• 원예과학기술지
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• 제31권3호
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• pp.371-379
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• 2013

Colletotrichum orbiculare에 의한 탄저병은 오이, 수박 및 멜론 등의 박과작물에 전세계적으로 발생하여 많은 피해를 주고 있다. 본 연구에서는 시판 중인 박과작물 112개 품종의 탄저병에 대한 저항성 정도를 조사하였다. 각 품종의 2-3엽기 유묘에 C. orbiculare KACC 40809의 포자 농도가 4.0 C $40^5spores/mL$인 포자현탁액을 분무하여 접종하였다. 실험한 36개 오이 품종 중 '아시아스트라이크', '통일백다다기', '대선', '청록맛짱', '녹야청청' 및 '아시아노각' 등 6품종은 중도저항성을 나타내었으며, 나머지 품종들은 감수성을 보였다. 멜론 및 참외 33개 품종과 수박 4개 품종들은 C. orbiculare에 대하여 모두 감수성을 나타내었다. 이와 달리 호박 품종들은 실험한 다른 박과작물에 비하여 낮은 감수성을 보였다. 호박 17개 품종 중 '감미락단호박'과 '텃밭풋호박'은 저항성을, 12개 품종은 중도저항성을 나타냈다. 박과작물을 위한 대목 22개 품종 중 '쯔야까EX', '눈부셔', '유니온', 'RS111', '강근토좌', '황제토좌', 'NO.8', '신토좌', '불패토좌' 및 '뉴타입' 등 10개 품종은 저항성을 보였고, 4개 품종은 중도저항성을 나타냈다. 이상의 결과로부터 선발된 저항성 품종들은 박과작물 탄저병 저항성 육종을 위한 유전자원으로 이용될 수 있으리라 생각되었다.

• Mycobiology
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• 제29권1호
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• pp.19-26
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• 2001

Defense mechanisms against anthracnose disease caused by Colletotrichum orbiculare on the leaf surface of cucumber plants after pre-treatment with plant growth promoting rhizobacteria(PGPR), amino salicylic acid(ASA) or C. orbiculare were compared using a fluorescence microscope. Induced systemic resistance was mediated by the pre-inoculation in the root system with PGPR strain Bacillus amylolquefaciens EXTN-1 that showed direct antifungal activity to C. gloeosporioides and C. orbiculare. Also, systemic acquired resistance was triggered by the pre-treatments on the bottom leaves with amino salicylic acid or conidial suspension of C. orbiculare. The protection values on the leaves expressing SAR were higher compared to those expressing ISR. After pre-inoculation with PGPR strains no change of the plants was found in phenotype, while necrosis or hypersensitive reaction(HR) was observed on the leaves of plants pre-treated with ASA or the pathogen. After challenge inoculation, inhibition of fungal growth was observed on the leaves expressing both ISR and SAR. HR was frequently observed at the penetration sites of both resistance-expressing leaves. Appressorium formation was dramatically reduced on the leaves of plants pre-treated with ASA, whereas EXTN-1 did not suppress the appressorium formation. ASA also more strongly inhibited the conidial germination than EXTN-1. Conversely, EXTN-1 significantly increased the frequency of callose formation at the penetration sites, but ASA did not. The defense mechanisms induced by C. orbiculare were similar to those by ASA. Based on these results it is suggested that resistance mechanisms on the leaf surface was different between on the cucumber leaves expressing ISR and SAR, resulting in the different protection values.

• The Plant Pathology Journal
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• 제20권3호
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• pp.172-176
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• 2004

Bacterial isolates TRL2-3 and TRK2-2 showing anti-fungal activity in vitro test against some plant pathogens were identified as Pseudomonas putida and Micrococcus luteus, respectively. Pre-treatment with both bacterial isolates at the concentration 1.0$\times$ $10^7$ and $10^6$cfu/ml in the rhizosphere could trigger induced systemic resistance in the aerial part of cucumber plants against anthracnose caused by Colletotrichum orbiculare. However, the pre-treatment with the higher concentration at 1.0 $\times$ $10^8$ cfu/ml of both isolates could not induce resistance after challenge inoculation with C. orbiculare. As a positive control, the treatment with DL-3 amino butyric acid caused a remarkable reduction of disease severity whereas the lesions on the leaves of untreated plants developed apparently after the fungal inoculation. From these results, it was recomended that disease control using both bacterial isolates inducing systemic resistance in the field where chemical application is forbid.

• Applied Biological Chemistry
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• 제50권3호
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• pp.178-186
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• 2007

항균균활성이 있는 4-isopropylphenol(I)과 2-isopropylphenol (II)을 출발물질로 하여 ester, sulfonyl ester, phosphoyl ester와 ether계열 유도체 42종을 합성하였으며, 확인은 IR, $^{1}H-NMR$과 GC/MS를 이용하였다. 이들 유도체들에 대한 in vitro 항균활성 실험을 오이탄저병균(Colletotrichum orbiculare) 외 9종에 대하여 실시하였다. 그 결과, 2-isopropylphenyl piperonyloate(II-7a)가 오이탄저병균(Colletotrichum orbiculare)과 토마토잎마름병균(Phytophthora infestans)에 효과가 있었으며, 4-isopropylphenyl bromoacetate(I-3a)가 오이잿빛곰팡이병균(Botrytis cinerea), 4-isopropylphenyl-4-methoxybenzenesulfonate(I-6b)는 벼도열병균(Pycularia oryzae)에 탁월한 효과를 나타내었으며, 4-isopropylphenylbenzyl ether(I-4d)가 오이탄저병균(Colletotrichum orbiculare)에 우수한 효과를 나타내었다. In vivo 실험에서는 2-isopropylphenyl piperonyloate(II-7a)가 오이탄저병(Colletotrichum orbiculare)과 토마토잎마름병(Phytophthora infestans), 4-isopropylphenyl 4-methoxybenzenesulfonate(I-6b)가 벼도열병(Pycularia oryzae)에 매우 우수한 항균활성을 나타내었다.

• The Plant Pathology Journal
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• 제21권3호
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• pp.237-243
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• 2005

Resistance inductions on the leaves of cucumber plant by an arbuscular mycorrhiza Glomus intraradices were investigated. In addition, the infection structures were observed at the penetration sites on the leaves of plant inoculated with Colletotrichum orbiculare using a fluorescence microscope. The severity of anthracnose disease caused by Colletotrichum orbiculare was significantly decreased on the leaves of cucumber plant colonized with G intraradices compared with those of non-treated control plants. As a positive control, pre-treatment with DL-3-aminobutyric acid (BABA) caused a remarkable reduction of the disease severity on the pathogen-inoculated leaves. There were no significant differences in the frequency of either germination or appressorium formation of the plant pathogen between mycorrhiza colonized and non-treated plants. It was also the same on the BABA pre-treated plants. However, the frequency of callose formation was significantly high on the leaves of G intraradices colonized plants compared to those of non-treated control plants at 5 days after challenge inoculation. On the leaves of BABA treated plants callose formation was not significantly high than those of non-treated, although the disease severity was more strongly suppressed. It was suggested that the resistance induced by colonization with G. intraradices might be related to the enhancement of callose formation at the penetrate sites on the leaves invaded by the pathogen, whereas resistance by BABA did not.

• Mycobiology
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• 제33권3호
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• pp.131-136
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• 2005

Infection structures were observed at the penetration sites on the leaves of cucumber plants inoculated with Colletotrichum orbiculare using a fluorescence microscope. The cucumber plants were previously drenched with suspension of bacterial strains Pseudomonas putida or Micrococcus luteus. The plants pre-inoculated with both bacterial strains were resistant against anthracnose after inoculation with C. orbiculare. To investigate the resistance mechanism by both bacterial strains, the surface of infected leaves was observed at the different time after challenge inoculation. At 3 days after inoculation there were no differences in the germination and appressorium formation of conidia of C. orbiculare as well as in the callose formation of the plants between both bacteria pre-inoculated and non-treated. At 5 days, the germination and appressorium formation of the fungal conidia were, however, significantly decreased on the leaves of plants pre-inoculated with M. luteus at the concentration with $1.0{\times}10^7\;cfu/ml$. Furthermore, callose formation of plants cells at the penetration sites was apparently increased. In contrast, there were no defense reactions of the plants at the concentration with $1.0{\times}10^6\;cfu/ml$ of M. luteus. Similarly, inoculation P. putida caused no plant resistance at the low concentration, whereas increase of callose formation was observed at the higher concentration. The results of this study suggest that the resistant mechanisms might be differently expressed by the concentration of pre-treatment with bacterial suspension.

• 한국유기농업학회지
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• 제29권4호
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• pp.575-588
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• 2021

본 연구에서는 오이 지상부에 발생하는 두 가지 병원균 B. cinerea와 C. orbiculare에 항균활성을 가지는 유용한 방선균을 선발하고자 하였다. 토양에서 분리한 방선균 560 균주 중 두 병원균에 대해 동시 항균활성을 나타낸 7균주를 일차적으로 선발한 후, 배양여액의 항균활성 검정을 위한 대치배양과 오이 식물체 검정을 통해 최종적으로 S20-465 균주를 선발하였다. 이 균주는 염기서열 비교 분석을 통해 Streptomyces sp.로 동정하였다. S20-465 균주의 배양여액은 두 병원균의 균사 생장을 60%이상 억제하였다. 배양여액의 20배, 40배 희석액을 분무 처리할 경우 오이 잎에서의 잿빛곰팡이병에 의한 병반길이를 감소시켰을 뿐만 아니라 탄저병의 발병도도 대조구에 비해 50% 이상 감소시켜 생물검정에서도 병억제 효과가 있는 것을 확인하였다. 따라서 최종 선발한 S20-465는 앞으로 생물방제 미생물소재로써 활용할 수 있을 것으로 사료된다.

• The Plant Pathology Journal
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• 제19권2호
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• pp.85-91
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• 2003

Pre-treatment with DL-3-aminobutyric acid (BABA) in the cucumber plants caused the decrease of disease severity after inoculation with anthracnose pathogen Colletotrichum orbiculare. In this study, ultrastructures of the vascular bundle and the infection structures in the leaves of BABA-treated as well as untreated cucumber plants were observed after inoculation with the anthracnose pathogen by electron microscopy. The ultrastructures of vascular bundle in the leaves of BABA-treated plants were similar to those of the untreated plants except plasmodesmata. In the BABA-treated plants, the plasmodesmata were more numerous than in the untreated plants, suggesting that the BABA treatment may cause the active transfer of metabolites through the vascular bundle. In the leaves of untreated plants, the fungal hyphae were spread widely in the plant tissues at 5 days after pathogen inoculation. Most cellular organelles in the hyphae were intact, indicating a compatible interaction between the plant and the parasite. In contrast, in the leaves of BABA pre-treated plants the growth of most hyphae was restricted to the epidermal cell layer at 5 days after inoculation. Most hyphae cytoplasm and nucleoplasm was electron dense or the intracellular organelles were degenerated. The cell walls of some plant cells became thick at the site adjacent to the intercellular hyphae, indicating a mechanical defense reaction of the plant cells against the fungal attack. Furthermore, hypersensitive reaction (HR) of the epidermal cells was often observed, in which the intracellular hyphae were degenerated. Based on these results it is suggested that BABA causes the enhancement of defense mechanisms in the cucumber plants such as cell wall apposition or HR against the invasion of C. orbiculare.

• Mycobiology
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• 제30권1호
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• pp.31-36
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• 2002

Soil bacteria were screened for the ability to control cucumber anthracnose caused by Colletotrichum orbiculare through induced systemic resistance(ISR). Sixty-four bacterial strains having in vitro antifungal activity were used for selecting ISR-inducing strains in cucumber. Cucumber seeds(cv. Baeknokdadagi) were sown in potting mixtures incorporated with the soil bacteria, at a rate of ca. $10^8$ cells per gram of the mixture. Two week-old plants were then transplanted into the steam-sterilized soil. Three leaf-stage plants were inoculated with a conidial suspension($5{\times}10^5$ conidia/ml) of C. orbiculare. Diseased leaf area(%) and number of lesions per $cm^2$ leaf were evaluated on third leaves of the plants, $5{\sim}6$ days after inoculation. Among 64 strains tested, nine strains, GC-B19, GC-B35, GK-B18, MM-B22, PK-B14, RC-B41, RC-B64, RC-B65, and RC-B77 significantly(P=0.05) reduced anthracnose disease compared to the untreated control. In contrast, some bacterial strains promoted susceptibility of cucumber to the disease. From the repeated experiments using the nine bacterial strains, GC-B19, MM-B22, PK-B14, and RC-B65 significantly(P=0.05) reduced both diseased leaf area(%) and number of lesions per $cm^2$ leaf in at lease one experiment. These strains with control efficacy of $37{\sim}80%$ were determined to be effective ISR-inducing strains.

• Mycobiology
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• 제47권3호
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• pp.308-318
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• 2019

Bio-sulfur can be produced in the process of desulfurization from a landfill and collected by some microorganism such as Thiobacillus sp. as a sulfur element. In order to investigate practical use of bio-sulfur as an agent for controlling plant disease, in vitro antifungal activity of bio-sulfur was tested against Colletotrichum orbiculare known to cause cucumber anthracnose. Efficacy of bio-sulfur for suppressing anthracnose disease was also evaluated in vivo using cucumber leaves. Mycelial growth of C. orbiculare on medium containing bio-sulfur was inhibited. Disease severity of cucumber leaves pre-treated with bio-sulfur was significantly decreased compared to that of untreated ones. To illustrate how bio-sulfur could suppress anthracnose disease, structures of cucumber leaves infected with C. orbiculare were observed under a fluorescent microscope and a scanning electron microscope (SEM). Cucumber leaves pre-treated with bio-sulfur showed a low rate of appressorium formation whereas untreated ones showed abundant appressoria. Shrunk fungal hyphae were mostly observed on bio-sulfur-pretreated leaves by SEM. Similar results were observed on leaves pre-treated with a commercial fungicide Benomyl(R). These results suggest that inhibition of appressorium formation of C. orbiculare by bio-sulfur may contribute to its suppression of cucumber anthracnose.