A closer look at the Cereal Disease Lab

The mission of the Cereal Disease Lab (CDL) is clear: to reduce losses in wheat, oat, and barley to major diseases including leaf rust, stem rust, and Fusarium head blight. These fungal diseases are some of the most damaging diseases among cereal crops. In extreme cases, cereal diseases cause yield losses as high as 50%. 

While that mission seems simple, preventing cereal diseases, especially rusts, is tricky. 

Rust diseases have the ability to become airborne and move across regions and continents. In fact, cereal rust fungi are superbly adapted for long distance spread. With the right wind patterns, a wheat rust outbreak in Texas can sweep north all the way to Manitoba, Canada, infecting the wheat crops grown in all the states along the way. 

Despite that, the most dangerous characteristic of rust pathogens is their ability to change and become more virulent, or severe, in response to previously resistant varieties. This means small grains breeders can work for years to develop varieties resistant to a particular strain of rust, but that work can be quickly wiped out by a shift in the rust pathogen populations. 

At the Cereal Disease Lab, USDA researchers work closely with faculty, staff and students in the CFANS Department of Plant Pathology to better understand the biology of the pathogens and prevent disease outbreaks. Researchers collect and analyze thousands of pathogen samples from across the U.S., as well as from many other countries, for changes in pathogen populations. 

“We work with emerging virulent races of cereal rust pathogens from around the world, notably with strains such as Ug99 and other virulent stem rust pathogens,” says Matt Rouse, who holds a joint appointment with the USDA and the Department of Plant Pathology. “We're the only place in the United States working on virulent races in a large capacity and one of few institutions in the world.”

The CDL also screens germplasm from breeding programs to assist in the development of resistant varieties, screen wild cereal germplasm for resistance to incorporate in breeding programs, screen commercial barberry varieties for resistance to stem rust since barberry can be an alternate host for the disease, and conduct detailed research on the genetics/genomics of both the pathogen and the host cereals to reduce the damaging impact of these plant diseases.

Take a closer look at the Cereal Disease Lab

Slideshow - Cereal Disease Lab - 2023-02

Between USDA and U of M efforts, thousands of pathogen samples from across the US and hundreds more from across the world are collected and analyzed for changes in pathogen populations. The CDL is home to the largest collection of cereal rust pathogen isolates in the world (30,000+).

“At the University of Minnesota, we rely on our USDA-ARS colleagues to complement and extend our research,” says U of M Professor Brian Steffenson. “The CDL has a strong program in characterizing the worldwide virulence of the rust pathogens, particularly stem rust and leaf rust. Knowing our enemy, that is the virulence of the rust pathogens, helps us to select the resistance genes that will be effective against the known races of the pathogen.”

The CDL was established in 1915 to study stem rust. The significance of the lab’s research was realized in 1935 when stem rust destroyed more than 135 million bushels of wheat followed by periodic outbreaks throughout the following decades. The lab’s collaborative work identified common barberry as the alternate host of the pathogen (where stem rust overwinters in the Great Plains of the US) and ultimately to the barberry eradication program. Barberry is still screened for rust resistance in the lab today.

The CDL provides critical data on the virulence dynamics of the rust pathogens across the country and world. University breeders rely on this information to select the best and most widely effective resistance genes for wheat and barley.

“Together CDL and PlPa represent the only center for cereal rust research in the world with the extensive collection and expertise to ‘protect small grain cereal crops from the enemy that never sleeps’,” explains USDA Research Leader Shahryar Kianian (pictured here).

In 1999, a widely virulent race called Ug99 was found in Uganda and threatened the world's wheat and barley crops because it had virulence for 80-90% of all cultivars worldwide. The CDL took the lead in addressing this problem and also helped to set up screening nurseries in Ethiopia and Kenya to test materials in the field.

The CDL screens thousands of breeding germplasm to assist in development of resistant varieties and thousands of wild cereal germplasm for resistance to identify new sources of resistance for incorporation into various breeding programs.