• 한국균학회지
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• 제42권1호
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• pp.34-39
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• 2014

완도의 동백나무 자생지역에서 동백나무의 근권과 주변 일반 식물의 근권 토양을 수집하여 토양 내 수지상균근균(AMF)의 다양성 및 군집 구조를 확인하였다. 분석 결과 두 근권은 모두 Acaulospora mellea 포자로 우점되어 있지만 동백나무 근권에 비해 일반 기주식물의 근권에서 AMF종 다양성 지수와 종 수 및 포자 수가 더 높게 나타나는 경향을 확인하였다. 기주식물의 종류에 상관없이 A. mellea가 높은 빈도로 출현하는 것으로 보아 A. mellea가 다른 AMF종에 비해 산림 토양 및 목본 식물에 특이적으로 적응된 것으로 생각된다. 두 근권에서 발견된 AMF 군집간의 유사도를 분석한 결과 동백나무의 근권에서 발견된 AMF 군집간의 유사도가 동백나무 근권 AMF 군집 일반 기주식물 근권 AMF 군집 간의 유사도나 일반 기주식물 근권 AMF 군집간의 유사도에 비해 더 높은 것으로 나타났다. 이는 동백나무 근권이 다른 일반 기주식물의 근권과는 다른 독특한 AMF 군집 구조를 형성하고 있으며, 식물의 근권 주변의 AMF 군집은 기주식물에 의해 유의미한 수준으로 달라질 수 있음을 보여준다.

• Journal of Microbiology and Biotechnology
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• 제18권5호
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• pp.805-814
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• 2008

Liming of acidic soils can prevent aluminum toxicity and improve crop production. Some maize lines show aluminum (Al) tolerance, and exudation of organic acids by roots has been considered to represent an important mechanism involved in the tolerance. However, there is no information about the impact of liming on the structures of bacterial and fungal communities in Cerrado soil, nor if there are differences between the microbial communities from the rhizospheres of Al-tolerant and Al-sensitive maize lines. This study evaluated the effects of liming on the structure of bacterial and fungal communities in bulk soil and rhizospheres of Al-sensitive and Al-tolerant maize (Zea mays L.) lines cultivated in Cerrado soil by PCR-DGGE, 30 and 90 days after sowing. Bacterial fingerprints revealed that the bacterial communities from rhizospheres were more affected by aluminum stress in soil than by the maize line (Al-sensitive or Al-tolerant). Differences in bacterial communities were also observed over time (30 and 90 days after sowing), and these occurred mainly in the Actinobacteria. Conversely, fungal communities from the rhizosphere were weakly affected either by liming or by the rhizosphere, as observed from the DGGE profiles. Furthermore, only a few differences were observed in the DGGE profiles of the fungal populations during plant development when compared with bacterial communities. Cloning and sequencing of 16S rRNA gene fragments obtained from dominant DGGE bands detected in the bacterial profiles of the Cerrado bulk soil revealed that Actinomycetales and Rhizobiales were among the dominant ribotypes.

• 한국균학회소식:학술대회논문집
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• 한국균학회 2018년도 춘계학술대회 및 임시총회
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• pp.35-35
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• 2018

Arbuscular mycorrhizal fungi (AMF) are one of the most widespread symbionts globally. Owing to their enhanced nutrient absorption capacity, AMF significantly contribute to the survival of individual plants and the ecosystem functioning. Community structures of AMF are affected by many environmental factors Inland wetlands have a different environment from common forest soils, therefore, plants inhabiting wetlands may have characteristic AMF communities. The purpose of this study was to compare the AMF communities in wetlands, among the species of host plants. We sampled the roots of 3 host plant species, Phragmites communis, Miscanthus sacchariflorus, and Trisetum bifidum with rhizospheres from 3 isolated areas in Upo wetland, Korea. We extracted DNA from AMF spores in rhizospheres and the roots of 3 plant species. We amplified 18S rDNA of AMF using AMF specific primer. As a result, we confirmed 9 species from 5 genera in AMF spores, and 5 species from 3 genera in plant roots. Funneliformis caledonium was the most dominant species in field soils, on the other hand, Diversispora aurantia was the most dominant species in plant roots. We confirmed that species diversity and abundance of AMF communities were different among host plant species. These results showed that the AMF community had specific to host plants in the inland wetland.

• Journal of Microbiology
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• 제44권6호
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• pp.591-599
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• 2006

To address the diversity of cyclodextrin-producing P. graminis strains isolated from wheat roots and rhizospheres of maize and sorghum sown in Australia, Brazil, and France, restriction fragment length polymorphism analysis of part of genes encoding RNA polymerase (rpoB-RFLP) and DNA gyrase subunit B (gyrB-RFLP) was used to produce genetic fingerprints. A phylogenetic tree based on rpoB gene sequences was also constructed. The isolates originated from Brazil could be separated from those from Australia and France, when data from the rpoB-based phylogenetic tree or gyrB-RFLP were considered. These analyses also allowed the separation of all P. graminis strains studied here into four clusters; one group formed by the strains GJK201 and $RSA19^T$, second group formed by the strains MC22.02 and MC04.21, third group formed by the strains TOD61, TOD 221, TOD302, and TOD111, and forth group formed by all strains isolated from plants sown in Cerrado soil, Brazil. As this last group was formed by strains isolated from sorghum and maize sown in the same soil (Cerrado) in Brazil, our results suggest that the diversity of these P. graminis strains is more affected by the soil type than the plant from where they have been isolated.

• Journal of Microbiology and Biotechnology
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• 제32권10호
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• pp.1275-1283
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• 2022

Understanding soil microbial community structure in the Arctic is essential for predicting the impact of climate change on interactions between organisms living in polar environments. The hypothesis of the present study was that soil microbial communities and soil chemical characteristics would vary depending on their associated plant species and local environments in Arctic mature soils. We analyzed soil bacterial communities and soil chemical characteristics from soil without vegetation (bare soil) and rhizosphere soil of three Arctic plants (Cassiope tetragona [L.] D. Don, Dryas octopetala L. and Silene acaulis [L.] Jacq.) in different local environments (coal-mined site and seashore-adjacent site). We did not observe any clear differences in microbial community structure in samples belonging to different plant rhizospheres; however, samples from different environmental sites had distinct microbial community structure. The samples from coal-mined site had a relatively higher abundance of Bacteroidetes and Firmicutes. On the other hand, Acidobacteria was more prevalent in seashore-adjacent samples. The relative abundance of Proteobacteria and Acidobacteria decreased toward higher soil pH, whereas that of Bacteroidetes and Firmicutes was positively correlated with soil pH. Our results suggest that soil bacterial community dissimilarity can be driven by spatial heterogeneity in deglaciated mature soil. Furthermore, these results indicate that soil microbial composition and relative abundance are more affected by soil pH, an abiotic factor, than plant species, a biotic factor.

• Mycobiology
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• 제44권4호
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• pp.277-282
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• 2016

In this study, we collected rhizosphere soils and root samples from a post-mining area and a natural forest area in Jecheon, Korea. We extracted spores of arbuscular mycorrhizal fungi (AMF) from rhizospheres, and then examined the sequences of 18S rDNA genes of the AMF from the collected roots of plants. We compared the AMF communities in the post-mining area and the natural forest area by sequence analysis of the AMF spores from soils and of the AMF clones from roots. Consequently, we confirmed that the structure of AMF communities varied between the post-mining area and the natural forest area and showed significant relationship with heavy metal contents in soils. These results suggest that heavy metal contamination by mining activity significantly affects the AMF community structure.

• Plant Resources
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• 제2권2호
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• pp.81-87
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• 1999

Sixteen isolates showing relatively strong antagonicity against the ginger rhizome rot pathogen, Pythium zingiberum, were selected among the 155 isolates from ginger rhizome surfaces and rhizospheres of ginger cultivation fields in Wanju, Chonbuk. The isolate, 'HB 26-5'showing the strongest antagonicity was finally selected by testing duration of inhibition effect and pathogenicity to ginger. The isolated antagonistic microorganism, 'HB 26-5' was rod shape, gram positive and formed endospore. The isolate produced acids utilizing glucose, arabinose, xylose and mannitol, and acetoin at VP test, and grew anaerobically. Temperature range for growth was from 10 to 4$0^{\circ}C$ . Reaction to catalase and gelatin, hydrolysis were positive, and casein hydrolysis and indol production were negative. Based on the mycological characters and the fatty acid composition, it was identified as Bacillus polymyxa. The pathogenicity test of isolated Bacillus polymyxa 'HB 26-5'on 22 crop cultivars resulted that only the lettuce was influenced in germination, and the others were not affected.

• Mycobiology
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• 제48권1호
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• pp.37-43
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• 2020

A serious leaf disease caused by Colletotrichum dematium was found during the cultivation of Sarcandra glabra in Jingxi, Rong'an, and Donglan Counties in Guangxi Province, which inflicted huge losses to plant productivity. Biological control gradually became an effective control method for plant pathogens. Many studies showed that the application of actinomycetes in biological control has been effective. Therefore, it may be of great significance to study the application of actinomycetes on controlling the diseases caused by S. glabra. Strains of antifungal actinomycetes capable of inhibiting C. dematium were identified, isolated and screened from healthy plants tissues and the rhizospheres in soils containing S. glabra. In this study, 15 actinomycetes strains were isolated and among these, strains JT-2F, DT-3F, and JJ-3F, appeared to show antagonistic effects against anthracnose of S. glabra. The strains JT-2F and DT-3F were isolated from soil, while JJ-3F was isolated from plant stems. The antagonism rate of strain JT-2F was 86.75%, which was the highest value among the three strains. Additionally, the JT-2F strain also had the strongest antagonistic activity when the antagonistic activities were tested against seven plant pathogens. Strain JT-2F is able to produce proteases and cellulase to degrade the protein and cellulose components of cell walls of C. dematium, respectively. This results in mycelia damage which leads to inhibition of the growth of C. dematium. Strain JT-2F was identified as Streptomyces tsukiyonensis based on morphological traits and 16S rDNA sequence analysis.

• The Plant Pathology Journal
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• 제28권1호
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• pp.68-74
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• 2012

Biocontrol microbes have mainly been screened among large collections of microorganisms $via.$ nutrient-rich $in$ $vitro$ assays to identify novel and effective isolates. However, thus far, isolates from only a few genera, mainly spore-forming bacilli, have been commercially developed. In order to isolate field-effective biocontrol microbes, we screened for more than 200 oligotrophic bacterial strains, isolated from rhizospheres of various soil samples in Korea, which induced systemic resistance against the soft-rot disease caused by $Pectobacterium$ $carotovorum$ SCC1; we subsequently conducted in $planta$ bioassay screening. Two oligotrophic bacterial strains were selected for induced systemic disease resistance against the $Tobacco$ $Mosaic$ $Virus$ and the gray mold disease caused by $Botrytis$ $cinerea$. The oligotrophic bacterial strains were identified as $Pseudomonas$ $manteilii$ B001 and $Bacillus$ $cereus$ C003 by biochemical analysis and the phylogenetic analysis of the 16S rRNA sequence. These bacterial strains did not exhibit any antifungal activities against plant pathogenic fungi but evidenced several other beneficial biocontrol traits, including phosphate solubilization and gelatin utilization. Collectively, our results indicate that the isolated oligotrophic bacterial strains possessing induced systemic disease resistance could provide useful tools as effective biopesticides and might be successfully used as cost-effective and preventive biocontrol agents in the field.

• Journal of Microbiology and Biotechnology
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• 제20권12호
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• pp.1605-1613
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• 2010

Twenty-nine P. polymyxa strains isolated from rhizospheres of various crops were clustered into five genotypic groups on the basis of BOX-PCR analysis. The characteristics of several plant growth-promoting factors among the isolates revealed the distinct attributes in each allocated group. Under gnotobiotic conditions, inoculation of pepper roots with P. polymyxa isolates significantly increased the biomass in 17 of total 29 treated plants with untreated plants. Experiments on induced systemic resistance (ISR) against bacterial spot pathogen Xanthomonas axonopodis pv. vesicatoria in pepper by P. polymyxa strains were conducted and only one isolate (KNUC265) was selected. Further studies into ISR mediation by the KNUC265 strain against the soft-rot pathogen Erwinia carotovora subsp. carotovora in tobacco demonstrated that the tobacco seedlings exposed to either bacterial volatiles or diffusible metabolites exhibited a reduction in disease severity. In conclusion, ISR and plant growth promotion triggered by P. polymyxa isolates were systemically investigated on pepper for the first time. The P. polymyxa KNUC265 strain, which elicited both ISR and plant growth promotion, could be potentially used in improving the yield of pepper and possibly of other crops.