Scientists say they have isolated and cloned a gene that provides resistance to Fusarium head blight, or wheat scab, a crippling disease that caused several billion dollars in direct grower losses in U.S. wheat fields between 1993 and 2001. University of Minnesota researchers assisted in the decades-long research that reached the breakthrough that was discovered by Kansas State University (KSU).
Their findings are published online in the journal Nature Genetics. The article details nearly 20 years of research that included scientists in China, the University of Minnesota and other American universities.
"This has been a very difficult project," said KSU Distinguished Professor of Plant Pathology and Director of the Wheat Genetics Resource Center Bikram Gill. He estimates that nearly 100 scientists, faculty, staff and students have participated in the work.
Among several, Gill credited University of Minnesota Professor of Wheat Breeding and Genetics James Anderson, whose research team has been working on resistance to Fusarium head blight since 1993 and was the first to genetically map the location of the gene to a small segment of the wheat chromosome. That small segment has been used by wheat breeders worldwide as a diagnostic marker to indicate presence of the gene. Anderson has worked closely with researchers at KSU and Washington State University to help prove the identity of the resistance gene.
“The Minnesota Wheat Growers and Council are very proud of the work that Anderson and his colleagues are doing to help solve a devastating wheat disease like scab,” said Minnesota Wheat Grower and Wheat Council Executive Director David Torgerson. “Jim is not only doing the work of wheat breeding and releasing varieties for Minnesota wheat growers, but he has taken the time to do the world class research that will have positive impacts not only in rural areas of Minnesota but nationally and internationally. We look forward to when Jim and his breeding team can use this new discovery to delivery varieties with even more resistance then they have already.”
Gill also acknowledged Mike Pumphrey, an associate professor in the department of crop and soil sciences at Washington State University, for his work leading to the discovery. Pumphrey was a graduate student at Minnesota under Anderson and later with Gill at Kansas State University.
"The breakthrough that we're reporting is the cloning of a resistance gene," Gill said. "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."
A disease that shows up periodically in more humid growing regions, Fusarium head blight caused severe damage in Minnesota and North Dakota in 1993 and subsequent years. Gill noted that a 1993 epidemic in Minnesota, which ruined 50 percent of the state's wheat crop that year, caused an estimated $1 billion in losses.
Fusarium head blight is caused by the fungus Fusarium graminearum, which produces a toxin that makes the crop unfit for human and animal consumption. University of Minnesota Professor of Wheat Breeding and Genetics James Anderson said there are frequent epidemics of the disease reported in the United States, Canada, Europe, Asia and South America.
In 1993, all spring wheat varieties grown in the region were susceptible or moderately susceptible. As recently as 2006, 85% (23 out of 27) of regionally adapted varieties were rated as susceptible or moderately susceptible, whereas today about 35% of varieties are susceptible, partially due to the incorporation of this resistance gene into new varieties. This improvement is the result of two decades of research funded by state and federal programs to help reduce losses to the disease.
KSU 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, now at the University of Maryland, and Mike Pumphrey, now at Washington State University, sifted through the library.
"It's like searching for the proverbial needle in the haystack to find one clone that contained the resistance gene," Gill said.
"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.
The project was funded by the U.S. Department of Agriculture's Wheat and Barley Scab Initiative and the National Science Foundation. The agricultural experiment stations at each of the participating universities also provided support.
UMN Scientists Assist in Breakthrough Wheat Gene Research was orginally published on the University of Minnesota, Twin Cities website.