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College of Food, Agricultural, and Environmental Sciences


Technology Offers Green Method to Tackle Top Disease of Cereal Crops

May 26, 2010

Editor's note: High-resolution photos are available. Contact Candace Pollock at 614-292-3799 or e-mail Captions are provided following the press release.

COLUMBUS, Ohio – Technology developed by researchers at The Ohio State University and the U.S. Department of Agriculture Agricultural Research Service (USDA-ARS) that will help manage the spread of one of the worst diseases affecting crops such as wheat and barley, has been licensed to Sci Protek, Inc., based in Vista, Calif.

The licensed technology is a yeast that offers a "green" method to protect cereal crops from a devastating fungal disease.

Researchers worked nearly 12 years to develop, identify and patent the naturally occurring yeast – isolated from Ohio fields – as a biological control method for controlling Fusarium graminearum, the fungus that causes Fusarium head blight or head scab.

Bio Control of Head Scab full3

Annual crop losses from the fungus in the U.S. alone exceed $1 billion per year. In addition, consumption of diseased grains causes human and animal disease and epidemics in developing world countries

Mike Boehm, professor and chair of Ohio State University's Department of Plant Pathology and a plant pathologist and principal investigator with the Ohio Agricultural Research and Development Center, said that biological control gives growers additional options for disease management.

"There are many ways to manage disease: genetics, crop rotation, fungicides and biological control or the use of beneficial microorganisms," said Boehm, who also holds an OSU Extension appointment. "This isn't the first biological control labeled for managing head scab, but a ‘green' fungicide is advantageous. It allows for managing head scab during a targeted timeframe that chemical fungicides may not adequately provide. In addition, the product could be used in organic production where fungicides are not a tool or in situations where fungicide use is restricted."

Controlling head scab is important. The fungal pathogen affects cereal grains, specifically wheat and barley, during the crop's flowering period. In addition, the fungal pathogen infects corn, causing stalk rot, and may lead to lodging. The disease causes yield losses, as well as produces a mycotoxin, known as vomitoxin, that is harmful to livestock and humans if eaten. Infected grain submitted to grain elevators as livestock feed or to be processed by millers and bakers can be rejected. During head scab epidemics, an entire crop can be wiped out.

Controlling head scab development and preventing toxin buildup, however, can be tricky. The disease only affects wheat and barley during a brief period when the plant is flowering – and then, only if environmental conditions are right. Spraying fungicides on wheat plants prior to flowering is not very effective. Spraying fungicides after flowering can contaminate the harvested grain with chemicals.

"Control really depends on the crop's stage of development, the weather, and if and when the plant may be susceptible to attacks from the pathogen," said Boehm. "Having such a targeted window for fungicide applications is a challenge, but also provides an excellent opportunity to use biological control."

That's why Boehm and his USDA-ARS colleague David Schisler turned to exploring the use of beneficial microorganisms as a means for managing this disease.

"Microorganisms are everywhere, even on plants. Some do nothing, others are parasitic, and there are others that may provide a benefit to the plant. Knowing this and dreaming a little bit, we set out to find microorganisms that live naturally on wheat, in particular on the wheat heads and flower parts, that can suppress the pathogen and reduce disease and toxin levels."

During the 12 years of lab, greenhouse and field trials across the Midwest, researchers screened hundreds of beneficial microorganisms (bacteria and yeasts) they found living on the wheat plant. Out of those hundreds, seven bacteria and yeasts were identified that exhibited the behavior they were looking for. Out of that group came the yeast that has been licensed to Sci Protek, Inc.

"We think this new development is going to be an incredibly important contribution in future cereal management programs for Fusarium head blight and the associated mycotoxins that this pathogen produces," said Nigel Grech, vice president and director of research and development of Sci Protek, Inc, in the company's press release.

Sci Protek, Inc. is a global leader in innovative and reduced-risk plant health solutions from the laboratory to the field. The company's current product portfolio includes Nematec and Dispense.

The yeast, known as Cryptococcus noadensis, has been found to reduce disease severity by as much as 50 percent while at the same time significantly reducing the amount of toxin in the infected grain. Researchers suspect the biocontrol yeast functions by either gobbling up the nutrients on the wheat flowers that the fungal pathogen needs to grow and colonize, or by feeding on the pathogen directly.

"It's been a very productive collaboration and rewarding project to have been a part of and the fact that this technology has now been licensed with an eye on making it available commercially throughout the world's wheat and barley growing regions is very exciting," said Boehm. "This is a great example of the type of collaborative research and partnering done at Ohio State University that not only has a global reach in the fight against hunger and food security, but one that also typifies the entrepreneurial spirit that exists on campus."

Terms of the license were not disclosed. This research has been funded by the USDA-ARS and the U.S. Wheat and Barley Scab Initiative. Other researchers involved in the project included Ohio State University post-doctoral researchers Naseem Khan and Shouan Zhang.

Photo captions:

1. Ohio State University plant pathologist Mike Boehm explains how head scab infects wheat and how the beneficial yeast that was identified protects the crop from disease development. (Photo credit – Ken Chamberlain, OARDC)

2. USDA-ARS plant pathologist David Shisler (left) and fellow Ohio State University colleagues prepare to treat wheat plots with a fungicide solution that contains colonies of the yeast, Cryptococcus noadensis. (Photo credit – Ohio State University)

3. The yeast, Cryptococcus noadensis, as seen via electron scanning microscopy. (Photo credit – USDA-ARS).

4. Head scab (Fusarium graminearum), or head blight, infecting wheat heads. The disease causes upwards of $1 billion a year in crop losses nationwide. (Photo credit – Ohio State University).

Candace Pollock
Mike Boehm