Molecular evaluation of Plasmodiophora brassicae collections for the presence of divergent genetic pathogen populations before and after the release of clubroot resistant canola

Plasmodiophora brassicae Woronin, the cause of clubroot of crucifers, is now established across most of Alberta, Canada, and has become a major constraint in canola (Brassica napus L.) production. Disease control is achieved mainly by planting clubroot-resistant (CR) canola varieties. The first CR c...

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Bibliographic Details
Published inCanadian journal of plant pathology Vol. 44; no. 1; pp. 94 - 102
Main Authors Holtz, Michael D., Hwang, Sheau-Fang, Manolii, V.P., Strelkov, Stephen E.
Format Journal Article
LanguageEnglish
Published Taylor & Francis 02.01.2022
Subjects
canola
clubroot
dried galls
galles sèches
hernie
PCR quantitative
Plasmodiophora brassicae
quantitative PCR
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Summary:Plasmodiophora brassicae Woronin, the cause of clubroot of crucifers, is now established across most of Alberta, Canada, and has become a major constraint in canola (Brassica napus L.) production. Disease control is achieved mainly by planting clubroot-resistant (CR) canola varieties. The first CR canola in Canada was released in 2009. In 2013, severe clubroot was detected on CR canola in several fields in Westlock County, Alberta, and found to be caused by a 'new' strain of P. brassicae termed '5X'. These strains have been shown to be genetically distinct from other P. brassicae strains in Alberta ('population one') and belong to a second population ('population two') of the pathogen. In this study, multiple molecular markers, specific for 'population two', were used to determine the occurrence of members of this population over time throughout central Alberta. Two hundred and twenty-four clubroot galls collected from 2005 to 2016 from non-CR canola varieties were examined. The presence of 'population two' DNA was detected at low levels in at least 47 of the galls, and it was the predominant population of P. brassicae in another 10 of the samples. These samples were found in Flagstaff County starting in 2008, Westlock County starting in 2009, the County of Vermillion River in 2011 and Red Deer County in 2014. Although relatively uncommon, members of this population were widespread, occurring at locations 168 km apart prior to the release of CR canola.
ISSN:0706-0661
1715-2992
DOI:10.1080/07060661.2021.1950320