• 미생물학회지
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• 제42권1호
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• pp.7-11
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• 2006

조류의 효과적인 제어방법 개발의 일환으로 해양암석분말의 효과를 보기위하여 해양암석분말과 곰팡이 배양 상등액을 이용하여 해양조류 제거율을 조사하였다. 편조류인 H. akashiwo와 P.minimum는 해양암석 분말을 30g/1의 농도로 살포한 실험군에서 높은 구제효과를 나타내었고, P. oxalicum (HCLE-34)배양상등액 살포는 5 mg/l 살포군에서도 구제효과를 나타내었다. 혼합 살포군에서도 배양 상등액 단독 살포군에서와 동등한 정도의 구제효과를 나타내었고, 완충용액 (pH 2.8)은 15 mg/l 살포군에서 60분 경과 후 75%의 구제효과를 나타내었으나, 전자현미경적 관찰에서는 암석분말과 배양 상등액 혼합 살포군, 배양 상등액 살포군, 암석분말 살포군 및 완충용액 살포군 순으로 세포의 파괴정도가 관찰되었다. 이러한 결과는 암석분말과 곰팡이 배양상등액이 해양에서 발생되는 편조류의 대발생을 조절할 수 있는 물질로 작용함을 시사한다.

• 식물병연구
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• 제15권2호
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• pp.101-105
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• 2009

Serratia plymuthica A21-4는 양파(Allitum fistulosum L.) 근권에서 분리된 고추 역병 생물적 방제 미생물이다. 토양 환경이 S. plymuthica A2l-4 근권정착에 미치는 영향을 알아본 결과 사질이 많이 포함되어 공극이 많은토양에 3% 중량(w/w)의 부숙된 옥수수 줄기를 첨가하고 토양 수분함양이 40% 정도, 토양온도가 $20^{\circ}C$, 토양 pH가 중성이거나 약산성 토양이 S. plymuthica A2l-4의 근권정착에 유리하였다. 그리고 토착미생물이 있는 것이 살균한 토양에서 보다 S. plymuthica A21-4의 근권정착에 유리하였다.

• The Plant Pathology Journal
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• 제29권1호
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• pp.52-58
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• 2013

Fusarium head blight (FHB) caused by the filamentous fungus Fusarium graminearum is one of the most severe diseases threatening the production of small grains. Infected grains are often contaminated with mycotoxins such as zearalenone and trichothecences. During survey of contamination by FHB in rice grains, we found a bacterial isolate, designated as BN1, antagonistic to F. graminearum. The strain BN1 had branching vegetative hyphae and spores, and its aerial hyphae often had long, straight filaments bearing spores. The 16S rRNA gene of BN1 had 100% sequence identity with those found in several Streptomyces species. Phylogenetic analysis of ITS regions showed that BN1 grouped with S. sampsonii with 77% bootstrap value, suggesting that BN1 was not a known Streptomyces species. In addition, the efficacy of the BN1 strain against F. graminearum strains was tested both in vitro and in vivo. Wheat seedling length was significantly decreased by F. graminearum infection. However, this effect was mitigated when wheat seeds were treated with BN1 spore suspension prior to F. graminearum infection. BN1 also significantly decreased FHB severity when it was sprayed onto wheat heads, whereas BN1 was not effective when wheat heads were point inoculated. These results suggest that spraying of BN1 spores onto wheat heads during the wheat flowering season can be efficient for plant protection. Mechanistic studies on the antagonistic effect of BN1 against F. graminearum remain to be analyzed.

• Mycobiology
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• 제43권3호
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• pp.333-338
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• 2015

In a previous study, we identified a Streptomyces sp., A3265, as exhibiting potent antifungal activity against various plant pathogenic fungi, including Botrytis cinerea, Colletotrichum gloeosporioides, and Rhizoctonia solani. This strain also exhibited a biocontrolling effect against ginseng root rot and damping-off disease, common diseases of ginseng and other crops. In this study, we isolated two antifungal substances responsible for this biocontrolling effect via Diaion HP-20 and Sephadex LH-20 column chromatography, medium pressure liquid chromatography, and high-performance liquid chromatography. These compounds were identified as guanidylfungin A and methyl guanidylfungin A by spectroscopic methods. These compounds exhibited potent antimicrobial activity against various plant pathogenic fungi as well as against bacteria.

• The Plant Pathology Journal
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• 제37권5호
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• pp.465-475
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• 2021

The aim of this study was to characterize potential fungal species affecting mangrove species in Mexico. The phytopathogens were identified based on morphological and molecular characteristics using internal transcribed spacer (ITS1/ITS4) primers then sequenced and compared with the other related sequences in GenBank (NCBI). Three fungal species were identified as Colletotrichum queenslandicum (Weir and Johnst, 2012) from black mangrove (Avicennia germinans); Colletotrichum ti (Weir and Johnst, 2012) from white mangrove (Laguncularia racemosa) and buttonwood mangrove (Conocarpus erectus); Fusarium equiseti (Corda) from red mangrove (Rhizophora mangle). In addition, C. ti and F. equiseti were identified from mango Mangifera indica L. sampled close by the mangrove area. This study provides first evidence of anthracnose on four mangrove species caused by Colletotrichum and Fusarium species in the "Términos" coastal lagoon in Campeche State southern Mexico. This is the first time that C. queenslandicum and C. ti are reported in Mexico. F. equiseti has not been reported affecting M. indica and R. mangle until the present work. Little is known regarding fungal diseases affecting mangroves in Mexico. These ecosystems are protected by Mexican laws and may be threatened by these pathogenic fungus. This is the first report of the effect of Trichoderma harzianum TRICHO-SIN as an effective biological control against of Colletotrichum and Fusarium species.

• 한국환경농학회지
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• 제29권1호
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• pp.39-46
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• 2010

Environmental-friendly agriculture (EFA) is defined as the cultivation of crops with reduced amounts or without chemical-synthetic pesticides. Recently, the use of chemical pesticides has decreased significantly; therefore, we cultivated peppers following EFA- and conventional methods and compared their antioxidant activities. To accomplish this, the environmental-friendly cultivated peppers (EFPE) and conventionally cultivated peppers (CCPE) were extracted with 70% methanol and the effects of the extracts on the cell viability, intracellular ROS generation, lipid peroxidation and catalase activity of HepG2 cells were evaluated. EFPE showed a stronger protective effect against oxidative stress induced-cell death than that of CCPE. EFPE also reduced intracellular ROS generation (42.7% to 26.4%) following treatment with hydrogen peroxide more effectively than that of CCPE (24.2% to 6.3%). Furthermore, EFPE and CCPE showed protective effects against lipid peroxidation and induced catalase activity, although these effects were not statistically significant. Taken together, these results suggest that EFPE showed stronger antioxidant activities than CCPE, and thus represent evidence that EFA with biocontrol materials may improve the functional properties of crops and/or secondary metabolites with antioxidant activities when compared with conventional agricultural practices.

• Mycobiology
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• 제40권1호
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• pp.59-65
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• 2012

Antagonistic microorganisms against $Rhizoctonia$ $solani$ were isolated and their antifungal activities were investigated. Two hundred sixteen bacterial isolates were isolated from various soil samples and 19 isolates were found to antagonize the selected plant pathogenic fungi with varying degrees. Among them, isolate C9 was selected as an antagonistic microorganism with potential for use in further studies. Treatment with the selected isolate C9 resulted in significantly reduced incidence of stem-segment colonization by $R.$ $solani$ AG2-2(IV) in Zoysia grass and enhanced growth of grass. Through its biochemical, physiological, and 16S rDNA characteristics, the selected bacterium was identified as $Bacillus$ $subtilis$ subsp. $subtilis$. Mannitol (1%) and soytone (1%) were found to be the best carbon and nitrogen sources, respectively, for use in antibiotic production. An antibiotic compound, designated as DG4, was separated and purified from ethyl acetate extract of the culture broth of isolate C9. On the basis of spectral data, including proton nuclear magneric resonance ($^1H$ NMR), carbon nuclear magneric resonance ($^{13}C$ NMR), and mass analyses, its chemical structure was established as a stereoisomer of acetylbutanediol. Application of the ethyl acetate extract of isolate C9 to several plant pathogens resulted in dose-dependent inhibition. Treatment with the purified compound (an isomer of acetylbuanediol) resulted in significantly inhibited growth of tested pathogens. The cell free culture supernatant of isolate C9 showed a chitinase effect on chitin medium. Results from the present study demonstrated the significant potential of the purified compound from isolate C9 for use as a biocontrol agent as well as a plant growth promoter with the ability to trigger induced systemic resistance of plants.

• 한국축산식품학회지
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• 제38권1호
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• pp.88-98
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• 2018

In this study, we isolated and characterized a bacteriocin-producing strain and two bacteriophages (P4, A3), showing antimicrobial effects against Clostridium perfringens, from chicken and swine feces by the spot-on-the lawn antagonism method. The selected strain was identified as Streptococcus hyointestinalis by 16S rRNA gene sequencing. The bacteriocin from the isolated strain exhibited strong inhibitory activity against four strains of C. perfringens and all the tested strains of Listeria monocytogenes, and the bacteriocin were highly heat- and pH-stable even at pH 2, pH 10 and $121^{\circ}C$ for 15 min. We also evaluated the combined effects of the isolated bacteriocin and phages. Combining the phage treatments and bacteriocin resulted in a synergetic effect compared with the phage or the bacteriocin alone. In addition, during the probiotic test, the bacteriocin-producing S. hyointestinalis B19 strain reduced the population of C. perfringens significantly. Treatment with S. hyointestinalis B19 and a cocktail of lytic bacteriophages eradicated the C. perfringens KCTC $3269^T$, completely. Consequently, the isolated bacteriocin and bacteriophages represent candidates for effective biocontrol of C. perfringens, and bacteriocin-producing S. hyointestinalis B19 is a potential probiotic candidate for use in domestic animals.

• The Plant Pathology Journal
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• 제27권3호
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• pp.207-224
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• 2011

Diseases caused by plant pathogenic bacteria constitute an emerging threat to global food security. Xanthomonas is a large genus of Gram-negative bacteria that cause disease in several host plants leading to considerable losses in productivity and quality of harvests. Despite the ranges of controlling techniques available, the microbiological safety of economically important crops and crop plants including fruits and vegetables continues to be a major concern to the agriculture industry. On the other hand, many of the currently available antimicrobial agents for agriculture are highly toxic, non-biodegradable and cause extended environmental pollution. Besides, the use of antibiotics has provoked an increased resistance among the bacterial pathogens and their pathovars. Thus, novel efficient and safe remedies for controlling plant bacterial diseases are necessary. There has been an increasing interest worldwide on therapeutic values of natural products such as essential oils, hence the purpose of this review is to provide an overview of the published data on the antibacterial efficacy of essential oils that could be considered suitable for application in agriculture as biocontrol measures against plant pathogenic bacteria of Xanthomonas species. The current knowledge on the use of essential oils to control Xanthomonas bacteria in vitro and in vivo models has been discussed. A brief description on the legal aspects on the use of essential oils against bacterial pathogens has also been presented. Through this review, a mode of antibacterial action of essential oils along with their chemical nature and the area for future research have been thoroughly discussed.

• 농약과학회지
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• 제20권4호
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• pp.369-374
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• 2016

Bacillus velezensis YP2 균주는 쌈채소에서 분리한 Cercospora sp. 1~3, Septoria sp., Colletotrichum sp., Sclerotinia sclerotiorum, Phoma sp., Botrytis cinerea에 대하여 균사생육을 억제하였다. B. velezensis YP2 균주의 LB배양액을 10배 희석액은 적겨자와 청겨자에 발생하는 Erysiphe cruciferarm에 의한 흰가루병을 91.8%와 80.9% 방제효과을 보였다. B. velezensis YP2 균주의 배양액을 10배 희석하여 5일 간격 4회 처리구가 적겨자 흰가루병을 70.6%, 7일 간격 3회 처리구는 65.0%, 10일 간격 2회 처리구는 49.5% 방제하였다. 또한 B. velezensis YP2 균주는 적겨자 종자 발아를 증가시켜고 생육을 촉진하였다. 이상의 결과에서 YP2 균주는 겨자채 흰가루병 방제에 매우 효과적이었다.