• Mycobiology
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• 제42권2호
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• pp.158-166
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• 2014

In this study, bacterial strains were isolated from soils from 30 locations of Samcheok, Gangwon province. Of the isolated strains, seven showed potential plant growth promoting and antagonistic activities. Based on cultural and morphological characterization, and 16S rRNA gene sequencing, these strains were identified as Paenibacillus species. All seven strains produced ammonia, cellulase, hydrocyanic acid, indole-3-acetic acid, protease, phosphatase, and siderophores. They also inhibited the mycelial growth of Fusarium oxysporum f. sp. radicis-lycopersici in vitro. The seven Paenibacillus strains enhanced a range of growth parameters in tomato plants under greenhouse conditions, in comparison with non-inoculated control plants. Notably, treatment of tomato plants with one identified strain, P. polymyxa SC09-21, resulted in 80.0% suppression of fusarium crown and root rot under greenhouse conditions. The plant growth promoting and antifungal activity of P. polymyxa SC09-21 identified in this study highlight its potential suitability as a bioinoculant.

• The Plant Pathology Journal
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• 제35권2호
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• pp.137-148
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• 2019

In search of an effective biological control agent against the tomato pathogen Fusarium oxysporum f. sp. lycopersici, rhizospheric soil samples were collected from eight agro-ecological zones of Bangladesh. Among the bacteria isolated from soil, 24 isolates were randomly selected and evaluated for their antagonistic activity against F. oxysporum f. sp. lycopersici. The two promising antagonistic isolates were identified as Brevundimonas olei and Bacillus methylotrophicus based on morphological, biochemical and molecular characteristics. These two isolates were evaluated for their biocontrol activity and growth promotion of two tomato cultivars (cv. Pusa Rubi and Ratan) for two consecutive years. Treatment of Pusa Rubi and Ratan seeds with B. olei prior to inoculation of pathogen caused 44.99% and 41.91% disease inhibition respectively compared to the untreated but pathogen-inoculated control plants. However, treatment of Pusa Rubi and Ratan seeds with B. methylotrophicus caused 24.99% and 39.20% disease inhibition respectively. Furthermore, both the isolates enhanced the growth of tomato plants. The study revealed that these indigenous bacterial isolates can be used as an effective biocontrol agent against Fusarium wilt of tomato.

• Mycobiology
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• 제32권3호
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• pp.119-122
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• 2004

The intergenic spacer(IGS) sequence of Fusarium oxysporum have been reported to provide reliable information concerning intraspecific variation and phylogeny of fungal species. The eleven strains of Fusarium oxysporum and its formae speciales belonging to section Elegans were compared with sequencing analysis. The direct sequencing of partial IGS was carried out using PCR with primer NIGS1(5'-CTTCGCCTCGATTTCCCCAA-3')/NIGS2(5'-TCGTCGCCGACAGTTTTCTG-3') and internal primer NIGS3(5'-TCGAGGATCGATTCGAGG-3')/NIGS4(5'-CCTCGAATCGATCCTCGA-3'). A single PCR product was found for each strain. The PCR fragments were sequenced and revealed a few within species polymorphisms at the sequence level. The size of partial IGS sequencing of F. oxysporum was divided into three groups; $526{\sim}527$ bp including F. o. f. sp. chrysanthemi, cucumerinum, cyclaminis, lycopersici, and fragariae; $514{\sim}516$ bp including F. o. f. sp. lilii, conglutinans, and raphani; 435 bp for F. o. f. sp. cucumerinum from Korea. Sequence analysis of PCR products showed that transitions were more frequent than transversions as well as the average numbers of substitution per site were range 0.41% to 3.54%.

• 농업과학연구
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• 제48권1호
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• pp.151-161
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• 2021

Fusarium wilt disease of tomato plants caused by Fusarium oxysporum f.sp. lycopersici (FOL race2) is one of the most important diseases of tomatoes worldwide. In the competition between tomato and FOL, the FOL can win by overcoming the immune system of tomato plants. Resistant interaction between the FOL race2 and tomato plants is controlled by avirulence genes (AVR2) in FOL and the corresponding resistance genes (I2) in tomato plants. In this study, 7 FOL isolates (KACC) were used to test their pathogenicity, and FOL race2 was selected because it is a broad problem in Korea. The Fol40044 isolates showed the most severe pathogenicity, and the avr2 gene was also isolated and identified. Moreover, to select resistance, 20 tomato varieties were inoculated with the Fol40044, and the degree of pathogenicity was evaluated by analyzing the expression of the avr2 gene. As a result, three resistant tomato varieties (PCNUF73, PCNUF101, PCNUF113) were selected, and the expression of the avr2 gene was much lower than that of the control Heinz cultivar. This result shows that the screening assay is very efficient when the avr2 gene is used as a marker to evaluate the expression level when selecting varieties resistant to tomato wilt disease. Based on these results, it is possible to isolate the I2 gene, which exhibits resistance and molecular biological interactions with the AVR2 gene from the three tomato-resistant varieties. The I2 gene provides breeders more opportunities for Fusarium disease resistance and may contribute to our understanding of their interactions with the FOL and host plant.

• The Plant Pathology Journal
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• 제38권1호
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• pp.33-45
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• 2022

To screen antagonistic fungi against plant pathogens, dual culture assay (DCA) and culture filtrate assay (CFA) were performed with unknown soil-born fungi. Among the different fungi isolated and screened from the soil, fungal isolate ANU-301 successfully inhibited growth of different plant pathogenic fungi, Colletotrichum acutatum, Alternaria alternata, and Fusarium oxysporum, in DCA and CFA. Morphological characteristics and rDNA internal transcribed spacer sequence analysis identified ANU-301 as Aspergillus terreus. Inoculation of tomato plants with Fusarium oxysporum f. sp. lycopersici (FOL) induced severe wilting symptom; however, co-inoculation with ANU-301 significantly enhanced resistance of tomato plants against FOL. In addition, culture filtrate (CF) of ANU-301 not only showed bacterial growth inhibition activity against Dickeya chrysanthemi (Dc), but also demonstrated protective effect in potato tuber against soft rot disease. Gas chromatography-tandem mass spectrometry analysis of CF of ANU-301 identified 2,4-bis(1-methyl-1-phenylethyl)-phenol (MPP) as the most abundant compound. MPP inhibited growth of Dc, but not of FOL, in a dose-dependent manner, and protected potato tuber from the soft rot disease induced by Dc. In conclusion, Aspergillus terreus ANU-301 could be used and further tested as a potential biological control agent.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 1999년도 정기총회 및 춘계 학술발표회
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• pp.29-29
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• 1999

• 미생물학회지
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• 제48권1호
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• pp.16-21
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• 2012

여러 식물의 근권에서 세균 균주들을 분리하여 이들의 항진균성 물질 생성능을 조사하였다. 분리균주 중 Fusarium oxysproum을 포함한 5가지 주요 식물병원성 진균에 대한 생장저해가 우수한 7개 균주를 16S rRNA 유전자 염기서열로 동정하였다. 이들 중 Paenibacillus peoriae RhAn32, Pseudomonas otitidis TK1과 Bacillus cereus TK2가 가장 넓은 생장 저해범위를 나타내었으며 항진균성 물질 중 siderophore 생성능은 P. otitidis TK1이 3.21 mM/ml로 가장 높았고 HCN은 Pseudomonas koreensis Rh2와 Rh7 균주만이 생성하였으며 Brevibacterium frigoritolerans EnA9와 P. peoriae RhAn32는 각각 1558.9와 $1436.7{\mu}M$ glucose/min/mg protein의 높은 chitinase 활성을 나타내었다. P. otitidis TK1과 P. peoriae RhAn32의 항진균능을 진균과의 공동배양을 통해 정량분석한 결과 세 종류의 Fusarium oxysproum의 생장을 유의성 있게 저해하였다. P. otitidis TK1은 식물생장을 촉진하는 호르몬인 auxin의 생성능도 가장 높았는데 이 균주를 4주 자란 토마토 유묘에 F. oxysporum f. sp. lycopersici와 동시에 접종하여 8주간 재배하였을 때 줄기와 뿌리 길이 및 습윤 중량이 비접종 대조군에 비해 각각 45.7, 64.9와 118%로 유의성 있게 증가하였다. 따라서 이 균주들은 유기합성농약을 대체하면서 식물생장을 촉진하는 미생물제로서의 적용이 가능할 것으로 기대된다.

• The Plant Pathology Journal
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• 제25권3호
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• pp.256-262
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• 2009

The potential of. nonpathogenic Fusarium oxysporum strain Avr5, either alone or in combination with chitosan and Bion, for inducing defense reaction in tomato plants inoculated with F. oxysporum f. sp lycopersici, was studied in vitro and glasshouse conditions. Application Bion at concentration of 5, 50, 100 and $500{\mu}g$/ml, and the highest concentration of chitosan reduced in vitro growth of the pathogen. Nonpathogenic F. oxysporum Avr5 reduced the disease severity of Fusarium wilt of tomato in split plants, significantly. Bion and chitosan applied on tomato seedlings at concentration $100{\mu}g$ a.i./plant; 15, 10 and 5 days before inoculation of pathogen. All treatments significantly reduced disease severity of Fusarium wilt of tomato relative to the infected control. The biggest disease reduction and increasing tomato growth belong to combination of nonpathogenic Fusarium and Bion. Growth rate of shoot and root markedly inhibited in tomato plants in response to tomato Fusarium wilt as compared with healthy control. These results suggest that reduction in disease incidence and promotion in growth parameters in tomato plants inoculated with nonpathogenic Fusarium and sprayed with elicitors could be related to the synergistic and cooperative effect between them, which lead to the induction and regulation of disease resistance. Combination of elicitors and non-pathogenic Fusarium synergistically inhibit the growth of pathogen and provide the first experimental support to the hypothesis that such synergy can contribute to enhanced fungal resistance in tomato. This chemical could provide a new approach for suppression of tomato Fusarium wilt, but its practical use needs further investigation.

• 한국식물병리학회지
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• 제14권3호
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• pp.278-285
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• 1998

Effects of chitosan on growth of tomato plant, and suppression of Fusaruim wilt caused by Fusarium oxysporum f. sp. lycopersici and late blight casued by Phytophthora infestans, were examined. Both late blight and fusarium wilt were suppressed by spray and irrigation of chitosan, respectively. Inhibition of mycelial growth was not greatly affected by molecular size of chitosan but, concentration dependent effects was observed. Ninty percent of P. infestans and 80% of F. oxysporum f. sp. lycopersici of mycelial growth was inhibited by 1,000 ppm of chitosan (MW 30,000~50,000) when amended in plate media. Induction of defense-related gene expression in plant by chitosan treatments were observed when chitosan treated tobacco and tomato RNA samples were hybridized with several defense-related genes as probes. The results revealed that $\beta$-1,3-glucanase and chitinase genes were strongly induced, while pathogenesis-related protein-1, 3-hydroxy-3-methylglutaryl coenzyme A reductase, anionic peroxidase, phenylalanine ammonia lyase genes were weakly induced by chitosan treatment. These results suggest that chitosan have dual effects on these host-pathogen interactions. Possible roles of chitosan in suppression of tomato diseases by inhibition of mycelial growth and activation of plant defense responses are discussed.

• 한국응용곤충학회지
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• 제23권2호
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• pp.74-81
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• 1984

딸기${\cdot}$시들음병의 발생분포, 병원균의 몇가지 성질, 방제효과 및 품종 저항성에 대하여 조사한 결과를 요약하면 다음과 같다. 1. 본병은 수년 전 경남의 삼낭진, 김해 지역에서 발견된 이후 발생지역이 급속히 확대되어 현재 우리나라 딸기재배 전 지역에 발생되고 있으며 그 피해도 격심하다. 2. 본 분리균은 V-8 Agar상에서 대형, 소형분생포자와 후막포자가 형성되었고 단포의 소형분생포자는 무격막의 분생자병의 선단에 의두상으로 형성되어 F. oxysorum에 속하였다. 3. 본 균의 대형분생포자 형성은 균주와 재배종류에 따라 차이가 심하였으나 균주 모두 V-8 Agar에서 풍부히 형성되었고 PDA, PSA와 Malt extract Agar 에서는 극히 불량하였다. 4. F. oxysporum의 분화형이 다른 f. sp. curumerinum, f. sp. melonsis, f. sp lycopersici, f sp. lini, f. sp. fragariae 및 본 균을 공시하여 오이, 토마토, 참외 , 수박, 수세미 , 양배추, 말기에 cross inoculation 시험결과 각 분화형은 각자의 기주에만 병원성을 나타내었고 본 균은 딸기 만을 침해하였으며 본 균과 f.sp. fragariae의 2균주와의 형태, 기생성 및 병징 등에서 거의 일치되었으므로 본 균의 분화형은 Fusarium oxysporum Schl. f sp. fragariae Winks & Williams로 동정되었다. 5. 본 균의 균계생육과 포자형성 저지효과에 있어서 Benomyl과 Homai가 가장 우수하였으나 Homai에 의한 포자형성 저지효과가 Benomyl 보다 높은 경향이었다. 6. 접종에 의한 품종 저항성 검정결과, 구류미 38, Himiko, Senga gigana 및 Daehak 1은 저항성이었고, 보교조생, Instiate Z-4, Juspa, Puget beauty 및 Marshall 은 감수성이었다.