Pathotype Characterization of Plasmodiophora brassicae, the Cause of Clubroot in Central Europe and Sweden (2016-2020)

Nazanin Zamani-Noor; Ann-Charlotte Wallenhammar; Joanna Kaczmarek; Usha Rani Patar; Miloslav Zouhar; Marie Manasova; Małgorzata Jędryczka

doi:10.3390/pathogens11121440

Pathotype Characterization of Plasmodiophora brassicae, the Cause of Clubroot in Central Europe and Sweden (2016-2020)

Pathogens. 2022 Nov 29;11(12):1440. doi: 10.3390/pathogens11121440.

Authors

Nazanin Zamani-Noor¹, Ann-Charlotte Wallenhammar², Joanna Kaczmarek³, Usha Rani Patar⁴, Miloslav Zouhar⁴, Marie Manasova⁴, Małgorzata Jędryczka³

Affiliations

¹ Julius Kühn-Institute (JKI), Institute for Plant Protection in Field Crops and Grassland, D-38104 Braunschweig, Germany.
² Rural Economy and Agricultural Society, HS Konsult AB, Gamla vägen 5G, SE-702 22 Örebro, Sweden.
³ Pathogen Genetics and Plant Resistance Team, Institute of Plant Genetics, Polish Academy of Sciences, 60-479 Poznań, Poland.
⁴ Department of Plant Protection, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences, 165 00 Praha-Suchdol, Czech Republic.

Abstract

Clubroot, caused by Plasmodiophora brassicae, is a crucial oilseed rape disease worldwide. Information on the virulence of P. brassicae populations is essential to apply disease control with proper clubroot-resistant cultivars. In 2016-2020, 84 isolates of P. brassicae were collected in the Czech Republic (CZ), Germany (DE), Poland (PL), and Sweden (SW). Pathotypes were designated using 17 Brassica hosts, including the European Clubroot Differentials (ECD), Somé set, and clubroot-resistant oilseed rape cv. Mendel. According to the ECD set, virulence analyses differentiated the isolates into 42 pathotypes. The most common pathotypes were 16/31/31 (in DE, PL, and SW) and 16/06/12 (in CZ, DE, and PL). Six pathotypes were found according to the Somé set, including 1-4 pathotypes per country. P1 was most prevalent in DE, PL, and SW, while P3 was abundant in CZ, DE, and PL. The current study provides clear evidence for a shift towards increased virulence in P. brassicae populations compared to previous studies. Several isolates overcame the resistance of cv. Mendel and of Brassica rapa genotypes ECD 01 to ECD 04. Considering all investigated samples, significant negative correlations were found between clubroot incidence and the frequency of oilseed rape in crop rotation, as for clubroot incidence and soil pH.

Keywords: Brassica napus; clubroot; differential set; disease incidence; disease severity index; oilseed rape; pathogenicity; pathotype; physiological race; virulence.

Grants and funding

The visit of Usha Rani Patar to study the Moravian pathotypes of Plasmodiophora brassicae at the Institute of Plant Genetics PAS in Poznań, Poland, was funded by the Erasmus Plus Traineeship Program, financed by the European Commission (Grant Agreement No. 2019-1-CZ01-KA103-060621). In Germany, the study was funded by the Julius Kühn-Institute. In Poland, the study was funded by the Ministry of Agriculture and Rural Development under the program Biological Progress, the project for the years 2014–2020 (HOR hn-801-8/14) task 50 “The use of conventional and molecular phytopathological tools in the search for sources of resistance to clubroot and the characteristics of the current population of the pathogen in Poland.” In Sweden, the study was funded by the Swedish Farmers’ Foundation for Agricultural Research (grant number O-16-20-765), the Foundation for Swedish Oil Plant Research, and the Carl Robert Prytz Donation fund.