• Journal of Crop Science and Biotechnology
• /
• v.11 no.2
• /
• pp.101-106
• /
• 2008

To identify inheritance of clubroot disease resistance genes in Chinese cabbage, seedling tests of $BC_1P_1,\;BC_1P_2$, and $F_2$ populations derived from $F_1$ hybrid(var. CR Saerona) using single spore isolate(race 4 identified with William's differential host) from Plasmodiophora brassciae were conducted. Resistance(R) and susceptible(S) plants segregated to 1:0 in backcross to the resistant parent. The $F_2$ population segregated in a 3(R):1(S) ratio. This result implied that the resistance of clubroot disease is controlled by a single dominant gene to the race 4 of P. brassicae in CR Saerona. To develop DNA markers linked to clubroot resistance genes, 185 plants of CR Saerona among $F_2$ populations were used. A total of 300 arbitrary decamer was applied to $F_2$ population using BSARAPD(Bulked segregant analysis-Randomly amplified polymorphic DNA). One RAPD marker linked to clubroot resistance gene in CR Saerona($OPJ_{1100}$) was identified. This marker was 3.1 cM in distance from resistance gene in $F_2$ population. This marker may be useful for a marker-assisted selection(MAS) and gene pyramiding of the clubroot disease resistant gene in Chinese cabbage breeding programs.

• Horticultural Science & Technology
• /
• v.34 no.3
• /
• pp.433-441
• /
• 2016

Clubroot caused by the protist Plasmodiophora brassicae is one of the most destructive diseases of Brassica crops. Developing Chinese cabbage cultivars with durable clubroot resistance (CR) is an important goal of breeding programs, which will require new genetic resources to be identified and introduced. In this study, we evaluated resistance to P. brassicae race 4 using 26 Chinese cabbage (B. rapa ssp. pekinensis ) cultivars compared to the clubroot-susceptible Chinese cabbage inbred line 'BP079' and the clubroot-resistant European turnip (B. rapa ssp. rapifera ) inbred line 'IT033820'. No symptoms of clubroot disease were found in 'IT033820' infected with P. brassicae race 4, whereas the Chinese cabbage cultivars exhibited disease symptoms to various degrees. The Chinese cabbage cultivars that were reported to be clubroot-susceptible were susceptible to P. brassicae race 4; however, seven of the 20 cultivars reported to be clubroot-resistant were susceptible to this race of P. brassicae to varying degrees. Resting spores of P. brassicae were abundant within the infected root tissues of 'BP079', as revealed by light microscopy and scanning electron microscopy (SEM), but they were not detected in root tissues of 'IT033820'. Although resting spores were not detected by light microscopy in root tissues of the clubroot-resistant Chinese cabbage cultivar 'Kigokoro 75', a few spores were observed by SEM. The $F_1$ hybrids from a cross between 'IT033820' and 'BP079' showed no disease symptoms, and all $BC_1P_1$ progenies from a cross between the $F_1$ hybrid and 'IT033820' exhibited a resistance phenotype. In the $BC_1P_2$ population from a cross between the $F_1$ hybrid and 'BP079', this trait segregated at a ratio of 3(R):1(S) (${\chi}^2=1.333$, p = 0.248) at a 5% significance level. Inoculated $BC_1P_2$ plants were either highly resistant or highly susceptible to the pathogen, indicating that the CR to race 4 of P. brassicae carried by 'IT033820' is dominant. In the $F_2$ population, this trait segregated at a ratio of 15(R):1(S) (${\chi}^2=0.152$, p = 0.696) at a 5% significance level, suggesting that CR in 'IT033820' is mainly controlled by two dominant genes. Therefore, 'IT033820' represents a promising genetic resource for developing durable CR breeding lines in Chinese cabbage.

• Korean Journal Plant Pathology
• /
• v.13 no.4
• /
• pp.244-247
• /
• 1997

The experiment was conducted to obtain a basic information on the enviroumental factors favoring the disease development and chemical control of clubroot in chinese cabbage. The inoculation by insertion of infested soil was the most effective for the disease development as compared to the other inoculation methods such as pouring the spore suspension into soil and dipping roots into the spore suspension. On the environmental factors favoring the clubroot development, optimum slil pH and soil temperature were pH 5-6 and $20{\sim}30^{\circ}C$, respectvely. The combination of soil treatment and seed coating treatment was more effective than each single treatment in the chemical control of clubroot by 0.5% of fluazinam dust.

• Mycobiology
• /
• v.37 no.1
• /
• pp.69-71
• /
• 2009

Clubroot symptoms occurred severely on roots of Pak-Choi (Brassica campestris ssp. chinensis) grown in greenhouses in Gwangju city, Gyeonggi province, Korea in September, 2008. The incidence of the disease symptoms reached as high as 90% in three greenhouses investigated. The root galls collected from the greenhouses were sectioned using a scalpel and observed by light microscope. Many resting spores were found in the cells of the root gall tissues. Suspension of resting spores was prepared from the root galls and inoculated to roots of healthy Pak-Choi plants. Each of five resting spore suspensions caused clubroot symptoms on the roots, which were similar to those observed during the greenhouse survey. Resting spores of the pathogen were observed in the cells of the affected roots. The clubroot pathogen was identified as Plasmodiophora brassicae based on its morphological and pathological characteristics. This is the first report that Plasmodiophora brassicae causes clubroot of Pak-Choi.

• Plant Disease and Agriculture
• /
• v.5 no.2
• /
• pp.90-94
• /
• 1999

Effect of inoculum concentration inoculation method and plant age on development of clubroot disease of Chinese cabbage seedling were examined in growth chambers. Root galls were developed at the concentration of 105 resting spore or above per ml of incoulum and as the inoculum concentration became higher rate of development of root galls was faster. In the plants with root gall development fresh weight of above ground parts was reduced to 30-44% of that of healthy plants but root weight increased by 4-10 times. Growth of diseased plants was greatly reduced as compared to healthy plants. Planting in the diseased soil as a inoculation method was most effective for disease development showing uniform infections but time of initial root gall development was delayed by root soaking inoculation. Some plants inoculated by soil drenching method did not develop root galls. However root gall enlargement after its initial formation did not differ greatly among inoculation methods. Nine-day-old seedlings showed poor development of root gall but 16-days-old seedlings was found to be most adequate for inoculation for gall development.

• Research in Plant Disease
• /
• v.16 no.1
• /
• pp.59-65
• /
• 2010

This study was conducted to select the cultivars and strains which are suitable in cultivation of the Chinese cabbage having good horticultural characteristics and the resistance to clubroot caused by Plasmodiophora brassicae, which is a widespread disease that causes serious problems in many Brassica growing areas. Thirty four cultivars and nineteen strains of the Chinese cabbage were planted in the contaminated fields in highland and investigated the wilting symptom due to the initial disease occurrence and high temperature. Disease occurrence rate and severity of clubroot and the horticultural characteristics were also examined. According to the results, Bulamplus, Kangryeokyeoleumbaechu among cultivars of Chinese cabbage, SP-05, SP-02, CR DB 50, and CR DB 29 among strains of Chinese cabbage were resistant to hot weather by showing delayed above-ground symptom (wilting) of clubroot in 30 days after transplanting. In case of below-ground clubroot rate, Daetong, super CR Kimi 85 and super CR Hiroki among the cultivars of Chinese cabbage were resistant to clubroot in 60 days after transplanting. When fresh weight of Chinese cabbage among cultivars were compared, super CR Hiroki of over 2,500 g was the highest among other cultivars. Although the resistant and susceptible reactions of Chinese cabbage cultivars and strains against clubroot disease were somewhat different from the above-ground symptoms (wilting) of clubroot in 30 days and below-ground symptoms of clubroot in 60 days, we recommend that super CR Hiroki, CR Kimi 85, CR Janggun among cultivars of Chinese cabbage and CR DB 50 and CR DB 29 among strains of Chinese cabbage will be more suitable in cultivation of Chinese cabbage in highland.

• Research in Plant Disease
• /
• v.6 no.1
• /
• pp.39-42
• /
• 2000

This study was conducted to improvement of control efficiency on clubroot disease. To improve the control efficiency on clubroot disease of chinese cabbage by chemical persistent effect, Flusulfamide DP was examined with soil mixed treatment. When Flusulfamide DP was applied, the more application times, the higher control value. The control value and marketable yield per 10a of the untreated cultivation plot after two application of Flusulfamide DP were 53.9%, 4,822kg, respectively. However, based on marketability and marketable yield, untreated cultivation plot after two application of Flusulfamide DP has been thought as economic application times compared to three times application. On the other hand, the combination of soil mixing and bed soil mixing treatment Flusulfamide DP was more effective than each treatment. The control value and marketable yield of the combination treatment was 73.3∼88.9%, 5,633∼5,770kg, those of soil mixing 66.7∼70.0%, 2,847∼3,167kg, respectively.

• Research in Plant Disease
• /
• v.17 no.2
• /
• pp.155-160
• /
• 2011

To develop the efficient screening methods for antifungal compound active to Chinese cabbage clubroot caused by Plasmodiophora brassicae, the control efficacy of three fungicides fluazinam, ethaboxam, and cyazofamid on the disease was tested under several conditions such as soil types, cultivars of Chinese cabbage, growth stages of the host, and inoculum concentrations. The in vivo antifungal activities of the fungicides on clubroot of two Chinese cabbage cultivars were hardly different. At 7- and 14-day-old seedlings, the fungicides were more effective to control of clubroot than at 21-day-old seedlings. In a commercial horticulture media soil (CNS), disease severity of untreated controls was higher and control activity of the fungicides was less than in a mixture of CNS and upland soil (1:1, v/v). Disease development of the seedlings inoculated with P. brassicae at $1.8{\times}10^7$ spores/pot to $1.1{\times}10^9$ spores/pot was almost same, but control efficacy of the fungicides was negatively correlated with inoculum dosages. To effectively select in vivo antifungal compound on Chinese cabbage clubroot, 14-day-old seedlings need to be inoculated with P. brassicae by drenching the spore suspension to give $1{\times}10^8$ spores/pot 1 day after chemical treatment. To develop clubroot, the inoculated plants are incubated in a growth chamber at $20^{\circ}C$ for 2 days, and then cultivated in a greenhouse ($20{\pm}5^{\circ}$) for four weeks.

• Journal of Plant Biotechnology
• /
• v.42 no.4
• /
• pp.350-355
• /
• 2015

Clubroot disease is one of the most wide-spread and devastating diseases in the cultivation of Chinese cabbage. To develop a protein marker for resistance to clubroot disease in Chinese cabbage, a comparative proteome analysis was performed between a sensitive line, 94SK, and a resistant line, CR Shinki DH. Three proteins of two fold or higher accumulation that are specific to each line were found 3 days after innoculation of the Plasmodiphora brassicae. They are glutamine synthetase, malate dehydrogenase/oxidoreductase and fructose-bisphosphate aldolase in the 94SK and actin, phosphoglycerate kinase, and Cu/Zn superoxide dismutase in the CR Shinki line. From the comparison of the synthesized proteins in the 94SK and the CR Shinki, CR Shinki was found to produce more ATP-binding protein for the ABC transporter while 94SK showed a higher level of pathogenesis-related protein 1 production. All of these proteomic variations may lead to the development of molecular markers to accelerate the breeding process.

• Proceedings of the Korean Society of Plant Pathology Conference
• /
• 2003.10a
• /
• pp.9-12
• /
• 2003

Clubroot disease of curcifer crops caused by Plasmodiophora brassicae had been first reported in 1920 in Korea, and maintained mild occurrence until 1980s. Since 1990s the disease has become severe in alpine areas of Kyonggi and Kangwon, gradually spread to plain fields throughout the country, and remains as the greatest limiting factor for its production. Researches on the disease has begun in late 1990s in our laboratory after experiencing severe epidemics. Survey of occurrence and etiological and ecological studies have been carried out, particularly, on the pathogen physiology, race identification, quantification of soil pathogen population, host spectrum of the pathogen, and control measures.(중략)