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Close-up of a wheat
head infected with scab (Fusarium graminearum). Click the image for
more information about it. |
Healthy wheat field
outside Clay Center, Nebraska. Click the image for more information about
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Genomic "Jigsaw Puzzle" for Wheat Scab Fungus Is
Put Together
By Don Comis February
2, 2005
The Agricultural Research
Service has played a pioneering role in completing the mapping of the
genome of the fungus that causes wheat scab.
The worst ever wheat and barley disease first struck worldwide in the
1990s. Farmers and scientists quickly realized that the usual methods of
fighting crop disease--planting resistant crops and applying
fungicides--wouldn't be enough. They needed ways to control the fungus
genetically.
In 1999, geneticist
Corby
Kistler arrived at the ARS
Cereal
Disease Laboratory in St. Paul, Minn., to unravel the genome of the fungus
known as Fusarium graminearum. He and
University of Minnesota
geneticist Liane Gale mapped its DNA, linking about 99 percent of its genome
into a genetic map.
The project attracted a $1.9 million grant from the Microbial Genome
Sequencing Program administered jointly by the U.S. Department of Agriculture and the
National Science Foundation. Kistler shared
the award with colleagues at Purdue
University in West Lafayette, Ind.; Michigan
State University in East Lansing; and the
Broad Institute, a major genomics
research center, in Cambridge, Mass.
The Broad Institute used sophisticated computer techniques to assemble
a physical map from the hundreds of thousands of little bits of DNA sequences
that make up all of F. graminearum's genes. Kistler and Gale linked
together the last odd pieces. Last year, the institute integrated the
Kistler/Gale genetic map into its physical map. The combined map is on the
Broad Institute's website at:
www.broad.mit.edu/annotation/fungi/fusarium
The genetic map gives an overview of the order of the fungal
chromosomes, while the physical map is more detailed. Information gained from
the combined map has already accelerated the search for new ways to control
wheat scab genetically. For example, the map is helping scientists find the
genes that produce toxins that can render surviving wheat and barley unfit for
consumption.
Read
more about the research in the February 2005 issue of Agricultural
Research magazine available online.
ARS is USDA's principal scientific research agency.