• 아시안잔디학회지
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• 제25권2호
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• pp.177-183
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• 2011

벤트그라스 3종류의 품종에 대한 감수성을 잎 조각 검정와 전체식물에 대하여 9개의 Microdochum nivale 균주를 이용하여 온도가 조절된 공간에서 평가 하였다. 위스콘신 골프장에서 감염된 병반에서 얻은 자주색 설부병 균주에 대하여 온도와 살균제에 대한 반응시험을 하였다. 잎 조각 검정과와 전체식물을 이용한 시험은 80일된 잔디로 평가하였다. 9균주는 2종류의 살균제에 감수성이 었으며, 온도에 대하여 균주간에 차이를 보였다. 잎조각을 이용한 검정에서도 벤트그라스 품종과 종간에도 뚜렸한 차이를 보였다. 전체식물을 이용한 시험에서도 품종과 종간에 병 심각성에 차이를 보였는데, 특별히 4배수체인 크리핑과 콜로니얼 벤트그라스와 2배체인 벨벧벤트그라스 종과 품종간에 M. nivale 균주에 대한 감수성 차이를 보였다. 이 연구는 자주색 설부병에 대한 벤트그라스 평가에 응용될 수 있고, 육종을 하는데도 품종간에 전망적인 예측 평가을 하는데 필요한 자료로 쓰일 수 있을 것이다.

• Mycobiology
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• 제44권2호
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• pp.85-92
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• 2016

Mycoherbicides are exclusive biotechnology products which offer a non-chemical solution to control noxious weeds on the land as well as aquatic in systems, viz a viz saving environment from hazardous impact of synthetic chemicals. The present paper highlights the mycobiota associated with Eichhornia crassipes infesting Harike wetland area of Punjab and evaluation of their pathogenic potential for futuristic application as a mycoherbicide. Of the 20 isolates tested by leaf detached assay and whole plant bioassays, only one isolate (#8 BJSSL) caused 100% damage to E. crassipes. Further, the culture filtrate of this isolate also exhibited a similar damage to the leaves in an in vitro detached leaf assay. The potential isolate was identified as Phaeoacremonium italicum using classical and modern molecular methods. This is the first report of P. italicum as a pathogen of E. crassipes and of its potential use as a biological control agent for the management of water hyacinth.

• BMB Reports
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• 제38권1호
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• pp.82-88
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• 2005

Bacillus cereus 28-9 is a chitinolytic bacterium isolated from lily plant in Taiwan. This bacterium exhibited biocontrol potential on Botrytis leaf blight of lily as demonstrated by a detached leaf assay and dual culture assay. At least two chitinases (ChiCW and ChiCH) were excreted by B. cereus 28-9. The ChiCW-encoding gene was cloned and moderately expressed in Escherichia coli DH5$\alpha$. Near homogenous ChiCW was obtained from the periplasmic fraction of E. coli cells harboring chiCW by a purification procedure. An in vitro assay showed that the purified ChiCW had inhibitory activity on conidial germination of Botrytis elliptica, a major fungal pathogen of lily leaf blight.

• Journal of Microbiology and Biotechnology
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• 제32권2호
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• pp.160-169
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• 2022

In the present study we evaluated the efficacy of a bioformulation of Streptomyces cameroonensis for control of black pod disease in cocoa and enhancement of seedling growth. The formulation developed using talc powder and cassava starch as carriers showed high shelf-life of 1.07 × 10⁶ CFU/g after six months storage at 4℃. The formulation was tested for inhibition of spore germination in Phytophthora megakarya and showed 100% inhibition at 10% (w/v) of formulation. To determine the efficacy of the formulation, we performed an in planta assay in the greenhouse on two hybrids of cocoa seedlings, the tolerant SNK413 × (♂) T79/467 and the susceptible UPA 134× (♂) SCA 12. Detached leaf assay showed a significant reduction in the disease severity index of about 67% for the tolerant hybrid and 55% for the susceptible hybrid compared to non-treated plants. A significant enhancement in stem length, leaf surface area and root weight was observed. Analysis of biochemical markers of defense showed a significant increase in total polyphenol, flavonoid, and total protein contents. There was also significant upregulation of PR-proteins such as chitinases, peroxidases and β-1, 3-glucanases following treatment of both tolerant and susceptible hybrids, though with a higher level of synthesis in the tolerant hybrids. A significant increase was also observed in polyphenol oxidase activities in plants treated with the formulation. This work demonstrated the stability and effectiveness of the S. cameroonensis powder formulation in suppressing black pod disease in cocoa and subsequently enhancing the growth of seedlings.

• 식물병연구
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• 제18권4호
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• pp.338-348
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• 2012

감자역병은 감자재배에서 가장 중요한 병 중의 하나다. 감자역병의 친환경방제를 위하여 SH-1와 SH-2을 이용하여 감자역병균의 균사생장, 예방효과, 잎을 이용한 생물검정 및 포장시험을 통해 평가하였다. 실내에서 유묘를 이용한 시험에서 SH-1와 SH-2 제형을 살포 후 역병균을 접종 후 예방효과를 조사한 결과 95% 이상 발병을 억제하는 효과가 있었다. SH-1과 SH-2의 균사생장 억제 효과는 $300{\mu}g/ml$의 농도에서 균총의 크기를 74% 이상을 억제하였다. 잎을 이용한 생물검정에서 1% SH-1와 SH-2을 살포 후 1시간 뒤에 병원균을 접종한 결과 병의 발달을 줄였다. 감자 줄기에 총 폴리페놀 함량도 SH-1와 SH-2을 살포한 구에서 증가하였다. 포장에서 역병방제효과 시험에서 1% SH-1와 SH-2을 7일 간격 4회 살포한 처리구에서 각각 72%와 53%의 역병 방제 효과가 있었으며, 14일간 3회 살포한 구에도 유사한 병 방제효과를 보였다. 감자비대기에 1% SH-1와 SH-2 살포는 감자 생체 중을 증가시켰으며, 상품의 비율도 높았다. 이 결과에 의하면 SH-1와 SH-2의 살포는 친환경 유기농업에서 천연살균제로서 역병 방제에 사용 할 수 있으며, 감자 수확량도 증가시킬 수 있다.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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• pp.68.2-69
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• 2003

Genetic transformation carried out to induce the pathogenicity mutants from the two isolates, Elsinoe fawcettii R-34 and MUD of citrus scab fungus to hygromycin resistant by transferring plasmides (pUCATPH) that contain hygB gene. We produced protoplast for transformation by using of combinations of available enzymes including ${\beta}$-D-glucanase, ${\beta}$ -glucuronidase, Iyticase and driselase. The protoplasts regenerated at 64 $\mu\textrm{g}$/ml of hygromycin B but not 128 $\mu\textrm{g}$ in sensitivity test to identify the concentration of useful marker for the selection of transformants. Approximately 1200 and 67 hygromycin resistant isolates from strain R-34 and strain MUD, respectively, were isolated on PDA added with 200 $\mu\textrm{g}$ /ml of hygromycun B. Fifty seven and 4 of hygromycin resistant isolates from strain R-34 and MUD, respectively, did not produce necrotic lesions on the leaf in detached-leaf assay. Finally, 9 isolates were isolated from strain R-34, and these Isolates produced non or very few symptoms on seedlings of citrus in greenhouse pathogenicity test. And it's very interesting that some isolates produced melanose-like symptom on very young leaves which it was not typical symptom and somtimes produced on only expanded leaf.

• The Plant Pathology Journal
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• 제31권3호
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• pp.252-258
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• 2015

This is the first study reporting the evaluation of transgenic lines of tomato harboring rice chitinase (RCG3) gene for resistance to two important fungal pathogens Fusarium oxysporum f. sp. lycopersici (Fol) causing fusarium wilt and Alternaria solani causing early blight (EB). In this study, three transgenic lines TL1, TL2 and TL3 of tomato Solanum lycopersicum Mill. cv. Riogrande genetically engineered with rice chitinase (RCG 3) gene and their R1 progeny was tested for resistance to Fol by root dip method and A. solani by detached leaf assay. All the R0 transgenic lines were highly resistant to these fungal pathogens compared to nontransgenic control plants. The pattern of segregation of three independent transformant for Fol and A. solani was also studied. Mendelian segregation was observed in transgenic lines 2 and 3 while it was not observed in transgenic line 1. It was concluded that introduction of chitinase gene in susceptible cultivar of tomato not only enhanced the resistance but was stably inherited in transgenic lines 2 and 3.

• The Plant Pathology Journal
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• 제38권2호
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• pp.115-130
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• 2022

Though information exists regarding the pathogenesis of the shot-hole disease (SH) in flowering cherry (FC), there has been a lack of research focusing on SH management. Therefore, here, we investigated the inhibitory activities of antagonistic bacteria against SH pathogens both in vitro and in vivo as well as their biochemical characteristics and bioactive compounds. Two biosurfactant-producing bacterial antagonists, identified as Bacillus velezensis strains JCK-1618 and JCK-1696, exhibited the best effects against the growth of both bacterial and fungal SH pathogens in vitro through their cell-free culture filtrates (CFCFs). These two strains also strongly inhibited the growth of the pathogens via the action of their antimicrobial diffusible compounds and antimicrobial volatile organic compounds (VOCs). Crude enzymes, solvent extracts, and biosurfactants of the two strains exhibited antimicrobial activities. Liquid chromatography/electrospray ionization time-of-flight mass spectrometric analysis of the partially purified active fractions revealed that the two antagonists produced three cyclic lipopeptides, including iturin A, fengycin A, and surfactin, and a polyketide, oxydifficidin. In a detached leaf assay, pre-treatment and co-treatment of FC leaves with the CFCFs led to a large reduction in the severity of the leaf spots caused by Epicoccum tobaicum and Bukholderia contaminans, respectively. In addition, the two antagonists produced indole-3-acetic acid, siderophore, and a series of hydrolytic enzymes, along with the formation of a substantial biofilm. To our knowledge, this is the first report of the antimicrobial activities of the diffusible compounds and VOCs of B. velezensis against the SH pathogens and their efficiency in the biocontrol of SH.

• Journal of Microbiology and Biotechnology
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• 제27권10호
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• pp.1763-1772
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• 2017

This study aimed to isolate and characterize antibacterial metabolites from Pharbitis nil seeds and investigate their antibacterial activity against various plant pathogenic bacteria. The methanol extract of P. nil seeds showed the strongest activity against Xanthomonas arboricola pv. pruni (Xap) with a minimum inhibition concentration (MIC) value of $250{\mu}g/ml$. Among the three solvent layers obtained from the methanol extract of P. nil seeds, only the butanol layer displayed the activity with an MIC value of $125{\mu}g/ml$ against Xap. An antibacterial fraction was obtained from P. nil seeds by repeated column chromatography and identified as pharbitin, a crude resin glycoside, by instrumental analysis. The antibacterial activity of pharbitin was tested in vitro against 14 phytopathogenic bacteria, and it was found to inhibit Ralstonia solanacearum and four Xanthomonas species. The minimum inhibitory concentration values against the five bacteria were $125-500{\mu}g/ml$ for the n-butanol layer and $31.25-125{\mu}g/ml$ for pharbitin. In a detached peach leaf assay, it effectively suppressed the development of bacterial leaf spot, with a control value of 87.5% at $500{\mu}g/ml$. In addition, pharbitin strongly reduced the development of bacterial wilt on tomato seedlings by 97.4% at $250{\mu}g/ml$, 7 days after inoculation. These findings suggest that the crude extract of P. nil seeds can be used as an alternative biopesticide for the control of plant diseases caused by R. solanacearum and Xanthomonas spp. This is the first report on the antibacterial activity of pharbitin against phytopathogenic bacteria.