Click image for caption and other photo
story to find out more.
Gene Jockeys Fight Fusarium
By Marcia Wood
August 15, 2002
Tomorrow's wheat and barley plants might be equipped with genes
that protect against a formidable fungal foe, Fusarium graminarium.
This destructive fungus is responsible for a disease commonly
known as wheat scab, or Fusarium head blight, which causes plump kernels to
shrivel and take on an unhealthy, bleached, scabby appearance. Right now,
there's no effective control for this plant disease, which caused estimated
losses of $2.7 billion in 1998 to 2000 in the north-central and Great Plains
In a "dirty trick" strategy, scientists with the
Agricultural Research Service, together
with industry and university researchers, hope to use genes from
Fusarium itself to undermine the fungus.
Their approach revolves around a natural process that
Fusarium uses to invade plants. The fungus, in order to keep adding onto
its rootlike growing tip, or hypha, has to periodically tear down its old
hyphal cell walls and make new ones.
To do that, Fusarium manufactures cell wall-degrading
enzymes called chitinase and glucanase. The scientists are inserting genes into
experimental wheat plants that enable the plants to manufacture these same
enzymes. Their goal? Disrupt the Fusarium growing tip's orderly invasion
by overwhelming the fungus with chitinase and glucanase that it didn't make and
Research geneticists Patricia A. Okubara with the ARS Root
Disease and Biological Control Research Unit in Pullman, Wash., and Ann E.
Blechl at the ARS
Improvement and Utilization Research Unit, Albany, Calif., are
collaborating in the research. Okubara, Blechl and co-inventors Thomas M. Hohn
of Syngenta at Research Triangle Park,
N.C., and Randy M. Berka of Novo
Nordisk, Davis, Calif., are seeking a patent for the work.
Scientists have known about the role of chitinase and glucanase
for years. But Okubara and Blechl are the first to use pieces of the
Fusarium microbe's own chitinase and glucanase genes as
anti-Fusarium genes in wheat.
Details are in Agricultural Research magazine on
the World Wide Web at:
ARS is the U.S. Department of Agriculture's chief research