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Major Wheat Pathogen Chosen for Genome Sequencing

By Don Comis
March 31, 2005

Agricultural Research Service (ARS) scientists and a cooperator from The Netherlands are leading a project to sequence the genome of a key wheat pathogen.

The U.S. Department of Energy's Joint Genome Institute has chosen Mycosphaerella graminicola--one of the top five wheat disease pathogens--for genome sequencing. Stephen Goodwin, an ARS plant pathologist, and Gerrit Kema, a plant pathologist from Plant Research International in Wageningen, The Netherlands, are leading the M. graminicola genome sequencing project. Goodwin is with the ARS Crop Production and Pest Control Research Unit at West Lafayette, Ind.

M. graminicola causes major wheat damage worldwide and costs American wheat farmers $275 million a year in yield losses. The cost of fungicide sprays against M. graminicola in Europe is more than $800 million a year. If left unchecked, the fungus causes lesions in wheat leaves that interfere with plant growth and grain formation.

M. graminicola belongs to a family of fungi that cause similar leaf-spotting diseases in bananas, citrus, strawberries, cereal crops and many other plants. Some of these fungi--but not M. graminicola--produce toxins that increase their ability to infect plants. The effect of these toxins on people and animals is not known. The species that attacks bananas costs the world $2.5 billion per year in fungicides.

The mapping of M. graminicola genes can help researchers understand how the fungus infects crops. This information should help in controlling the fungus and related species.

Goodwin and Kema, a visiting scientist at the ARS facility in West Lafayette, laid the foundation for the genetic sequencing by assembling a genetic map with more than 300 gene markers. The Joint Genome Institute's equipment and expertise will enable efficient sequencing of the entire genome, which probably contains about 15,000 genes, by next summer.

ARS is the U.S. Department of Agriculture's chief scientific research agency.