• Korean Journal Plant Pathology
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• v.10 no.3
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• pp.157-162
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• 1994

Erwinia rhapontici causes soft-rot disease in a number of plants such as onion, garlic and hyacinth. There has been no report that E. rhapontici produces pectate lyase. Pel gene was cloned from genomic DNA of the parasitic soft-rot E. rhapontici polymerase chain reaction by using synthetic oligonulceotide primers designed from the pel 1 to E. carotovora. The recombinant plasmid pJE101 containing pectate lyase gene, when introduced into E. coli DH5$\alpha$, produced pectate lyase an macerated hyacinth tissue.

• Korean Journal Plant Pathology
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• v.10 no.3
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• pp.163-168
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• 1994

Erwinia rhapontici causes soft-rot disease in a number of plants such as rhubarb, onion, hyacinth and garlic. Pectate lyase (Pel) depolymerizes pectin and other polygalacturonates, which is though to play a role in bacterial invasion of plants. Pel activity was not detected in E. rhapontici cultured in a minimal salts medium containing glycerol, polygalacturonate, or citrus pectin as a carbon source. However, when sterilized potato tuber and Chinese cabbage slices were added to minimal salts polygalacturonate (0.5%) medium, E. rhapontici produced pectate lyase enzyme. Also Pel activity was consistently detected from macerated potato tubers, Chinese cabbage leaves, lettuce leaves and celery petioles tissue. Pel in the extract of macerated Chinese cabbage caused by E. rhapontici strain 1, resulted in electrolyte loss, tissue maceration and cell death of potato tuber tissue. These results indicate that E. rhapontici produces pectate lyase only in the presence of non-diffusible plant components, and that this enzyme probably contributes to its pathogenicity.

• Korean Journal Plant Pathology
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• v.12 no.1
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• pp.129-131
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• 1996

Pecatate lyase(Pel)는 펙틴과 펙틴산을 분해하며, 기주식물의 감염에 관여한다. Erwinia rhapontici에 있어서 기주와 병원균이 병원성과의 상호관계를 구명하기 위하여 pectate lyase(Pel) 활성에 미치는 식물체 추출물과 세포벽의 효과를 검토하였다. 본 균은 glycerol이 포함된 minimal salts(MSG) 배지와 식물체 추출물이 첨가된 MSP 배지에서는 Pel 활성이 검출되지 않았다. 그러나 배추, 상추 잎, 감자 괴경, 셀러리 잎자루, 양파 인경, 당근 뿌리의 세포벽이 첨가된 MSP 배지에서는 Pel의 활성이 검출되었다. Pel을 유도하는 식물 인자는 불용성이고, 열처리에 불안전하였다.

• Korean Journal of Agricultural Science
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• v.16 no.1
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• pp.19-25
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• 1989

Twelve isolates of bacteria obtained from infected onions were classified into genus Erwinia based on diagnostic characteristics. Of twelve isolates studied, five were identified as E. carotovora subsp. carotovora, six as E. rhapontici and one as E. chrysanthemi on the bases of bacteriological properties. Symptoms caused by the genus Erwinia were different to be identified among the species. Therefore, we propose to name the disease of onion caused by E. carotovora subsp. carotovora, E. rhapontici and E. chrysanthemi as "bacterial soft rot of onion".

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.1
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• pp.104-109
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• 1994

For Selection of powerful antagonistic bacteria for biological control of soil borne Erwinia rhapontici causing rot of the vegetables and fruit, excellent straints (S43, S62) were selected from rhizopere in vegetables root rot suppressive soil. Selected strains were identified to be Pseudomonas sp. with Apl 20NE kit tests. Optimum culture condition for the maximum production of antagonistic substance was determined , when isolate was cultured in 523 synthetic broth media at pH 7.0 and 30 during 3 days. Antagonistic substance productivity of isolated Pseudomonas sp. (S43, S62) in the fertilizer soil were increased to about 40-50% compared to that in the non fertilizer soil.

• KSBB Journal
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• v.7 no.1
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• pp.79-83
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• 1992

The characteristics of Erwinia rhapontici cells with $\alpha$-glucosyltransferase activity immobilized in Ca-alginate beads and the performance of two different types of reactor-stirred tank reactor(STR) and packed bed reactor(PBR)-charged with these immobilized cells to produce palatinose from sucrose were investigated. The optimal pH(5.5-6.0) and temperature($30-35^{\circ}C$) showed no appreciable difference between free and immobilized cells. The apparent Km value of the immobilized cells(0.28M) was approximately two times higher than that of free cells(0.13M) at $30^{\circ}C$. The half life of the immobilized cells was found to be 380 h with STR while much greater operational stability was achieved with PBR. Continuous operation of PBR at a space velocity of $0.2h^{-1}$ for 30 days showed only 5% loss of initial activity.

• Journal of Mushroom
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• v.9 no.2
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• pp.87-89
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• 2011

This study was performed to investigate the antibacterial activities and the minimal inhibitory concentration (MIC) of 6 strains of Beauveria bassiana against mulberry pathogenic bacteria. The antibacterial activities and the MIC were measured using paper disc method and broth dilution method, respectively. The antibacterial activities were found out just B. bassiana J200, and shown at 13 mm from Erwinia rhapontici KACC 10407 and at 17 mm from Pseudomonas syringae KACC 10390 and Xanthomonas campestris KACC 12134. The MIC were all observed at 4.0% from E. rhapontici KACC 10407, P. syringae KACC 10390 and X. campestris KACC 12134. The results suggest that B. bassiana could play a good role for biological control against mulberry pathogenic bacteria.

• The Plant Pathology Journal
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• v.16 no.2
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• pp.98-104
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• 2000

For the taxonomic evaluaition, 15 strains of the genus Pectobacterium and Erwinia were analyzed for 16S-23S rDNA intergenic spacer regions (ISRs). These species contained two types of ISRs, large and small ISRs. Large ISRs were on the range of 474-569 bp size, and coding transfer $\textrm{RNA}^{11e}$($\textrm{tRNA}^{11e}$) and $\textrm{tRNA}^{Ala}$. Small ISRs were 354-459 bp in length and coding $\textrm{tRNA}^{Glu}$. The sequence variations of two ISRs among species and strains were very high as compared with 16S rRNA gene sequences. By phylogenetic trees on the basis of two ISRs, Pectobacterium ere differentiated into P. carotovorum-P. cactiaidum group and P. chrysanthemi group. However, the taxonomic position of E. cypripedii and E. rhapontici, which were not clear on taxonomic delineation between Pectobacterium and Erwinia, were not clearly resolved on the basis of ISRs.

• Journal of Food Hygiene and Safety
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• v.18 no.4
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• pp.189-194
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• 2003

Approved chemical preservatives have been widely used to preserve foods and increase their shelf life. There are increasing demends of the partial or complete removal of chemical preservatives from foods vecause of adverse health effect of chemicals. In this study, the possibility of natural antimicrobial compounds, Korean propolis as food preservatives are investigated. Propolis samples were extracted on various concentration of ethanol. Propolis extracts extracted with 100% ethanol showed the highest inhibitory effect aginst food spoilage microorganisms. The 100% ethanol extracts of propolis were selected and the antimicrobial activites of 100% ethanol extracts of proplis against several food spoilage microorganisms were examined. Bacillus subtilis, Micrococcus luteus, Escherichia coli, Staphylcoccus aureus, Bacillus cereus, Shigella sonnei, Salmonella choleraesuis, Erwinia rhapontici, and Vibrio parahaemolyticus as food poisoning microorganisms were chosen for the examination. The Propolis extracts had antimicrobial activity against food spoilage microorganisms. When the microorganisms were treated with propolis extracts, the population of food spolige microorganisms were decreased by 1~9 log.