• 한국응용과학기술학회지
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• 제37권6호
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• pp.1489-1495
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• 2020

Gotjawal, Jeju Island, Korea is a lava-formed forest with low soil content that is unique in the world. Around 6 percent of the Jeju Iand is classified as a lava-based specific forest. The forest has been gradually disappearing during the last several decades, with approximately one half having been destroyed. Our study undertakes a detailed analysis of the landscape of the lava subsidence, and describes the fungi, vegetation, and soils of Cheongsu Gotjawal. Soil samples from the Gotjawal were collected, and soil analyses as well as pyrosequencing of the internal transcribed spacer gene for fungal communities were performed. Soil fungal communities are represented by Discisedars, Fusarium, Pleochaeta, and Fuscoporia genera. Endemic vegetation of the Gotjawal includes the plants Pleris critical, Machilus japonica, Quercus glauca, Arachniodes aristata, and Neocheiropteris ensata. Results of soil analysis indicate sandy loam with 31.70% organic matter, and 1.36 mg/kg of total nitrogen. This fundamental information can help understand the invaluable and unique nature of Cheongsu Gotjawal, and the necessity for more studies on Gotjawal.

• 한국균학회지
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• 제49권1호
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• pp.109-118
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• 2021

국내 석회암지대에 서식하는 참나무류의 뿌리에서 외생균근균(ectomycorrhizal fungi, ECM)의 다양성을 분석하였다. 분자분석을 통해 참나무류에 공생하고 있는 45속의 ECM을 확인하였다. ECM의 종 다양성 지수는 pH, 칼슘 농도, 유효인산 농도가 증가할수록 감소하는 경향을 보였고, 전질소 함량과 유기물 함량이 증가할수록 증가하는 경향을 보였다. 군집분석 결과 석회토양의 특징인 pH와 칼슘 농도와 양의 상관관계를 갖는 ECM은 Sebacina, Tomentella, Tuber, Densospora, Inocybe, Suillus, Piloderma속에 속하는 균주들 이였으며, 이들은 토양 안정성이 약화된 석회암지대의 생태복원에 활용될 수 있을 것으로 판단된다.

• Journal of Ecology and Environment
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• 제41권9호
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• pp.271-280
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• 2017

Background: Soil microorganisms play key roles in nutrient cycling and are distributed throughout the soil profile. Currently, there is little information about the characteristics of the microbial communities along the soil depth because most studies focus on microorganisms inhabiting the soil surface. To better understand the functions and composition of microbial communities and the biogeochemical factors that shape them at different soil depths, we analyzed microbial activities and bacterial and fungal community composition in soils up to a 120 cm depth at a fallow field located in central Korea. To examine the vertical difference of microbial activities and community composition, ${\beta}$-1,4-glucosidase, cellobiohydrolase, ${\beta}$-1,4-xylosidase, ${\beta}$-1,4-N-acetylglucosaminidase, and acid phosphatase activities were analyzed and barcoded pyrosequencing of 16S rRNA genes (bacteria) and internal transcribed spacer region (fungi) was conducted. Results: The activity of all the soil enzymes analyzed, along with soil C concentration, declined with soil depth. For example, acid phosphatase activity was $125.9({\pm}5.7({\pm}1SE))$, $30.9({\pm}0.9)$, $15.7({\pm}0.6)$, $6.7({\pm}0.9)$, and $3.3({\pm}0.3)nmol\;g^{-1}\;h^{-1}$ at 0-15, 15-30, 30-60, 60-90, and 90-120 cm soil depths, respectively. Among the bacterial groups, the abundance of Proteobacteria (38.5, 23.2, 23.3, 26.1, and 17.5% at 0-15, 15-30, 30-60, 60-90, and 90-120 cm soil depths, respectively) and Firmicutes (12.8, 11.3, 8.6, 4.3, and 0.4% at 0-15, 15-30, 30-60, 60-90, and 90-120 cm soil depths, respectively) decreased with soil depth. On the other hand, the abundance of Ascomycota (51.2, 48.6, 65.7, 46.1, and 45.7% at 15, 30, 60, 90, and 120 cm depths, respectively), a dominant fungal group at this site, showed no clear trend along the soil profile. Conclusions: Our results show that soil C availability can determine soil enzyme activity at different soil depths and that bacterial communities have a clear trend along the soil depth at this study site. These metagenomics studies, along with other studies on microbial functions, are expected to enhance our understanding on the complexity of soil microbial communities and their relationship with biogeochemical factors.

• Mycobiology
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• 제47권2호
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• pp.180-190
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• 2019

In this study, eight-month-old ectomycorrhizae of Tuber borchii with Corylus avellana were synthesized to explore the influence of T. borchii colonization on the soil properties and the microbial communities associated with C. avellana during the early symbiotic stage. The results showed that the bacterial richness and diversity in the ectomycorrhizae were significantly higher than those in the control roots, whereas the fungal diversity was not changed in response to T. borchii colonization. Tuber was the dominant taxon (82.97%) in ectomycorrhizae. Some pathogenic fungi, including Ilyonectria and Podospora, and other competitive mycorrhizal fungi, such as Hymenochaete, had significantly lower abundance in the T. borchii inoculation treatment. It was found that the ectomycorrhizae of C. avellana contained some more abundant bacterial genera (e.g., Rhizobium, Pedomicrobium, Ilumatobacter, Streptomyces, and Geobacillus) and fungal genera (e.g., Trechispora and Humicola) than the control roots. The properties of rhizosphere soils were also changed by T. borchii colonization, like available nitrogen, available phosphorus and exchangeable magnesium, which indicated a feedback effect of mycorrhizal synthesis on soil properties. Overall, this work highlighted the interactions between the symbionts and the microbes present in the host, which shed light on our understanding of the ecological functions of T. borchii and facilitate its commercial cultivation.

• Mycobiology
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• 제48권5호
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• pp.392-398
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• 2020

This study was conducted to understand the dynamics of microbial communities of soil microorganisms, and their distribution and abundance in the indigenous microorganisms (IMOs) manipulated from humus collected from the forest near the crop field. The soil microorganisms originated from humus and artificially cultured microbial-based soil amendments were characterized by molecular and biochemical analyses. The bacterial population (2 × 10⁶~13 × 10⁶ CFU/g sample) was approximately 100-fold abundant than the fungal population (2 × 10⁴~8 × 10⁴ CFU/g sample). The 16S rDNA and ITS sequence analyses showed that the bacterial and fungal communities in humus and IMOs were mainly composed of Bacillus and Pseudomonas, and Trichoderma and Aspergillus species, respectively. Some of the bacterial isolates from the humus and IMOs showed strong inhibitory activity against soil-borne pathogenic fungi Fusarium oxysporum and Sclerotinia sclerotiorum. These bacteria also showed the siderophore production activity as well as phosphate solubilizing activity, which are requisite traits for biological control of plant pathogenic fungi. These results suggest that humus and IMOs could be a useful resource for sustainable agriculture.

• The Plant Pathology Journal
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• 제40권5호
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• pp.498-511
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• 2024

Bacterial wilt caused by Ralstonia solanacearum is a destructive disease that affects potato production, leading to severe yield losses. Currently, little is known about the changes in the assembly and functional adaptation of potato rhizosphere microbial communities during different stages of R. solanacearum infection. In this study, using amplicon and metagenomic sequencing approaches, we analyzed the changes in the composition and functions of bacterial and fungal communities in the potato rhizosphere across four stages of R. solanacearum infection. The results showed that R. solanacearum infection led to significant changes in the composition and functions of bacterial and fungal communities in the potato rhizosphere, with various microbial properties (including α,β-diversity, species composition, and community ecological functions) all being driven by R. solanacearum infection. The relative abundance of some beneficial microorganisms in the potato rhizosphere, including Firmicutes, Bacillus, Pseudomonas, and Mortierella, decreased as the duration of infection increased. Moreover, the related microbial communities played a significant role in basic metabolism and signal transduction; however, the functions involved in soil C, N, and P transformation weakened. This study provides new insights into the dynamic changes in the composition and functions of potato rhizosphere microbial communities at different stages of R. solanacearum infection to adapt to the growth promotion or disease suppression strategies of host plants, which may provide guidance for formulating future strategies to regulate microbial communities for the integrated control of soil-borne plant diseases.

• 한국균학회소식:학술대회논문집
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• 한국균학회 2014년도 추계학술대회 및 정기총회
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• pp.50-50
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• 2014

In this study, we used pyrosequencing method to analysis of soil fungal communities on the Ulleungdo and Dokdo islands. 768 operational taxonomic units (OTUs) were analyzed from the Ulleungdo sample and 640 OTUs and 382 OTUs were analyzed from the Dongdo and Seodo samples, respectively. Compared to the species richness of Ulleungdo and the Dokdo sample, the Ulleungdo sample was higher than in the Dongdo and Seodo samples. Species diversity was much the same. The phylum Basidiomycota was dominant in the Ulleungdo sample, while the phylum Ascomycota was dominant in the Dongdo sample.

• Journal of Plant Biotechnology
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• 제44권2호
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• pp.156-163
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• 2017

A greenhouse experiment was conducted for evaluation of ecological effects of transgenic melon plants in the rhizospheric soil in terms of soil properties, enzyme activities and microbial communities. Organic matter content of soil under transgenic melon plants was significantly higher than that of soil with non-transgenic melon plants. Significant variations were observed in organic matter, total P and K in soil cultivation with transgenic melon plants. There were also significant variations in the total numbers of colony forming units of fungi, actinomycetes and bacteria between soils treated with transgenic and non-transgenic melon plants. Transgenic and non-transgenic melon significantly enhanced several enzymes activities including urease, acid phosphatase, alkalin phosphatase, arysulphtase, ${\beta}$ glucosidase, dehydrogenase, protease and catalase. Soil polyphenoloxidase activity of $T_1$ transgenic melon was lower than that of $T_0$ transgenic melon and a non-melon plant during the same period. The first generation transgenic melon plants ($T_0$) showed significantly greater (p<0.05) effect on the activitiy of arylsulfatase, which increased from $2.540{\times}10^6CFU\;g^{-1}$ (control) to $19.860{\times}10^6CFU\;g^{-1}$ ($T_0$). These results clearly indicated that transgenic melon might change microbial communities, enzyme activities and soil chemical properties.

• 생명과학회지
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• 제31권4호
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• pp.377-384
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• 2021

진달래(Rhododendron mucronulatum)는 우리나라에서 어렵지 않게 볼 수 있는 개화식물로 꽃이 아름다워 관상목으로 이용되고 있고 생태학적, 약리적으로 잠재력이 있는 중요한 산림자원이다. 우리나라의 대표적 진달래나무군락지인 비슬산군립공원에서 진달래나무 아래의 토양을 채집하여 그 진균 군집의 특성을 조사하였다. 위치와 계절에 따른 진균 군집의 차이를 확인하기 위하여 토양 샘플은 총 3개의 위치에서 2월과 8월에 각각 한번씩 채집하였다. Pyrosequencing을 통해 총 454,157개의 서열을 얻을 수 있었다. 첫번째 채집포인트에서 얻은 샘플의 진균 군집이 6개 샘플 중 가장 종 풍부도가 높았고 가장 다양한 진균들로 구성되어 있음을 확인하였다. 분류 단위 별 분석으로는, Basidiomycota, Ascomycota, Mortierellomycota가 대표적인 문(phylum)으로 나타났으며, Agaricales_f, Mortierellaceae, Clavariaceae가 주요한 과(family)인 것으로 분석되었다. Mortierella 속(genus)은 모든 샘플중에서 가장 우점한 속이었다. 또한 총 진달래와 관련이 있는 것으로 추정되는 19개의 속이 확인되었다. 8월에 채집한 샘플에서 위치에 따라 각각 109개, 111개, 112개의 특이적인 속이 발견되었고, 2월의 샘플과 비교했을 때 2월의 샘플에는 존재하지 않는 28개의 공통된 속이 발견되었다. 이 연구는 추후 진달래나무에 특이적인 진균의 새로운 종을 규명하거나 토양 진균류와 식물의 상호작용을 규명하는 기초자료로 활용될 수 있다.

• 한국환경농학회지
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• 제39권1호
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• pp.65-74
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• 2020

BACKGROUND: Soil carbon sequestration has been investigated for a long time because of its potential to mitigate the greenhouse effect. No- or reduced tillage, crop rotations, or cover crops have been investigated and practiced to sequester carbon in soils but the roles of soil biota, particularly microorganisms, have been mostly ignored although they affect the amount and stability of soil organic matters. METHODS AND RESULTS: In this study we analyzed the organic matter and microbial community in organically cultivated corn field soils where no-tillage (NT) or conventional tillage (CT) had been practiced for about three years. The amounts of organic matter and recalcitrant carbon pool were 18.3 g/kg dry soil and 4.1 g C/kg dry soil, respectively in NT soils, while they were 12.4 and 2.5, respectively in CT soils. The amounts of RNA and DNA, and the copy numbers of bacterial 16S rRNA genes and fungal ITS sequences were higher in NT soils than in CT soils. No-tillage treatment increased the diversities of soil bacterial and fungal communities and clearly shifted the bacterial and fungal community structures. In NT soils the relative abundances of bacterial phyla known as copiotrophs, Betaproteobacteria and Bacteroidetes, increased while those known as oligotrophs, Acidobacteria and Verrucomicrobia, decreased compared to CT soils. The relative abundance of a fungal phylum, Glomeromycota, whose members are known as arbuscular mycorrhizal fungi, was about two time higher in NT soils than in CT soils, suggesting that the higher amount of organic matter in NT soils is related to its abundance. CONCLUSION: This study shows that no-tillage treatment greatly affects soil microbial abundance and community structure, which may affect the amount and stability of soil organic matter.