• Korean Journal of Veterinary Research
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• v.28 no.2
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• pp.345-353
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• 1988

The present study was carried out to investigate the incidence of C jejuni and C coli in chicken. Also were examined the pathogenicity of the isolates in chick by experimental inoculation. Thermophilic Campylobacter were isolated from 34(45.9%) of the 74 specimens, and classified as 21.6% C jejuni, and 24.3% C coli. In the biotyping of 16 stranis of C jejuni isolates, 37.5% of the strains were grouped as biotype I, 62.5% as biotype II. In the case of 18 strains of C coli isolates, 49.9% of isolates were grouped as biotype I, 55.6% as biotype II. n oral inoculation with $10^4cfu$ of Campylobacter isolates into infant chicks(1 to 3 days-old), 17 days-old and 34 days-old chicks, 32.5% of the chicks developed diarrhea on day 1, 52.5% on day 3, 70.0% on day 5, and 27.5% on day 7, and the peak incidence of diarrhea was reached on day 5. The organisms were found to be discharged in feces one day afterwards. C jejuni and C coli strains were detected from the feces in 87.5% of the chicks on day 5. The organisms were multiplied from $10^4$ to $10^6cfu/gm$ in feces 5 to 7 days after inoculation. C jejuni and C coli recovered from 100% of the cecum, 64.3% of the duodenum, 50.0% of the spleen, 42.9% of the livers, and from 21.4% of gallbladders 7 days after inoculation.

• Journal of Microbiology and Biotechnology
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• v.30 no.5
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• pp.717-725
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• 2020

The use of plant growth-promoting rhizobacteria is economically viable and environmentally safe for mitigating various plant stresses. Abiotic stresses such as flood and drought are a serious threat to modern agriculture. In the present study, the indole-3-acetic acid-producing rhizobacterium R. sphaeroides KE149 was selected, and its effects on the growth of adzuki bean plants under flood stress (FS) and drought stress (DS) were investigated. IAA quantification of bacterial pure culture revealed that KE149 produced a significant amount of IAA. Moreover, KE149 inoculation notably decreased stress-responsive endogenous abscisic acid and jasmonic acid and increased salicylic acid in plants under DS and FS. KE149 inoculation also increased proline under DS and methionine under FS. In addition, KE149 inoculation significantly increased the levels of calcium (Ca), magnesium (Mg), and potassium (K) while lowering the sodium (Na) content in the plant shoot under stress. KE149-treated plants had markedly greater root length, shoot length, stem diameter, biomass, and higher chlorophyll content under both normal and stressed conditions. These results suggest that KE149 could be an efficient biofertilizer for mitigating water stress.

• The Plant Pathology Journal
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• v.31 no.2
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• pp.132-139
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• 2015

Bt-cotton germplasm, consisting of 75 genotypes was evaluated against cotton leaf curl disease (CLCuD) under high inoculum pressure in the field and using graft inoculation in glasshouse by visual symptom scoring assessments. None of the tested genotype was found disease free under both evaluation tests. Under field conditions in 2011, 3 genotypes were found resistant, 4 moderately resistant, 3 tolerant, 2 moderately susceptible and one susceptible; in 2012, 3 genotypes were tolerant, 7 moderately susceptible, 5 susceptible and 38 highly susceptible; in 2013, one was moderately susceptible and 51 were highly susceptible with varying degree of percent disease index (PDI) and severity index (SI). However, through graft evaluation in glasshouse, none of the graft inoculated plant was symptomless. All tested genotypes showed disease symptoms with SI values ranging between 5.0 and 6.0, and latent period between 12 and 14 days. Of the 75 genotypes evaluated using graft inoculation, 11 were found susceptible with SI values of 5.0 to 5.4 while remaining 64 were highly susceptible with SI values of 5.5 to 6.0. Inoculated plants of all tested genotypes exhibited severe disease symptoms within 10 days after the appearance of initial symptoms. No reduction in SI value was observed until the end of the experiment i.e., 90 days after grafting. Information generated under the present study clearly demonstrates that no sources of resistance to CLCuD are available among the tested Bt-cotton genotypes. So, a breeding programme is needed to introgress the CLCuD-resistance from other resistant sources to agronomically suitable Bt-cotton genotypes.

• Korean Journal of Environmental Agriculture
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• v.30 no.2
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• pp.223-228
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• 2011

BACKGROUND: Rhizosphere bacteria may improve plant growth and productivity both by supply nutrients and hormonal stimulation. Although many experiments have shown improvements in plant growth with inoculation of bacterial cultures to the rhizosphere, the main obstacle in the applications of plant growth promoting rhizobacteria in a large scale is the inconsistency of the results. We tested the growth promoting effects of Azospirillum and Methylobacterium strains on red pepper plant. METHODS AND RESULTS: Red pepper seedlings were grown for 25 days in a growth media inoculated with A. brasilense CW903 or M. oryzae CBMB20. The seedlings were transplanted and grown for 45 days in pots with soil in a greenhouse, at half the recommended level of fertilizer. Bacterial culture, $4.0{\times}10^9$ for A. brasilense CW903 and $5.8{\times}10^8$ CFU for M. oryzae CBMB20, was applied in root zone soil periodically every 10 days during the experiment. Inoculation of M. oryzae CBMB20 significantly increased the red pepper plant growth in terms of leaf number, height and mass of shoot, or root mass compared to uninoculated control plants. Although beneficial effects of A. brasilense on plant growth of many crops were observed, the growthpromoting effect of A. brasilense CW903 on red pepper plant was not found in this study. CONCLUSION(s): The factors responsible for the irregularities in plant growth promoting of rhizobacteria are difficult to elucidate. Extensive inoculation experiments in the greenhouse and in the field should enable us to define the factors critical to obtain successful application of plant growth promoting rhizobacteria.

• Research in Plant Disease
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• v.9 no.1
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• pp.39-41
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• 2003

Bacterial soft rot by Erwinia carotovora subsp. carotovora is one of the diseases causing the biggest damages in Chinese cabbage cultivation. This study was conducted to evaluate disease resistance of Chinese cabbage cultivars and breeding lines to E. carotovora subsp. carotovora by new inoculation method, mineral oil inoculation method, inoculating 10 ml of the mixture (4:1, v/v) of bacterial suspension and mineral oil on the central bases of Chinease cabbage seedling. Total 43 Chinese cabbage cultivars and lines obtained from 3 domestic seed companies and universities were screened for disease resistance using the above mentioned inoculation method. This screening test showed that Chinese cabbage C3-26, C3-28, C3-29 and C29-51-51-53 lines were resistant, Gangta, Gumchonyealgali, Mini, DB50, Jibu, Pyungchng, Sanchon and Yellow King No.2 cultivars were susceptible, and the others were moderate resistant.

• Journal of Microbiology and Biotechnology
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• v.33 no.7
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• pp.886-894
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• 2023

During the rhizoremediation of diesel-contaminated soil, methane (CH₄), a representative greenhouse gas, is emitted as a result of anaerobic metabolism of diesel. The application of methantrophs is one of solutions for the mitigation CH₄ emissions during the rhizoremediation of diesel-contaminated soil. In this study, CH₄-oxidizing rhizobacteria, Methylocystis sp. JHTF4 and Methyloversatilis sp. JHM8, were isolated from rhizosphere soils of tall fescue and maize, respectively. The maximum CH₄ oxidation rates for the strains JHTF4 and JHM8 were 65.8 and 33.8 mmol·g-DCW^-1·h^-1, respectively. The isolates JHTF4 and JHM8 couldn't degrade diesel. The inoculation of the isolate JHTF4 or JHM8 significantly enhanced diesel removal during rhizoremediation of diesel-contaminated soil planted with maize for 63 days. Diesel removal in the tall fescue-planting soil was enhanced by inoculating the isolates until 50 days, while there was no significant difference in removal efficiency regardless of inoculation at day 63. In both the maize and tall fescue planting soils, the CH₄ oxidation potentials of the inoculated soils were significantly higher than the potentials of the non-inoculated soils. In addition, the gene copy numbers of pmoA, responsible for CH₄ oxidation, in the inoculated soils were significantly higher than those in the non-inoculated soils. The gene copy numbers ratio of pmoA to 16S rDNA (the ratio of methanotrophs to total bacteria) in soil increased during rhizoremediation. These results indicate that the inoculation of Methylocystis sp. JHTF4 and Methyloversatilis sp. JHM8, is a promising strategy to minimize CH₄ emissions during the rhizoremediation of diesel-contaminated soil using maize or tall fescue.

• Korean Journal of Soil Science and Fertilizer
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• v.22 no.3
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• pp.245-252
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• 1989

This experiment was carried out to study the effects of nitrogen concentration of cultural solution, rhizobium inoculation, and planting density on nodulation, contents of total-N and allantoin-N of the plants, and contents of crude fat and protein of the seeds with 4 cultivars and 1 non-nodulation isogenic line (Hwangeumkong, Jangbaegkong, Paldalkong, Clark, non-nodulating Clark) in nutri-culture. Modulation was increased significantly by the rhizobium inoculation and decreased by the increase of nitrogen concentration of the cultural solution and planting density, and more nodule per plant was observed in Hwangeumkong than other cultivars. Total nitrogen contents of the soybean plant were higher in Hwangeumkong and Janbaegkong compared with other two cultivars, and were increased by rhizobium inoculation and the increase of nitrogen concentration of the cultural solution except in case of $R_3$ stage of non-inoculation of rhizobium, and was decreased by the increase of planting density. Allantoin nitrogen contents of stem were lower in Paldalkong compared with other cultivars and was increased significantly by the rhizobium inoculation, and thus was correlated significantly with nodulation. Allantoin-N contents were also decreased by the increase of planting density and nitrogen concentration of the solution, and was very low in case of non-nodulating isogenic line at any level of nitrogen concentration. The contents of crude fat of the seed were lower in cases of higher nitrogen concentration of the solution and more plants per pot, but no effects of rhizobium inoculation was observed. The contents of crude protein were tend to increase by the increase of nitrogen concentration, but were little effected by rhizobium inoculation and planting density.

• Journal of Mushroom
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• v.17 no.2
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• pp.64-69
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• 2019

The present study was conducted to investigate the synergistic effects caused by single and co-inoculation of the phosphate solubilizing bacteria (PSB), Paraburkholderia phenazinium YH3 and Paraburkholderia metrosideri YH4. Phosphate solubilization was assessed by measuring the phosphorus contents for 7 days in a single and co-inoculation medium. Co-inoculation of the two strains was found to release the highest content of soluble phosphorus ($1,250{\mu}g\;mL^{-1}$) into the medium, followed by the single inoculation of P. metrosideri YH4 ($1196.59{\mu}g\;mL^{-1}$) and P. phenazinium YH3 ($994.34{\mu}g\;mL^{-1}$). The highest pH reduction, organic acid production and glucose consumption was also observed in the co-inoculation medium of the two strains. A plant growth promotion bioassay revealed that co-inoculation with the two strains enhanced the growth of romaine lettuce more than single inoculation with either of the two strains (28.5% for leaf and 16.6% for root). Although there was no significant difference between single and co-inoculation of bacterial strains in terms of phosphorous release and plant growth, the synergistic effects of co-inoculation with PSB could be beneficial for crop growth.

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.1
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• pp.68-75
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• 1999

This study was conducted to examine the effects of Arbuscular Mycorrhizae inoculation and phosphorus application on early growth of hot pepper. Gigaspora margarita and Acaulospora spinosa were chosen for this investigation and inoculated into soils of different P levels by varying inoculation time and density. After treatment, some relevant growth responses of hot pepper were measured. Regardless of soil P levels, hot peppers treated with arbuscular mycorrhizal fungi had 5~34% more fresh weight than those untreated, but the effect of inoculation time and density was not different between two species. With decreased P levels, the infection rate and dependency of hot peppers increased. The content of P and K of AMF-inoculated hot peppers increased with increasing P levels, but the shoot to root ratio of those elements decreased. The results of this study showed that inoculation of AMF would be effective in promoting growth of hot pepper seedlings and increase transplant adaptation due in part to the resulted higher root development.

• Research in Plant Disease
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• v.20 no.4
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• pp.270-274
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• 2014

Division of Forest Diseases & Insect Pests, Korea Forest Research Institute, Seoul 130-712, Korea The objective of this study was to evaluate the virulence of geographically different isolates of oak wilt pathogen, Raffaelea quercus-mongolicae and other Raffaelea species. In this study, mature trees of Quercus mongolica were inoculated with the various isolates of Raffaelea spp. and their virulence was evaluated by measuring the extent of sapwood discoloration resulting from the inoculation. The average length of discolored sapwood in a lateral direction was longest in the trees inoculated with the isolates from Korea (8.69 cm) followed by R. quercivora (7.51 cm) and the other Raffaelea spp. (3.35 cm). The lateral length of discolored sapwood caused by the inoculation with Korean strains varied from 4.71 to 14.90 cm indicating their differences in virulence. The area of discolored sapwood caused by the inoculation with Raffaelea spp. varied from 1.57 to $8.42cm^2$ indicating their differences in virulence. Based on the length and area of the discolored sapwoods, isolated YY and wj43 appeared to have the highest virulence among all the Raffaelea isolates tested. Each of the two isolates was obtained from Gangwon Province and Jeonbuk Province, respectively.