• Proceedings of the Korean Society of Life Science Conference
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• 2008.10a
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• pp.72.2-72.2
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• 2008

• Proceedings of the Korean Society of Life Science Conference
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• 2007.10a
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• pp.69.1-69.1
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• 2007

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• Research in Plant Disease
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• v.21 no.4
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• pp.261-267
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• 2015

During the period from 2013 to 2014, disease occurrences by various pathogens in apple cultivars have been investigated in northern Gyeongbuk province of Korea. Anthracnose, white rot, Alternaria leaf spot, Marssonina blotch, and bacterial shoot blight as major diseases have been observed. Pathogens isolated from the symptomatic plants were identified as Colletotrichum gloeosporioides for anthracnose, Botryosphaeria dothidea for white rot, Alternaria alternata for Alternaria leaf spot, Marssonina mali for Marssonina blotch, and Pseudomonas syringae pv. syringae for bacterial shoot blight. Of all diseases, the bacterial shoot blight has been severely increased in chronically infested fields in Gyeongbuk province.

• Journal of Microbiology and Biotechnology
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• v.18 no.10
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• pp.1659-1662
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• 2008

Pseudomonas chlororaphis O6 exhibits induced systemic resistance (ISR) against P. syringae pv. tabaci in tobacco. To identify one of the ISR metabolites, O6 cultures were extracted with organic solvents, and the organic extracts were subjected to column chromatography followed by spectroscopy analyses. The ISR bioassay-guided fractionation was carried out for isolation of the metabolite. High-resolution mass spectrometric analysis of the metabolite found $C_{9}H_{9}O_{3}N$ with an exact mass of 179.0582. LC/MS analysis in positive mode showed an $(M+H)^{+}$ peak at m/z 180. Nuclear magnetic resonance ($^{1}H,\;^{13}C$) analyses identified all protons and carbons of the metabolite. Based on the spectroscopy data, the metabolite was identified as 4-(aminocarbonyl) phenylacetate (4-ACPA). 4-ACPA applied at 68.0 mM exhibited ISR activity at a level similar to 1.0 mM salicylic acid. This is the first report to identify an ISR metabolite produced by P. chlororaphis O6 against the wildfire pathogen P. syringae pv. tabaci in tobacco.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 1995.06b
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• pp.97-117
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• 1995

Copper resistance in Pseudomonas syringae pv. tomato is determined by copper-resistance operon (cop) on a highly conserved 35 kilobase plasmid. Copper-resistant strains of Pseudomonas syringae containing the cop operon accumulate copper and develop blue clonies on copper-containing media. The protein products of the copper-resistance operon were characterized to provide an understanding of the copper-resistance mechanism and its relationship to copper accumulation. The Cop proteins CopA (72 kDa), CopB (39 kDa), and CopC (12 kDa) were produced only under copper induction. CopA and CopC were periplasmic proteins and CopB was an outer membrane protein. Leader peptide sequences of CopA, CopB, and CopC were confirmed by amino-terminal peptide sequencing. CopA, CopB, and CopC were purified from strain PT23.2, and their copper contents were determined. One molecule of CopA bound 10.9${\pm}$1.2 atoms of copper and one molecule of CopC bound 0.6${\pm}$0.1 atom of copper. P. syringae cells containing copCD or copBCD cloned behind the lac promoter were hypersensitive to copper. The CopD (32 kDa), a probable inner membrane protein, function in copper uptake with CopC. The Cop proteins apparently mediate sequestration of copper outside of the cytoplasm as a copper-resistance mechanism.

• Microbiology and Biotechnology Letters
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• v.22 no.5
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• pp.485-490
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• 1994

A restriction endonuclease, PsyI, has been isolated from Pseudomonas syringae pv. pha- seolicola, and its catalytic properties have been studied. This enzyme was purified through strepto- mycin sulfate and ammonium sulfate fractionation, phosphocellulose Pll, DEAE-cellulose, hydroxy- apatite and Sephadex G-100 column chromatography. It's molecular weight was about 50,000 dalton as determined by 7.5% polyacrylamide gel electrophoresis containing 0.1% SDS. In catalytic proper- ties, PsyI shows stable at wide ranges of pH between 7.0 and 10.0, of temperature between 30$\circ$C and 37$\circ$C, and its thermal stability is between 25$\circ$C, and 45$\circ$C, at the presence Of 10 mM MgCl$_{2}$-PsyI essentially require Na salt for enzyme reaction, is rather inhibited in the high Na salt concent- ration. The presence of 2-mercaptoethanol is absolutely required for the enzyme activity. This endonuclease, PsyI was determined to be an isoschizomer of SalI from the results of the restriction mapping and DNA sequencing.

• The Plant Pathology Journal
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• v.30 no.3
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• pp.245-253
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• 2014

Antimicrobial peptides (AMPs) are small but effective cationic peptides with variable length. In previous study, four hexapeptides were identified that showed antimicrobial activities against various phytopathogenic bacteria. KCM21, the most effective antimicrobial peptide, was selected for further analysis to understand its modes of action by monitoring inhibitory effects of various cations, time-dependent antimicrobial kinetics, and observing cell disruption by electron microscopy. The effects of KCM21 on Gram-negative strain, Pseudomonas syringae pv. tomato DC3000 and Gram-positive strain, Clavibacter michiganensis subsp. michiganensis were compared. Treatment with divalent cations such as $Ca^{2+}$ and $Mg^{2+}$ inhibited the bactericidal activities of KCM21 significantly against P. syringae pv. tomato DC3000. The bactericidal kinetic study showed that KCM21 killed both bacteria rapidly and the process was faster against C. michiganensis subsp. michiganensis. The electron microscopic analysis revealed that KCM21 induced the formation of micelles and blebs on the surface of P. syringae pv. tomato DC3000 cells, while it caused cell rupture against C. michiganensis subsp. michiganensis cells. The outer membrane alteration and higher sensitivity to $Ca^{2+}$ suggest that KCM21 interact with the outer membrane of P. syringae pv. tomato DC3000 cells during the process of killing, but not with C. michiganensis subsp. michiganensis cells that lack outer membrane. Considering that both strains had similar sensitivity to KCM21 in LB medium, outer membrane could not be the main target of KCM21, instead common compartments such as cytoplasmic membrane or internal macromolecules might be a possible target(s) of KCM21.

• Microbiology and Biotechnology Letters
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• v.19 no.1
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• pp.14-20
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• 1991

- The purpose of this work is to investigate the effects of various substrates on biosynthesis of ethylene by the Kudzu strain of Pseudomonas syn'ngae pv. Phaseolicola causing halo blight. In the intact cell of P. sym'ngue, optimal condition for ethylene production was achieved at p1-I 7.5 and $30^{\circ}C$ for 9 to 10 hours of culture. Ethylene was most effectively produced from amino acids such as Asn, Gln, Asp ans Glu, compared to those of various kinds of sugars. While ethylene production from $\alpha$-ketoglutarate ($\alpha$-KG) was gradually increased throughout 51 hours incubation period tested. Ethylene production derived from citrate, $\alpha$-KG and oxalacetate as well as a few amino acids was further enhanced by the addition of histidine or arginine. In cell-free ethylene-forming system, ethylene was most effectively produced from $\alpha$-KG, compared to those from citrate, oxalacetate, Glu, Arg, or Asp, at 0.5 mM among the range from 0.25 mM to 5 mM. Anlinooxyacetate, an inhibitor of a pyridoxal phosphate-linked enzyme, completely inhibited ethylene evolution derived from Glu but not affect that derived from $\alpha$-KG. The results obtained in this work suggest that $\alpha$-KG might be a direct precursor of ethylene production in this organism than any other substrates tested.

• The Korean Journal of Pesticide Science
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• v.10 no.3
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• pp.230-236
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• 2006

Eighty-five percent methanol extract of Agrimonia pilosa has antibacterial activity against Pseudomonas syringae pv. lacrymans (bacterial leaf spot pathogen), Ralstonia solanacearum (tomato bacterial wilt pathogen) and Pseudomonas syringae pv. tabaci (Tobacco wild fire pathogen.). The active substance was purified by silica gel column chromatography and HPLC. The molecular weight of the active compound was determined by LC-Mass as 687.2. With NMR analysis, the active substance was identified as Agrimol B.

• Research in Plant Disease
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• v.21 no.2
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• pp.67-73
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• 2015

Bacterial blossom blight of kiwifruit (Actinidia deliciosa) caused by Pseudomonas syringae pv. syringae is known to be largely affected by weather conditions during the blooming period. While there have been many studies that investigated scientific relations between weather conditions and the epidemics of bacterial blossom blight of kiwifruit, no forecasting models have been developed thus far. In this study, we collected all the relevant information on the epidemiology of the blossom blight in relation to weather variables, and developed the Pss-KBB Risk Model that is based on the Maryblyt model for the fire blight of apple and pear. Subsequent model validation was conducted using 10 years of ground truth data from kiwifruit orchards in Haenam, Korea. As a result, it was shown that the Pss-KBB Risk Model resulted in better performance in estimating the disease severity compared with other two simple models using either temperature or precipitation information only. Overall, we concluded that by utilizing the Pss-KBB Risk Model and weather forecast information, potential infection risk of the bacterial blossom blight of kiwifruit can be accurately predicted, which will eventually lead kiwifruit growers to utilize the best practices related to spraying chemicals at the most effective time.