• Applied Biological Chemistry
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• v.49 no.4
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• pp.259-265
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• 2006

Effect of the fungicide mepanipyrim on the resistant and sensitive isolates of Botrytis cinerea was studied in vitro and also tested to control Botrytis rot of strawberry, cucumber and grape in the field. These isolates were selected by relative mycelial growth and spore germination on potato dextrose agar(PDA) incorporated with $100{\mu}g\;a.i./ml$ of benomyl and procymidone, respectively, compared to the unamended PDA. Mycelial growth of the selected resistant isolates was significantly inhibited by mepanipyrim but the inhibition rate was similar to other fungicides belong to benzimidazole or dicarboximide, although spore germination was not inhibited even by the higher concentration of mepanipyrim. When the benomyl and procymidone resistant isolates were inoculated to cucumber leaves, lesion development was significantly inhibited with application of $250{\mu}g\;a.i./ml$ of mepanipyrim but not with that of benomyl and procymidone. In addition, when $250{\mu}g\;a.i./ml$ of mepanipyrim was applied to strawberry, cucumber, and grape in the field, the control of Botrytis rot was significantly different from that of the untreated control(Duncan's multiple range test, p<0.05). The results suggested that mepanipyrim might be an alternative fungicide for the control of benomyl- and procymidone-resistant pathogens of Botrytis rot.

• The Korean Journal of Mycology
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• v.40 no.4
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• pp.282-287
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• 2012

Sclerotium cepivorum is a causal agent of white rot disease on different plants including Allium species such as garlic. A mycoparasite, Paraconiothyrium minitans S134 was selected for biological control of sclerotinia rot of garlic caused by S. cepivorum. The experiment was carried out in a garlic field in Taean from October in 2011 to June in 2012. Spore suspension of the mycoparasite was treated twice onto soil surface around garlic plants in sowing in 2011 and late Feb. in 2012, and disease rating was made June in 2012. Incidence of white rot in the twice-application plot of the mycoparasite ($5{\times}10^6$ spores/mL) and in the fluquinconazole (WP)-treated plot was 6.8% and 0.4%, respectively, whereas that of control was 19.5%. As the results, P. minitans S134 could be a prospective biofungicide for biological control of white rot of garlic.

• Korean Journal of Environmental Biology
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• v.24 no.1 s.61
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• pp.38-45
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• 2006

Ecological characteristics of microbial populations inhabiting heavy metal polluted soil were investigated. The samples were collected from 293 sites around an factory and industry at Gyeoungsangbuk-do. We measured the contents of seven heavy metal elements (Cd, Cu, As, Hg, Pb, $Cr^{6+}$, CN), seven sites have been seriously contaminated by mercury and chrome. A quantitative evaluation of microbial populations in mercury and chrome contaminated soil was examined by using plate count method. Bacterial numbers in polluted soil samples ranged from $7.4X10^5\;to\;9.3X10^7\;cfu\;g^{-1}$, about $10\sim100$ fold less than the count for the unpolluted soil. Moulds were not detected in chrome polluted soil. The log values of actinomycetes of each contaminated soil samples were log ranged from 6.18 to 7.52. The ratio of actinomycetes was similar to unpolluted soil. The investigation showed actinomycetes to be the major microbial population inhabiting the mercury and chrome polluted soil. Thirty-one isolates among the total isolates were examined for antibacterial activity. These isolates were identified based on a phylogenetic analysis using 16S rRNA gene nucleotide sequences, they were categorized in three major phylogenetic groups, belong to the Streptomyces (6 strains), Saccharopolyspora (3 strains), Nocardiodes (1 strain). On the phylogenetic tree, the clade consisting of five isolates were distantly related to all of the established Streptomycetes genera, indicating the possibility as members of new species.

• Korean Journal of Microbiology
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• v.50 no.4
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• pp.319-326
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• 2014

Two bacterial strains, named as LE17 and LE22, were isolated from traditionally fermented soybean products in order to select lactic acid bacteria for the reduction of biogenic amines and harmful bacteria. Both strains were identified as Pediococcus pentosaceus by 16S rRNA sequence analysis and additional biochemical tests. The strain LE17 reduced the amines by 13.7% for histamine and by 25.9% for tyramine, when it grew in minimal synthetic media containing 0.1% (w/v) histamine and 0.1% tyramine at $30^{\circ}C$ for 48 h, while the strain LE22 reduced the amines by 23.7% for histamine and by 15.7% for tyramine. Both strains also had broad inhibition spectra against pathogens. Considering their properties, they could be used as starters for industrial soybean fermentation.

• Journal of Sericultural and Entomological Science
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• v.43 no.2
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• pp.83-87
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• 2001

This study was carried out to investigate the optimal medium and optimal dextrose concentration of 12 entomopathogenic fungi. The colonies of Cordyceps gracilioides, C. sp.(J23), Paecilomyces farinosus(J5), P tenuipes, Paecilomyces sp.(J4), Beauveria bassiana and B. brongniartii on SLA(silkworm larva agar) medium are similar to those on PDA(Potato dextrose agar) medium. On the contrary, the colonies of 5 fungi are very various according to its medium. The optimal medium for 1 1 fungi was SLA-A medium, which was better than PDA medium with regard to the mycelial growth. The optimal concentration on mycelial growth was superior to 6% for 6 fungi. When silkworm larvae was injected with P. tenuipes on SLA medium for fruiting body production. Infection rate, fruiting body formation rate, synnemata number and synnemata length were 91.3 $\pm$ 1.5%, 88.6 $\pm$ 2.3%, 56.6 $\pm$ 3.2 and 33.4 $\pm$ 2.88 ㎜ respectively. In economical analysis, the prototype medium can reduce 61.9% of production cost per 1 liter compared with PDA medium.

• The Korean Journal of Mycology
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• v.49 no.3
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• pp.303-313
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• 2021

Peanuts in storage were estimated for mycotoxigenic fungi and mycotoxins. Peanut samples collected from storages in Gochang were mainly contaminated with Fusarium (17.2±28.0%), Penicillium (12.4±28.0%), and Aspergillus (8.0±7.6%). Other genera, including Talaromyces, Rhizopus, Rhizoctonia, Trichocladium, Clonostachys, Mucor, Chaetomium, Trametes, Epicoccum, and Humicola, were also found. Although aflatoxins were not detected in the peanut samples, 29 strains of Aspergillus flavus were identified using molecular marker genes. Among them, 17 selected isolates produced aflatoxins in solid culture media ranging from 0.61-187.82 ㎍/kg. All of them could produce both aflatoxin B₁ and B₂ and some (n=5) produced additional G₁, G₂, or both. This study is the first report that A. flavus stains obtained from Korean stored peanut are aflatoxigenic.

• Korean Journal of Organic Agriculture
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• v.28 no.3
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• pp.417-430
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• 2020

Drought stress is one of major environmental stresses in plants; this leads to reduce plant growth and crop yield. In this study, we selected fungal isolate for mitigating drought stress in pepper plants. To do this, 41 fungi were isolated from rhizosphere or bulk soils of various plants in Jeju, Gangneung, Hampyeong in Korea. Out of 41 isolates, we screened two isolates without phytotoxicity through seed germination of tomato, pepper, and cabbage treated with fungal spores; through following plant assay, we selected GL02 as a candidate for alleviating drought stress in pepper plants. As a result of greenhouse test of pepper plants in drought condition, the stomatal conductance on leaves of pepper plants treated with GL02 was increased, whereras the malondialdehyde (MDA) and electrolyte leakage were decreased compared to that in control plants. When stressed plants were rewatered, stomatal conductance of the plants treated with GL02 was increased; the electrolyte leakage was decreased. Based on internal transcribed spacer (ITS) sequencing analysis, isolate GL02 was belonging to genus Trichoderma. Taken together, drought stress in pepper plants treated with GL02 was alleviated, when it was rewatered after drought-stressed, the plants could be recovered effectively. Therefore, Trichoderma sp. GL02 could be used as a bio-fertilizer to alleviate drought stress in pepper plants.

• Korean Journal of Soil Science and Fertilizer
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• v.23 no.2
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• pp.146-151
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• 1990

The viability of rhizobia according to various kinds of carrier materials, inoculum size, storage temperature and sterilization methods was investigated for the development of legume inoculat. The results were followings. 1. Peat and perlite were favorable as a carrier material. 2. Rhizobia counts were reached to $5{\times}10^8cells/g$ carrier 1-2 weeks after inoculation with inoculum size below $10^4cells/g$ carrier. 3. $10^9cells/g$ carrier was maintained 12 weeks after storage at room temperature. 4. Steam heat sterilization was the best method for carrier sterilization among methods used in this study. Dry heat and ${\gamma}$-ray sterilization were also applicable.

• Korean Journal Plant Pathology
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• v.12 no.2
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• pp.255-265
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• 1996

토양에 존재하는 진균인 Gliocladium virens는 식물병을 감소 또는 방제할 수 있는 생물학적인 특성에 의하여 G. virens는 지난 수십년간 실용가능성이 큰 생물학적 방제균(또는 길항균)으로 집중적으로 연구되었다. 이 균이 식물병의 발생을 감소시키는 생물적 방제효과는 항생작용, 중복기생, 근권에서의 생존과 집단번식, 뿌리표면에서의 정착 등에 의한 것으로 분류되고 있다. 특히, 항생물질인 gliotoxin, gliovirin, viridin 등은 Rhizoctonia solani 및/또는 Pythium spp. 등에 항생효과가 뚜렷하고, 식물병의 발생과 직접적인 상관관계를 나타내고 있어 G. virens의 식물병의 방제에 관련된 중요한 작용기작으로 제시되어 있다. 또한, 근권에서 이균의 생존과 집단증식 및 뿌리표면에서의 정착은 식물병의 방제와 상관관계를 나타낼 수 있는 중요한 작용기작으로 제시되고 있다. 그러나 이균이 R. solani 등에 기생하는 현상은 식물병의 생물적 방제의 직접적인 연관관계를 나타내고 있지 않다. G. virens을 이용의 생물적 방제효과를 증진시키기 위한 방법으로 다음과 같은 두 가지 방법을 들 수 있다. 첫째, 길항효과가 높은 G. virens 균주를 선발하기 위하여 여러 종류의 토양에서 길항력이 높은 G. virens의 선발이 지난 수십년간 진행되고 있다. 또한, 특정 길항효과를 발현하는 유전자를 G. virens의 염색체에 도입하고 이를 발현시킴으로써 생물적 방제효과를 증진시키는 것으로 이러한 방법은 1980년 후반부터 진행되고 있다. 둘째, G. virens의 길항효과가 최대의 효율로 발현될 수 있도록 최적의 미세환경을 갖추고 있으며 농민이 편리하게 사용할 수 있는 G. virens의 운송매체의 개발이 중요하다. 운송매체의 개발에 의한 'Glioguard'는 G. virens의 포자를 alginate 입자에 제형화한 것으로서 미국에서 시판되고 있다. Aldicarb, metalaxyl, atrazine 등의 농약을 분해할 수 있는 능력은 G. virens의 다른 생물적 특성중의 하나이다. 특히, parathion을 분해할 수 있는 Flavobacterium sp.의 유전자(opd)가 G. virens의 염색체에 도입되여 발현될 수 있는 방법이 제시되었으며, 이는 G. virens을 이용한 토양에서의 특정한 농약의 분해효율을 증진시킬수 있는 가능성을 제시한 것이다. 그러나, G. virens를 이용한 농약의 생물적 분해에 관한 연구는 기초단계로 평가되고 있으며, 포장에서 이를 실용화하기 위해서는 향후 지속적인 연구가 필요하다.

• Journal of Mushroom
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• v.18 no.3
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• pp.214-220
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• 2020

We undertook a breeding program to produce a white button mushroom cultivar with high temperature tolerance in preparation for climate change. The results were as follows. The strains KMCC00540, KMCC00591, and KMCC00643 were selected, and homokaryons were selected and hybrids were identified with ISSR and SSR markers, respectively. The selected hybrids were cultivated in three repetitions at a temperature of 20-25 ℃ and a humidity of 80% or higher. The variation in agricultural traits and fruiting body characteristics was least in the Abs4-2016-121 strain. This line is a hybrid of KMCC00591 and KMCC00875, and field experiments at Gyeongju and Buyeo farms found that the Abs4-2016-121 line has high fruiting body with hardness and delayed opening of pileus at high temperatures, so it was bred as a high-temperature cultivar named 'Hadam'.