• Research in Plant Disease
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• v.18 no.3
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• pp.225-230
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• 2012

Bacteriophages of Pectobacterium carotovorum subsp. carotovorum which causes soft rot on diverse vegetables had been isolated from 6 major Chinese cabbage cultivation areas in Korea. In order to isolate bacteriophages, total 15 different strains of P. carotovorum subsp. carotovorum isolated from nation-wide of Korea had been used as a host. When we tested 30 different soil samples individually from Pyeongchang and Taebaek with 15 different strains as a host, Taebek soil samples showed bacteriophage plaques with almost all different indicator strains but Pyeongchang soil samples showed plaques only with P. carotovorum subsp. carotovorum Pcc2 and Pcc3 strains. Especially, P. carotovorum subsp. carotovorum Pcc3 strain was able to produce plaques with almost all soil samples. Thus, this strain can be used as an indicator strain for P. carotovorum subsp. carotovorum bacteriophage screening. Electron microscope observation revealed P. carotovorum subsp. carotovorum bacteriophages isolated in Korea were belonged to three different families, Myoviridae, Siphoviridae and Podoviridae in order Caudovirales.

• The Plant Pathology Journal
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• v.38 no.2
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• pp.102-114
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• 2022

Pectobacterium carotovorum subsp. carotovorum (Pcc) is a gram-negative, broad host range bacterial pathogen which causes soft rot disease in potatoes as well as other vegetables worldwide. While Pectobacterium infection relies on the production of major cell wall degrading enzymes, other virulence factors and the mechanism of genetic adaptation of this pathogen is not yet clear. In the present study, we have performed an in-depth genome-wide characterization of Pcc strain ICMP5702 isolated from potato and compared it with other pathogenic bacteria from the Pectobacterium genus to identify key virulent determinants. The draft genome of Pcc ICMP5702 contains 4,774,457 bp with a G + C content of 51.90% and 4,520 open reading frames. Genome annotation revealed prominent genes encoding key virulence factors such as plant cell wall degrading enzymes, flagella-based motility, phage proteins, cell membrane structures, and secretion systems. Whereas, a majority of determinants were conserved among the Pectobacterium strains, few notable genes encoding AvrE-family type III secretion system effectors, pectate lyase and metalloprotease in addition to the CRISPR-Cas based adaptive immune system were uniquely represented. Overall, the information generated through this study will contribute to decipher the mechanism of infection and adaptive immunity in Pcc.

• Journal of Life Science
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• v.17 no.9 s.89
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• pp.1182-1190
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• 2007

The gene encoding for isoamylase of the Pectobacterium carotovorum subsp. carotovorum (Pcc) LY34 was cloned and expressed into Escherichia coli $DH5{\alpha}$. Isoamylase catalyzes the hydrolysis of ${\alpha}-1,6-glycosidic$ linkages specifically in amylopectin, glycogen, and derived oligosaccharides, while the enzyme did not hydrolyze ${\alpha}-1,4-glycosidic$ linkages of amylose. The isoamylase gene (glgX) had an open reading frame of 1,977 bp encoding 658 amino acid residues with a calculated molecular weight of 74,188 Da. The molecular weight of the enzyme was also estimated to be 74 kDa by activity staining of a SDS-PA gel. The mature GlgX had a calculated pI of 4.91. Isoamylase from Pcc LY34 had 70% amino acid identity with isoamylase from Pectobacterium chrysanthemi and contained the four regions conserved among all amylolytic enzymes. The isoamylase was optimally active at pH 7.0 and $40^{\circ}C$. GlgX was $Ca^{2+}-dependent$. The changes of Asp-335, Glu-370, and Asp-442 into Ala, respectively, using site-directed mutagenesis techniques showed that three residues are essential to isolamyalse (GlgX) activity. The sequences around those residues were highly conserved in isoamylase of different origins and GlgX of the glg operon in glycongen biosynthesis.

• The Plant Pathology Journal
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• v.16 no.5
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• pp.252-256
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• 2000

The 16S-23S rRNA intergenic spacer regions (ISRs) were sequenced and analyzed to design specific primer for identification of Pectobacterium chrysanthemi. Two types ISRs, large and small ISRs, were identified from three strains (ATCC 11663, KACC 10163 and KACC 10165) of P. chrysanthemi and Pectobacterium carotovorum subsp. carotovorum ATCC 15713.Large ISRs contained transfer RNA-Ile(tRNA$^{Ile}$)and tRNA$^{Ala}$, and small ISRs contained tRNA$^{Glu}$. Size of the small ISRs of P. chrysanthemi ranged on 354-356 bp, while it was 451 bp in small ISR of P. carotovorum subsp. carotovorum ATCC 15713. From hypervariable region of small ISRs, species-specific primer for P. chrysanthemi with 20 bp length (CHPG) was designed from hypervariable region of small ISRs, which was used as forward promer to detect P. chrysanthemi strains with R23-1R produced PCR product of about 260bp size (CHSF) only from P. chrysanthemi strains, not from other Pectobacterium spp. and Erwinia spp. Direct PCR from bacterial cell without extracting DNA successfully amplified a specific fragment, CHSF, from P. chrysanthemi ATCC 11663. The limit of PCR detection was 1${\pm}10^2$ cfu/ml.

• The Plant Pathology Journal
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• v.27 no.3
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• pp.242-248
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• 2011

Several soil bacteria were found to degrade N-Acylhomoserine lactones (NAHLs), thereby interfering with the bacterial quorum sensing system. In this research, fifteen strains of NAHL degrading rhizobacteria were isolated from potato rhizosphere. Based on phenotypic characteristics and 16S rDNA sequence analyses, the strains were identified as members of genera Bacillus, Streptomyces, Arthrobacter, Pseudomonas and Mesorhizobium. All tested isolates were capable to degrade both synthetic and natural NAHL produced by Pectobacterium carotovorum subsp. carotovorum (Pcc) strain EMPCC. In quorum quenching experiments selected isolates, especially Mesorhizobium sp., were markedly reduced the pathogenicity of Pcc strain EMPCC in potato tubers and totally suppressed tissue maceration on potato tubers. These led to consider the latter as a useful biocontrol agent against Pectobacterium spp.

• The Plant Pathology Journal
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• v.25 no.3
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• pp.286-290
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• 2009

The stability of three different kinds of pUC-derived plasmids, pDsRed, pZsYellow, and pGFPuv, was investigated in Pectobacterium strains to utilize those plasmids as tracers. All three plasmids pDsRed, pZsYellow and pGFPuv showed their specific colors in Pectobacterium strains. Especially, the plasmid pDsRed conferred bright pink colonies on the Pectobacterium strains. When the bacteria lost the plasmid pDsRed, the colonies turned white, suggesting that the plasmid could be a good marker system for Pectobacterium strains on different environmental conditions. The effect of the antibiotic pressure on the stability of the plasmid was different depending on the host bacteria. P. carotovorum subsp. betavasculorum was more sensitive to the antibiotic pressure than P. carotovorum subsp. carotovorum Pcc21. However, temperature change significantly affected plasmid stability on both Pectobacterium strains. Almost all strains lost the plasmids with the shift in temperature from $28^{\circ}C$ to $37^{\circ}C$. Presence of the plasmids did not affect bacterial pathogenicity on their own host plants. Among three plasmids, pZsYellow was not useful as a marker because the yellow fluorescent proteins from pZs Yellow were interfered with the yellow natural fluorescence of the plant tissues induced by the defense system. Since the red color of DsRed can be seen with naked eyes, plasmid pDsRed was applicable as a marker. However, the color change was slow so that additional manipulation to increase the expression speed was necessary. Plasmid pGFPuv could serve as a perfect marker without any problem, tracing the reproduction and spread of the plant pathogens perfectly.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2002.11a
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• pp.43.2-44
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• 2002

• Journal of Sericultural and Entomological Science
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• v.44 no.2
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• pp.64-68
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• 2002

The antibacterial protein gene, nuecin was expressed in Sf9 cells using baculovirus expression vector system (BEVS). The antibactetial activity of mature nuecin against Pectobacterium carotovorum subsp. carotovorum, Ralstonia solanacearum and Pseudomonas tolaasii was significantly high, demonstrating that nuecin had a wider antibacterial spectrum on gram negative and positive bacteria. The result appears to be superior to other antibacterial peptide, attacin. The nuecin was purified by SP-sepharose and Mono Q HR ion-exchange chromatography, and then by Superdex 200 HR 10/30 column. The purified nuecin is quite stable at 80$\^{C}$ and 100$\^{C}$ for several hours of incubation and in a wide pH range (pH 2-12).

• The Plant Pathology Journal
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• v.39 no.2
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• pp.207-219
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• 2023

Soft rot is a widespread, catastrophic disease caused by Pectobacterium carotovorum subsp. carotovorum (Pcc) that severely damages the production of Amorphophallus spp. This study evaluated the rhizosphere bacterial and fungal communities in Pcc-infected and uninfected plants of two species of Amorphophallus, A. muelleri and A. konjac. Principal component analysis showed that the samples formed different clusters according to the Pcc infection status, indicating that Pcc infection can cause a large number of changes in the bacterial and fungal communities in the Amorphophallus spp. rhizosphere soil. However, the response mechanisms of A. muelleri and A. konjac are different. There was little difference in the overall microbial species composition among the four treatments, but the relative abundances of core microbiome members were significantly different. The relative abundances of Actinobacteria, Chloroflexi, Acidobacteria, Firmicutes, Bacillus, and Lysobacter were lower in infected A. konjac plants than in healthy plants; in contrast, those of infected A. muelleri plants were higher than those in healthy plants. For fungi, the relative abundances of Ascomycota and Fusarium in the rhizosphere of infected A. konjac plants were significantly higher than those of healthy plants, but those of infected A. muelleri plants were lower than those of healthy plants. The relative abundance of beneficial Penicillium fungi was lower in infected A. konjac plants than in healthy plants, and that of infected A. muelleri plants was higher than that of healthy plants. These findings can provide theoretical references for further functional research and utilization of Amorphophallus spp. rhizosphere microbial communities in the future.

• The Plant Pathology Journal
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• v.40 no.2
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• pp.151-159
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• 2024

Bacterial soft rot caused by Pectobacterium carotovorum subsp. carotovorum (Pcc) is one of the most severe diseases in radish cultivation. To control this plant disease, the most effective method has been known to cultivate resistant cultivars. Previously, we developed an efficient bioassay method for investigating resistance levels with 21 resistant and moderately resistant cultivars of radish against a strain Pcc KACC 10421. In this study, our research expanded to investigate the resistance of radish cultivars against six Pcc strains, KACC 10225, KACC 10421, ATCC 12312, ATCC 15713, LY34, and ECC 301365. To this end, the virulence of the six Pcc strains was determined based on the development of bacterial soft rot in seedlings of four susceptible radish cultivars. The results showed that the Pcc strains exhibited different virulence in the susceptible cultivars. To explore the race differentiation of Pcc strains corresponding to the resistance in radish cultivars, we investigated the occurrence of bacterial soft rot caused by the six Pcc strains on the 21 resistant and moderate resistant cultivars. Our results showed that the average values of the area under the disease progress curve were positively correlated with the virulence of the strains and the number of resistant cultivars decreased as the virulence of Pcc strains increased. Taken together, our results suggest that the resistance to Pcc of the radish cultivars commercialized in Korea is more likely affected by the virulence of Pcc strains rather than by race differentiation of Pcc.