• Korean Journal Plant Pathology
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• v.3 no.4
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• pp.300.2-303
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• 1987

• Plant Disease and Agriculture
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• v.1 no.1
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• pp.14-18
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• 1995

This study was carried out to investigate effect of transplanting method, environmental factor, and fertilizing level on occurrence of Pseudomonas glumae in south-west coastal area of Chonnam province. Occurrence in filed began after heading and increased gradually during 3-4 weeks. Occurrence of this disease was great at daily minimum temperature of 23-$25^{\circ}C$ and series of rainfall during early and mid. August Degree of infection by fertilization of nitrogen and by transplanting fertilizing level of 50% than standard fertilization of nitrogen and by transplanting method was greater machine-transplanting than hand-transplanting. Rate of degradation was 6.5% in case of 10% of infected panicle, 14.5% in 30%, 22% in 50% and 35.9% in 70%. We can reduce occurrence of this disease by sawing non -infected seed and balanced fertilizing in cultural practice and applying oryza 4kg/a in early transplanting or Kasugamin EC and Allta in heading stage.

• Journal of Microbiology and Biotechnology
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• v.14 no.1
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• pp.48-55
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• 2004

Six strains of an obligate predatory bdellovibrio isolate that preys on Burkholderia glumae in rice paddy field water and rhizosphere soil, were identified and characterized. The numbers of Bdellovibrio cells varied from $3.2{\times}10^3$ to $9.2{\times}10^3$ plaque-forming unit/g after enrichment in cells of B. glumae. Prey range tests with six Bdellovibrio strains and 17 prey strains of rice-pathogenic, antibiosis-related, or nitrogen-fixing bacteria resulted in unique predation patterns in related prey cells. Strain BG282 had the widest prey range on 7 plant pathogenic bacteria among the 17 prey strains tested. However, no predation occurred with strains of Azospirillum brasilense, Paenibacillus polymyxa, Pseudomonas fluorescens, P. putida, and Serratia marcescens that are associated with antibiosis or nitrogen fixation in the rice ecosystem. Identification was confirmed by the presence of typical bdelloplast in the prey cells of B. glumae and by a PCR assay using B. bacteriovorus-specific primers. Furthermore, 16S rDNA sequencing of the six bdellovibrio strains showed a homology range of 97.2% to 99.2% to the type strain of B. bacteriovorus.

• Korean Journal Plant Pathology
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• v.12 no.1
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• pp.11-20
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• 1996

한 쌍의 R16-1과 R23-2R primer를 이용한 PCR에 의해 증폭된 16S와 23S rDNA 사이의 rDNA spacer 부위의 다형성들이 Pseudomonas avenae, P. glumae, P. fuscovaginae, P. syringae pv. syrngae, Xanthomonas oryzae pv. oryzae, X. oryzae, Xanthomonas herbicola 등 벼 종자전염성 51개 균주의 구분을 위하여 적용되었다. 증폭산물은 820∼950bp의 크기였으며, 각각의 종에 특이적이었고 구분이 가능하였다. Pseudomonas species의 증폭산물은 P. avenae는 950bp, P. glumae는 850bp, P. fuscovaginae는 770pb 및 P. syringae pv. syringae는 1,240, 1,100 및 820bp로 특이적이었다. P. avenae와 P. glumae의 국내균주들은 다형성에 있어 종내 변이는 없었다. X. oryzae pv. oryzae의 860bp와 X. oryzae pv. oryzicola의 890, 440 및 370bp의 이차산물에서 Xanthomonas species의 종내에서 균주에 관련없이 단일화된 다형성을 보였다. CXO 211을 제외한 모든 국내 균주는 a형에 속한 반면 하나의 국내 균주를 포함하여 4개 균주는 b형이었다. E. herbicola의 spacer 부위 증폭은 여러 개의 band를 보였으며, 증폭상은 각각 동일하였고, strain간의 종내 변이는 없었다. 본 실험 결과에 의하여 16S와 23S rDNAdp R16-1과 R23-2R primer를 이용하여 PCR 증폭된 spacer 다형성의 구별은 종자전염성 세균의 신속한 구별에 이용될 수 있을것이다.

• Plant Disease and Agriculture
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• v.5 no.1
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• pp.1-7
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• 1999

The grain rot of caused by Bukholderia glumae was fist reported in japan in 1955 and then reported in other countries as well as in Korea in 1986. The pathogen causes both seedling and grain rot of rice but it cannot attack any other parts of adult rice plant. Bacterial colonies grow slowly, and are circular and greyish white. The causal bacterium is Gram-negative and rod shape with 1-3 polar flagella, and produce a diffusible yellow-greenish nonfluorescent pigment on King's medium B. Biochemical characteristics such as negative in arginine dehydrolase, oxidase reaction and nitrate reduction and positive in lecithinase, and the utilization of L-arginine and inositol are useful in differentiation of this from other nonfluorescent bacteria pathogenic to rice. This pathogenic bacterium had belonged to the genus of Pseudomonas but recently was transferred to the new genus Burkholderia on the basis of physiological characteristics and DNA-DNA hybridization data. However, other characteristics such as colony heterogenicity or colonial variation after subcultures, phytotoxin, secreting antibiotics, and relationship between yellow greenish pigment production and pathogenicity need to be clarified more. To develop an effective control strategy for this disease, understanding of detailed life cycle of the disease and critical environmental factors affecting disease development is prerequisite. Although 5,435 ha of rice paddy in Korea was infested during 1998, there is no exact estimation of yield losses and distribution of the pathogen. The review will focus on recent progress on the understanding of the bacteriological and ecological characteristics of the causal bacterium and control means of the disease.

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.775-779
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• 2003

Cultivation environment for effective production of shrimp in shrimp aquaculture, Institute of Marine & Fishery, Soonchunhyang University located at Tae-An, Chung-Nam Province, with the ultimate aim of probiotics development, was monitored. Several environmental factors including dissolved oxygen, water body temperature, pH, salinity, $NH_4-N$, $NO_2-N$, $NO_3-N$, chlorophyll a affecting on the growth of shrimp were examined. Concentrations of $NH_4-N$, $NO_2-N$, and $NO_3-N$ dissolved in water samples were determined to 0.024-0.034 mg/L, 0.03-0.02, and 0.004-0.009 mg/L, respectively. Chlorophyll a content was examined in the range of 0.002-0.118 $ug/m^3$. In order to understand the distribution of different bacteria in water samples collected in shrimp aquaculture, bacteria were isolated and enumerated on the marine agar plates. Total number of bacteria were increased to approximately $6.5\;{\times}\;10^4$. Thirteen predomonant bacteria were isolated and identified. As the results of BIOLOG test of the isolates, these bacteria were identified as Corynebacterium nirilophilus, Clavibacter agropyri, Sphingomonas adhaesiva, Brevundimonas vesicularis, Vibrio parahaemolyticus, Pseudomonas bathycetes, Vibrio tubiashii, Sphingomonas macrogoltabidus, Rhodococcus, rhodochrous, Burkholderia glumae, Corynebacterium urealyticus, Rhodococcus fascians, Psychrobacter immobilis, respectively. Further work will stimulate the elucidation of pathogenicity, corresponding bacteria related to environment and probiotics, providing good information for effective production of shrimp.

• Journal of Life Science
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• v.24 no.7
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• pp.757-761
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• 2014

Olive flounder (Paralichthys olivaceus) is an important aquaculture fish species in Jeju Island, South Korea. Due to the intensification of flounder fish farming, huge amounts of chemical antibiotics are used against several fish diseases. This has many harmful side effects on fish, as well as human consumers. Hence, an alternative to chemical antibiotic agents is needed for disease control. In this study, three strains of rhizobacteria (BRH433-2, TRH415-2, and THJ609-3) were isolated from the rhizosphere of plants. Assays of their antibacterial activity against fish pathogens, such as S. iniae, S. parauberis, V. anguillarum, and E. tarda, were performed with untreated broth culture (without cell separation), supernatant, and precipitated pellets separated by centrifugation. Among these, the cell suspension prepared from the precipitated pellet showed significant antimicrobial activity when compared with that of the untreated broth culture and centrifugal supernatant. These results indicate that the three isolated rhizobacterial strains exhibit antibacterial activity. Analysis of the 16S rDNA sequences of the BRH-433-2, THJ609-3, and TRH415-2 strains showed the highest similarity to Burkholderia gladioli (99.5%), Pseudomonas baetica (97.7%), and P. koreensis and P. baetica (98.4%), respectively. We suggest that the strains hold promise in disease management of fish.