Discovery to improve resistance in canola

AUSTRALIAN researchers have discovered three genes associated with resistance to sclerotinia stem rot, marking a major step towards developing improved disease-resistant canola varieties.

The genes have links to sclerotinia stem rot susceptibility and resistance. 

Sclerotinia stem rot is a fungal disease which can significantly reduce the productivity of canola crops and the discovery could arm breeders with information about how to develop varieties with improved resistance.

Researchers from the Centre for Crop and Disease Management, in collaboration with the New South Wales Department of Primary Industries and Agriculture and Agrifood Canada, identified the genes.

CCDM researcher and lead author Dr Toby Newman said the finding represent a major step in the development of genes that canola breeders can use to produce varieties with much improved resistance to sclerotinia stem rot.

“It’s tricky to breed resistance to sclerotinia stem rot in canola because a broad range of genes contribute to susceptibility and resistance,” Dr Newman said.

“As far as we know, no single gene will provide a good level of resistance against sclerotinia stem rot, and unfortunately, we are unlikely to achieve complete resistance to this disease, but we can put together smaller puzzle pieces to create a strong partial resistance.

“We must develop varieties with numerous genes, each with small effects that together create crops strong enough to reduce the severity of sclerotinia stem rot for the industry, and this is exactly what we are on the path to achieving with this discovery.”

Dr Newman said their research used the model species Arabidopsis thaliana, which is in the same family of plants (Brassicaceae) as canola (Brassica napus).

“We found two genes which make Arabidopsis more susceptible to the disease and one gene which increases resistance to it,” he said.

“Identifying these genes means we can infer the corresponding genes in canola are likely to react similarly, working to make the plant more susceptible or resistant, but this resistance is yet to be proven in this crop.”