Getting Tough On A Corn Disease

Scientists from University of Guelph and Agriculture and Agri-Food Canada (AAFC) researchers in Ottawa are exploring two methods for increasing resistance to Fusarium graminearum ear mold in corn. They say the research could give Ontario an edge in corn production.

"If we can solve the fusarium problem, Ontario corn producers will be able to a grow a unique, toxin-free crop," says University of Guelph Prof. Peter Pauls, Department of Plant Agriculture.

Fusarium, a fungal disease, attacks the roots of agriculturally significant plants such as potatoes and corn. It blocks the xylem, preventing water from reaching the plant. This causes wilting, white mold on corn kernels and crop devastation.

The problem's not as bad as elsewhere. Compared to the U.S., Ontario has a relatively cool climate for corn production. That means crops here aren't bothered by some of the fungi and bacteria that affect corn in warmer climates. But fusarium-contaminated corn is still a threat to Ontario livestock producers and millers who use or process corn for feed.

The researchers' first approach – called the agrobacterium/corn co-cultivation technique – is a transgenic method for inserting fusarium-resistance genes into corn, then breeding it. In nature, the agrobacterium might spread disease-causing or "pathogenic" genes through the plant. But researchers remove these pathogenic genes and replace them with what Pauls called "genes of interest." Fusarium-resistance genes will be inserted later if the technique succeeds.

Another approach under way is the development of a molecular marker-based method for faster and more effective screening for naturally occurring fusarium resistance in corn. The objective is to show a link between particular molecular markers (DNA or protein) and fusarium-resistance genes. The absence or presence of the markers will be used to decide whether a particular plant will be used for further rounds of breeding.

Marker- assisted selection minimizes time and space requirements in plant-breeding programs. It allows analysis to be carried out at the seedling stage rather than the full grown stage that current methods require. As well, the analysis can be completed in just two days.

Pauls says the researchers need about two or three more years to identify the specific molecular markers for marker-assisted selection. But he believes it is well worth the effort.

"This research could have significant implications for the future of Ontario corn crops," he says. "If this research proves to be successful, Ontario could market fungal-toxin free corn in about five to 10 years."

This research is being sponsored by Agriculture and Agri-Food Canada (AAFC) through the CanAdapt program administered by the Agricultural Adaptation Council, the Ontario Ministry of Agriculture, Food and Rural Affairs, and the Ontario Research Enhancement Program (OREP), a federally funded research initiative administered by the Research Branch of AAFC with input from the agriculture and agri-food sector, universities and the province.