Scientists at Agriculture and Agri-food Canada are analyzing soil fungi to uncover traits which could help protect crops from disease. With millions of potential fungi species in agricultural soils worldwide, finding the most useful ones is no small order.
Why it matters: The Canadian Collection of Fungal Cultures offers scientists the opportunity to study the ability of soil fungi to protect crops.
According to David Overy, adjunct professor at Carlton University and operator of a natural products discovery project at AAFC, some enzymes and chemical compounds in fungi can strengthen a plant’s infection barrier – the point at which a pathogen enters the plant’s cells – thus inhibiting expression of the disease.
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Strengthening that barrier is often all that’s needed to prevent disease from causing damage in crops, reducing or eliminating the need to kill the pathogen in the first place, says Overy.
“Our approach is ‘we’re not trying to kill you, we’re just trying to prevent you from infecting here. But you can happily grow in the soil,’” he says.
By employing fungi in this way, rather than trying to eliminate pathogens, better disease resistance can be achieved with lower risk of spurring resistance in the target organism. The compound “immunomodulide” is an example, as it helps plants detect pathogens earlier, triggering faster immune responses.
There can be other uses for fungi enzymes and chemical compounds as well. This could include those which, if applied to poor quality feed (e.g. silage), could encourage fermentation and breakdown, as well as those which could foster healthier microbial communities in soil.
“Let’s say we know a given soil is very resilient to disease. Let’s see what organisms are growing there. If we can understand the potential of what they can make, maybe they can be used as an amendment,” says Overy.
A unique repository
Key to Overy’s work is the Canadian Collection of Fungal Cultures – the country’s repository of living fungi species. Tara Rintoul, the scientist responsible for the preservation and provision of fungal cultures from the Collection, says the “fungal zoo” contains some 20,000 living fungi cultures, approximately half of which have also been genetically sequenced.
“We have 120,000, maybe 150-200,000 names associated with fungal organisms, but they expect there is 2.5 million in the world that are unknown,” Rintoul says, referring specifically to fungi projected to be in agricultural soils globally.
While Canada’s collection has been the source of commercialized additives in the past, its overall importance goes beyond the development of inputs.
“Tomorrow, if a new disease broke out and the borders closed and you couldn’t sell your stuff – and this has happened in the past -with one culture we could maybe save $30 billion, by proving we have had that in the past and it hasn’t been a trade issues.”
Overy also reiterates how unique Canada’s national fungal collection is.
“Our culture collection has fungal cultures, but we also have DNA sequences for the bulk of them, I’d say at least 50 per cent, which is very rare. Not many places around the world actually have that inventory of information,” says Overy. “We’re trying now to leverage that in our research projects to describe what is the capacity of these organisms for the farmer, but also for the industry in terms of biomaterials, bioprocessing.”
“Before, a lot of universities might have had those culture collections, but a lot of those culture collections have been closing and leaving. There’s an importance, I think, to maintain our national collections. To lose a whole zoo of [20,000] different animals, that would be a massive loss of potential.”
