Plant Pathology (2018) 67, 1582-1588

Q. Zhou, S.F. Hwang, S.E. Strelkov, R. Fredua-Agyeman and V.P. Manolii (2018)
A molecular marker for the specific detection of new pathotype 5-like strains of Plasmodiophora brassicae in canola
Plant Pathology 67 (7), 1582-1588
Abstract: Clubroot of crucifers, caused by Plasmodiophora brassicae, is managed in canola (Brassica napus) by the deployment of resistant cultivars. Recently, however, new strains of P. brassicae have been detected in Alberta, Canada, that can overcome this resistance. Some of these strains are classified as pathotype 5 on the differential system of Williams, but are distinguished by their ability to overcome host resistance. In order to expedite the identification of these new pathotype 5-like strains, three primer sets were developed based on the 18S-ITS region of the pathogen. With primers P5XF3 and P5XR3, a 127 bp product was amplified from all new pathotype 5-like strains following optimized PCR analysis. A TaqMan probe-based quantitative assay was also developed. These protocols could be used to detect as little as 0.5 pg P. brassicae DNA, and as few as 10⁴ mL^-1 pathogen resting spores; infection of host tissues could be detected as soon as 4 days after inoculation. The PCR and qPCR assays described in this study represent useful tools for the rapid and reliable diagnosis and quantification of new pathotype 5-like strains of P. brassicae.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Stephen E. Strelkov

Research topic(s) for pests/diseases/weeds:
resistance/tolerance/defence of host
surveys/sampling/distribution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Plasmodiophora brassicae	Rape/canola (Brassica napus)	Canada (west)