A TECHNIQUE FOR THE EXTRACTION AND PURIFICATION OF VIABLE PLASMODIOPHORA-BRASSICAE RESTING SPORES FROM HOST ROOT-TISSUE

An improved technique. for purifying Plasmodiophora brassicae resting spores from host root tissue and other contaminants is described. After extraction from macerated infected Chinese cabbage roots by a series of centrifugations in 50% sucrose and distilled water, P. brassicae resting spores were separated from other contaminants in a continuous gradient of LUDOX (40% silica suspended in NaOH, pH 9.8; DuPont)/deionized water. This purification technique produces clean suspensions of P. brassicae resting spores suitable for propagation of the organism, long-term storage, and extraction of DNA or other molecules of interest.