• The Plant Pathology Journal
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• 제26권4호
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• pp.421-423
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• 2010

New sources of barley (Hordeum vulgare L.) resistant to spot blotch, caused by Cochliobolus sativus, are needed to provide effective resistance because of the rapid change pathotype patterns of C. sativus in fields. The purposes of our study were to develop a method to screen barley for resistance to spot blotch disease and then use this methodology to screen barley genotypes for resistance to the major virulent pathotype Pt4 in barley populations in Syria. A transparent tape method, in which a conidial suspension of C. sativus was dropped onto transparent tape and placed, treated-side down, on the second leaf surface of barley plants. Disease symptoms of fungus were easily detected on the leaves covered by the transparent tape after 48h of inoculation. The transparent tape method was repeatable and the disease scores obtained were correlated (r = 0.91, P = 0.001) with those obtained by the seedling assay. This method may be beneficial in various plant pathology breeding programs.

• 한국응용곤충학회지
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• 제18권2호
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• pp.77-84
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• 1979

벼 흰빛잎마름병균의 10균주(I군 3균주, II군 4균주, III군 3균주)를 저항성이 서로 다른 벼품종 '밀양 23호'(김남풍군), '유신'(황옥군), '통일'(Rantaiemas군)의 유묘기와 분얼초기, 최고분얼기, 지엽기에 각각 접종하였다. 그 결과 1) 병원성 발현의 양상이 균주 간 매우 다양하였다. 2) 특히 II군의 균주들은 같은 군균내에서도 변이가 매우 큰 것으로 나타났다. II군은 더 많은 균형으로 세분될 수 있었다. 3) 생육시기 별로 병원성 발현 양상이 달랐으며, 대체로 지엽기 이후 높은 발병을 나타내었다. II군중 G 7716균주는 출수이후에야 비로소 '유신'품종에 발병을 일으킬 수 있었다. 4) 통계분산분석(ANOVA) 결과, 각각 다른 균형의 균주, 품종, 생육시기가 발병정도의 분산에 주요인으로 작용하였고, 균주와 품종간의 상호작용(interaction)에 유의성이 있었으나 다른 요인간에는 없었다.

• 대한수의학회지
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• 제46권4호
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• pp.371-379
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• 2006

Newcastle disease virus (NDV) is a single-stranded negative sense RNA virus, which has been classified as a member of the Avulavirus genus of the Paramyxoviridae family. It is also one of the most important pathogens in the poultry industry. The glycoproteins, fusion (F) and hemagglutinin-neuraminidase (HN), determine the virulence of NDV, and the relevant molecular structures have already been determined. NDV isolates differ in terms of virulence, and at least 2 of 9 genotypes (I-IX) have been shown to co-circulate. Therefore, it is clearly important to differentiate between vaccine strains and field isolates. In vivo pathogenicity tests have been the standard protocol for some time, but molecular methods appear preferable in terms of the rapidity of diagnosis, as well as animal welfare concerns. In this study, we have designed primer sets from HN gene for phylogenetic analysis and restriction enzyme analysis, and from F gene for pathotype-specific RT-PCR. Via the combination of 2 methods, 106 Korean NDV isolates obtained from 1980 to 2005 were differentiated into vaccine strains, and virulent genotypes VI and VII. The genotype VI viruses were only rarely isolated after 1999, and genotype VII, after it was initially isolated from poultry in 1995, recurred in 2000, and then became the main NDV constituting a threat to the Korean poultry industry.

• The Plant Pathology Journal
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• 제32권5호
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• pp.423-430
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• 2016

Clubroot disease caused by Plasmodiophora brassicae is one of the most serious diseases in Brassica crops worldwide. In this study, the pathotypes of 12 Korean P. brassicae field isolates were determined using various Chinese cabbage including 22 commercial cultivars from Korea, China, and Japan, and 15 inbred lines. All P. brassicae isolates exhibited the typical clubroot disease on non-clubroot resistant cultivar, indicating that the isolates were highly pathogenic. According to the reactions on the Williams' hosts, the 12 field isolates were initially classified into five races. However, when these isolates were inoculated onto clubroot-resistant (CR) cultivars of Chinese cabbage, several isolates led to different disease responses even though the isolates have been assigned to the same race by the Williams' host responses. Based on the pathogenicity results, the 12 field isolates were reclassified into four different groups: pathotype 1 (GN1, GN2, GS, JS, and HS), 2 (DJ and KS), 3 (HN1, PC, and YC), and 4 (HN2 and SS). In addition, the CR cultivars from Korea, China, and Japan exhibited distinguishable disease responses to the P. brassicae isolates, suggesting that the 22 cultivars used in this study, including the non-CR cultivars, are classified into four different host groups based on their disease resistance. Combining these findings, the four differential hosts of Chinese cabbage and four pathotype groups of P. brassicae might provide an efficient screening system for resistant cultivars and a new foundation of breeding strategies for CR Chinese cabbage.

• Journal of Microbiology and Biotechnology
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• 제13권1호
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• pp.110-118
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• 2003

Pseudomonas syringae pv. actinidiae strains, which cause canker disease in kiwifruit, were collected from kiwifruit orchards in Korea and identified using biochemical and physiological tests. The nucleotide sequences of the 16s rDNA and 16s-23s internally transcribed spacer of the isolates were found to be Identical to those of' the pathotype strain, Kwl 1, of P syringae pv. actinidiae. Remarkably, no coding sequence for phaseolotoxin biosynthesis or phaseolotoxin- resistant ornithine carbamoyltransferase was found by PCR amplification in any of the new Korean isolates of pseudomonas syringae pv. actinidiae, although this was clearly identified in the control pathotype Kwl 1 reference strain. In contrast, three primer sets derived from the coronatine biosynthetic gene cluster and DNA from the Korean strains yielded amplified DNA fragments of the expected size. A sequence analysis of the PCR products revealed that P. syringae pv. actinidiae and the Korean strains of pv. actinidiae contain coronafncate ligase genes (cfl)with identical sequences, whereas their. corR genes exhibited 91% sequence similarity. The production of coronatine, instead of phaseolotoxin, by the Korean strains of P. syringae pv. actinidiae was confirmed by a bioassay using reference pathovars known to produce coronatine and phaseolotoxin. The genes for coronatine biosynthesis in the Korean strains of P. syringae pv. actinidiae were found to be present on plasmids.

• 미생물학회지
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• 제13권4호
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• pp.143-156
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• 1975

A rotting bacterium was isolated from decayed root of ginseng (Panax ginseng Meyer), cultured purely, and its pathogenicity was confirmed by reinoculation test. The strain causing ginseng root rot was identified as Pseudomonas fluoresens biotype II. The strain was somewhat different from P.marginalis and P.talaasii, considering the number of flagella, pathotype and ability of indole production. The strain did not exhibit pathogenicity to other plants tested, such as red kidney bean(Phasolus vulgaris L.), soy bean (Glycine max Merr.), cucumber (Cucumis sativus L.) lettuce (Lactuca sativa L.) and cowpea bean (Vigna sinensis Savi.).

• 한국응용곤충학회지
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• 제18권2호
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• pp.73-76
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• 1979

벼 흰빛잎마름병균, Xanthomonas oryzae의 채집균주중에서 가장 병원성이 큰 2균주를 선발하여 각각 10대까지 계대배양하였다. 계대배양한 모든 세균을 "밀양23호", "유신", "통일"의 분얼기묘에 접종한 결과, 1) 병원성이 큰 III군균주(IN7721)가 작은 1군균주 (KB7785)보다 계대배양으로 인해 더 많은 감퇴를 나타내었다. 2) 품종의 저항성에 따라 병원성 감퇴정도가 다르게 나타났다. 병원성이 작은 균주(I군, KB7785)는 저항성 품종에서, 병원성이 큰 균주(III군, JN7721)는 이병성품종에서 각각 병원성감퇴가 더 컸다. 3) I군균주(KB7785)가 "통일" 품종의 분얼기 묘에 III군균주(JN7721)와 비슷한 정도로 침입할 수 있었다. 4) 10대까지의 계대배양 도중에 콜로니 형태가 다른 변이균은 관찰되지 않았다.

• 한국식물병리학회지
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• 제2권2호
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• pp.82-88
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• 1986

오래 저장해 둔 쇠비를 즙액에서 5종의 항균성 물질이 분리되었으며 이들 물질이 isobutyric acid, butyric acid, isovaleric acid, valeric acid 그리고 caproic acid 등과 C4-C6의 저급지방산으로 동정되었다. 각각의 지방산은 실내실험에서 다소간에 배나무 검은무늬병균(Alternaria alternata Japanese pear pathotype)의 포자발아나 균사신장을 다같이 저해하였다. 포자발아에 대한 각각 지방산의 항균력은 예외없이 균사신장에 대한 그것보다 컸다. 예컨데 200PPM 이하의 농도에서 균사생장을 완전히 저해하는 항균성 지방산은 하나도 없었지만 caproic acid의 50ppm과 valeric acid의 200ppm은 포자발아를 완전히 억제하였다. 또한 생물검정의 결과에서 이들 지방산의 탄소시술의 길이가 길수록 더욱 높은 항균력을 보여주었으므로 탄소사슬의 길이가 항균력과 관계가 있는 것으로 추정되었다.

• The Plant Pathology Journal
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• 제28권3호
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• pp.295-298
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• 2012

Genetic diversity among Pseudomonas syringae pv. morsprunorum isolates from Prunus mume in Korea and Japan was investigated by comparative sequence analysis of the 16S rRNA gene. The strains included 24 field isolates recovered from P. mume in Korea along with seven Japanese strains. Two strains isolated from P. salicina in Japan, one strain from P. avium in the United Kingdom, and the pathotype strain were also used for comparison with their 16S rRNA gene sequences. Nearly complete 16S rRNA gene sequences were sequenced in all 35 strains, and three sequence types, designated types I, II and III, were identified. Eleven strains consisting of five Korean isolates, five Japanese strains, and one strain from the United Kingdom belonged to type I, whereas the pathotype strain and another 19 Korean isolates belonged to type III. Another four Japanese strains belonged to type II. Type I showed 98.9% sequence homology with type III. Type I and II had only two heterogeneous bases. The 16S rRNA sequence types were correlated with the races of P. syringae pv. morsprunorum. Type I and II strains belonged to race 1, whereas type III isolates were included in race 2. Sequence analyses of the 16S rRNA gene from P. syringae pv. morsprunorum were useful in identifying the races and can further be used for epidemiological surveillance of this pathogen.

• 식물병연구
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• 제7권2호
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• pp.93-101
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• 2001

1996년부터 1998년까지 한국내 십자화과 채소작물의 포장에서 시들음병 발생을 조사한 결과, 배추와 무에서는 발생율이 최대 40%까지 심하게 발생하였으며, 양배추에서는 일부 포장에서만 약간 발생하였다. 시들음증상을 보이는 십자화과 채소작물의 병든 뿌리로부터 총 123균주의 Fusarium균이 분리하였으며, 공시균주들의 형태적 및 배양적 특성을 조사한 결과, 모두 Fusarium of oxysporum으로 동정되었다 공시균주들의 배추 및 양배추에 대한 병원성은 공시품종에 따라 다소 차이는 있었으나 균주들간에 뚜렷하게 구분되지 않았다. 무에 대한 병원성에 있어서는 대체로 무분리 균주들이 배추 및 양배추분리 균주들보다 강한 것으로 나타났다 공시균주들의 십자화과 이외의 채소작물에 대한 병원성검정 결과, 고추 등 8개 작물에 대해 모두 병원성이 없었다 이 연구결과, 배추감염 균주들의 병원형은 양배추감염 균주들의 병원형과 동일하고, 무감염 균주들의 병원형과는 다른 것으로 나타났다.