• Horticultural Science & Technology
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• v.30 no.2
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• pp.192-200
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• 2012

For the development of genetically modified plants, it is important to verify various factors which potentially affect the risk assessment as well as to establish an experimental program to produce scientific and reliable data. However, it is a time and cost consuming process to develop GM plants as well as to prepare scientific and convincible data for government's approval. Therefore, using the transgenic hot pepper tolerant to a new CMV pathotype, we attempted to suggest few methodological procedures, such as probe saturation for southern blot analysis and RT-PCR and ELISA for expression analysis, for identification and stability evaluation of inserted gene in genetically modified plant which are required for submission for approval. Ten partially overlapped probes covering full length of inserted gene were produced. We could identify that the inserted gene was stacked as a single copy as well as no partial element existed. Also, we could identify the stability of the inserted gene stacked in hot pepper using probe saturation. In the expression analysis with RT-PCR and ELISA, we also could provide the stable expression of transcript and proteins in leaves and placenta and pericarp of fruits of the CMV-resistant hot pepper.

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

• Research in Plant Disease
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• v.22 no.4
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• pp.264-268
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• 2016

The nursery test against rice blast in Korea from 2014 to 2015 was analyzed. The average of disease severity of leaf blast in 12 sites showed $3.7{\pm}2.1$ in 2014 and $4.4{\pm}2.1$ in 2015. Disease severity of leaf blast in Icheon and Cheolwon was increased ranging from $2.8{\pm}2.2$ in 2014 to $6.3{\pm}1.8$ in 2015. Using a designation system, a total of 588 isolates collected those years were categorized into 34 races in 2014 and 51 races in 2015 based on the reaction pattern of Korean differential varieties. The blast isolates of 2015 were more diverse than those in 2014. The ratios of KI race to KJ race were 54:46 in 2014 and 70:30 in 2015; however, the predominant race population was KJ-301 as 16%, and KI-101 as 15% in 2014 and 2015, respectively. These results indicate that the distribution of the blast races is getting more diverse in Korea, therefore, this research would provide the possibility to predict race distribution and change to prevent the outbreak of rice blast and will also serve as a useful information for breeding of resistant rice cultivar against blast.

• Korean journal of applied entomology
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• v.24 no.2 s.63
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• pp.97-101
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• 1985

Pathogenic variations of Xanthomonas campestris pv. oryzae were observed to Korean rice cultivars depending upon isolates in the same pathotype of the pathogen grouped by reactions of Japanese rice differentials. Using 201 Korean isolates of X. campestris pv oryzae 1,307 rice cultivars and promising lines were inoculated, and they were grouped into four varietal groups based on reactions. Of rice cultivars showing similar reactions to X. campestris pv. oryzae, five Korean rice cultivars Milyang 42, Hangangchalbyeo, Pungsanbyeo, Cheongcheongbyeo, and Milyang 23 were selected for classification of the pathogen into races The isolates only virulent to Milyang 23 were designated as race K1, the isolates virulent to Cheongcheongbyeo and Milyang 23 were designated as race K2, the isolates virulent to Pungsanbyeo, Cheongcheongbyeo and Milyang 23 were designated as race K3, the isolates virulent to Hangangchalbyeo, Pungsanbyeo, Cheongcheongbyeo and Milyang 23 were designated as race K4, and the isolates virulent to Milyang 42, Hangangchalbyeo, Pungsanbyeo, Cheongcheongbyeo and Milyang 23 were designated as race K5. Of 201 isolates tested, 114 isolates (56.7%) were classified as race K1, 47 isolates (23.4%) as race K2, 38 isolates (18.9%) as race K3, and 2 isolates (1.0%) as race K4. Reaction in each rice cultivar used as differentials in this test was also compared with that of rice differentials used for classification of X. campestris pv. oryzae into pathotypes in the previous work.

• Korean Journal of Microbiology
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• v.50 no.4
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• pp.285-295
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• 2014

This study was conducted to survey the epidemiological characteristics and the isolated strains for pathogenic E. coli which was the major causative organisms for food poisoning occurred at school food services in the Gyeonggi-do area during the past three years. We investigated 19 accidents of food-borne disease outbreaks by pathogenic E. coli at school food services from 2010 to 2012. Food-borne disease outbreaks by pathogenic E. coli were usually occurred at direct management type (18 accidents, 95%) and high schools. For the seasonal factors, 13 accidents (65%) were occurred in June to September, especially the end of August and September after the summer holidays. The first patients were occurred on Wednesday (7 accidents, 37%) and Thursday (7 accidents, 37%), and they were mainly reported on Thursday (7 accidents, 37%) and Friday (5 accidents, 26%). The exposure of risk was estimated in Monday (4 accidents, 21%), Tuesday (7 accidents, 37%) and Wednesday (4 accidents, 21%), and kimchi (5 accidents, 50%) was estimated as the food of the high risk responsible for the outbreaks. 98 isolates of pathogenic E. coli consisted of PEC (50%), ETEC (34%), EAEC (15%), and EHEC (1%). The antibiotic resistance of pathogenic E. coli showed in the descending order of ampicilline (40%), nalidixic acid (37%), trimethoprim/sulfamethoxazole (24%), and tetracycline (19%). The antibiotics of second and third generation cephalosporins, cabarpenem, aminoglycosides, and second generation quinolones had antimicrobial susceptibilities and cefalotin, ampicillin/sulbactam and chloramphenicol showed medium resistance at 29%, 25%, and 6% respectively, and 70% of isolates were resistant to more than one antibiotic. By the PFGE analysis, they were classified into nine major groups and 31 profiles with 57% pattern similarity. It was very difficult to find the correlation of antimicrobial susceptibilities and genotype in the small scale-food poisoning, but the similarity of antimicrobial resistance and PFGE patterns in the large scale-food poisoning enabled the outbreaks to estimate the same pathotype of E. coli derived from identical origins.