Canada part of international effort to protect global wheat crop

Wheat producers in Canada, the United States and around the world are struggling to deal with a growing threat to this essential food crop — Fusarium graminearum, a fungus that causes a disease called fusarium head blight, often referred to simply as FHB.

The fungus attacks the seeds of the plant — the part we eat — leaving behind a number of mycotoxins (mycotoxins are toxins produced by a fungus). Even if the fungus does not kill the plant, the mycotoxins can cause serious illness in people or animals who consume food or feed made from infected wheat. As a result, many countries, including Canada, have regulations to ensure no more than trace amounts of these mycotoxins can be present in wheat that is used for human or animal consumption.

Canada a key contributor

Finding an effective way to control the fungus is a key priority for researchers around the world. Some of the most promising research involves the relatively new science of genomics, which is leading to a greater understanding of how the fungus infects the plant and produces the harmful toxins.

With funding from the Government of Canada's Genomics Research and Development Initiative (GRDI), Canadian researchers are playing a key part in the international effort to control FHB.

Research produced by Dr. Linda Harris and her team at Agriculture and Agri-Food Canada, for example, has helped to identify and position many novel genes that are part of the genome of the fungus that causes FHB. Thanks in part to this work, the international research community now has access to the most complete and accurate sequencing of the genome, an essential prerequisite to understanding how the disease infects the plant.

Looking inside the black box

"When we started with GRDI funding in 1999, the Fusarium graminearum genome was really a black box — we knew the function of only a very few genes," says Dr. Harris. "We were able to develop a library of genes and how they operate under a variety of conditions. From there, we were able to contribute to the annotation of the genome sequence, correcting a number of errors produced by automated gene calling done in the past."

Dr. Harris and her colleagues have also identified specific genes the fungus uses to produce a number of different mycotoxins, as well as when they are produced and under what conditions.

At United States Department of Agriculture labs in Peoria, Illinois, research scientist Dr. Susan McCormick and her team are making good use of Dr. Harris's findings, which Dr. McCormick calls "a wonderful resource."

"We don't have the same genomics capacity here, so having access to the gene library created by Dr. Harris has helped us identify additional genes involved in mycotoxin production," says Dr. McCormick. "By understanding how the fungus causes the disease and produces the mycotoxins, it may be possible to engineer something to block it."

More to learn

In Ottawa, Dr. Harris agrees on the end-game, but concedes there is a lot of work to do. "Identifying the genes that produce the mycotoxins is just one part of the puzzle," says Dr. Harris. "We also need to identify the genes that tell the mycotoxin-producing genes when to go to work, and what triggers them to give the command."

Dr. Harris says her work and the international collaboration that helps to inform her research would not be possible without the GRDI. "GRDI has allowed us to be part of a global genomics research community," says Dr. Harris. "It's important to understand that we can't just be along for the ride — if we don't do our share of the work, other countries would be reluctant to share their work with us."

Long-term impact

It's difficult to over-state the importance of this research to Canada and the world. Wheat is second only to rice as the main human food crop. It is also a staple of Canada's agricultural industry — wheat exports generate close to $5.4 billion in revenue every yearFootnote 1, making it Canada's most valuable agricultural export. The rate of FHB infection continues to rise in Canada and elsewhere. Beyond its impact on the food supply, it's estimated FHB has cost Canadian wheat producers more than $1.5 billion in lost income since the mid-1990sFootnote 2.

Footnotes

Footnote 1

Canadian Wheat Board

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Footnote 2

GRDI Annual Performance Report 2007-2008

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