• Korean Journal Plant Pathology
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• v.10 no.4
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• pp.314-318
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• 1994

Incidence of stem rot on carnation (Dianthus caryophyllus L.) ranged 11 to 29% in Namwon and Chongup area during the growing seasons from 1993 to 1994. Among 129 isolates from carnations in Namwon, 77 isolates were identified as Rhizoctonia solani, 38 isolates were Fusarium oxysporum and 14 isolates were not identified. Among 169 isolates in Chongup, 19 isolates were identified as R. solani, 106 isolates as F. oxysporum and 44 isolates were not identified. Among 77 isolates of R. solani isolated from the specimens of Namwon, 52 isolates were classified as anastomosis group AG 2-2 by anastomosis test, 14 isolates as AG 2-1 and 11 isolates as AG 4. Among 19 isolates from specimens of Chongup, 14 isolates were classified as anastomosis group AG 2-2 and 5 isolates as AG 4. Pathogenicity tests revealed that isolates of F. oxysporum and R.solani AG 2-2 were highly virulent and isolates of R.solani AG 2-1 and AG 4 were mildly virulent.

• Korean Journal Plant Pathology
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• v.14 no.6
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• pp.700-704
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• 1998

A total of 26 and 55 isolates of fungi were isolated from corn and wheat samples collected from different markets in Korea, respectively. The number of Penicillium isolates from corn and wheat was 9 and 33, respectively. The Penicillium species isolated from corn were P. chrysogenum (3 isolates) and P. oxalicum (6 isolates), and from wheat were P. aurantiogriseum (16 isolates), P. citrinum (1 isolate), P. commun (4 isolates), P. griseofulvum (1 isolate), P. verrucosum (7 isolates), and P. viridicatum (4 isolates). Production of major mycotoxins in the yeast extract sucrose medium cultures of Penicillium isolates was analysed. Penicillium cultures were extracted with chloroform and purified by thin-layer chromatograhy (TLC), and high performance liquid chromatography (HPLC). Among 9 isolates of Penicillium from corn, 2 isolates of P. chrysogenum produced patulin, 1 isolate of the fungus produced patulin and citrinin, 2 isolates of P. oxalicum produced penicillic acid, 4 isolates produced pencillic acid and griseofulvin. Of the 33 isolates of Penicillium from wheat, 6 isolates of P. aurantiogriseum produced patulin, 8 isolates produced penicillic acid, 1 isolate produced patulin and penicillic acid, 1 isolate of P. citrinum produced citrinin and patulin, 2 isolates of P. commun produced brefeldin A and patulin, 1 isolate of P. griseofulvum produced brefeldin A, griseofulvin and patulin. Five isolates of P. verrucosum produced patulin, 1 isolate of the fungus produced penicillic acid, and 3 isolates of P. viridicatium produced penicillic acid.

• The Plant Pathology Journal
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• v.24 no.1
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• pp.52-57
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• 2008

Twenty isolates of Bacillus spp. obtained from livestock manure composts and cotton-waste composts were tested for in vitro antagonistic effects against soilborne plant pathogenic fungi, Fusarium oxysporum, Phytophthora capsici, Rhizoctonia solani AG-4, and Sclerotinia sclerotiorum. Seven isolates of Bacillus spp. had antagonistic effects on mycelial growth of all the isolates of F. oxysporum tested. The bacterial isolate RM43 was the most effective to inhibit the mycelial growth of the fungal isolates. Twelve isolates of Bacillus spp. had antagonistic effects on mycelial growth of all the isolates of P. capsici tested. The bacterial isolates M34 and M47 were very effective to inhibit the mycelial growth of the fungal isolates. Thirteen isolates of Bacillus spp. had antagonistic effects on mycelial growth of all the isolates of R. solani AG-4 tested. The bacterial isolates M27 and M75 were very effective to inhibit the mycelial growth of the fungal isolates. Fourteen isolates of Bacillus sp. had antagonistic effects on mycelial growth of all the isolates of S. sclerotiorum tested. The bacterial isolates M49 and M75 were very effective to inhibit the mycelial growth of the fungal isolates. The antagonistic effects of most Bacillus spp. isolates against the isolates of the four fungi differed depending on the fungal species and the isolates of each fungus. The bacterial isolates M27 and M75 were the most effective to inhibit the mycelial growth of all four fungi.

• The Plant Pathology Journal
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• v.19 no.3
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• pp.143-147
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• 2003

Sensitivity of Phytophthora infestans isolates to fungicides metalaxyl and ethaboxam in Korea was examined with 260 isolates for 3 years (9 isolates in 2000,93 isolates in 2001, and 158 isolates in 2002). Both Al and A2 mating types were found from the isolates collected for 3 years. Al mating type was dominant in the population with 8 isolates (88.9%) in 2000, 84 isolates (89.4%) in 2001, and 138 isolates (87.3%) in 2002. Only some isolates from diseased tomatoes in Buyergun and diseased potatoes in Pyeongchanggun were of the A2 mating type. As for metalaxyl sensitivity, 77.0% of the isolates were moderately resistant with 8 isolates (88.9%) in 2000, 73 isolates (77.7%) in 2001, and 120 isolates (75.9%) in 2002. Meanwhile, those found resistant were 1 isolate (11.1%) in 2000, 16 isolates (17.0%) in 2001, and 33 isolates (20.9%) in 2002. Only 5 isolates (3.2%) were sensitive to metalaxyl in 2002. There was no significant difference in the sensitivity among years. As for ethaboxam, no isolate was able to grow at 5.0 $\mu\textrm{g}$ /ml, and only four isolates (1.5 %) grew at 1.0 $\mu\textrm{g}$ /ml with heavy retardation compared with the untreated control. Based on these 3-year results, the minimum inhibitory concentration (MIC) of ethaboxam to p. infestans was determined to be 0.2-1.0 $\mu\textrm{g}$ /ml. Results indicate that resistance development by p. infestans to ethaboxam is not likely to occur in the natural condition. furthermore, there was no indication of cross resistance between metalaxyl and ethaboxam because all the isolates, regardless of classification for their sensitivity to metalaxyl, were not able to grow at 5.0 $\mu\textrm{g}$ /ml of ethaboxam.

• The Plant Pathology Journal
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• v.25 no.1
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• pp.13-20
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• 2009

Ninety isolates of Colletotrichum species from new persimmon tree twigs and 50 isolates from pepper plant fruits were isolated via single-spore isolation. Of the 140 isolates, 26 were examined for mycelial growth, carbendazim sensitivity, and ITS sequence. Four of the isolates from the persimmon trees, which were cultivated exclusively in an orchard, showed fast mycelial growth and sensitivity to carbendazim, while five of the pepper isolates showed slower mycelial growth and were resistant to the fungicide. However, 17 isolates from persimmon trees cultivated with pepper plants in the same orchard showed slow mycelial growth like the pepper isolates and they were sensitive to carbendazim like the persimmon isolates. ITS sequence analysis of these 27 isolates led to the identification of the 22 persimmon isolates as C. gloeosporioides and the five pepper isolates as C. acutatum. PCR with species-specific primers confirmed that the 90 isolates from persimmon were C. gloeosporioides whereas the 50 isolates from pepper were C. acutatum. The 90 persimmon isolates of C. gloeosporioides and 50 pepper isolates of C. acutatum were compared by a wound inoculation test to determine their capacity for host cross-infection. All of the C. acutatum isolates from pepper caused typical symptoms of anthracnose on the fruits of pepper plants and twigs of persimmon; they differed from the C. gloeosporioides isolates from persimmon, more than 90% of which were able to infect only persimmon. Amplified fragment length polymorphism analysis revealed the existence of two groups (C. gloeosporioides and C. acutatum isolates group). At 80% genetic similarity, the C. gloeosporioides group was defined within four clusters, while the C. acutatum group was within three clusters. However, these clusterings were unrelated with the virulence of Colletotrichum species against pepper fruits.

• Journal of Microbiology and Biotechnology
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• v.17 no.6
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• pp.985-992
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• 2007

The diversity of archaeal strains from six hypersaline environments in Turkey was analyzed by comparing their phenotypic characteristics and 16S rDNA sequences. Thirty-three isolates were characterized in terms of their phenotypic properties including morphological and biochemical characteristics, susceptibility to different antibiotics, and total lipid and plasmid contents, and finally compared by 16S rDNA gene sequences. The results showed that all isolates belong to the family Halobacteriaceae. Phylogenetic analyses using approximately 1,388 bp comparisions of 16S rDNA sequences demonstrated that all isolates clustered closely to species belonging to 9 genera, namely Halorubrum (8 isolates), Natrinema (5 isolates), Haloarcula (4 isolates), Natronococcus (4 isolates), Natrialba (4 isolates), Haloferax (3 isolates), Haloterrigena (3 isolates), Halalkalicoccus (1 isolate), and Halomicrobium (1 isolate). The results revealed a high diversity among the isolated halophilic strains and indicated that some of these strains constitute new taxa of extremely halophilic archaea.

• Korean Journal Plant Pathology
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• v.14 no.6
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• pp.571-577
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• 1998

Variability in virulence of Calonectria ilicicola isolates form different hosts and geographic origin provides important information for breeding cultivars resistant to red crown rot. A wide range in virulence for 25 isolates of C. ilicicola from soybean and peanut was observed on six soybean cultivars. Soybean isolates were pathogenic on soybean although some were less virulent. Virulence of isolates was not affected greatly by cultivar and relatively consistent regardless of virulence level. Soybean isolates were more virulent on soybean than were peanut isolates. When virulence of two soybean and tow peanut isolates was compared between laboratory and greenhouse tests, it was stable across a range of cultivars. Mycelial growth of isolates from either soybean or peanut was reduced significantly on potato dextrose chlorate showed significant reduction of fungal growth than isolates from peanut did although their growth on potato dextrose agar was not significantly different. Evidence for physiologic specialization was not recognized in this system. However, the findings that soybean isolates of C. ilicicola were more virulent on soybean and reduction of fungal growth on potato dextrose chlorate than were peanut isolates suggest that host specialization may exist in this fugus.

• Korean Journal of Veterinary Research
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• v.52 no.3
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• pp.177-181
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• 2012

Actinobacillus (A.) pleuropneumoniae is the causative agent of pleuropneumonia which is one of the most important respiratory diseases in pigs worldwide. A total of 32 A. pleuropneumoniae isolates from diseased pigs during 2008 to 2010 were serotyped by polymerase chain reaction method. The susceptibility of the isolates to 13 antimicrobial agents were determined by disk diffusion test. In all the 32 isolates examined in this study, serotype 5 (16 isolates: 50%), 1 (7 isolates: 21.9%), 2 (5 isolates: 15.6%) and 12 (1 isolate: 3.1%) were found. Of all tested antimicrobial agents, resistance to oxytetracycline was found in 96.9% of isolates, followed by resistance to amikacin (81.2%), neomycin (68.7%), kanamycin (53.1%), penicillin (50.0%), gentamicin (43.7%), florfenicol (25.0%), ampicillin (18.7%), colistin (9.4%), trimethoprim/sulfamethoxazole, ceftiofur (8.3%), amoxicillin/clavulanic acid (3.1%) and enrofloxacin (0%). Oxytetracycline or florfenicol-resistant isolates were examined for the presence of resistance gene. Among the 31 oxytetracycline-resistant isolates, tetB, tetH and tetO genes were detected in 22 (71%), 8 (26%) and 1 (3%) isolates, respectively. The floR genes were detected in 8 (100%) of the 8 florfenicol-resistant A. pleuropneumoniae isolates.

• Journal of Microbiology
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• v.40 no.2
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• pp.98-103
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• 2002

Twenty-eight clinical isolates of Escherichia coil, composed of thirteen norfloxacin resistant isolates (MIC of >16${\mu}$g/ml), one intermediately resistant isolate (MIC of 8${\mu}$g/ml), and fourteen susceptible isolates (MIC of <4${\mu}$g/ml), were randomly selected to study the norfloxacin resistance mechanism and phylogeny in clinical isolates in Korea. Eleven nofloxacin resistant isolates and one susceptible isolate were multi-drug resistant (MDR). Every norfloxacin resistant isolate with MIC higher than 32${\mu}$g/ml had the same three mutations: Ser83\longrightarrowLeu and Asp87\longrightarrowAsn or Tyr in GyrA and Ser80\longrightarrowIle in ParC. Whereas a resistant isolate with MIC of 16${\mu}$g/ml had three mutations but Asp87 in GyrA was replaced with Gly instead of Asn. The intermediately resistant isolate had the same two mutations in GyrA but a different mutation in ParC, Glu84\longrightarrowLys. Among the susceptible isolates, two isolates with MIC of 4${\mu}$g/ml had one mutation: Ser83\longrightarrowiLeu in GyrA, and no mutation was found in the susceptible isolates. Resistant isolates showed higher efflux activity than the susceptible ones, with random amplification of polymorphic DNA (RAPD), six susceptible isolates form a separate group from the rest of the isolates.

• Korean Journal Plant Pathology
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• v.10 no.1
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• pp.7-12
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• 1994

Incidence of radish disease caused by Rhizoctonia solani ranged from 1 to 30% in fields located at Hwaseong, Naju and Yeoncheon in Korea during the growing seasons in 1989, 1990 ad 1993. A total of 133 isolates of R. solani was obtained from the diseased seedlings, leaves and roots of radish collected. The fungus was most commonly isolated from the roots. Among 133 isolates of R. solani, 56 isolates were classified as anastomosis group AG-1 by anastomosis test, 37 isolates as AG-2-1, and 40 isolates as AG-4. Among the isolates of AG-1, 26 isolates were grouped as cultural type IA, and the others as cultural type IB. Cultural types IA and IB of AG-1, were isolated from the leaves, AG-2-1 from the roots, and AG-4 from the seedlings, leaves and roots. Pathogenicity tests revealed that the AG-1(IA) isolates were highly virulent on leaves of radish, but avirulent on the seedlings, petioles and roots. The AG-1(IB) isolates were highly virulent on the leaves, but mildly virulent on the seedlings and avirulent or mildly virulent on the petioles and roots. The AG-2-1, isolates were mildly virulent on the leaves and seedlings and mildly or highly virulent on the petioles and roots. The AG-4 isolates were highly virulent on the seedlings and mildly or highly virulent on the leaves, petioles and roots.