• Korean Journal of Environmental Agriculture
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• v.28 no.4
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• pp.435-441
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• 2009

In the present study, we analyzed the defensin protein deduced from Korean radish (Raphanus sativus L.) seeds.To express the genes in E. coli, we constructed a recombinant expression vector with a defensin gene, named rKRs-AFP gene isolated from Korean radish seeds. Over expressed rKRs-AFP proteins was separated by SDS-PAGE to determine the purity, and protein concentration was determined by the Bradford method. Antifungal activity was assessed by disk assay method against the tested fungi. As a result, when 500 mL of cell culture were disrupted by sonicator, 32.5 mg total proteins were obtained. The purified protein showed a single band on SDS-PAGE with estimated molecular weight about 6 KDa, consistent with the molecular mass calculated from the deduced amino acid sequence. The purified rKRs-AFP protein showed remarkable antifungal activities against several fungi including Aspergillus niger, Botrytis cinerea causing the gray mold disease, and Candida albicans. In field tests using the purified rKRs-AFP protein, the protein showed the reducing activity of disease spot and the mitigating effect of spreading of disease like agrichemicals. The immuno-assay of rKRs-AFP protein showed that the purified protein entirely accumulated at B. cinerea cytoplasm through the hyphal septa shown by fluorescence imaging. There was no fluorescence inside the cell, when the hypha was incubated without the protein. These all results indicate that the recombinant rKRs-AFP proteins can be utilized as a potential antifungal drug to control harmful plant fungal pathogens.

• Mycobiology
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• v.41 no.2
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• pp.108-111
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• 2013

The use of a microorganism, or its secretions, to prevent plant disease offers an attractive alternative or supplement to synthetic fungicides for the management of plant disease without the negative effects of chemical control mechanisms. During a screening for microorganisms with the potential to be used as microbial fungicides, Bacillus sp. BS061 was isolated from a plant leaf. The strain BS061 potently inhibited the mycelial growth of Botrytis cinerea, and significantly reduced disease incidence of powdery mildew in cucumber and strawberry. We also found that the culture filtrate of BS061 inhibited the mycelial growth of various plant pathogens.

• Research in Plant Disease
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• v.20 no.3
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• pp.182-188
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• 2014

Because bacterial isolates from only a few genera have been developed commercially as biopesticides, discovery and characterization of novel bacterial strains will be a key to market expansion. Our previous screen using plant bioassays identified 24 novel biocontrol isolates representing 12 different genera. In this study, we characterized the 3 isolates showing the best biocontrol activities. The isolates were Pantoea dispersa WCU35, Proteus myxofaciens WCU244, and Exiguobacterium acetylicum WCU292 based on 16S rRNA sequence analysis. The isolates showed differential production of extracellular enzymes, antimicrobial activity against various fungal or bacterial plant pathogens, and induced systemic resistance activity against tomato gray mold disease caused by Botrytis cinerea. E. acetylicum WCU292 lacked strong in vitro antimicrobial activity against plant pathogens, but induced systemic resistance against tomato gray mold disease. These results confirm that the trait of biological control is found in a wide variety of bacterial genera.

• Research in Plant Disease
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• v.13 no.3
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• pp.170-176
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• 2007

Effects of fungicides on the mycelial growth of Botrytis cinerea isolated from ginseng leaves were investigated by an agar dilution method. By using a agar dilution method, it was investigated the effect of fungicides, procymidone, carbendazim and the mixture with both of carbendazim and diethofencarb, on the mycelial growth of Botrytis cinerea isolates, which were isolated from infected leaves of ginseng in 2005 and 2006. With MIC (minimum inhibiton concentration) of procymidone against B. cinerea, pathogens were divided into two groups. While one showed the low MIC between 0.8 and $4.0{\mu}g/ml$, the other showed higher MIC above $20{\mu}g/ml$. In terms of the inhibition ratio of mycelial growth at the indicated concentration of procymidone, isolates of B. cinerea were divided into three groups; the sensitive, the intermediate resistant, and the resistant group. Each group was differentiated by $EC_{50}$; the sensitive group showed below $2.0{\mu}g/ml$, the intermediate resistant group between 2.0 to $5.0{\mu}g/ml$, and resistant group above $5.0{\mu}g/ml$. Compared with the ratio of resistant isolates of B. cinerea in 2005, the ratio in 2006 increased from 19.3% to 27.5%. Furthermore, the average $EC_{50}$ value of them increased from $10.0{\mu}g/ml$ in 2005 to $237.3{\mu}g/ml$ in 2006. The ratio of isolates showing the multiple resistance between procymidone and carbendazim was 40.2%, whereas the ratio was 4.0% showing the multiple resistance in the mixture.

• The Korean Journal of Pesticide Science
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• v.19 no.3
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• pp.329-334
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• 2015

With 86 isolates of Botrytis cinerea obtained from diseased fruits of tomato, strawberry and cucumber, it was conducted to detect the fungicide resistance of B. cinerea against mepanipyrim through an agar dilution method. FGA medium was used for monitoring the resistance. Among 86 isolates of B. cinerea, resistant isolates were composed by 23.3%, which was different according to regions isolating the pathogen. In accordance with isolation region, the isolation frequency of resistant isolates was as follows; that of Gyeonggi, Gyeongnam/Pusan and chungnam was 28.6%, 33.3% and 12.8%, respectively. The resistant isolates of B. cinerea showed the cross resistance between mepanipyrim and pyrimethanil. Also the pathogenicity of B. cinerea resistant to mepanipyrim was high as like that of sensitive isolates. Because of them, it should be necessary to manage the spraying system of mepanipyrim and the monitoring for the fungicide resistance.

• Horticultural Science & Technology
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• v.28 no.6
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• pp.1072-1077
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• 2010

Plant diseases including gray mold caused by Botrytis cinerea are often reduced when calcium compounds are used as alternative materials in paprika. However, much less information is available about the effects of calcium compounds on controlling of $B.$ $cinerea$. Seven calcium compounds such as calcium sulfate dihydrate, calcium chloride, calcium nitrate, calcium oxide, calcium hydroxide, calcium carbonate, and calcium hydride were evaluated for their effectiveness against $B.$ $cinerea$ on potato dextrose agar medium. The pH of selected calcium compounds was higher (pH 8.2-10) than that of the control (pH 6.6). Calcium carbonate, calcium oxide, calcium hydride, and calcium hydroxide among seven calcium compounds were more effectively inhibited the growth of $B.$ $cinerea$ than other calcium compounds. In the case of spraying the spore suspension on paprika applied with the selected four calcium compounds and supplied with the selected calcium supplements in a hydroponic culture system, the paprika treated with calcium compounds showed less severity of disease than those untreated plants. On the basis of our results, we propose that the suppressive effects of calcium compounds on $B.$ $cinerea$ in paprika resulted from the supply of calcium and a certain degree of salt stress.

• Korean Journal Plant Pathology
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• v.14 no.6
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• pp.668-675
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• 1998

These surveys were conducted to check the occurrence of disease in various horticultural crops in alpine areas, especially Daekwallyong areas, Pyongchang-Gun, and Hyeongseong-Gun in Kangwon province. TuMV on Chinese cabbage was one of the most serious diseases, especially in 1994 and 1997. The incidence of soft rot and clubroot has been increased gradually. Brittle root rot on Chinese cabbage was significantly decreased. Soft rot, gray mold, downy mildew, powdery mildew, bottom rot and Alternaria leaf spot were the common diseases on most vegetable crops. Gray mold (Botrytis cinerea) on celery, cercospora leaf spot (Cercospora sp.) on melon, powdery mildew (Erysiphe cichoracearum) on lettuce, and clubroot (Plasmodiophora brassicae) on parsley are newly found in Korea. The most common and predominant diseases were viruses, especially CMV, TMV, TuMV, BBMV, and gray mold, wilts, and cercospora leaf spot on many flowers in alpine areas. Fusarium oxysporum f. sp. eustomae causing wilting on lisianthus (Eustoma grandiflorum), Turnip mosaic virus causing mosaic and color breaking on stock, Cercospora spp. causing cercospora leaf spot on various wild lily, Cladosporum echinulatum causing leaf spot on carnation, and phytoplasma causing witches' broom on statice (Limonium sinuatum) and blazing star (Liatris spp.) were newly found during these surveys in Korea.

• The Korean Journal of Pesticide Science
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• v.3 no.2
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• pp.86-89
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• 1999

A series of methanesulfonamide (I a- I g) and phenylhydrazone (IIa-IIh) derivatives were synthesized and their fungicidal activity in vitro against gray mold (BC: Botrytis cinerea), phytophthora blight (PC: Phytophthora capsici) and sheath blight (RS: Rhizoctonia solani) were measured by agar dilution method. The (II) deriviatives showed higher activity than ( I ) derivitives. And the relative orders of the fungicidal activity are BC=PC>RS, Among these compounds, 3-chlorophenyl substituent, IIg showed the most highest activity ($pI_{50}=3.96$) against PC. From the parameter focusing technique, major factors on the activity were ovality, polar and logP constant and so on.

• Microbiology and Biotechnology Letters
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• v.34 no.1
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• pp.63-69
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• 2006

We isolated a bacterium which produces antifungal substances from the Lake of Saimaa soils in Fin-land. The isolated strain was identified as Bacillus sp. and shown a strong antifungal activity on plant pathogenic fungi. Bacillus sp. KMU-1011 produced maximum level of antifungal substances under incubation aerobically at $24^{\circ}C$ for 48 hours in nutrient broth containing 1.0% glucose and 1.0% polypeptone at 180 rpm and initiated pH adjusted to 6.0. Precipitate of culture broth by $30{\sim}60%$ ammonium sulfate precipitation exhibited strong antifungal activity against Botrytis cinerea KACC 40573 by dry cell weight. Chloroform extract of cultured broth also shown fungal growth inhibitory activity against C. gloeosporioides KACC 40804, D. bryoniae KACC 40669, F. oxysporum KACC 40037, F. oxysporum KACC 40052, F. oxysporum f. sp. radicis-lycopersici KACC 40537, F. oxysporum KACC 40902, M. cannonballus KACC 40940, P. cambivora KACC 40160, R. solani AG-1 KACC 40101, R. solani AG-4 KACC 40142, and S. scleotiorum KACC by agar diffusion method.

• Horticultural Science & Technology
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• v.29 no.2
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• pp.151-155
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• 2011

The fungus Botrytis cinerea causes fruit rot of strawberry and the damages can result in harvest losses upto 50%. Proper timing of fungicide application is essential for successful control of Botrytis fruit rot, fenhexamid plus iminoctadine tris, cyprodinil plus fludioxonil, fludioxonil alone, and Bacillus subtilis QST713 were applied to individual buds, flowers, and green and red fruit of cultivar 'Seolhyang' ex vivo. Cyprodinil plus fludioxonil or fludioxonil alone was applied i) before and after a 5-hr period of low-temperature ($0^{\circ}C$) incubation ex vivo ii) in field trials. Strawberry flowers and red fruit were more susceptible to B. cinerea than the green fruits. Incidence of Botrytis rot with fenhexamid plus iminoctadine tris and cyprodinil plus fludioxonil was the lowest at flowering, whereas B. subtilis QST713 did not significantly among treatments. In 2010, incidence of Botrytis fruit rot was significantly reduced when fludioxonil was applied two times at 1 week intervals from 50% bloom in field trials. Cultivars Redpearl and Seolhyang were more susceptible to low-temperature than cvs. Maehyang and Akihime. Cyprodinil plus fludioxonil application was effective when applied before onset of the low-temperature treatment period. Fludioxonil showed the most effective when it was sprayed one and more than two times in before and post low-temperature condition, respectively. These results demonstrate that fungicide selection and timing can interact with stage of fruit development and low-temperature in determining effectiveness of suppression of Botrytis fruit rot.