• Mycobiology
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• 제42권1호
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• pp.66-72
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• 2014

Roselle (Hibiscus sabdariffa L.) family Malvaceae is an important crop used in food, cosmetics and pharmaceutics industries. Roselle is cultivated mainly in Upper Egypt (Qena and Aswan governorates) producing 94% of total production. Root rot disease of roselle is one of the most important diseases that attack both seedlings and adult plants causing serious losses in crop productivity and quality. The main objective of the present study is to identify and characterize pathogens associated with root rot and wilt symptoms of roselle in Qena, Upper Egypt and evaluate their pathogenicity under greenhouse and field condition. Fusarium oxysporum, Macrophomina phaseolina, Fusarium solani, Fusarium equiseti and Fusarium semitectum were isolated from the natural root rot diseases in roselle. All isolated fungi were morphologically characterized and varied in their pathogenic potentialities. They could attack roselle plants causing damping-off and root rot/wilt diseases in different pathogenicity tests. The highest pathogenicity was caused by F. oxysporum and M. phaseolina followed by F. solani. The least pathogenic fungi were F. equiseti followed by F. semitectum. It obviously noted that Baladi roselle cultivar was more susceptible to infection with all tested fungi than Sobhia 17 under greenhouse and field conditions. This is the first report of fungal pathogens causing root rot and vascular wilt in roselle in Upper Egypt.

• The Plant Pathology Journal
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• 제23권4호
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• pp.295-299
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• 2007

These experiments were carried out to examine efficacy of soil solarization for control of pink root disease by means of mulching with transparent polyethylene sheets in the hot season. The effects of soil solarization on incidence of pink-root disease caused by Pyrenochaeta terrestris and on onion growth and on populations of soil fungi were investigated. Solarization was dramatically effective in reducing pink root incidence in onion seedling and harvested onion bulb. A 30-day and 40-day solarization treatment significantly improved seedling survival and increased yield of 'Changnyeong-deago' onion while decreasing incidence of pink root. Populations of soil fungi from fields planted to onion were assayed on selective media. Solarization treatment was effective in reducing populations of P. terrestris, Pythium spp., and Rhizoctonia sp. in soil. Increase of yield of onion bulbs was associated with control of soil-borne pathogenic fungi. Soil solarization had beneficial effects on yield, bulb diameter, or incidence of pink root.

• Mycobiology
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• 제46권1호
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• pp.13-23
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• 2018

Depending on the mode of nutrition exploitation, major fungal guilds are distinguished as ectomycorrhizal and saprotrophic fungi. It is generally known that diverse environmental factors influence fungal communities; however, it is unclear how fungal communities respond differently to environment factors depend on fungal guilds. In this study, we investigated basidiomycetes communities associated with Quercus mongolica using 454 pyrosequencing. We attempted to detect guild pattern (ectomycorrhizal or saprotrophic fungal communities) by comparing the influence of geography and source (root and surrounding soil). A total of 515 mOTUs were detected from root (321) and soil (394) of Q. mongolica at three sites of Mt. Jeombong in Inje County. We found that patterns of diversity and community structure were different depending on the guilds. In terms of alpha diversity, only ectomycorrhizal fungi showed significant differences between sources. In terms of community structure, however, geography significantly influenced the ectomycorrhizal community, while source appeared to have a greater influence on the saprotrophic community. Therefore, a guildbased view will help to elucidates novel features of the relationship between environmental factors and fungal communities.

• 한국토양비료학회지
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• 제45권4호
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• pp.582-592
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• 2012

Microorganisms present in the rhizosphere soil plays a vital role in improving the plant growth and soil fertility. Many kinds of fertilizers including chemical and organic has been approached to improve the productivity. Though some of them showed significant improvement in yield, they failed to maintain the soil properties. Rather they negatively affected soil eventually, the land became unsuitable for agricultural. To overcome these problems, microorganisms have been used as effective alternative. For past few decades, plant growth promoting rhizobacteria (PGPR) and arbuscular mycorrhizal fungi (AMF) have been used as effective inoculants to enhance the plant growth and productivity. PGPR improves the plant growth and helps the plant to withstand biotic and abiotic stresses. AM fungi are known to colonize roots of plants and they increase the plant nutrient uptake. Spore associated bacteria (SAB) are attached to spore wall or hyphae and known to increase the AMF germination and root colonization but their mechanism of interaction is poorly known. Better understanding the interactions among AMF, SAB and PGPR are necessary to enhance the quality of inoculants as a biofertilizers. In this paper, current knowledge about the interactions between fungi and bacteria are reviewed and discussed about AMF spore associated bacteria.

• Mycobiology
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• 제49권3호
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• pp.235-248
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• 2021

This study aimed to understand whether the geo-ecological segregation of native plant species affects the root-associated fungal community. Rhizoplane (RP) and rhizosphere (RS) fungal microbiota of Sedum takesimense native to three geographically segregated coastal regions (volcanic ocean islands) were analyzed using culture-independent methods: 568,507 quality sequences, 1399 operational taxonomic units, five phyla, and 181 genera were obtained. Across all regions, significant differences in the phyla distribution and ratio were confirmed. The Chao's richness value was greater for RS than for RP, and this variance coincided with the number of genera. In contrast, the dominance of specific genera in the RS (Simpson value) was lower than the RP at all sites. The taxonomic identity of most fungal species (95%) closely interacting with the common host plant was different. Meanwhile, a considerable number of RP only residing fungal genera were thought to have close interdependency on their host halophyte. Among these, Metarhizium was the sole genus common to all sites. These suggest that the relationship between potential symbiotic fungi and their host halophyte species evolved with a regional dependency, in the same halophyte species, and of the same natural habitat (volcanic islands); further, the fungal community differenced in distinct geographical regions. Importantly, geographical segregation should be accounted for in national culture collections, based on taxonomical uniqueness.

• 한국균학회지
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• 제42권4호
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• pp.269-275
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• 2014

7종의 자생 염생식물은 천일사초, 갯질경, 퉁퉁마디, 나문재, 칠면초, 해홍나물, 그리고 지채로서 태안반도에서 채집되었다. 염생식물의 뿌리로부터 분리된 37균주의 내생진균은 ITS영역 염기서열에 대하여 분석하였다. 모든 내생진균들은 다양성 지수들을 이용하여 분석되었다. 분리된 내생진균은 Eurotiales (78%), Capnodiales (5%), Hypocreales (5%), Agaricales (3%), Corticiales (3%), Glomerellales (3%), Pleosporales (3%)으로 7개 목으로 분류되었다. 그리고 분리된 내생진균의 속을 분석한 결과 자낭균문과 담자균문에 포함되는 Alternaria, Aspergillus, Cladosporium, Paecilomyces, Penicillium, Phanerochaete, Schizophyllum, Talaromyces, Verticillium등 9개 속으로 분류되었다. 내생진균을 분석하였을 때, Penicillium이 염생식물로부터 가장 많이 분포하고 있었다. 본 연구는 태안반도에 자생하는 염생식물들에 대한 내생진균의 분포와 다양성을 분석하였다.

• Journal of Microbiology and Biotechnology
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• 제24권3호
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• pp.324-333
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• 2014

The Black Pine, Pinus thunbergii, is widely distributed along the eastern coast of Korea and its importance as a shelterbelt was highlighted after tsunamis in Indonesia and Japan. The root endophytic diversity of P. thunbergii was investigated in three coastal regions; Goseong, Uljin, and Busan. Fungi were isolated from the root tips, and growth rates of pure cultures were measured and compared between PDA with and without 3% NaCl to determine their saline resistance. A total of 259 isolates were divided into 136 morphotypes, of which internal transcribed spacer region sequences identified 58 species. Representatives of each major fungi phylum were present: 44 Ascomycota, 8 Zygomycota, and 6 Basidiomycota. Eighteen species exhibited saline resistance, many of which were Penicillium and Trichoderma species. Shoreline habitats harbored higher saline-tolerant endophytic diversity compared with inland sites. This investigation indicates that endophytes of P. thunbergii living closer to the coast may have higher resistance to salinity and potentially have specific relationships with P. thunbergii.

• Mycobiology
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• 제34권4호
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• pp.185-190
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• 2006

Endophytic fungi were isolated from healthy leaf and root samples of Taraxacum coreanum. Of the 72 isolates recovered, 39 were from leaves and 33 from roots with an isolation frequency of 54% and 46%, respectively. Based on ITS sequence analysis, 72 isolates were classified into 19 genera of which 17 were under the phylum Ascomycota and 2 were under Basidiomycota. Diverse genera were found and Alternaria, Cladosporium, Fusarium and Phoma were dominant. Out of 19 genera, Apodus, Ceriporia, Dothideales, Leptodontidium, Nemania, Neoplaconema, Phaeosphaeria, Plectosphaerella and Terfezia were new to Korea. Seventy two isolates were screened for antifungal activity, of which 10 isolates (14%) were found active at least against one of the tested fungi. Isolate 050603 had the widest antifungal spectra of activity, and isolates 050592 and 050611 were active against three plant pathogenic fungi.

• Journal of Microbiology and Biotechnology
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• 제29권1호
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• pp.105-113
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• 2019

Although siderophore compounds are mainly biosynthesized as a response to iron deficiency in the environment, they also bind with other metals. A few studies have been conducted on the impact of heavy metals on the siderophore-mediated iron uptake by microbiome. Here, we investigated siderophore production by a variety of rhizosphere fungi under different concentrations of $Zn^{2+}$ ion. These strains were specifically isolated from the rhizosphere of Panax ginseng (Korean ginseng). The siderophore production of isolated fungi was investigated with chrome azurol S (CAS) assay liquid media amended with different concentrations of $Zn^{2+}$ (50 to $250{\mu}g/ml$). The percentage of siderophore units was quantified using the ultra-violet (UV) irradiation method. The results indicated that high concentrations of $Zn^{2+}$ ion increase the production of siderophore in iron-limited cultures. Maximum siderophore production by the fungal strains was detected at $Zn^{2+}$ ion concentration of $150{\mu}g/ml$ except for Mortierella sp., which had the highest siderophore production at $200{\mu}g/ml$. One potent siderophore-producing strain (Penicillium sp. JJHO) was strongly influenced by the presence of $Zn^{2+}$ ions and showed high identity to P. commune (100% using 18S-rRNA sequencing). The purified siderophores of the Penicillium sp. JJHO strain were chemically identified using UV, Fourier-transform infrared spectroscopy (FTIR), and matrix-assisted laser desorption/ionization time-of-flight mass spectrometer (MALDI-TOF-MS) spectra.

• Journal of Forest and Environmental Science
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• 제15권1호
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• pp.77-88
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• 1999

소나무류의 뿌리나 토양에서 분리된 균근균의 배양특성 비교와 인공접종에 의한 소나무 묘목에의 균근형성을 시도하였다. 소나무류 균근균은 다양한 생장특성을 지니고 있었는데, 배지별 생장에서 민자주방망이버섯(Ln73/92)은 PDA 에서, Paxillus sp.는 FDA 에서, 알버섯(FRI91017)은 Hagem배지에서, 나머지 균근균들은 MP배지에서 생장이 양호하였다. 용도나 pH를 달리한 배양조건에서 대부분의 균근균들은 $25^{\circ}C$에서 생장이 양호하였으나 모래밭버섯(FRI91004와 Pt 1)은 $30^{\circ}C$가 최적온도였고, pH도 균근균의 종류에 따라 약산성에서부터 약알칼리성에 이르기까지 최적 pH가 다양하였다. 생장시에 선호하는 탄소원의 종류도 균근균의 종류에 따라 다양하였으나 탄소원으로 xylose를 첨가한 배지에서는 모든 균근균의 생장이 불량하였다. 질소원은 $KNO_3$ 또는 asparagine을 선호하는 종류가 많았고 urea를 첨가한 배지에서는 거의 모든 균근균이 생장하지 못하였다. 균근균을 해송묘목에 인공접종하여 균근균을 형성시킨 결과, 모래밭버섯인 Pt1균주만 3개월만에 성공적으로 균근을 형성하여 외생균근의 전형적인 특징인 두꺼운 균사막으로 덮인 분지된 세근이 관찰되었으며 조직염색법에 의해 처리된 균근형성뿌리의 횡단절단면을 Nomarski interference microscope로 관찰하여 표피세포에 형성된 fungal mantle과 피층세포에 형성된 Hartig net을 확인하였다.