Occurrence of Clubroot Caused by Plasmodiophora brassicae in Baecheongchae

Wan-Gyu Kim1,*   Sang-Keun Oh2   Marc Semunyana2   Man-Jong Han1   Gyo-Bin Lee1   Weon-Dae Cho1   

1Global Agro-Consulting Corporation, Hwaseong 18330, Korea
2Department of Applied Biology, Chungnam National University, Daejeon 34134, Korea.


Clubroot symptoms were frequently observed on the roots of Baecheongchae plants grown in vinyl greenhouses of a farmer located in Yangpyeong area of Korea during a disease survey in June 2019. The incidence of diseased Baecheongchae plants ranged from 30 to 90% in the vinyl greenhouses investigated. Many resting spores were found in the tissue of root galls collected. The resting spores were hyaline and spherical and measured 2.5−4.2 ㎛ in diameter. Three inoculum suspensions of resting spores prepared from the root galls were inoculated to the roots of healthy Baecheongchae plants. All the inoculum suspensions caused clubroot symptoms to appear on the roots of the inoculated Baecheongchae plants. The symptoms on the roots induced by artificial inoculation were similar to those observed in the plants of the vinyl greenhouses during the disease survey. Resting spores of the pathogen were recovered from the root galls of the inoculated plants. Three root gall isolates obtained from the inoculated plants were used for molecular identification. Comparing the isolates to the Plasmodiophora brassicae strains in GenBank, the amplification products demonstrated 100% similarity with the internal transcribed spacer (ITS2) sequences. The clubroot pathogen was identified as P. brassicae according to its morphological, pathological, and molecular characteristics. This is the first report of P. brassicae causing clubroot in Baecheongchae.

Figures & Tables

Fig. 1.Clubroot symptoms of Baecheongchae and detection of the pathogen, . A and B, aboveground symptoms of clubroot on Baecheongchae plants observed in the vinyl greenhouse; C, galls produced on the roots of the diseased plants; D, resting spores released from a root gall tissue observed under a light microscope; E, root galls induced by artificial inoculation tests with . F, non-inoculated plants (control) showing normal growth of roots.