Tiny allies: soil microbiome research opens new paths for potato wart management

Soils and plant tissues are alive with tiny, microscopic organisms, such as bacteria and fungi. Some of these microorganisms, or microbes for short, can naturally help protect plants from disease or support healthy plant growth. Agriculture and Agri-Food Canada (AAFC) scientists are exploring whether these naturally occurring microorganisms could one day contribute to new biological control (biocontrol) approaches for managing potato wart.

"We discovered that potato wart tissues and affected soils from the Netherlands were associated with certain Bacillus and Pseudomonas, and other bacterial groups," says Dr. Wen Chen, research scientist at the AAFC Ottawa Research and Development Centre. “Some members of these groups have been reported to suppress certain fungal plant pathogens in other agricultural systems, making them promising candidates for further investigation.”

Potato wart is caused by a persistent soil-borne fungus, Synchytrium endobioticum, the infection of which produces cauliflower-like, warty growths, mainly on potato tubers and underground stems. Although potato wart poses no threat to human health or food safety, it can reduce yields, make potatoes unmarketable, and restrict the use of affected fields for potato production. The pathogen’s resting spores can survive in soil for more than 40 years, making the disease extremely difficult to manage. Currently there is no treatment that can eliminate potato wart from fields, so managing the disease relies on preventing its spread through surveillance and diagnostics, growing resistant potato varieties, and strict regulatory measures.

Looking for allies: exploring the potato wart-associated microbiome

Rather than focusing only on the pathogen, Dr. Chen is studying the broader community of microorganisms that are naturally associated with the pathogen, potato wart tissues, and surrounding soils.

"Our approach was to study microbial communities already adapted to potato-growing environments, including samples from the Netherlands, Prince Edward Island, Newfoundland and Labrador, and other regions worldwide,” explains Dr. Chen. “Rather than introducing new organisms, we're exploring the microorganisms that naturally occur in potato wart tissues and affected soils to better understand their relationship with the pathogen and with potato plants."

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