• 한국식물병리학회지
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• 제10권4호
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• pp.333-335
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• 1994

In 1991, the leaves and roots brown rot disease of scarlet kafir lily were found in Taejon and Seoul. The symptoms were appeared as dark-brown and water soaked on leaves. The discolored area of the leaves become halo. The roots revealed blight gray and water soaked. The pathogenic bacteria were isolated from the diseased leaves of the scarlet kafir lily were identified as Erwinia cypripedii on the bais of bacterial characteristics. E. cypripedii is first described bacteria which cause the disease on scarlet kafir lily in Korea. Therefore, we would like to propose to the name of scarlet kafir lily disease caused by E. cypripedii as“bacterial brown-rot of scarlet kafir lily”hereafter.

• 식물병연구
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• 제10권1호
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• pp.73-77
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• 2004

본 연구는 우리나라에서 육성된 대안벼, 화선찰벼, 대진벼, 내풍벼, 화진벼, 수라벼의 흰잎마름병 저항성 유전자를 밝히기 위하여 실시하였다. 이들 품종을 단일 저항성 유전자를 갖고 있는 준동질계통과 교배한 F$_1$ 개체와 F$_2$ 집단을 Kl race 균주와 일본의 race 1을 사용하여 분석하였다. 검정품종은 모두 Xa1 저항성 유전자를 갖고 있는 IRBB101 계통과 대립관계를 나타냈고 Xa4와 xa-5 유전자를 갖고 있는 IRBB104와 IRBB105 계통과는 비대립 관계를 나타내었다. 따라서 대안벼, 화선찰벼, 대진벼, 내풍벼, 화진벼, 수라벼가 Xal 저항성 유전자를 갖고 있는 것으로 판단되었다.

• The Plant Pathology Journal
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• 제34권4호
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• pp.269-285
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• 2018

Bacterial leaf blight is a major disease of eucalypt, especially under nursery conditions. Different bacterial species have been associated with the disease in several countries, and despite its importance worldwide, it is not clear to date whether similar disease symptoms are caused by the same or by different etiological agents. In this study, 43 bacterial strains were isolated from blighted eucalypt leaves collected in different geographic areas of Brazil and inoculated onto a susceptible eucalypt clone. Polyphasic taxonomy, including morphological, physiological, biochemical, molecular, and pathogenicity tests showed that only certain strains of Xanthomonas axonopodis caused symptoms of the disease. Strains varied in their aggressiveness, but no correlation with geographic origin was observed. MLSA-based phylogenetic analysis using concatenated dnaK, fyuA, gyrB and rpoD gene sequences allocated the strains in a well-defined clade, corresponding to Rademarker's group RG 9.6. Inoculation of nineteen plant species belonging to seven botanical families with representative strain LPF 602 showed it to be pathogenic only on Eucalyptus spp, and Corymbia spp. Based on distinct biochemical and pathogenic characteristics that differentiate the eucalypt strains from other pathovars of the X. axonopodis species, here we propose their allocation into the new pathovar X. axonopodis pv. eucalyptorum pv. nov.

• The Plant Pathology Journal
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• 제25권4호
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• pp.408-416
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• 2009

A molecular survey was conducted to identify the presence of the bacterial blight resistance genes (Xa1, Xa4, xa5, xa13 and Xa21) in 86 accessions of aromatic rice obtained from germplasm. The results revealed that the resistance gene Xa4 (32.5%), Xa21 (17%), and xa5 (16%) were widely observed in tested rice germplasm. Among tested rice germplasm, 49 accessions showed the presence of more than one of five R genes, and 37 accessions possessed none of the R gene. TALLi and 05-IRRi-M-46 showed the presence of Xa4, xa5, xa13 and Xa21. Rice race $415{\times}Ir352$ exhibited positive amplicon for the Xa1, Xa4, xa5 and Xa21. Hyangmibyeo1hos, Ir841-85-1-1-2 and Jasmine85 showed the positive amplicon for the Xa1, Xa4 and xa5 genes. Yekywin Yinkya Hmwe and Khao Dawk Mali105 showed the presence of Xa1, Xa4 and Xa21 gene. Masino Basmati showed the presence of xa5, xa13, Xa21 genes. Xa1 and Xa21 genes were noticed in Mihayngbyeo, Tarana Deshi, Mayataung and AZUCENA. Hyangmibyeo2ho, Basmati 6311 and Basmati405 possessed only two R genes such as Xa4 and xa5, and xa5 and xa13, respectively. The evaluation results of bacterial blight resistance genes in aromatic rice germplasm will help in breeding of multi disease resistant varieties.

• The Plant Pathology Journal
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• 제34권5호
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• pp.393-402
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• 2018

Rice world production is affected due to the growing impact of diseases such as bacterial panicle blight, produced by Burkholderia glumae. The pathogen-induced symptoms include seedling rot, grain rot and leafsheath browning in rice plants. It is currently recognized the entrance of this pathogen to the plant, from infected seeds and from environmental sources of the microorganism. However, it is still not fully elucidated the dynamics and permanence of the pathogen in the plant, from its entry until the development of disease symptoms in seedlings or panicles. In this work it was evaluated the infection of B. glumae rice plants, starting from inoculated seeds and substrates, and its subsequent monitoring after infection. Various organs of the plant during the vegetative stage and until the beginning of the reproductive stage, were evaluated. In both inoculation models, the bacteria was maintained in the plant as an endophyte between $1{\times}10^1$ and $1{\times}10^5cfu$ of B. $glumae.g^{-1}$ of plant throughout the vegetative stage. An increase of bacterial population towards initiation of the panicle was observed, and in the maturity of the grain, an endophyte population was identified in the flag leaf at $1{\times}10^6cfu$ of B. $glumae.g^{-1}$ fresh weight of rice plant, conducting towards the symptoms of bacterial panicle blight. The results found, suggest that B. glumae in rice plants developed from infected seeds or from the substrate, can colonize seedlings, establishing and maintaining a bacterial population over time, using rice plants as habitat to survive endophyticly until formation of bacterial panicle blight symptoms.

• The Plant Pathology Journal
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• 제25권1호
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• pp.62-69
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• 2009

In this study, we characterized the bacterial strain KJ2C12 in relation with its biocontrol activity against Phytophthora capsici on pepper, and identified this strain using morphological, physiological, biochemical, fatty acid methyl ester, and 16S rRNA gene sequence analyses. Strain KJ2C12 significantly (P=0.05) reduced both final disease severity and areas under the disease progress curves of 5-week-old pepper plants inoculated with P. capsici compared to buffer-treated controls. As for the production of antibiotics, biofilms, biosurfactant, extracellular enzyme, HCN, and swarming activity, strain KJ2C12 produced an extracellular enzyme with protease activity, but no other productions or swarming activity. However, Escherichia coli produced weak biofilm only. Strain KJ2C12 could colonize pepper roots more effectively in a gnotobiotic system using sterile quartz sand compared to E. coli over 4 weeks after treatments. However, no bacterial populations were detected in 10 mM $MgSO_4$ buffer-treated controls. Strain KJ2C12 produced significantly higher microbial activity than the $MgSO_4$-treated control or E. coli over 4 weeks after treatments. Bacterial strain KJ2C12 was identified as Bacillus luciferensis based on morphological, physiological, and biochemical characteristics as well as FAME and 16S rRNA gene sequence analyses. In addition, these results suggested that B. luciferensis strain KJ2C12 could reduce Phytophthora blight of pepper by protecting infection courts through enhanced effective root colonization with protease production and an increase of soil microbial activity.

• 식물병연구
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• 제28권3호
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• pp.143-151
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• 2022

국내의 고추 포장에서 나타나는 시듦 증상의 원인을 규명하기 위하여 2010년부터 2014년까지 5년 동안 충북 괴산의 고추 재배 포장에서 시듦 증상을 보이는 고추의 발병도를 조사하였다. 조사한 연도에 따라서 시듦 증상에 대한 발병에는 차이가 있었지만, 조사하는 시기가 6월과 7월을 지나 8월이 되면서 발병도가 높게 상승하였다. 이 시기 동안 시듦 증상을 보이는 고추에서 Ralstonia solanacearum이 Phytophthora capsici보다 4배 높은 비율로 분리되었다. 충북 괴산과 경북 안동의 포장에서 2013년과 2014년의 2년 동안 채집한 시든 고추에서 병원균을 분리하여 보아도, 조사한 전체 포장 중의 20.3%에서 R. solanacearum이 분리되었으며, 역병균인 P. capsici는 3.8%의 포장에서만 분리되었다. 시듦 증상이 높은 비율로 나타났던 해에는 평균기온이 높았으며, 고추 풋마름병 예찰 모델로 추정된 풋마름병의 초발생일도 빨라짐을 알 수 있었다. 역병 발생 위험 일수와 실제 시듦 증상 발생 빈도의 결과가 부합하지 않는 것은 재배 현장에서 역병 저항성 품종의 사용이 일반화되어 있기 때문이라고 생각한다. 이런 결과를 통해서 역병 저항성 고추 품종이 재배 현장에 도입된 이후, 포장에서 관찰할 수 있는 시듦 증상의 원인은 P. capsici에 의한 역병보다는 R. solanacearum에 의한 풋마름병이었다.

• 식물병연구
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• 제11권2호
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• pp.89-92
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• 2005

2004년은 전년에 비해 기온이 높았고 강수량이 적었다. 벼 못자리 병, 잎도열병 발생 필지, 잎집무늬마름병, 흰잎마름병과 고추 역병, 탄저병 및 바이러스병, 시설참외의 급성 시들음 증상, 흰가루병 등이 2003년에 비해 증가하였다. 특히 벼잎집무늬마름병과 흰잎마름병은 전년에 비해 2배 이상 병 발생이 증가하였다. 벼 이삭도열병이 전년 $3\%$에서 2004년 $0.7\%$로 감소된 것은 출수기 동안 평균기온은 높았으나 강수일수, 강수량 및 습도가 낮아 잎도열병균이 이삭으로의 전파를 억제한 것으로 추정되었다. 고추역병은 전년에 비해 크게 감소되었다. 그리고 발표하지 않은 다른 병에 의한 피해는 다소 감소 혹은 유사한 수준이었다.

• 식물병연구
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• 제19권3호
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• pp.208-215
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• 2013

3-(4-Hydroxyphenyl)-propionic acid (HPP)는 곤충 병원 세균인 Xenorhabdus nematophila K1의 대사산물이다. 이 물질의 고추의 역병과 탄저병에 대한 방제가능성을 평가하였다. HPP는 역병균과 탄저병균의 균사생장을 현저하게 억제하였다. 이 항균력은 자연 태양광 아래에서 25일이상 유지되었으며, 토양수 내에서도 상실되지 않았다. HPP의 고추 뿌리를 통한 식물체 내 침투 및 상향이행성이 입증되었다. HPP 현탁액을 고추의 근권토양에 관주하고 지상부에 10일 간격으로 살포하였을 때, 약해 발생 없이 역병과 탄저병 발생이 크게 감소되었다. 이러한 결과는 HPP를 고추 역병 및 탄저병 방제를 위한 침투성농약으로 개발할 가능성이 있음을 의미한다.

• The Plant Pathology Journal
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• 제34권2호
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• pp.104-112
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• 2018

Accurate and rapid detection of bacterial plant pathogen is the first step toward disease management and prevention of pathogen spread. Bacterial plant pathogens Clavibacter michiganensis subsp. nebraskensis (Cmn), Pantoea stewartii subsp. stewartii (Pss), and Rathayibacter tritici (Rt) cause Goss's bacterial wilt and blight of maize, Stewart's wilt of maize and spike blight of wheat and barley, respectively. The bacterial diseases are not globally distributed and not present in Korea. This study adopted comparative genomics approach and aimed to develop specific primer pairs to detect these three bacterial pathogens. Genome comparison among target pathogens and their closely related bacterial species generated 15-20 candidate primer pairs per bacterial pathogen. The primer pairs were assessed by a conventional PCR for specificity against 33 species of Clavibacter, Pantoea, Rathayibacter, Pectobacterium, Curtobacterium. The investigation for specificity and sensitivity of the primer pairs allowed final selection of one or two primer pairs per bacterial pathogens. In our assay condition, a detection limit of Pss and Cmn was $2pg/{\mu}l$ of genomic DNA per PCR reaction, while the detection limit for Rt primers was higher. The selected primers could also detect bacterial cells up to $8.8{\times}10^3cfu$ to $7.84{\times}10^4cfu$ per gram of grain seeds artificially infected with corresponding bacterial pathogens. The primer pairs and PCR assay developed in this study provide an accurate and rapid detection method for three bacterial pathogens of grains, which can be used to investigate bacteria contamination in grain seeds and to ultimately prevent pathogen dissemination over countries.