• 한국농림기상학회지
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• 제4권1호
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• pp.23-28
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• 2002

CART(Classification and Regression Tree) 모형을 이용해서 결로시간 예측에 필요한 기상변수들을 평가하였다. 입력 기상 변수들은 0.3m와 1.5m에서 측정된 기온, 상대습도, 풍속의 시간별 측정값으로서 이 관측 값들은 1997년부터 1999년 5월에서 9월 사이에 미국의 Iowa, Illinois 및 Nebraska주에 위치한 15개 자동 기상 관측소에서 관측된 것이다. 0.3 m에서 측정된 기온, 상대습도, 그리고 풍속을 이용해서 얻어진 모형이 가장 높은 결로시간의 예측 적중율(85.5%)을 보였으며, 이 모형은 Gleason 등(1994)의 CART/SLD 모형의 적중률(84.7%) 보다 다소 높았다. 그러나 새로운 변수를 추가한 경우에 정확도의 향상이 다소 있었으나 CART/SLD 모형을 대체할 정도는 아니었다. 따라서, 기온, 상대습도, 풍속들의 종관 기상관측값들을 입력변수로 사용하는 CART/SLD 모형이 종관 기상관측 자료 이외의 추가적인 자료를 필요로 하는 모형으로 결로시간을 예측하는 것보다 합리적일 것으로 보인다.

• 식물병연구
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• 제18권4호
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• pp.268-276
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• 2012

Broad bean wilt virus 2 (BBWV2), genus Fabavirus, subfamily Comovirinae, family Secoviridae, causes damage in many economically important horticultural and ornamental crops. Sequence alignments showed several conserved sequences in 5' non-coding regions (5' NCRs) of RNA 1 and RNA 2 in all BBWV2 strains characterized so far. Based on this observation, we generated a hpRNA construct (pIR-BBWV2) harboring an inverted repeat containing a 210 bp cDNA fragment homologous to 5' NCR portion of BBWV2 RNA 1 to investigate the silencing potential for its ability to interfere with a rapidly replicating BBWV2. Agrobacterium-mediated transient expression of the IR-BBWV2 had a detrimental effect on BBWV2 infection, showing no distinct symptoms in non-inoculated leaves of the agroinfiltrated Nicotiana benthamiana plants. BBWV2 genomic RNAs were not detected by RT-PCR from tissues of both the inoculated leaves and upper leaves of the agroinfiltrated plants. Accumulation of virus-derived small interfering RNAs was detected in the inoculated leaf tissues of N. benthamiana plants elicited by transient expression of IR-BBWV2 indicating that RNA silencing is responsible for the resistance to BBWV2.

• 식물병연구
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• 제18권4호
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• pp.324-330
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• 2012

벼 도열병균의 레이스분리 비율이 분리품종과 지역간에 어떤 차이가 있는지를 구명하기 위하여 시험을 수행하였다. 벼 도열병균의 레이스 분포는 채집지역이 동일하여도 분리품종이 상이하거나, 품종이 동일하여도 채집지역이 상이하면 레이스 종류와 비율에 있어서 큰 차이가 있었다. 정확한 레이스 조사를 위해서는 도열병균 채집지역의 객관적인 선정과 재배품종의 면적비율에 의하여 도열병균을 분리 동정하여야 할 것으로 생각된다. 식물체의 저항성측면에서 도열병균에 대한 유묘기 밭못자리상태에서의 저항성 정도와 성체기 본답상태에서의 잎도열병과 이삭도열병 발병정도와는 일치하지 않았다. 벼 품종에 대한 도열병균 침해 레이스의 수와 포장에서 밭못자리 검정의 저항성 정도와 본답상태의 잎도열병과 이삭도열병 발병정도와는 일정한 관계가 없었다.

• The Plant Pathology Journal
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• 제22권4호
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• pp.348-352
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• 2006

Barley mild mosaic virus(BaMMV) is a soilborne Bymovirus vectored by root-infecting fungus, Polymyxa graminis. Mechanism of cultivar's resistance to BaMMV in field tests are difficult to assess since resistance could be either due to the virus or to P. graminis, or both. Whereas, available mechanical inoculation methods for BaMMV and other related viruses are labor intensive, give inconsistent results and generally result in low infection rates. Inoculation method using stick with gauze(SWG) was developed for BaMMV. The improved method proved to be simple, efficient, and reliable. The infected leaf tissues were preserved by drying in a frozen state under high vaccum(freeze dried barley infected leaves) to circumvent reduction of virus infectivity during storage. Five Korean barley cultivars were mechanically inoculated with BaMMV-infected sap by the improved method. Infection rates obtained were compared with natural infection. Cultivar Naehanssalbori showed resistance to BaMMV in the field trials but was found highly susceptible in the greenhouse tests by mechanical inoculation, indicating that the field resistance may be possibly due to resistance to P. graminis.

• 식물병연구
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• 제14권2호
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• pp.134-137
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• 2008

경북 청도지역의 단 고추 과일에 나타난 큰 괴저 반점 및 과일 괴저와 잎에 엽맥 녹대 및 기형 병징을 일으키는 바이러스는 오이모자이크바이러스의 새로운 계통인 CMV-NP로 분류동정되었다. CMV-NP는 직경이 26 nm의 구형이었으며, VC/RT-PCR 유전자 진단결과 CMV로 확인되었다. CMV-NP는 오이(Cucumis sativus) 등 9개 지표식물에 전신감염을 일으켰으며, 명아주(Chenopodim amaranticolor; C. quinoa)에 국부감염을 일으켰다. CMV-NP는 담배(N. rustica)와 번행초(Tetragonia expansa)의 접종잎과 상엽에 특이한 괴저 원형 반점을 일으켰다. 특히 오이에서는 상엽에 큰 퇴록 원형반점과 엽맥퇴록 병징을 일으켰으며 독말풀(Datura stramonium)에서는 병원성이 없었다.

• The Plant Pathology Journal
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• 제25권2호
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• pp.179-183
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• 2009

To facilitate the genetic manipulation of Cladosporium phlei, a causal agent of leaf spot disease in timothy (Phleum pretense), protoplast-mediated transformation of C. phlei has been developed and the resulting transformants were characterized in this study. Hygromycin B resistance was applied as a dominant selection marker due to the sensitivity of C. phlei to this antibiotic. The transformation efficiency ranged from approximately 20-100 transformants per experiment. Southern blot analysis of stable transformants revealed that transformation occurred by way of stable integration of the vector DNA into the fungal chromosome. PCR analysis and plasmid rescuing of randomly selected transformants suggested that integration of tandem repeat copies of vector DNA was common. In addition, multiple integrations of the transforming vector at different chromosomal sites were also observed. The establishment of a transformation method for C. phlei facilitates strain improvement of this fungus and can be applied as an initial step in the molecular analysis of pigment production in this fungus.

• 식물병연구
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• 제8권4호
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• pp.207-214
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• 2002

대구시와 경상북도 지역에서 Tobacco rattle virus(TRV) 감염에 의한 증상으로 보이는 글라디올러스(Gladiolus hybridus), 크로커스(Crocus spp.), 수선화(Narcissus spp.)를 채집하였다. 톱니무늬(notch), 줄무늬(stripe), 변형 (malformation)등의 증상의 잎 조직을 시료로 하여 direct negative staining method(DN) 및 immunosorbent electron microscopy(ISEM)법에 의해 투과전자현미경으로 바이러스 입자를 관찰한 결과, 각각의 시료에서 긴 입자는 170~200 X 22nm, 짧은 입자는 40~114$\times$22nm 크기의 막대모양 입자가 다수 확인되었다. 글라디올러스에서 분리한 tobacco rattle virus(TRV-K)를 담배(Nicotiana tabacum)에 즙액 접종, 증식시킨 후, 정제하여 항혈청을 제작하였다. TRV-K 의 coat protein(CP)유전자를 특이적인 올리고뉴클레오타 이드 프라이머를 이용하여 역전사-중합효소연쇄반응(RT-PCR)으로 증폭시킨 후에 염기서열분석법으로 확인하였다. 그 결과 TRV-ORY의 CP와 99.5%의 상동성을 나타냈다.

• The Plant Pathology Journal
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• 제24권3호
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• pp.337-351
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• 2008

Host-pathogen interaction in rice bacterial blight pathosystem was analyzed for a better understanding of their relationship and recognition of stable pathogenicity among the populations of Xanthomonas oryzae pv. oryzae. A total number of 52 bacterial strains isolated from diseased leaf samples collected from 12 rice growing states and one Union Territory of India, were inoculated on 16 rice varieties, each possessing known genes for resistance. Analysis of variance revealed that the host genotypes(G) accounted for largest(78.4%) proportion of the total sum of squares(SS), followed by 16.5% due to the pathogen isolates(I) and 5.1% due to the $I{\times}G$ interactions. Application of the Additive Main effects and Multiplicative Interaction(AMMI) model revealed that the first two interaction principal component axes(IPCA) accounted for 66.8% and 21.5% of the interaction SS, respectively. The biplot generated using the isolate and genotypic scores of the first two IPCAs revealed groups of host genotypes and pathogen isolates falling into four sectors. A group of five isolates with high virulence, high absolute IPCA-1 scores, moderate IPCA-2 scores, low AMMI stability index '$D_i$' values and minimal deviations from additive main effects displayed in AMMI biplot as well as response plot, were identified as possessing stable pathogenicity across 16 host genotypes. The largest group of 27 isolates with low virulence, small IPCA-1 as well as IPCA-2 scores, low $D_i$ values and minimal deviations from additive main effect predictions, possessed stable pathogenicity for low virulence. The AMMI analysis and biplot display facilitated in a better understanding of the host-pathogen interaction, adaptability of pathogen isolates to specific host genotypes, identification of isolates showing stable pathogenicity and most discriminating host genotypes, which could be useful in location specific breeding programs aiming at deployment of resistant host genotypes in bacterial blight disease control strategies.

• Journal of Microbiology and Biotechnology
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• 제15권1호
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• pp.112-117
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• 2005

Abstract Griseofulvin has been used as an antifungal antibiotic for the treatment of mycotic diseases of humans and veterinary animals. The purpose of this work was to identify a griseofulvin-producing endophytic fungus from Abies holophylla and evaluate its in vivo antifungal activity against plant pathogenic fungi. Based on nuclear ribosomal ITS1-5.8SITS2 sequence analysis, the fungus was identified and labeled as Xylaria sp. F0010. Two antifungal substances were purified from liquid cultures of Xylaria sp. F0010, and their chemical identities were determined to be griseofulvin and dechlorogriseofulvin through mass and NMR spectral analyses. Compared to dechlorogriseofulvin, griseofulvin showed high in vivo and in vitro antifungal activity, and effectively controlled the development of rice blast (Magnaporthe grisea), rice sheath blight (Corticium sasaki), wheat leaf rust (Puccinia recondita), and barley powdery mildew (Blumeria graminis f. sp. hordei), at doses of 50 to 150 ${\mu}$g/ml, depending on the disease. This is the first report on the production of griseofulvin and dechlorogriseofulvin by Xylaria species.

• Mycobiology
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• 제36권4호
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• pp.236-241
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• 2008

The colonization of an arbuscular mycorrhizal fungus Glomus intraradices BEG110 in the soil caused a decrease in disease severity in cucumber plants after fungal inoculation with Colletotrichum orbiculare. In order to illustrate the resistance mechanism mediated by G. intraradices BEG110, infection patterns caused by C. orbiculare in the leaves of cucumber plants and the host cellular responses were characterized. These properties were characterized using transmission electron microscopy on the leaves of cucumber plants grown in soil colonized with G. intraradices BEG110. In the untreated plants, inter- and intra-cellular fungal hyphae were observed throughout the leaf tissues during both the biotrophic and necrotrophic phases of infection. The cytoplasm of fungal hyphae appeared intact during the biotrophic phase, suggesting no defense response against the fungus. However, several typical resistance responses were observed in the plants when treated with G. intraradices BEG110 including the formation of sheaths around the intracellular hyphae or a thickening of host cell walls. These observations suggest that the resistance mediated by G. intraradices BEG110 most often occurs in the symplast of the host cells rather than in the apoplast. In addition, this resistance is similar to those mediated by biotic inducers such as plant growth promoting rhizobacteria.