional soybeans. But the Japanese soybeans
could not be grown as far north as the upper Midwest, and their oil required
hydrogenation. In research conducted at ISU’s plant breeding nursery in Puerto
Rico, Fehr developed soybeans with high oleic acid content but low levels of
linolenic acid.
“Its performance exceeded our expectations,” he said.