Clubroot, caused by Plasmodiophora brassicae, is a soil-borne disease that occurs in cruciferous crops worldwide. P. brassicae usually exists as a mixture of several pathotypes, which has hampered the research on resistance mechanisms of cruciferous crops against P. brassicae. In this study, clubroot galls were collected from a field in Shenyang, China, as a pathogen source to develop an efficient protocol for a single-spore isolation system of P. brassicae by optimizing the seedling age for inoculation, host inoculation method, and plant culture method. The operational steps of the single-spore isolation method were optimized as follows: the use of two-day-old seedlings for inoculation, substituting a cryobox (100 × 2.0 mL vials) for culture dishes, the addition of nutrient solution culture, and microscopic observations of single spores. The rate of infection success was substantially improved, and single-spore isolates of four pathotypes: 4, 8, 9, and 11, were acquired in this system. Subsequently, the optimized system was used to isolate and characterize the pathotypes of single-spore isolates of P. brassicae collected from five fields in regions in China. Approximately 4 to 9 pathotypes were isolated from each region. Among these, pathotype 4 was the most prevalent. This study provides a source of valuable information that can eventually be used for the genetic analysis of host–P. brassicae interaction.
Dataset for the metabolic and physiological characterization of seeds from oilseed rape (Brassica napus L.) plants grown under single or combined effects of drought and clubroot pathogen Plasmodiophora brassicae