• Journal of Microbiology and Biotechnology
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• v.12 no.5
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• pp.760-765
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• 2002

Mucor miehei KCTC 6011, which grew successfully in ginseng-steaming effluents and produced a large amount of chitosan efficiently, was selected from various fungi. Approximately 120 mg of chitosan per g-dry mycelium was maximally produced in 84 h at $25^{\circ}C$ when grown in the ginseng-steaming effluent (pH 8.0) supplemented with 0.5% yeast extract and 0.002% CuSO$_4$. Chitosan produced by Mucor miehei KCTC 6011 was identified by the IR-spectra to have deacety lated approximately 56%. Viscosity and molecular weight of the chitosan were 80 cps and $1.07\times10^3$ kDa, respectively. The chitosan at 1.5 mg/ml inhibited 73.9% of the mycelium growth of Rhizoctonia solani in 60 h.

• Korean Journal Plant Pathology
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• v.10 no.2
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• pp.144-147
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• 1994

About 450 phytopathogenic fungal cultures were stored in sterile distilled water ar room temperature by the sterile water storage method, which has been known as a simple, convenient, and long-term storage method of microorganisms. After 12 months, viability and pathogenicity of the stored isolates were tested. Among 205 tested, 175 isolates (84.5%) survived. Of these, Rhizoctonia solani, Botrytis cinerea, Pyricularia oryzae, Phytophthora infestans, and Sclerotinia sclerotiorum showed relatively lower survival rate; 92%, 74.1%, 62.5%, 45.8%, and 30%, respectively. Twenty seven isolates belonging to seven important phytopathogenic fungi were tested for pathogenicity, and all isolates tested maintained pathogenicity until at least 12 months after storage.

• Mycobiology
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• v.35 no.2
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• pp.72-75
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• 2007

Antifungal activity of 2-hydroxy 4,4'6'trimethoxy chalcone individually was tested against spore germination of ten fungi of different genera. Efficacy of the chemical was also tested against conidial germination and other growth parameters of Erysiphe pisi on excised pea leaves. 2-Hydroxy 4,4'6'trimethoxy chalcone inhibited spore germination at all the concentrations. Maximum inhibition was observed at 2000 ppm where more than 78 per cent inhibition of spore germination was observed in Ustilago cynodontis, Alternaria brassicicola, A. solani and Aspergillus flavus. It also reduced conidial germination of E. pisi significantly, when applied as pre-inoculation treatment.

• Korean Journal of Soil Science and Fertilizer
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• v.50 no.6
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• pp.598-605
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• 2017

To isolate rhizobacteria exhibiting antifungal activities for for five pathogenic fungi (Sclerotinia sclerotiorum, Fusarium solani, Collectotricum gloeosporides, Fusarium oxysporum, and Botrytis cinerea) which cause damage to Ginseng root in Ginseng grown fields, four soils were collected from Cheorlwon gun, in Korea. From 4 soils, a total of 160 bacterial strains were isolated by dilution plate method. Among 160 strains, 32 strains showed antifungal activities for one or more pathogens. From 32 strains, three strains exhibited antifungal activities for all pathogens. These are two Burkholderia cepacia (ATCC 25416 and ET 13) and one Paenibacillus polymyxa (ATCC 842). These potent antifungal strains showed high identities (99% using 16S-rRNA sequencing).

• Journal of Life Science
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• v.25 no.8
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• pp.910-916
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• 2015

Scientists have recently shown an interest in the characteristics of Bacillus mojavensis strains because of their increasing use in plants as a defense against diseases and mycotoxins. We have shown here that B. mojavensis KJS-3 possesses the typical characteristics of B. mojavensis strains including a strong resistance to high temperatures (≤50℃), tolerance to high salt concentrations (7% NaCl), ethanol tolerance (40% ethanol), and pH range for growth (pH 5-9). B. mojavensis KJS-3 has been used for the production of cyclic lipopeptides including important antifungal substances such as surfactin, iturin, and fengycin. Polymerase chain reaction analysis in this study showed that B. mojavensis KJS-3 can be used for the production of fengycin and the findings of LC-MS/MS analyses suggest that B. mojavensis KJS-3 can be used to produce iturin and surfactin. Antifungal activity analys is confirmed that B. mojavensis KJS-3 has antifungal effects on Botrytis cinerea, Rhizoctonia solani AG-4, Sclerotinia sclerotiorum, and Colletotricum goeosporioides. A microscopy assessment of the roots of wild ginseng plants planted together with B. mojavensis KJS-3 revealed that the roots contained B. mojavensis KJS-3, confirming the bacteria to be a plant growth promoting endophyte (PGPE) which acts against plant diseases and mycotoxins. Our findings lead us to conclude that B. mojavensis KJS-3 can be produced at an industrial level as a microbial pesticide or microbial fertilizer.

• Research in Plant Disease
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• v.21 no.1
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• pp.12-19
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• 2015

Antimicrobial activities of nano-materials were tested against several plant pathogens. Twelve different nano-materials were used to observe the antagonistic activity against three kinds of mold and sixteen different kinds of watermelon fruit rot pathogens (Acidovorax citrulli). According to the results, no antagonism have been found against the pathogen, Cylindrocarpon destructans. However in the case of Pythium ultimum, combination of Brass/Glucose 1,000 ppm confirmed the mycelial growth reduction by 94%. In addition, little effect was found against Rhizoctonia solani by Ag/Glucose 3,000 ppm. The remaining other nano-materials have different antimicrobial effect depending on the strains of A. citrulli. But in the case of lime (Cu/Salt 1,000 ppm) highest antimicrobial activity was observed with 97%. Moreover growth of five different strains of A. citrulli was checked by 99% with the combination of Ag/Glucose 1,000 ppm. 92% reduction of A. citrulli growth was observed with $Brass/CaCO_3$ 3,000 ppm. Tested nano-materials against different plant pathogens in this study showed the antimicrobial activity at the range of 24-70%.

• Microbiology and Biotechnology Letters
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• v.31 no.3
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• pp.235-241
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• 2003

For the biological control of Phytophthora blight of red-pepper caused by Phytophthora capsici, an antibiotic-producing plant growth promoting rhizobacteria (PGPR) Bacillus sp. KL 39 was selected from a local soil of Kyongbuk, Korea. The strain KL 39 was identified as Bacillus megaterium by various cultural, biochemical test and API and Microlog system. B. megaterium KL 39 could produce the highest antifungal antibiotic after 40 h of incubation under the optimal medium which was 0.4% fructose, 0.3% yeast extract, and 5 mM KCl at 30 C with initial pH 8.0. The antifungal antibiotic KL 39 was purified by Diaion HP-20 column, silica gel column, Sephadex LH-20 column, and HPLC. Its RF value was confirmed 0.32 by thin-layer chromatography with Ethanol:Ammonia:Water = 8:1:1. The crude antibiotic KL39 was active against a broad range of plant pathogenic fungi, Rhizoctonia solani, Pyricularia oryzae, Monilinia fructicola, Botrytis cinenea, Alteranria kikuchiana, Fusarium oxysporum and Fusarium solani. The purified antifungal antibiotic KL39 had a powerful biocontrol activity against red-pepper phytophthora blight disease with in vivo pot test as well as the strain B. megaterium KL 39.

• The Korean Journal of Pesticide Science
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• v.19 no.4
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• pp.402-410
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• 2015

The purpose of this study was to estimate the chitinolytic and antifungal activity of Actinomycetes sp.isolated from waste mushroom media. In five kinds of waste mushroom media, Sinyeong mushroom and Yangsongi were the order of the population density of actinomycetes. Totally 91 chitinolytic isolates of Actinomycetes sp. were obtained from waste mushroom media. The isolates were categorized into 3 groups based on chitinolytic activity and antagonisms against Phytophthora capsici, Rhizoctonia solani, Sclerotinia sclerotiorum, Collectotrichum gloeosporioides, and Cladosporium cucumerinum in vitro. CA-23 was selected as a representative isolate of a group showing strong chitinolytic and antagonistic activities to all of the plant pathogens, while AA-65 was selected as a representative isolate showing no chitinolytic activities but strong antagonistic activities to the pathogens. CA-23 and AA-65 were highly effective on control of Phytophthora blight of hot-pepper, powdery mildew and scab of cucumber in a greenhouse tests. Among the isolates tested, CA-23 showed highest control efficacy, while AA-65 not only effectively controlled the diseases but also consistently increased plant growth and yield. Although the isolates are similarly affected on suppression of plant pathogens, the isolates could be differ from each other in modes of action. Further studies on mechanisms and practical applications are being progressed.

• Journal of Life Science
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• v.12 no.3
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• pp.242-249
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• 2002

The optimal culture conditions in 500$m\ell$ flask suture, 5$\ell$ jar fermenter and 2,000 $\ell$ large stale culture were investigated to maximize the production of antibiotic on Rhizoctonia solani AC4, the causal agent of vegetables damping-off, by the strain Bacillus ehimensis YJ-37. Starch (1.5%) as a carbon source, peptone (0.6%) as a nitrogen source and MgC1$_2$(0.15%) as a metal ion in the medium containing N $a_2$HP $O_4$(0.3%) showed the highest production of the antibiotic(s) in a rotary shake (200 rpm). Optimal initial pH of the culture medium, culture temperature and culture time for the antibiotic(s) production were pH 8.0, 32$^{\circ}C$ and 54hrs, respertively. Under the optimal renditions in flask culture, cell growth and antifungal activity (clear zone size) were 1.42 $\times$ 10$^{8}$ cfu/$m\ell$ (21g-DCW/ $\ell$) and 13.9 mm, respectively. In 5 $\ell$ jar fermenter (medium 3 $\ell$), optimal air flow, agitation speed and culture time for the antibiotic(s) production were 2 vvm, 200 rpm and 48hrs, respectively. Under the optimal conditions in 5 $\ell$ jar fermenter, tell growth and antifungal activity were 2.06 $\times$ 10$^{8}$ cfu/$m\ell$ (30g-DCW/ $\ell$) and 13.4 mm, respectively. Under the culture conditions of air flow (30 vvm) and agitation speed (200 rpm) at 32$^{\circ}C$ for 10 days in 2,000 $\ell$ large scale culture (medium 1,800 $\ell$, pH 8.0), cell growth and antifungal activity were 0.81$\times$10$^{8}$ cfu/$m\ell$ (12g-DCW/ $\ell$) and 8.6 mm, respectively.

• Korean journal of applied entomology
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• v.24 no.2 s.63
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• pp.65-70
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• 1985

The locational preference of the brown planthopper (BPH) Nilaparvata lugens ($St{\aa}l$) and the whitebacked plant hopper (WBPH) Sogatella furcifera(Horvath) was studied on rice cultivars IR22 and IR36 as an integral part of subsequent research on insect-fungal pathogen relationships. The BPH was observed to stay consistently on the basal portion while the WBPH showed a general preference for the upper portion regardless of varieties, rice growth stages and insect population density levels. The habitat preference of both species (BPH and WBPH) was found not to be affected by the presence of the other species when both species are present on the same host plant Five rice cultivars with different reactions to BPH biotype 2 were used in the study on BPH-Rhizoctonia solani relationship: IR22 and TN1 (susceptible); Triveni and ASD7 (moderately resistant); and IR42 (resistant). Test plants were inoculated with R. solani (Kuhn) $3{\sim}4$days after insect infestation. Sheath blight disease severity/incidence was significantly higher in the treatment where BPH+R. solani were together than in the treatment with only the pathogen. Symptom expression of the disease in the BPH-pathogen combination was faster and mycelial growth was more profuse inducing the formation of more infection structures. Regardless of varietal reaction to BPH biotype 2, the degree of hopperburn was significantly higher in the combination of the two pests as compared with that of BPH alone. There could be a synergistic relationship between the insect pest and the pathogen indicated by a positive interaction between the two species.