In vitro culture of Plasmodiophora brassicae

Key Result

This project is still in progress, but is focused on the objective of developing methods for consistent in vitro culture of P. brassicae and to produce pure cultures of some of the major pathotypes of P. brassicae (to better breed for resistance and improved management strategies).

Project Summary

Plasmodiophora brassicae is a plant pathogen causing clubroot disease of Brassica crops including canola. Clubroot can cause severe yield loss and the pathogen persists in soil for many years. Using resistant canola varieties is the best management strategy for protecting canola from clubroot. However, the resistance is not durable and is breaking down rapidly, especially when there are high concentrations of the pathogen in a field.

Knowledge about the biology and genetic diversity of this pathogen is limited because it cannot be grown in culture. If this organism could be grown in pure culture in the lab, it would be much easier to produce and bulk up single spore isolates and to discover target genes for breeding purposes.

Single spore isolates of the pathogen can be used to test for clubroot resistance in new canola lines. There are many other uses for pure lab cultures, such as determining the direct effects of chemicals and biocontrols on growth and survival of the pathogen. There are currently no methods to produce these cultures, but others have found ways to culture other obligate plant pathogens, such as rusts.

However, rust plant pathogens are very different from the clubroot pathogen. McDonald lab has developed a method to remove the cell wall while the cell itself stayed viable and intact.

The proposed study will build on these methods and determine the optimum culture media for cell culture. Pure cultures of P. brassicae will lead to better breeding for resistance and improved management strategies. The results of this research will benefit plant breeders, and the canola industry, through improved resources to breed clubroot resistant canola.