Barley genome? Done
U professor makes news as genome-mapping is completed, opening doors to drought- and disease-resistant crops and tastier beer
A St. Anthony Park resident was in the news recently for a discovery that could potentially influence things as seemingly unrelated as the health of the world’s fourth-largest cereal crop, agriculture’s response to global warming and the taste of beer.
Prof. Gary Muehlbauer, 49, who holds the Endowed Chair in Molecular Genetics Research and Education at the University of Minnesota, was part of an international team that completed the sequencing of the barley genome. Published results of their research “provide a detailed overview of the functional portions of the barley genome, the order and structure of most of its 32,000 genes,” according to a university statement.
To put things in perspective, Muehlbauer says that, although the humble barley genome contains about the same number of genes as the human genome, it’s twice as big as ours. And if that isn’t enough to cut our anthropocentric pretensions down to size, Muehlbauer adds that barley is far from the most complex plant genome. In fact, for plant science, you could say that completing the barley genome is something of a warm-up act for the real brass ring of crop sequencing.
“The barley genome is only one-third as big as the wheat genome,” he notes.
Why wheat and barley have so much more genetic material than humans is a mystery of science.
“There’s more repetitive DNA between the genes,” says Muehlbauer. “No one really knows yet what these redundancies mean.”
Meanwhile, there’s lots of work to be done in applying the discoveries of barley sequencing to crop improvement. Muehlbauer is the organizer of a large-scale project designed to develop wheat and barley varieties suited to our changing climate. There are 55 scientists at 18 research institutions working on the Triticeae Coordinated Agricultural Project (TCAP).
“For the TCAP,” Muehlbauer says, “the barley genome sequence will be quite useful and a powerful tool to increase the efficiency of barley breeding.
“Once we have the sequence, we can zoom in on those lines that confer specific traits—like drought tolerance. You can identify types of genes important for different traits, and then assess them in standard field trials.”
Resistance to dry conditions has a special value for barley cultivation, because of a nasty, moisture-loving, fungal pathogen that causes a plant disease called fusarium head blight. Apart from damage it does to the crop, fusarium causes uncontrolled vomiting in humans and animals that consume the grain.
“It’s a huge problem,” says Muehlbauer. “All the barley [cultivation] is moving to drier places where the fungus is not so much of a problem.” Twenty years ago, for example, Minnesota had 10 times as many acres growing barley than it does now. Barley cultivation has shifted to drier regions in the Dakotas and Canada.
The newly mapped genome may hold the key to eventually developing a strain of fusarium-resistant barley. Currently, there is no completely resistant barley strain, but there are strains that show partial resistance. “The genome can show multiple gene sequences providing some areas of resistance,” Muehlbauer says. Success might lie in combining partially resistant strains.
Fusarium is not the only disease threat to barley. “When the environment changes,” says Muehlbauer, “the pathogens change.” Global warming, in other words, doesn’t merely overtax our air conditioning systems, create frequent megastorms and melt the polar ice caps. Talk with Muehlbauer long enough and you’ll learn about potential vegetable threats that rank right up there with nuclear annihilation and a return of the 1918 flu pandemic. There is Ugan99, for example, a pathogen discovered in Uganda in 1999. “Eighty to 90 percent of barley and wheat worldwide is susceptible to this,” Muehlbauer says, and a big enough outbreak could conceivably devastate world grain supplies.
Scientists like Muehlbauer are clearly in the frontlines of the global struggle against agricultural disease, but happily that’s not the only use that they will find for the barley genome. Basic barley rarely finds its way onto the supper menu. Aside from the occasional can of beef and barley soup, it’s hardly a household staple. “There’s too much chaff in barley and it goes off-color really quickly,” says Muehlbauer.
But barley has another, far more noteworthy, role in the Midwestern American diet. Although three-quarters of barley is used for animal feed, a vital 20 percent of the crop finds its way into beer.
Barley is a prime ingredient in beer, and thanks to gene sequencing, there may one day be more savor in the suds. Muehlbauer is already working with two microbreweries—New Glarus of Wisconsin and Sierra Nevada of California—to investigate whether different lines of barley yield different flavors in the beer. “We want brewing companies to work with us,” he says.
For Muehlbauer, crop improvement is something of a family business. He grew up in Pullman, Wash., where his father was a plant scientist at Washington State University specializing in pea and lentil breeding. Muehlbauer remembers the day in 1982 when his father decided to buy a computer. A teenager at the time, Muehlbauer says, “we laughed. Why would he need a computer? But [my father] was convinced that he would need it in his future.”
His dad was right, of course, and Muehlbauer and his graduate students spend plenty of time generating computer data these days. Still, an observer senses that much of his enthusiasm is reserved for what he calls “wet lab” work, assessing the results of breeding experimentation. His most satisfying professional moments come “when my students and post-doc[tural fellows] come up with new results that we can understand and interpret.” Unfortunately, the scientific process being what it is, those interesting discoveries don’t occur all that frequently.
“Science is never like a Eureka moment,” says Muehlbauer. “You can see the progression toward the result. It would be good if there was always a new result every other week.”
But reality is otherwise. “Every three years you get a result, and then you spend the next two years writing it up.”
Judy Woodward is a regular contributor to the Park Bugle.