• Korean Journal Plant Pathology
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• v.12 no.2
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• pp.150-155
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• 1996

1993년과 1994년에 걸쳐 한국의 고추 재배 지역에서 분리한 고추 더뎅이병균은 66개의 균주중 24개가 race 1이었으며, 나머지는 42균주가 race 3이었다. Race 2균주는 발견되지 않았다. 총 66개의 균주중 8%가 200 $\mu\textrm{g}$/ml의 황산구리에 저항성을 보였으며, 100 $\mu\textrm{g}$/ml의 streptomycin sulfate에는 단지 한 균주만이 저항성을 나타냈다. Race 1균주중 21%가 구리에 저항성을 보였으나 race 3균주는 모두 구리에 감수성을 나타냈다. 모든 감수성 균주는 구리 농도 1 $\mu\textrm{g}$/ml에서 죽거나 아주 낮은 수준만이 생존하였으나 저항성 균주는 128 $\mu\textrm{g}$/ml에서도 생존하였다.

• Plant Disease and Agriculture
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• v.5 no.2
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• pp.105-110
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• 1999

Bacterial leaf spot by Xanthomonas campestris pv. vesicatoria has been known to cause serious problem in red pepper in Korea. However recent survey showed that most smptoms in the leaves were mixed with two different symptoms one was leaf spot and the other was canker. bacteria isolated from canker were identified as Clavibacter michiganensis subsp. michiganensis on the basis of biochemical and physiological characteristics. The causal bacteria were non-motile rod-shaped and Gram-positive. The lesions on pepper leaves appeared at first as small blisters or pimple-like white spots which enlarged in size at a later stage. The centers of some of the spots became necrotic and brown and were surrounded by a white halo. Pathogenicity tests were performed on pepper cv. Alchan seedling by spraying of bacterial suspension. During 1997 and 1998 total 17% of 527 fields surveyed were infected by C. michiganensis subsp. michiganensis. The canker of red pepper caused by C. michiganensis subsp. michiganensis was first identified in this study in Korea, and new name "gueyangbyung" was tentatively given to the disease.

• KSBB Journal
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• v.17 no.1
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• pp.26-32
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• 2002

The aerobic bacterium Xanthomonas campestris was cultivated continuously in a three-phase fluidized bed bioreactor to produce extracellular polysaccharide xanthan, Fluidized particles of 8.0 mm glass beads were used for disintegrating the large air bubbles even at high viscosities to improve the gas-liquid oxygen transfer rate. Xanthin productivity [kg xanthan/kg cell dry mass·h] and molecular weight increased, with dilution rate in the continuous xanthan fermentations. The specific xanthan productivities were not limited by the oxygen transfer rate and were much higher in the continuous cultivations than those predicted by the results of the batch xanthan fermentations.

• Applied Biological Chemistry
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• v.50 no.4
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• pp.262-267
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• 2007

To access the natural product antibiotics produced by uncultured microorganisms, six cosmid libraries of DNA extracted directly from soil samples (environmental DNA, eDNA) were constructed and screened for the production of antibacterial active molecules. Of the approximately 60,000 clones screened, one antibacterial clone (YS92B) was detected. Ethyl acetate extracts of clone YS92B showed antibacterial activity against various pathogenic bacteria (Listeria monocytogenes, Bacillus subtilis, Pseudomonas syringae, Xanthomonas campestris pv. oryzae, Staphylococcus epidemis). Active constituents from cultures of YS92B were isolated and purified using a bioassay-guided fractionation against B. subtilis through a series of procedures (ethyl acetate extraction, Sephadex LH20 column chromatography, High Performance Liquid Chromatography). NMR (Nuclear Magnetic Resonance) spectral analysis of a major antibacterial active YS92B-VII indicated that it is a lauric acid linked to tyrosine. This report describes the characterization of antibacterially active long chain N-acyl derivatives of tyrosine that are produced by eDNA clones hosted in Escherichia coli from Korean soils.

• The Plant Pathology Journal
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• v.24 no.4
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• pp.478-481
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• 2008

The cDNA clone of Brassica rapa WRKY7 (BrWRKY7) was obtained from EST collection in Brassica genomics team and its DNA sequence was determined. The cDNA clone is 1,037 bp long in nucleotides and encodes an open reading frame of 307 amino acids. Based on a phylogenetic tree, BrWRKY7 belongs to group IId. BrWRKY7 was induced by wound and SA. It was also induced by pathogen attack such as Xanthomonas campestris pv. campestris (Xcc), suggesting that this BrWRKY may play an essential role in defense response of chinese cabbages.

• The Plant Pathology Journal
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• v.31 no.2
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• pp.181-185
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• 2015

This study aimed to evaluate six cauliflower genotypes regarding their resistance to black rot and their production performance. To do so, it was conducted two field experiments in Ipameri, $Goi\acute{a}s$, Brazil, in 2012 and 2013. It was used a randomized block design, with four replications (total of 24 plots). Each plot consisted of three planting lines 2.5 m long (six plants/line), spaced 1.0 m apart, for a total area of $7.5m^2$. Evaluations of black rot severity were performed at 45 days after transplanting, this is, 75 days after sowing (DAS), and yield evaluations at 90 to 105 DAS. The Verona 184 genotype was the most resistant to black rot, showing 1.87 and 2.25% of leaf area covered by black rot symptom (LACBRS) in 2012 and 2013. However, it was not among the most productive materials. The yield of the genotypes varied between 15.14 and 25.83 t/ha in both years, Lisvera F1 (21.78 and 24.60 t/ha) and Cindy (19.95 and 23.56 t/ha) being the most productive. However, Lisvera F1 showed 6.37 and 9.37% of LACBRS and Cindy showed 14.25 and 14.87% of LACBRS in 2012 and 2013, being both considered as tolerant to black rot.

• The Plant Pathology Journal
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• v.30 no.3
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• pp.323-329
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• 2014

Two cultivars Buram-3-ho (susceptible) and CR-Hagwang (moderate resistant) of kimchi cabbage seedlings showed differential defense responses to anthracnose (Colletotrichum higginsianum), black spot (Alternaria brassicicola) and black rot (Xanthomonas campestris pv. campestris, Xcc) diseases in our previous study. Defense-related hormones salicylic acid (SA), jasmonic acid (JA) and ethylene led to different transcriptional regulation of pathogenesis-related (PR) gene expression in both cultivars. In this study, exogenous application of SA suppressed basal defenses to C. higginsianum in the 1st leaves of the susceptible cultivar and cultivar resistance of the 2nd leaves of the resistant cultivar. SA also enhanced susceptibility of the susceptible cultivar to A. brassicicola. By contrast, SA elevated disease resistance to Xcc in the resistant cultivar, but not in the susceptible cultivar. Methyl jasmonate (MJ) treatment did not affect the disease resistance to C. higginsianum and Xcc in either cultivar, but it compromised the disease resistance to A. brassicicola in the resistant cultivar. Treatment with 1-aminocyclopropane-1-carboxylic acid (ACC) ethylene precursor did not change resistance of the either cultivar to C. higginsianum and Xcc. Effect of ACC pretreatment on the resistance to A. brassicicola was not distinguished between susceptible and resistant cultivars, because cultivar resistance of the resistant cultivar was lost by prolonged moist dark conditions. Taken together, exogenously applied SA, JA and ethylene altered defense signaling crosstalk to three diseases of anthracnose, black spot and black rot in a cultivar-dependent manner.

• Research in Plant Disease
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• v.12 no.1
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• pp.51-54
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• 2006

The effectiveness of four plant oils (garlic, ginger, cinnamon and lemongrass) against a range of plant pathogenic organisms was tested in vitro. Of the four oils, two oils (garlic and cinnamon) showed relatively good antimicrobial activities. Activity of garlic oil was shown against the plant pathogenic bacteria Agrobacterium tumefaciens, Ewinia carotovora, Ralstonia solanacearum, Xanthomonas campestris, and the fungi Phytophthora infestans, Fusarium oxysporum, Collectotricum sp., whereas Acidovorax avenae and Pythium sp. showed the resistance towards garlic oil. Results from the planta bioassays under greenhouse conditions indicated that garlic oil significantly reduced the cucumber powdery mildew (Sphaerotheca fusca) and tomato powdery mildew (Erysiphe cichoracearum) showing control value 70.0-74.6% and 71.2%, respectively.

• Research in Plant Disease
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• v.13 no.2
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• pp.88-92
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• 2007

A total of 41 Pseudomonas syringae pv. syringae, the causal agent of bacterial blossom blight, were isolated from kiwifruit plants in Korea. Among them, two strains showing streptomycin resistance were examined to investigate the structure of resistant determinants by PCR and nucleotide sequence analysis. PCR results suggested that the streptomycin resistance is mediated by strA-strB genes carried on Tn5393a. Insertion sequences, IS6100 and IS1133, which were located within or downstream of tnpR gene in Xanthomonas campestris and Erwinia amylovora were not found. Nucleotide sequences of strA-strB were 100% identical with Tn5393a. Two stretomycin resistant strains had three plasmids. Southern blot hybridization using strA-strB probe indicated that the resistant genes were carried on a 100kb plasmid.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.66.1-66
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• 2003

The aim of this study was to characterize the interactions of rice and Burkholderia glumae, a causal agent of bacterial grain rot of rice, at molecular levels using whole genomic sequences and to identify genes important for pathogenicity and symptom development. To do these, we sequenced whole genome of the bacterium and constructed cosmid clone profiles. We generated pools of mutants using various transposons and determined mutation sites by sequencing rescued plasmids. We focused on studying toxoflavin biosynthetic genes, quorum sensing regulation, and Hrp type III protein secretion systems. We found that two possible operons consisting of five genes are involved in toxoflavin biosynthesis and their expression is regulated by quorum sensing and LysR-type regulator, ToxR. We have isolated the nn PAI of B. glumae and characterized by mutational analyses. The hrp cluster resembled most the putative Type III secretion systems of B. pseudomallei, which is the causative agent of melioidosis, a serious disease of man and animals. The Hrp PAI core region showed high similarity to that of Ralstonia solanacearum and Xanthomonas campestris, however some aspects were dissimilar.