• Journal of Ginseng Research
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• 제42권1호
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• pp.9-15
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• 2018

Cylindrocarpon destructans/Ilyonectria radicicola is thought to cause both rusty symptom and root-rot disease of American and Korean ginseng. Root-rot disease poses a more serious threat to ginseng roots than rusty symptoms, which we argue result from the plant defense response to pathogen attack. Therefore, strains causing rotten root are characterized as more aggressive than strains causing rusty symptoms. In this review, we state 1- the molecular evidence indicating that the root-rot causing strains are genetically distinct considering them as a separate species of Ilyonectria, namely I. mors-panacis and 2- the physiological and biochemical differences between the weakly and highly aggressive species as well as those between rusty and rotten ginseng plants. Eventually, we postulated that rusty symptom occurs on ginseng roots due to incompatible interactions with the weakly aggressive species of Ilyonectria, by the established iron-phenolic compound complexes while root-rot is developed by I. morspanacis infection due to the production of high quantities of hydrolytic and oxidative fungal enzymes which destroy the plant defensive barriers, in parallel with the pathogen growth stimulation by utilizing the available iron. Furthermore, we highlight future areas for study that will help elucidate the complete mechanism of root-rot disease development.

• 한국전자파학회논문지
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• 제19권12호
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• pp.1367-1374
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• 2008

음의 유전율 및 투자율을 갖도록 고안된 메타 물질을 안테나 상부 덮개(superstrate)로 사용한 와이브로(Wibro: wireless broadband internet) 기지국용 고 이득 Fabry-$P{\acute{e}}rot$ 공진기 안테나를 제안한다. 안테나의 상부 덮개로 사용된 새로운 메타 물질은 기존의 PCB 기술로 쉽게 제작 가능하도록 평판형으로 설계되었으며, 와이브로 서비스 주파수 대역 근방에서 음의 굴절률 및 '1'보다 작은 저 굴절률 값을 갖는다. 안테나의 이득 증대 효과를 유효매질 관점에서 추출된 메타 물질의 저 굴절률 특성과 Fabry-$P{\acute{e}}rot$ 공진기의 공진 조건이라는 두 가지 측면에서 분석하였다. 단일 정사각형 패치 안테나가 공진기 내부의 신호 피더로 사용되었으며, Fabry-$P{\acute{e}}rot$ 공진 조건을 충족시키기 위해 피더와 메타 물질 상부 덮개 사이의 이격 거리는 유전체 층을 포함한 접지면의 반사 위상과 메타 물질 상부 덮개의 반사 위상을 함께 고려하여 설정하였다. 시뮬레이션을 통한 예측 특성과 실험 결과가 잘 일치하였으며, 이를 통하여 본 논문에서 제시한 설계 방법이 타당함을 입증할 수 있었다.

• 미생물학회지
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• 제48권1호
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• pp.37-41
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• 2012

본 연구에서는 sesquiterpene류의 생물학적 변환을 위한 생촉매로서 목재부후균을 선발하고 생물변환 가능성을 확인하였다. Sesquiterpene류 합성 전구체로 알려진 trans,trans-farnesol을 기질로 하여 총 19종의 목재부후균에 대해여 저항성 실험을 실시하였다. 기질의 농도를 달리하여 저항성 테스트를 실시하여 생물변환 가능성을 갖는 5종의 균주를 선발하였으며 선정된 균주를 이용하여 액체배지 조건에서 trans,trans-farnesol의 생물변환을 시도하였다. GC/MS를 이용하여 분석한 결과 Laetiporus sulphureus var. miniatus (jungh) Imaz, Coriolus versicolor (L. Fr). Prlar, Fomitopsis pinicola, Lampteromyces japonicas 등 4개의 균주에서 각각 nerolidol, eicosane, isoborneol, isocyclocitral 등의 대사산물을 확인할 수 있었다. 이와 같은 결과로 sesquiterpene류의 생물학적 변환을 위한 생촉매로서 목재부후균의 가능성을 확인하였다.

• Journal of the Korean Wood Science and Technology
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• 제23권2호
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• pp.47-54
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• 1995

This study was to measure the properties of logs and classify them by non-destructive methods. The purpose of this experiment was focused at mensurability of logs by non-destructive methods. The non-destructive instrument, Stress-Wave Timer 239A which was made by Metriguard in U.S.A., was used. The stress wave velocities of log's cross direction were measured and compared with three different methods; 1. with hammer, 2. with hammer and D.B.H. meter, 3. with manufactured instrument. Number of used logs were seven logs, which were classified by naked eye into six groups; very severe rot, severe rot, mild rot & knot, mild rot & check, mild rot, sound log, and in diameter were into three groups; large(57.4cm), medium(36~41.2cm), small(28.9cm) log. The results, which were classified by mensurability with non-destructive methods, were followed; 1. The stress wave velocities were very different between rot and sound log. So it meant the possibility of mensurability of logs by non-destructive method even if high standard error. 2. The stress wave velocities decreased with checks more than with rots, which meant the checks affected speeds more. 3. The stress wave velocities increased with knot. 4. The velocities with manufactured instrument showed lower standard error, so more accurate results than other methods. Especially the required labour decreased from 3~4 to 2 persons. 5. Finally, the mensurability showed more accurate results and made the classification of logs scientific.

• 한국약용작물학회지
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• 제28권2호
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• pp.142-151
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• 2020

Background: Suppressive soil inhibits soil-borne diseases if pathogens are present, and ginseng does not show injury even if replanted in the same field. Methods and Results: Soil chemical properties and microbial community of soil were investigated in soil suppressive and conducive to ginseng root rot. Root rot disease in 2-year-old ginseng was tested by mixing conducive soil, with suppressive or sterilized suppressive soil. The root rot ratio in suppressive soil was 43.3% compared to 96.7% in conducive soil. Biological factors acted to inhibit the root rot because disease ratio was increased in the sterilized suppressive soil compared to that in non-suppressive soil. The suppressive soil had lower pH, nitrate nitrogen and sodium than the conducive soil. Dominat bacteria and fungi (more than 1.0%) were 3 and 17 species in conducive soil and 7 and 23 species in suppressive soil, respectively. The most predominant fungi were Pseudaleuria sp. HG936843 (28.70%) in conducive soil and Pseudogymnoascus roseus (7.52%) in suppressive soil. Conclusion: Microbial diversity was more abundant in the suppressive soil than in the conducive soil, and the proportion of pathogens (Nectriaceae sp.) causing root rot was significantly lower in the suppressive soil than in the conducive soil.

• 한국토양비료학회지
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• 제47권3호
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• pp.165-171
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• 2014

Assessment of sustainable production on a cropland can help to determine the most proper management practices. In this study, we evaluated the sustainable production on paddy field treated with green manure crops using sustainability index which based on nutrient index, microbiological index, and crop index related to nutrient-supplying capacity. Especially choosing appropriate indicators from a minimum data set (MDS) were used the principal components analysis (SI-2) as well as expert opinion (SI-1) usually used in sustainability index. Six treatments including the two tillage treatments and two green manure crops were investigated as follows; (i) moldrotary + rotary tillage without green manure crop (Con), with (ii) hairy vetch (Con-HV), and (iii) hairy vetch + green barely (Con-HV+GB), (iv) rotary tillage without green manure crop (Rot), with (ii) hairy vetch (Rot-HV), and (iii) hairy vetch + green barly (Rot-HV+GB). Con-HV and Rot-HV in SI-1 were maintained sustainability while Rot-HV and Rot-HV+GB in SI-2. Especially, treatments (Con and Rot) without green manure crops were more unsustainable than with green manure crops because of the low value of microbiological and crop index than with green manure crops. Meanwhile, sustainability indices and grain yield had the high correlation values ($R^2=0.756$ and 0.928 in SI-1 and SI-2, respectively). These results meant that application of green manure crops such as hairy vetch could improve both yield and soil quality in paddy.

• Mycobiology
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• 제45권4호
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• pp.392-400
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• 2017

Peanut yield and quality are seriously affected by pod rot pathogens worldwide, especially in China in recent years. The goals of this study are to analyze the structure of fungal communities of peanut pod rot in soil in three peanut cultivars and the correlation of pod rot with environmental variables using 454 pyrosequencing. A total of 46,723 internal transcribed spacer high-quality sequences were obtained and grouped into 1,706 operational taxonomic units at the 97% similarity cut-off level. The coverage, rank abundance, and the Chao 1 and Shannon diversity indices of the operational taxonomic units were analyzed. Members of the phylum Ascomycota were dominant, such as Fusarium, Chaetomium, Alternaria, and Sordariomycetes, followed by Basidiomycota. The results of the heatmap and redundancy analysis revealed significant variation in the composition of the fungal community among the three cultivar samples. The environmental conditions in different peanut cultivars may also influence on the structure of the fungal community. The results of this study suggest that the causal agent of peanut pod rot may be more complex, and cultivars and environmental conditions are both important contributors to the community structure of peanut pod rot fungi.

• 한국약용작물학회지
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• 제25권4호
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• pp.244-251
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• 2017

Background: The application of crop rotation systems may reduce the occurrence of soil-borne diseases by releasing allelochemicals and by subsequent microbial decomposition. Methods and Results: For reduction of ginseng root rot by the crop rotation system, after harvesting 6-year-old ginseng, fresh ginseng was grown along with continuous cultivation of sweet potato, peanut, and bellflower. Growth of 2-year-old ginseng was significantly inhibited in the continuous cultivation than in the first cultivation. Sweet potato, peanut and bellflower cultivations assisted in obtaining normal yields of ginseng in the first year after the harvest of 6-year-old ginseng. Salt concentration, potassium and sodium contents were gradually decreased, and, organic matter was gradually increased through cirp rotation. Phosphate, calcium and magnesium contents were not altered. The density of the root rot fungus was gradually decreased by the increase in crop rotation; however it was decreased distinctly in the first year compared to the second and third year. The severity of root rot disease tended to decrease gradually by the increase of crop rotation. Conclusions: Short-term crop rotation for three years promoted the growth of ginseng, however root rot infection was not inhibited significantly, although it was somewhat effective in lowering the density of the root rot pathogen.

• 식물병연구
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• 제24권4호
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• pp.321-327
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• 2018

2018년 경북 영천지역 사과과수원에서 미이라화 된 과실, 배꼽이 썩어 들어간 과실과 점무늬를 형성한 과실의 증상을 관찰하였다. 이 증상의 원인균을 증명하기 위해 이병체에서 균사체를 분리하여 병원성 검정을 수행한 결과 건전한 사과 과실이 급격히 썩으면서 발견 시의 병징과 일치하였다. 곰팡이의 특성은 흰색의 균사로 자라다가 시간이 지나면서 암회색으로 변하였다. 병자각 안에서 분생포자가 형성되고 분생포자는 갈색의 타원 형태였으며 격막이 없고 끝이 둥근 형태이다. 분생포자 크기는 $21.7-28.3{\times}9.9-15.3{\mu}m$이다. 병원균의 ITS, ${\beta}$-tubulin 유전자의 염기서열을 이용하여 유연관계를 분석한 결과 Diplodia seriata로 동정되었다. Diplodia seriata는 국내에서 식물병원균으로 보고된 바 없다. 사과에서 Diplodia seriata에 의한 Black rot은 우리나라에서 처음 보고되는 것이며 사과 검은썩음병으로 명명하여 보고하고자 한다.

• The Plant Pathology Journal
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• 제39권6호
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• pp.600-613
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• 2023

Fusarium oxysporum is the main pathogen causing Fusarium basal rot in onion (Allium cepa L.), which incurs significant yield losses before and after harvest. Among management strategies, biological control is an environmentally safe and sustainable alternative to chemical control. In this study, we isolated and screened bacteria for antifungal activity against the basal rot pathogen F. oxysporum. Isolates 23-045, 23-046, 23-052, 23-055, and 23-056 significantly inhibited F. oxysporum mycelial growth and conidial germination. Isolates 23-045, 23-046, 23-052, and 23-056 suppressed the development of Fusarium basal rot in both onion seedlings and bulbs in pot and spray inoculation assays. Isolate 23-055 was effective in onion seedlings but exhibited weak inhibitory effect on onion bulbs. Based on analyses of the 16S rRNA and rpoB gene sequences together with morphological analysis, isolates 23-045, 23-046, 23-052, and 23-055 were identified as Bacillus thuringiensis, and isolate 23-056 as Bacillus toyonensis. All five bacterial isolates exhibited cellulolytic, proteolytic, and phosphate-solubilizing activity, which may contribute to their antagonistic activity against onion basal rot disease. Taken together B. thuringiensis 23-045, 23-046, 23-052, and 23-055 and B. toyonensis 23-056 have potential for the biological control of Fusarium basal rot in onion.