Ames, Iowa
September 16, 2008
Identifying genes essential for the soybean plant’s defense
against three major diseases will be the aim of a new $2.1
million research project led by
Iowa State University.
“We expect that information resulting from the research will
help improve soybean cultivars for disease resistance by
accelerating plant breeding programs and by enabling the
engineering of new disease resistance traits,” said Steve
Whitham, associate professor of plant pathology.
Whitham leads the four-year project that earned a $2.1 million
National Science Foundation
grant.
The research is important for the state of Iowa, which leads the
nation in soybean production. Nationally, soybean yield losses
linked to diseases are estimated to cost farmers more than 400
million bushels every year. Even though soybean is the nation’s
second most economically important crop (behind corn),
scientists know little about specific genes in charge of
defending the soybean plant against diseases.
The ISU project will focus on genetic resistance against three
important soybean pathogens: soybean mosaic virus, Asian soybean
rust and soybean cyst nematode.
Whitham’s co-investigators are ISU plant pathologists John Hill
and Thomas Baum; Melissa Mitchum, a plant scientist at the
University of Missouri; Michelle Graham, a USDA research
geneticist and assistant professor in ISU’s Department of
Agronomy; Kerry Pedley, a USDA researcher at Fort Detrick, Md.;
and Ricardo Abdelnoor of Embrapa Soya, the soybean research unit
of the Brazilian Agricultural Research Corporation.
To help study gene function, the scientists will use an approach
called virus-induced gene silencing (VIGS). The technology uses
a virus equiped with a small segment of genetic material
matching a soybean gene of interest. When the virus infects the
soybean plant, the plant recognizes the invader and begins
defending itself. In the process, the plant is tricked into
destroying its own genetic material, but only the part that
matches what is carried by the virus. This prevents the gene of
interest from making its intended product—in effect, silencing
it.
When a gene is silenced, scientists can see how well the plant
fares against a certain disease without the gene’s help.
“Besides its effectiveness, the technology can help evaluate
high volumes of genes — a good thing, considering the soybean
genome is estimated to contain over 60,000 genes,” said Whitham.
VIGS was customized for use in soybeans by Hill and Whitham
through an ISU Plant Sciences Institute Innovative Grant award
in 2006.
Whitham said the success of the National Science Foundation
grant application also was rooted in results of earlier studies
supported by commodity groups including the Iowa Soybean
Association and the United Soybean Board. The soybean rust
component of the project was initiated by Baum and Whitham in
2005 as one of five research initiatives supported by ISU’s
Plant Sciences Institute.
“The project has become an outstanding example of Iowa State’s
ability to rapidly mobilize resources to combat an emerging
disease, and to move forward such projects to the level where
they can expand in scope, attracting prestigious national
funding awards,” said Stephen Howell, director of the Plant
Sciences Institute.
Whitham said the project also will help train ISU students and
may encourage them to consider careers in the biological
sciences. It also will improve scientific ties to Embrapa Soja,
an important partner in addressing Asian soybean rust problems. |
|
