• The Plant Pathology Journal
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• v.40 no.2
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• pp.151-159
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• 2024

Bacterial soft rot caused by Pectobacterium carotovorum subsp. carotovorum (Pcc) is one of the most severe diseases in radish cultivation. To control this plant disease, the most effective method has been known to cultivate resistant cultivars. Previously, we developed an efficient bioassay method for investigating resistance levels with 21 resistant and moderately resistant cultivars of radish against a strain Pcc KACC 10421. In this study, our research expanded to investigate the resistance of radish cultivars against six Pcc strains, KACC 10225, KACC 10421, ATCC 12312, ATCC 15713, LY34, and ECC 301365. To this end, the virulence of the six Pcc strains was determined based on the development of bacterial soft rot in seedlings of four susceptible radish cultivars. The results showed that the Pcc strains exhibited different virulence in the susceptible cultivars. To explore the race differentiation of Pcc strains corresponding to the resistance in radish cultivars, we investigated the occurrence of bacterial soft rot caused by the six Pcc strains on the 21 resistant and moderate resistant cultivars. Our results showed that the average values of the area under the disease progress curve were positively correlated with the virulence of the strains and the number of resistant cultivars decreased as the virulence of Pcc strains increased. Taken together, our results suggest that the resistance to Pcc of the radish cultivars commercialized in Korea is more likely affected by the virulence of Pcc strains rather than by race differentiation of Pcc.

• Journal of the Korean Society of Tobacco Science
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• v.6 no.2
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• pp.141-146
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• 1984

Two PVY strains (PVY-VB and PVY-VN) isolated from tobacco in Korea were compared for their serological relationship with other 8 strains which were obtained from tobacco or potato in different countries. One of these strains, PVY-Argentina showed the spur reaction to PVY-VB and PVY-VN antisera in SDS-agar gel double diffusion plates. The two Korean PVY strains were closely related to other strains except for one, PVY-Argentina when antigen-antibody reciprocal absorption tests were conducted. It is suggested that the strain, PVY-Argentina, is a new serotype containing a specific antigenic site different from other 9 strains tested.

• Journal of Mushroom
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• v.13 no.1
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• pp.41-49
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• 2015

In order to breed new strains of oak mushroom, Lentinula edodes, on the sawdust cultivation, we collected 10 from Korea, Taiwan and China respectively and examined somatic incompatibility, morphological features of fruiting body and productivity. Four strains(SANJO701HO, FMRI2534, FMRI2337 and FMRI2613) shown remarkable results, were confirmed with parental strains. 80 monokaryotic strains derived from the selected 4 parental strains, were selected and 117 hybrid strains were made by mono-mono mating. Aslo, Physiological characteristics were investigated. Average of the mycelial growth of hybrid strains of mating combination SANJO701HO-FMRI2337 was approximately 10% lower than other mating combinations. Overall, This study was founded to develop new varieties of L. edodes. The productivity of new 117 strains on sawdust cultivation needs continued research.

• The Plant Pathology Journal
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• v.17 no.5
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• pp.281-289
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• 2001

We analyzed 88 strains of Gibberella fujikuroi (Analmorph: Fusarium section Liseola) from maize in Korea for mating population, mating type, fumonisin production vegetative compatibility, and random amplified polymorphic DNA (RAPD) patterns. We found 50 strains that were MATA-2, 22 that were MATA-1, 1 that was MATD-1, and 15 that were not reproducibly fertile with any of the mating type testers. Of the 50 MATA-2, 15 were female fertile, while 10 of the 22 MATA-1 strains were female fertile. A total of 1,138 nitrate non-utilizing (nit) mutants were recovered from a total of 88 strains. These strains were grouped into 39 vegetative compatability groups (VCGs) by demonstrating heterokaryosis between nit mutants. A single maize ear could be infected by more than one VCG of F. moniliforme. RAPD analysis measured genetic diversity among 63 strains of F. moniliforme. Several VCGs were distinguished by RAPD fingerprinting patterns. Most strains produced significant levels of fumonisins. However, 6 MATA-2 strains from a single VCG produced higher levels of fumonisin $\textrm{B}_3$ than that of fumonisin $\textrm{B}_1$ or $\textrm{B}_2$. From these data, we concluded that most Korean strains of F. moniliforme associated with maize belonged to mating population A and produced significant levels of fumonisins. Futhermore, RAPD analysis could differentiate strains associated with different VCGs.

• The Plant Pathology Journal
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• v.30 no.1
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• pp.96-101
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• 2014

The molecular features of Pseudomonas syringae pv. actinidiae strains isolated in Korea were compared with strains isolated in Japan and Italy. Sequencing of eight P. syringae pv. actinidiae and three P. syringae pv. theae strains revealed a total of 44 single nucleotide polymorphisms across 4,818 bp of the concatenated alignment of nine genes. A multiplex PCR assay was developed for the detection of P. syringae pv. actinidiae and for the specific detection of recent haplotype strains other than strains isolated since the 1980s in Korea. The primer pair, designated as TacF and TacR, specifically amplified a 545-bp fragment with the genomic DNA of new haplotype of P. syringae pv. actinidiae strains. A multiplex PCR conducted with the TacF/TacR primer pair and the universal primer pair for all P. syringae pv. actinidiae strains can be simultaneously applied for the detection of P. syringae pv. actinidiae and for the differentiation of new haplotype strains.

• Journal of Microbiology and Biotechnology
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• v.8 no.5
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• pp.517-522
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• 1998

The cry1 gene content of a collection of Bacillus thuringiensis strains, which include new isolates from Malaysia and Indonesia, was determined by a multiplex PCR using a set of eight oligonucleotide forward primers specific to cry1Aa, cry1Ab, cry1Ac, cry1Ba, cry1Ca, cry1Da, cry1Ea, and cry1Fa genes, and two reverse primers, one specific to cry1Ab and the other common to the remaining cry1 genes. Two-thirds of the 59 strains screened were cry1 positive and contained one to four different genes. The cry gene profiles correlated well with toxicities of the strains to lepidopteran insects. The method can be used for rapid screening of a large number of new isolates as the total DNA extracted by boiling cells from single colonies can be used directly in the PCR. However, it is not suitable for follow-up monitoring of specific commercial strains after application in the field as the PCR product profiles of these strains could not be differentiated from those of new isolates.

• Korean Journal of Veterinary Research
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• v.49 no.3
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• pp.243-248
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• 2009

After the original identification of canine parvovirus (CPV) type 2 (CPV-2) in 1978, new antigenic variants such as CPV-2a, CPV-2b and CPV-2c have become widespread in the most countries. In this study, the genetic analysis of canine parvovirus was investigated in a total of 13 CPV vaccines, which have been licensed in Korea since late 1980s, and a field isolate of CPV from a dog with CPV infection clinical symptom. The partial VP2 gene of CPV was amplified and sequenced from 13 vaccine strains and one field isolate. The results showed that of the 13 vaccine strains, 10 strains belong to the CPV-2, 2 strains to CPV-2b, the remaining and one isolate to CPV-2a type, respectively. Several mutations of amino acids were detected at residues of the critical region of the commercial vaccine strains. These data suggest that new type of vaccines containing CPV-2a or CPV-2b/2c type may be required for the better prevention of new CPV infection in dog population in Korea, because CPV-2 contained in most licensed vaccines has been replaced by antigenic variants designated CPV-2a or CPV-2b/c in the worldwide dog population.

• Microbiology and Biotechnology Letters
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• v.24 no.5
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• pp.636-639
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• 1996

To develop new biologically active compounds produced by anaerobes, 677 soil samples were collected and used to isolate 1, 889 anaerobic bacteria. Among the isolates 427 strains were strict anaerobes and the remaining 1, 462 strains were facultative anaerobes. From 427 strictly anaerobic isolates, 88 strains showed antibacterial activities, and 21 strains were selected for the further studies.

• The Plant Pathology Journal
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• v.37 no.6
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• pp.652-661
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• 2021

Xanthomonas citri pv. glycines (Xcg) is a major pathogen of soybean (Glycine max) in South Korea, despite the availability of soybean varieties with some resistance. We conducted a nationwide survey of the incidence and severity of bacterial pustule caused by Xcg. The percentage of infected fields was 7% to 17% between 2015 and 2017. We characterized the diversity of a nationwide collection of 106 Xcg isolates based on avrBs3 banding patterns. The isolates fell into 11 groups, each represented by a type strain; only two of these were similar to isolates collected from 1999 to 2002. The diversity of Xcg strains increased and the dominant strains changed between 1999 and 2017, with three new type strains comprising 44% of the isolates examined in 2012 to 2017. Pathogenicity tests did not show evidence for a shift in the races or aggressiveness of Xcg strains. Korean soybean cultivars, including the widely-grown Daewon cultivar, were susceptible to the 11 new type strains. The cultivar CNS, which carries the rxp resistance gene, was susceptible to most type strains, including two representing 83% of the Korean Xcg strains. In contrast, Williams 82, which also carries rxp, showed resistance to at least five type strains. Collectively, these results suggest that Williams 82 has resistance loci in addition to rxp. The widespread distribution of Xcg, the high virulence of the current endemic strains, and the low resistance of most Korean soybean cultivars collectively favor widespread disease in Korea in years that are favorable to pustule development.

• YAKHAK HOEJI
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• v.47 no.6
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• pp.365-368
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• 2003

The bactericidal activities of DW286, a new fluoroquinolone were investigated by comparing the minimal bactericidal concentrations (MBCs) and the time-kill curve of it against some Gram-positive and Gram-negative bacterial strains. The MBCs of DW286 for the strains tested were either equal to or two-fold higher than the MICs, as were observed for the other fluoroquinolones. And DW286 exhibited rapid killing curves against the strains. Accordingly, it could be said that DW286 has bactericidal activity comparable to other fluoroquinolones.