The insects avoid infesting certain varieties of wheat because they don’t like the smell; new research tries to figure out why
Researchers want to help western Canadian farmers by figuring out why certain varieties of wheat smell bad to an invasive insect that typically causes about $60 million in damage to the crop each year.
Some non-commercial lines of wheat are releasing chemicals that female wheat midge don’t like, said assistant professor Boyd Mori of the University of Alberta’s Department of Agricultural, Food and Nutritional Science. These volatile organic compounds discourage the tiny orange-coloured insects from laying their eggs within kernels of wheat, he said.
“And we realized that this could be a very valuable trait for reducing damage within the fields and so we want to continue to pursue it and figure out exactly the kind of mechanisms behind it, and how we can get it into farmers’ fields.”
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Mori is part of a $1.2-million research project that will be looking for alternative traits or genes in wheat that could potentially be bred to create new resistant strains of the crop. It is being partly funded by $659,850 from Alberta’s Results Driven Agriculture Research (RDAR) agency and Genome Alberta’s Innovation in Agriculture Genomics Program.
Although wheat is a mainstay of agriculture in Western Canada, commercial varieties have only one genetic line of defence against wheat midge, said Mori, who is also an NSERC (National Sciences and Engineering Research Council of Canada) Industrial Research Chair in Agricultural Entomology.
This is a gene called Sm1, which allows wheat to release acidic chemical compounds that kill wheat midge larvae by stopping them from feeding on kernels, he said. Scientists are concerned the pests will eventually evolve resistance to the trait, he added.
As part of a strategy to prevent this from happening, about 10 percent of the wheat in a typical crop contains plants that lack the gene, allowing some wheat midge to survive and develop, he said. “If it was all Sm1 wheat, then we might see higher pressure on the insects to develop resistance against it.”
Outbreaks so far have typically consisted of “little pockets here and there,” meaning they have largely been regional, he said. “So, if we have an extreme outbreak across the Prairies, it’s hypothesized there could be a loss of around $300 million caused by wheat midge every single year, so it can be quite devastating.”
The two-year research project aims to identify which volatile organic compounds are discouraging the pests from laying eggs in wheat kernels, which scientists call oviposition deterrence, said Mori. It is currently not clear what or how many compounds are involved, and exactly why the plants are releasing them, he said.
Clearing up this mystery will help researchers figure out which genes and pathways are involved in creating the compounds, in turn potentially leading to the development of genetic markers that can help plant breeders create new lines of resistant wheat, he said.
The project is being led by James Harynuk, a professor in the U of A’s chemistry department. The co-lead is Alejandro Costamagna, an associate professor in the University of Manitoba’s entomology department.
Besides Mori, the project’s collaborators include Curt McCartney, an associate professor in the U of M’s plant science department.
