• 한국응용곤충학회지
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• 제21권4호
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• pp.216-221
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• 1982

시험은 흰빛잎마름병의 품종별 감수성과 수량 및 품질에 미치는 영향을 구명코자 시비량을 보비재배와 다비재배로 구분하여 전남지역에서 수행 되었다. 흰빛잎마름병은 발생은 다비조건에서 심했으며 심한 발병은 수도 품종들의 등숙에 영향을 주어 수량 감수를 초래하였고 청미율은 품질을 저하 시켰다. 또한 조생계품종에서는 지엽과 차엽이 발병되었지만 중, 만생계품종에서는 지, 차, 삼엽이 발병되었다. 이러한 차이는 보비조건에서 보다 다비조건에서 더욱 뚜렷하였다. 이 병에 대한 저항성품종은 태백벼, 백운찰벼, 팔공벼, 밀양 42호이었고 밀양 30호, 금강벼, 낙동벼, 진주벼는 감수성이었으며 이러한 경향은 시비 수준간에 같은 경향이었다.

• 식물병연구
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• 제29권4호
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• pp.433-439
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• 2023

당근 세균잎마름병은 세계적으로 가장 중요한 병에 속한다. 지난 10년 전 국내에서 처음 발견됨으로써 당근 생산에 큰 위협이 되는 병으로 간주되었다. 원인균으로 Xathomonas hortorum pv. carotae (Xhc)이며 본 연구는 제주도 당근재배지 토양에서 이 병원균을 분리 동정하고자 수행하였다. 분리한 세균 중 인공배지에서 균총의 형태가 당근 세균잎마름병균과 유사한 세균균총을 분리하여 선발하였다. 또한 이들 선발된 세균들을 대상으로 DNA 염기 서열과 NCBI 자료를 통해 몇몇 분리 세균이 Xhc으로 동정되었다. 게다가 이들 세균을 당근 잎에 접종하였더니 당근 세균잎마름병의 전형적인 병징이 나타났다. 본 연구 결과는 제주도 토양내 Xhc의 존재 가능성을 시사하고 앞으로의 당근 세균잎마름병 방제 수단을 강구하는 데 매우 필요한 자료로서 가치가 있다고 본다.

• 식물병연구
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• 제19권3호
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• pp.177-182
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• 2013

Resvestrol has been known to inhibit bacterial and fungal growth in vitro, and can be accumulated in plant to concentrations necessary to inhibit microbial pathogens. Hence, stilbene synthase gene has been used to transform to synthesize resveratrol in heterologous plant species to enhance resistance against pathogens. In the present study, we investigated the antimicrobial activities of resveratrol and piceid to bacterial and fungal pathogens, which causing severe damages to rice plants. In addition, disease resistance was compared between transgenic rice varieties, Iksan 515 and Iksan 526 transformed with stlibene synthase gene and non-transgenic rice varieties, Dongjin and Nampyeong. Minimum inhibitory concentration of resveratrol for Burkolderia glumae was 437.5 ${\mu}M$, and the mycelial growth of Biplaris oryzae was slightly inhibited at concentration of 10 ${\mu}M$. However, other bacterial and fungal pathogens are not inhibited by resveratrol and piceid. The expression of the stilbene synthase gene in Iksan 515 and Iksan 526 did not significantly enhanced resistance against bacterial grain rot, bacterial leaf blight, sheath blight, and leaf blight. This study is the first report on the effect of resveratrol and piceid against pathogens of rice plant, and changes of disease resistance of transgenic rice plants transformed with stilbene synthase gene.

• 한국자원식물학회지
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• 제10권2호
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• pp.128-134
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• 1997

This study was conducted to test on the resistance of varieties bred by crossing with Asominori to bacterial leaf blight. Nakdongbyeo and Dongjinbyeo which were susceptible to HB 9011, 8 resistant varieties including Ilmibyeo derived from Asominori and Asominori, Hwangok, 13 varieties including Chukoku 45 which were resistance to HB 9011, HB 9022 and HB 9033 were used to screen their res ponce depending on the various screening methods such as the true resistance, the secondary infection resistance and the disease common field test methods, and the results are as follows: Among 13 varieties tested, 11 varieties including llmibyeo showed tme resistance to HB 9011. Less than 1.0cm of disease lesion were developed on these varieties. Disease lesion was not developed on most of the Asominori lines including Daechongbyeo against IIB9011 and 1lmibyeo was also resistance to HB 9011, on this variety disease lesion area rate was 1.2%, and 7 varieties including Hwajinbyeo showed field resistance to HB 9022. Disease lesion area rate were 19.6% on Nakdongbyeo. 15.6% on Dongjinbyeo, from 3.0% to 2.4% on Asominori lines, and 0.5% on the Asominori when screened at disease common area. Disease was not developed on Keumnambyeo. Significant correlation coefficiences were found between the results from the test methods of the true resistance, the field resistance ancl the field resistance at disease common field tests on Asominori lines, but in some cases, even the varieties on which disease lesions developed, showed field resistance to HB 9022 and HB 9033.

• The Plant Pathology Journal
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• 제28권4호
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• pp.364-372
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• 2012

Xanthomonas oryzae pv. oryzae causing bacterial leaf blight disease in rice produces and secretes Hpa1 protein that belongs to harpin protein family. Previously it was reported that Hpa1 induced defense responses when it was produced in tobacco. In this study, we expressed hpa1 gene in rice and Arabidopsis to examine the effects of Hpa1 expression on disease resistance to both fungal and bacterial pathogens. Expression of hpa1 gene in rice enhanced disease resistance to both X. oryzae pv. oryzae and Magnaporthe grisea. Interestingly, individual transgenic rice plants could be divided into four groups, depending on responses to both pathogens. hpa1 expression in Arabidopsis also enhanced disease resistance to both Botrytis cineria and Xanthomonas campestris pv. campestris. To examine genes that are up-regulated in the transgenic rice plants after inoculation with X. oryzae pv. oryzae, known defense-related genes were assessed, and also microarray analysis with the Rice 5 K DNA chip was performed. Interestingly, expression of OsACS1 gene, which was found as the gene that showed the highest induction, was induced earlier and stronger than that in the wild type plant. These results indicate that hpa1 expression in the diverse plant species, including monocot and dicot, can enhance disease resistance to both fungal and bacterial plant pathogens.

• 식물병연구
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• 제11권2호
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• pp.146-151
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• 2005

2000년 수원, 홍천, 연천 지역의 참깨 포장에서 새로운 병해가 발견되었다. 처음에는 잎에 수침상의 작은 점무늬를 형성하다가 점점 커져 괴사가 일어나고 주위로 황화되었다. 심하게 감염된 경우는 병든 잎은 떨어졌다. YDC 배지에서 병원세균을 순수 분리 하였을 때 Xanthomonas 속 세균의 전형적인 특징인 노란색 색소를 띤 세균이 형성되었다. 분리된 세균을 $10^{8}cfu/ml$로 현탁한 후 3주 동안 자란 참깨 잎에 분무 접종하였을 때 처음과 같은 증상이 재현되었다. 분리된 세균은 대조균주 X. campestris pv. sesami LMG865와 지방산 조성 및 다양한 탄소원 이용정도를 이용하여 비교하였을 때 $100\%$의 가능성으로 X. campestris pv. sesami로 동정되었다. 분리된 병원균은 $18\~36^{\circ}C$에서 생장이 양호하였으며, $27^{\circ}C$에서 가장 우수하였다. 이 보고는 국내에서 참깨의 세균성잎마름병 최초 보고이며, P. syringae pv. sesami에 의한 세균성점무늬병과 외부적인 병징으로 구별하기가 매우 어렵다.

• Journal of Microbiology and Biotechnology
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• 제24권6호
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• pp.740-747
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• 2014

Bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is a very serious disease in rice-growing regions of the world. In spite of their economic importance, there are no effective ways of protecting rice plants from this disease. Bacteriophages infecting Xoo affect the population dynamics of the pathogen and consequently the occurrence of the disease. In this study, we investigated the diversity, host range, and infectivity of Xoo phages, and their use as a bicontrol agent on BLB was tested. Among the 34 phages that were isolated from floodwater in paddy fields, 29 belonged to the Myoviridae family, which suggests that the dominant phage in the ecosystem was Myoviridae. The isolated phages were classified into two groups based on plaque size produced on the lawn of Xoo. In general, there was a negative relationship between plaque size and host range, and interestingly the phages having a narrow host range had low efficiency of infectivity. The deduced protein sequence analysis of htf genes indicated that the gene was not a determinant of host specificity. Although the difference in host range and infectivity depending on morphotype needs to be addressed, the results revealed deeper understanding of the interaction between the phages and Xoo strains in floodwater and damp soil environments. The phage mixtures reduced the occurrence of BLB when they were treated with skim milk. The results indicate that the Xoo phages could be used as an alternative control method to increase the control efficacy and reduce the use of agrochemicals.

• The Plant Pathology Journal
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• 제37권4호
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• pp.396-403
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• 2021

Fire blight disease, caused by Erwinia amylovora, could damage rosaceous plants such as apples, pears, and raspberries. In this study, we designed to understand how E. amylovora affected other bacterial communities on apple rhizosphere; twig and fruit endosphere; and leaf, and fruit episphere. Limited studies on the understanding of the microbial community of apples and changes the community structure by occurrence of the fire blight disease were conducted. As result of these experiments, the infected trees had low species richness and operational taxonomic unit diversity when compared to healthy trees. Rhizospheric bacterial communities were stable regardless of infection. But the communities in endosphere and episphere were significanlty affected by E. amylovora infection. We also found that several metabolic pathways differ significantly between infected and healthy trees. In particular, we observed differences in sugar metabolites. The finding provides that sucrose metabolites are important for colonization of E. amylovora in host tissue. Our results provide fundamental information on the microbial community structures between E. amylovora infected and uninfected trees, which will contribute to developing novel control strategies for the fire blight disease.

• 식물병연구
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• 제22권3호
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• pp.202-207
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• 2016

쌀은 세계에서 가장 중요한 작물 중의 하나이지만 충분한 비타민을 제공하지 않고, 벼 도열병과 흰잎마름병은 전 세계적으로 가장 큰 피해를 주고 있는 병해이다. 리보플라빈, 비타민 B2는 인간의 건강에 필수적인 영양소이며, 식물의 병원균에 대한 식물의 방어 활성화로 알려져 있다. 본 연구에서는 BioDoctor (Hyunnong Co., Ltd., Gokseong, Korea)라는 리보플라빈 기반 제품을 벼에 경엽살포했을 때, 주요 병해에 대한 저항성 유도 및 벼 체내에 비타민 함량이 증가되는지에 대한 가능성을 조사하였다. 온실검정에서 BioDoctor 제품 500배와 1,000배로 희석하여 경엽처리 결과 벼 도열병과 흰잎마름병에 대해 현저한 병 저항성을 유도하였다. 또한, BioDoctor를 처리한 알곡과 잎에서 통계적으로 유의한 수준으로 리보플라빈 함량이 검출되었다. 본 연구는 비타민인 리보플라빈이 함유된 BioDoctor가 벼 도열병과 흰잎마름병에 대해 병 저항성을 유도할 뿐만 아니라 쌀 곡류 내에 비타민 함량을 증가시키는 큰 잠재력을 가지고 있는 것으로 나타났다.

• 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.