Journal of General Plant Pathology

, Volume 74, Issue 4, pp 281–288

Relation between pathogenicity and genetic variation within Plasmodiophora brassicae

  • Kohei Osaki
  • Shozo Fujiyama
  • Akiko Nakayama
  • Yoshiaki Shimizu
  • Shin-ichi Ito
  • Shuhei Tanaka
Fungal Diseases

Abstract

The relation between diversity of pathogenicity on clubroot-resistant (CR) cultivars of Chinese cabbage (Brassica rapa subsp. pekinensis) bred in Japan and DNA polymorphisms in 17 populations of Plasmodiophora brassicae from cruciferous plants was examined by inoculation tests and random amplified polymorphic DNA (RAPD) analysis using 18 arbitrary primers. Four pathotypes (A–D) were identified after inoculation of six CR cultivars of Chinese cabbage in the 17 populations from cruciferous crops. A relatively high level of genetic diversity was also detected among these populations in the RAPD analysis. Although the four pathotypes could not be clearly differentiated using the RAPD data, most populations of three pathotypes had a consistent location on the dendrogram. All pathotype B (virulent on five cultivars except Utage 70) and D (avirulent on all cultivars) populations, which were common in incompatible interactions with cv. Utage 70, were located in a single subcluster. All five pathotype C populations (virulent only on cv. Utage 70) except for one population grouped in another single subcluster. Because four pathotype A populations (virulent on all six cultivars, races 4 and 9) fell in different subclusters, the populations may be genetically polyphyletic. Populations from cruciferous weed Cardamine flexuosa differed remarkably from those from cruciferous crops in pathogenicity on common cultivars of Chinese cabbage and turnip and C. flexuosa, but they grouped in a single cluster with all race 9 populations from crops. Race 9 populations from crops may thus be closely related to populations from the weed rather than to races 1 and 4 from crops.

Keywords

Cardamine flexuosa Chinese cabbage Clubroot-resistant cultivars Pathotype Plasmodiophorabrassicae Random amplified polymorphic DNA 

Copyright information

© The Phytopathological Society of Japan and Springer 2008

Authors and Affiliations

  • Kohei Osaki
    • 1
  • Shozo Fujiyama
    • 2
    • 3
  • Akiko Nakayama
    • 2
  • Yoshiaki Shimizu
    • 2
    • 4
  • Shin-ichi Ito
    • 2
  • Shuhei Tanaka
    • 2
  1. 1.The United Graduate School of Agricultural SciencesTottori UniversityTottoriJapan
  2. 2.Department of Biological and Environmental Sciences, Faculty of AgricultureYamaguchi UniversityYamaguchiJapan
  3. 3.Yamaguchi Prefecture Agricultural Experiment StationYamaguchiJapan
  4. 4.Research Division, Yokohama Plant Protection StationMinistry of Agriculture, Forestry and Fisheries JapanNaka-ku, YokohamaJapan

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