• 한국환경농학회지
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• 제38권3호
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• pp.197-204
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• 2019

BACKGROUND: Living modified microorganisms (LMMs) have been focused in two very different aspects of positive and negative effects on ecology and human health. As a model experiment, wild type and a foreign origin gene-harboring modified E. coli strains were subjected to comparison of their metabolomes and potential effects on soil microbiota in the laboratory sets. This study assumes the unintentional release of LMMs and tries to suggest potential effects on the soil microbiota even at minimal settings. METHODS AND RESULTS: Metabolomes from the wild type and LM E. coli were analyzed by NMR and the profiles were compared. In the laboratory soil experiments, the two types of E. coli were added to the soils and monitored for the bacterial community compositions. Those metabolomic profiles did not show significant differences. The microbial community structures from the time series soil DNAs for both the sets using wild type and LMO also did not indicate significant changes, but minor by the addition of foreign organisms regardless of wild or LMO. CONCLUSION: Even if the recombinant microorganism (LMO) is released into the soil environment, the survival of microorganisms in the environment would be one of the major factors for the transfers of foreign genes to other organisms and diffusion into the soil environment.

• Journal of Microbiology and Biotechnology
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• 제29권10호
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• pp.1624-1628
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• 2019

Banana planting altered microbial communities and induced the enrichment of Fusarium oxysporum in rhizosphere compared with that of forest soil. Diseased plant rhizosphere soil (WR) harbored increased pathogen abundance and showed distinct microbial structures from healthy plant rhizosphere soil (HR). The enriched taxon of Bordetella and key taxon of Chaetomium together with some other taxa showed negative associations with pathogen in HR, indicating their importance in pathogen inhibition. Furthermore, a more stable microbiota was observed in HR than in WR. Taken together, the lower pathogen abundance, specific beneficial microbial taxa and stable microbiota contributed to disease suppression.

• Mycobiology
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• 제48권1호
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• pp.20-28
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• 2020

Soil degradation can have an impact on the soil microbiota, but its specific effects on soil fungal communities are poorly understood. In this work, we studied the impact of soil degradation on the richness and diversity of communities of soil fungi, including three different degrees of degradation in Germany and Panama. Soil fungi were isolated monthly using the soil-sprinkling method for 8 months in Germany and 3 months in Panama, and characterized by morphological and molecular data. Soil physico-chemical properties were measured and correlated with the observed values of fungal diversity. We isolated a total of 71 fungal species, 47 from Germany, and 32 from Panama. Soil properties were not associated with fungal richness, diversity, or composition in soils, with the exception of soil compaction in Germany. The geographic location was a strong determinant of the soil fungal species composition although in both countries there was dominance by members of the orders Eurotiales and Hypocreales. In conclusion, the results of this work do not show any evident influence of soil degradation on communities of soil fungi in Germany or Panama.

• 한국환경과학회지
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• 제30권12호
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• pp.1015-1025
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• 2021

Our research work aimed to evaluate cover crop effects of winter rye on soil characteristics, soil conservation, and yield productivities on potato fields with 15% slope during a fallowed period. There were two controls of bared field without any cultivation and conventional potato cultivation without winter rye. Potato cultivation increased soil pH, organic matter, available phosphate, and exchangeable cation regardless of cover crop cultivation. Sub-soil, particularly, all components of soil chemical properties showed higher value in winter rye cultivation than conventional cultivation. Higher soil density was observed on cover crop cultivation than conventional cultivation resulting from root residues of the cover crop both topsoil and subsoil. Cover crop residues positively affected plant growth and reduced the amount of soil erosion by holding the soil. Although severe soil erosion was seen in conventional cultivation, winter rye cultivation declined soil erosion by 47% during the fallow period on potato slope fields. Distinct soil bacterial communities were detected among treatments and some OTU(Operational Taxonomic Unit)s showed significantly higher abundance in winter rye treatment. Total yield and commercial rate demonstrated no significant differences while higher tuber phosphate, K⁺, and Mg²⁺ contents were observed in winter rye cultivation.

• 한국환경농학회지
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• 제35권1호
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• pp.32-38
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• 2016

본 연구는 상승온도가 벼재배나 볏짚 및 요소 투입과의 복합작용을 통해 토양미생물에 미치는 영향에 대한 평가를 하였다. 상승온도에 의해 토양이화학성이 부분적으로 영향을 받았으며, 이러한 환경변화는 토양미생물에 간접적인 영향을 줄것으로 판단된다. 온도가 전체 토양미생물 밀도에 미치는 효과는 크지 않았으며, 방선균만 온도의 증가로 감소하였기 때문에 미생물 군집구성이 온도변화에 의해 부분적으로만 영향을 받았다는 것을 보여준다. 또한, 벼 재배에 의해 전체 PLFA 수치가 1.3배 증가하였다는 것은 식물이 토양미생물에 크게 영향을 미칠 수 있는 인자라는 것을 의미한다. 따라서 이러한 미생물 밀도 및 군집 변화가 물질순환이나 토양의 기능성에 미치는 영향에 대한 추가적인 검토가 필요할 것으로 생각된다.

• 한국균학회지
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• 제51권4호
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• pp.447-460
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• 2023

식물병원 세균 Erwinia amylovora 의해 발생하는 과수화상병은 사과, 배 등 장미과에 속하는 식물에 심한 피해를 주고 있다. 병의 빠른 확산을 막기 위해 국내에서는 병이 발생한 사과나무와 배나무에 대해 매몰하는 병관리를 실시해 왔다. 방제방법의 안전성을 입증하기 위해 매몰한 이병식물과 이병식물 주변의 토양을 조사하였다. 매몰토양 미생물군 조사과정에서 Bisifusarium allantoides, Botryotrichum Domesticum, Microascus verrucosus, Paraphoma pye, Phaeosphaeria culmorum, Ramophialophora globispora, Sordaria tomentoalba, Striaticonidium brachysporum 등이 국내 미기록종으로 확인되었다. 이에 이들 8종 진균에 대한 형태학적, 분자유전학적 특성을 보고한다.

• 한국환경과학회지
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• 제30권5호
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• pp.379-389
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• 2021

Soil microorganism activity in an agricultural field is affected by various factors including climate conditions, soil chemical properties, and crop cultivation. In this study, we elucidate the correlation between microorganism activity and agricultural environment factors using the dehydrogenase activity (DHA) value, which is one of the indicators of soil microbial activity. As a result, the various factors noted above were related to the DHA value. Annual rainfall, soil Mg2+, bacterial and fungal diversities, types of crops, developmental stages, seasons, and cultivation status were highly correlated with the DHA value. Furthermore, next-generation sequencing (NGS) analysis was used to identify that the type of crop affected soil microbial compositions of both bacteria and fungi. Soil used for soybean cultivation showed the highest relative abundance for Verrucomicrobia, Planctomycetes, and Acidobacteria but Actinobacteria and Firmicutes had the lowest relative abundance. In the case of soil used for potato cultivation, Actinobacteria had the highest relative abundance but Proteobacteria had the lowest relative abundance. Armatimonadetes showed the highest relative abundance in soil used for cabbage cultivation. Among the fungal communities, Mortierellomycota had the highest relative abundance for soybean cultivation but the lowest relative abundance for cabbage cultivation; further, Rozellomycota, Chytridiomycota, and Cercozoa had the highest relative abundance for cabbage cultivation. Basidiomycota had the highest relative abundance for potato cultivation but the lowest relative abundance for soybean cultivation.

• 한국토양비료학회지
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• 제45권4호
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• pp.593-601
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• 2012

Heavy metals and metalloids removal can be considered as one of the most important world challenges because of their toxicity and direct impact on human health. Many processes have been introduced but biological processes of remediation seem to offer the most suitable solution in terms of efficiency and low cost. Actinobacteria constitute one of the major microbial populations in soil, and this can be attributed to their adaptive morphological structure as well as their exceptional metabolic power. Among microbes, actinobacteria are morphologic intermediate between fungi and bacteria. Studies on microbial diversities in metal contaminated lands have shown that actinobacteria may constitute a dominantly active microbiota in addition to ${\alpha}$ Proteobacteria. Furthermore, isolation studies have shown metal removal mechanisms which are reminiscent of notable multiresistant strains, such as Cupriavidus metallidurans. Apart from members of genus Streptomyces, which produce more than 90% of commercialized antibiotics, and the nitrogen fixing Frankia, little attention has been given to other members of this phylum. This is because of difficult culture condition requirements and maintenance. In this review, we focused on specific isolation of actinobacteria and their potential applications in metal bioremediation and plant growth promotion.

• 한국토양비료학회지
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• 제44권1호
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• pp.58-66
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• 2011

Arsenic pollution is a serious global concern which affects all life forms. Being a toxic metalloid, the continued search for appropriate technologies for its remediation is needed. Phytoremediation, the use of green plants, is not only a low cost but also an environmentally friendly approach for metal uptake and stabilization. However, its application is limited by slow plant growth which is further aggravated by the phytotoxic effect of the pollutant. Attempts to address these constraints were done by exploiting plant-microbe interactions which offers more advantages for phytoremediation. Several bacterial mechanisms that can increase the efficiency of phytoremediation of As are nitrogen fixation, phosphate solubilization, siderophore production, ACC deaminase activity and growth regulator production. Many have been reported for other metals, but few for arsenic. This mini-review attempts to present what has been done so far in exploring plants and their rhizosphere microbiota and some genetic manipulations to increase the efficiency of arsenic soil phytoremediation.

• Mycobiology
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• 제50권6호
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• pp.429-438
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• 2022

Two fungal strains belonging to Ascomycota were discovered in Gyeonggi-do, Korea, during this investigation of soil microfungi and microbiota of insects. The strain KNUF-20-047 produced milky white on the back and a milky creamy center to white toward the margin on the front side of colonies. Conversely, the closest Xenoacremonium falcatus displayed a pale luteous to luteous center, white toward margins on the front side, and pale luteous or luteous pigment on the back side, whereas X. recifei produced white colonies. The conidiophores of KNUF-20-047 were slightly larger than those of X. falcatus, and the conidia were distinct from X. recifei. Strain KNUF-20-NI-005 produced light brown to subhyaline conidiophores up to 56.0 lm tall, whereas Rhinocladiella anceps displayed golden to dark brown conidiophores up to 350 lm. Strain KNUF-20-NI-005 also produced larger conidia than R. anceps but smaller than R. coryli and R. fasciculata. Moreover, the molecular phylogeny strongly supports the detailed description and illustration of each proposed species to be designated as Xenoacremonium minutisporum sp. nov. and Rhinocladiella terrigenum sp. nov. in Korea.