WASHINGTON, Nov. 30, 2016 - There’s some good news for wheat
farmers around the globe. A research team led by Kansas State University
scientists says they have isolated and cloned a gene that provides resistance
to Fusarium head blight, or wheat scab, a crippling disease that caused $7.6
billion in losses in U.S. wheat fields between 1993 and 2001.
Bikram Gill, distinguished professor of plant pathology at
KSU and the director of the school’s Wheat Genetics Resource Center, estimates
that nearly 100 scientists, faculty, staff and students participated in the research.
The journal Nature Genetics published the team’s findings online, noting that
work on the project goes back about 20 years and includes contributions from
China and several American universities.
"The breakthrough that we're reporting is the cloning
of a resistance gene," Gill told K-State News in an interview. "We have
identified the DNA and protein sequence, and we are getting some idea of how
this gene provides resistance to the wheat plant for controlling the disease.
The cloning of this gene is the key to unlock quicker progress for control of
this disease."
Fusarium head blight is a disease that shows up periodically
in more humid growing regions. It caused severe damage in Minnesota and North
Dakota in 1993 and subsequent years. Gill noted that a 1997 epidemic in
Minnesota, which ruined 50 percent of the state's wheat crop, caused an
estimated $1 billion in losses.
Wheat scab is caused by the fungus Fusarium graminearum,
which produces a toxin that makes the crop unfit for human and animal
consumption. James Anderson, a professor of wheat breeding and genetics at the
University of Minnesota, said there are frequent epidemics of the disease reported
in the United States, Canada, Europe, Asia and South America.
The fungus is also a menace to the barley industry. Gill
noted that since the 1997 outbreak in Minnesota, malting barley is rarely grown
in the upper Midwest because the industry implemented zero tolerance for the
toxin Deoxynivalenol produced by fusarium.
Previously, the wheat variety known to best resist Fusarium
head blight was a Chinese cultivar named Sumai 3. But while scientists knew
Sumai 3 provided resistance, they did not know what DNA sequence was
responsible for resistance — until now.
Kansas State University faculty and students used
sophisticated wheat genome sequencing techniques to isolate the gene. Gill said
that Eduard Akhunov, associate professor of plant pathology, prepared a library
of "millions of clones" of Sumai 3 DNA. Lead scientists Nidhi Rawat
at the University of Maryland and Mike Pumphrey at Washington State University
sifted through the library.
Rawat told Agri-Pulse that her efforts were just the
“end of a very long chain,” and that researchers had been sifting through the
library for years.
Gill said it was “like searching for the proverbial needle
in the haystack” to find one clone that contained the resistance gene. "It
looks like when the fungus attacks the wheat plant, the resistance gene protein
has domains for binding and making pores in the cell wall of the fungus, and
stopping it from spreading and infecting the developing grain," he said.
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