• Research in Plant Disease
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• v.16 no.2
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• pp.136-140
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• 2010

Pectobacterium carotovorum subsp. carotovorum causes soft rot disease in diverse plants. Carocin D is bacteriocin that is produced by Pectobacterium carotovorum subsp. carotovorum Pcc21 strain. Nonpathogenic mutant P. carotovorum subsp. carotovorum Pcc21-M15 strain was obtained by mutagenesis with Tn5 insertion and screened pathogenesity. P. carotovorum subsp. carotovorum Pcc21-M15 and E. coli (pRG3431), carocin D gene-transformed E. coli, produce carocin D against P. carotovorum subsp. carotovorum Pcc3. Pathogenic P. carotovorum subsp. carotovorum Pcc3 and mixture with Pcc21-M15 or E. coli (pRG3431) were treated with lettuces. Pcc21-M15 and E. coli (pRG3431) effectively suppressed the development of soft-rot disease. While symptoms in 90% of Pcc3-treated lettuces were observed after 3 days, only 25% of Pcc3 and Pcc21-M15-treated lettuces were observed to be infected after 6 days. These results suggest that the nonpathogenic strain P. carotovorum subsp. carotovorum. Pcc21-M15 and E. coli (pRG3431) are effective to soft-rot disease suppression.

• Journal of Microbiology and Biotechnology
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• v.23 no.8
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• pp.1147-1153
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• 2013

Pectobacterium carotovorum subsp. carotovorum (formerly Erwinia carotovora subsp. carotovora) is a plant pathogen that causes soft rot and stem rot diseases in several crops, including Chinese cabbage, potato, and tomato. To control this bacterium, we isolated a bacteriophage, PP1, with lytic activity against P. carotovorum subsp. carotovorum. Transmission electron microscopy revealed that the PP1 phage belongs to the Podoviridae family of the order Caudovirales, which exhibit icosahedral heads and short non-contractile tails. PP1 phage showed high specificity for P. carotovorum subsp. carotovorum, and several bacteria belonging to different species and phyla were resistant to PP1. This phage showed rapid and strong lytic activity against its host bacteria in liquid medium and was stable over a broad range of pH values. Disease caused by P. carotovorum subsp. carotovorum was significantly reduced by PP1 treatment. Overall, PP1 bacteriophage effectively controls P. carotovorum subsp. carotovorum.

• 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.30 no.2
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• pp.117-124
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• 2014

The plant pathogenic bacterial genus Pectobacteirum consists of heterogeneous strains. The P. carotovorum species is a complex strain showing divergent characteristics, and a new subspecies named P. carotovorum subsp. brasiliensis has been identified recently. In this paper, we re-identified the P. carotovorum subsp. brasiliensis isolates from those classified under the subspecies carotovorum and newly isolated P. carotovorum subsp. brasiliensis strains. All isolates were able to produce plant cell-wall degrading enzymes such as pectate lyase, polygalacturonase, cellulase and protease. We used genetic and biochemical methods to examine the diversity of P. carotovorum subsp. brasiliensis isolates, and found genetic diversity within the brasiliensis subsp. isolates in Korea. The restriction fragment length polymorphism analysis based on the recA gene revealed a unique pattern for the brasiliensis subspecies. The Korean brasiliensis subsp. isolates were divided into four clades based on pulsed-field gel electrophoresis. However, correlations between clades and isolated hosts or year could not be found, suggesting that diverse brasiliensis subsp. isolates existed.

• The Plant Pathology Journal
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• v.24 no.2
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• pp.183-190
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• 2008

Plant-cell-wall-degrading enzymes (PCWDEs) of Pectobacterium carotovorum subsp. carotovorum are the key virulence factor in pathogenesis of soft rot disease of vegetables. The production of PCWDEs is controlled in a cell density dependent manner to avoid the premature production of PCWDEs and subsequent activation of plant defense. N-oxoacyl-homoserine lactone (OHL) is essential for quorum sensing in the soft rot pathogen and the expI gene is responsible for OHL production. The ExpI homolog isolated from P. carotovorum subsp. carotovorum SL940 had 94% identity with ExpI of E. carotovora subsp. carotovora scc3193 and 74% identity with Carl of E. carotovora subsp. atroseptica. The transgenic plants that express exp I uner the control of CaMV35S promoter were able to produce diffusible OHL. Transgenic plants producing OHL were very resistant to the infection of P. carotovorum subsp. carotovorum. Since the PR1 gene was strongly induced and NPR1 and NPR4 were induced weakly in transgenic plants compared to the wild type, salicylic acid-dependent pathways is likely involved in the resistance to the soft rot pathogen P. carotovorum subsp. carotovorum in ExpI transgenic plants.

• Journal of Microbiology and Biotechnology
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• v.19 no.1
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• pp.42-50
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• 2009

Fifty-four Pectobacterium carotovorum subsp. carotovorum strains isolated in Korea were characterized by a spectrum of antibacterial activities against 7 indicator strains chosen to represent various regions and host plants. All P. carotovorum subsp. carotovorum isolates tested could be grouped into 4 classes depending on the pattern of antibacterial substance production. All tested strains had DNA fragment(s) homologous to the genes encoding carotovoricin and 21 of them had genes homologous to DNA invertase. Sixteen strains had genes homologous to the genes encoding carocin S1. Several isolates produced antibacterial substances active against strains in Brenneria, Pantoea, and Pectobacterium genera that belonged formerly to the genus Erwinia. Strains in Pseudomonas or Xanthomonas sp. were not sensitive to the antibacterial substances produced by P. carotovorum subsp. carotovorum, except for X. albilineans that was sensitive to antibacterial substances produced by most strains in P. carotovorum subsp. carotovorum and P. betavasculorum KACC10056. These results demonstrated the diverse patterns of antibacterial substance production and the possibility of the existence of new antibacterial substance(s) produced by P. carotovorum subsp. carotovorum isolated in Korea.

• Korean Journal of Microbiology
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• v.47 no.2
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• pp.103-109
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• 2011

Pectobacterium carotovorum subsp. carotovorum is the causative agent of soft rot in crops such as potato and cabbages. Loop-mediated isothermal amplification (LAMP) is a simple DNA amplification method, as well as isothermal PCR technique. In this study, a new method for the rapid detection of Pectobacterium carotovorum subsp. carotovorum was developed using LAMP that named PCC-LAMP. Based on lytic murein transglycolase gene of Pectobacterium carotovorum subsp. carotovorum, a set of four primers for LAMP was designed. The optimal PCC-LAMP reaction temperature was established at $61^{\circ}C$. Under standard conditions, PCC-LAMP amplified $1{\times}10^3$ copies of clone PCC-pBX437 per reaction. Further, this method can also assay directly by SYBR Green I without electrophoresis. Amplification was not detected for five other bacterial species. In conclusion, PCC-LAMP may be a useful method for the detection Pectobacterium carotovorum subsp. carotovorum in the field.

• The Plant Pathology Journal
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• v.31 no.1
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• pp.83-89
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• 2015

In order to control Pectobacterium carotovorum subsp. carotovorum, a novel virulent bacteriophage PM2 was isolated. Bacteriophage PM2 can infect 48% of P. carotovorum subsp. carotovorum and 78% of P. carotovorum subsp. brasilliensis but none of atrosepticum, betavasculorum, odoriferum and wasabiae isolates had been infected with PM2. PM2 phage belongs to the family Myoviridae, and contains a large head and contractile tail. It has a 170,286 base pair genome that encodes 291 open reading frames (ORFs) and 12 tRNAs. Most ORFs in bacteriophage PM2 share a high level of homology with T4-like phages including IME08, RB69, and JS98. Phylogenetic analysis based on the amino acid sequence of terminase large subunits confirmed that PM2 is classified as a T4-like phage. It contains no integrase- or no repressor-coding genes related to the lysogenic cycle, and lifestyle prediction using PHACT software suggested that PM2 is a virulent bacteriophage.

• The Plant Pathology Journal
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• v.23 no.4
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• pp.314-317
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• 2007

A soft stem rot disease was observed on Chamaecereus silvestrii (Korean name: Sanchui), a scion of graft-cactus, in major growing areas of Suwon (National Horticulture Research Institute), Anseong, Eumseong, Cheonan, Daegu, and Goyang, Korea during 2000 and 2001. Typical symptoms were soft rots characterized by moist and watery decay of the whole cactus stem, which initiated as small water-soaked lesions and enlarged rapidly to the entire stem. The causal organism isolated from the infected stems was identified as Pectobacterium carotovorum subsp. carotovorum (Erwinia carotovora subsp. carotovora) based on its physiological and biochemical characteristics and confirmed by the cellular fatty acid composition and Biolog analyses. Artificial inoculation of the bacterium produced the same soft rot symptoms on the cactus stems, from which the same bacterium was isolated and identified. This is the first report of the P. carotovorum subsp. carotovorum in the graft-cactus C. silvestrii in Korea.

• 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.