• Research in Plant Disease
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• v.12 no.1
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• pp.46-50
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• 2006

The microorganisms with the antifungal activity against Phytophthora capsici and Colletotrichum acutatum and the plant growth-promoting activity were screened from a forest and natural fields of Gajang-Dong, Sangju-city. One of the isolates, Streptomyces griseofuscus 200401, was selected as a good plant growth-promoting strain in this study. In greenhouse test, the number of leaf, fresh weight, and dry weight of pepper plants, that were grown with treatment of culture suspension or powder containing S. griseofuscus 200401, were higher than those without the bacterial cells. Cultivation of S. griseofuscus 200401 strain for 7 days in a nutrient rich medium produced ammonium chloride up to 0.13 ${\mu}g/ml$ in the culture solution of S. griseofuscus. Treatment of the selected strain significantly reduced the severity of the late blight of pepper plants to show the equivalent disease control activity to chemical fungicide. This study suggests that S. griseofuscus 200401 strain could be a potential biological agent with the biocontrol activity and the plant growth-promoting activity.

• The Plant Pathology Journal
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• v.24 no.1
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• pp.63-66
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• 2008

The fermentation broth (FB) of Streptomyces griseofuscus 200401 isolated from non-farming soil showed antagonistic activity against powdery mildew fungus both in melon leaf/seedling assay and in field trials. The FB of S. griseofuscus 200401 was tested at different concentrations. In primary test, the control value of 2-fold diluted FB of S. griseofuscus 200401, compared to control, reached to 82.8%. The protective activity recorded 80.5% in 2-fold dilution of FB. The effect was reduced to 28.9% in high dilution (100-fold) treatment. The curative effect was relatively lower than protective activity. In field test, the antifungal activities of S. griseofuscus 200401 remained low in blocks sprayed with 100-fold diluted FB and the control values were 15.2 and 15.9% in 2005 and 2006, respectively. However, the activities were as high as 65% and 67.3% in the blocks treated with 2-fold dilution of FB during the same period.

• The Korean Journal of Pesticide Science
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• v.9 no.1
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• pp.102-107
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• 2005

To select microorganisms that exhibit antifungal activity against the fungal pathogens of pepper, Phytophthora capsici and Colletotrichum acutatum, soil samples from a forest and natural fields of Gajang-Dong, Sangju-city were tested in vitro and in vivo. Streptomyces griseofuscus 200401 was finally selected throughout antifungal activity test with dual culture, culture broth, and fruits. For the identification of the strain, nucleotide sequences of 16S rDNA and whole cell fatty acids were analyzed. It is like that the strain 200401 may be a novel biological control agent that can reduce application of chemical fungicides to control late blight and anthracnose on pepper.

• Microbiology and Biotechnology Letters
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• v.37 no.4
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• pp.322-332
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• 2009

Five hundred strains of actinomycetes were screened for inhibitory activity against the phytopathogenic fungi; Alternaria alternata, Botryotinia fuckeliana, Colletotrichum acutatum, Colletotrichum gleosporioides, Corticium sasaki, Cylindrocarpon destructans, Fusarium oxysporium, Magnaporthe grisea, Phytophthora infestans, Phytium ultimum, and Thanatephorus cucumeris. The strain CNU-A91231 (Korea Agricultural Culture Collection #20938) showed a strong activity against the phytopathogenic fungi and it was identified as Streptomyces griseofuscus based on the sequence of 16s rDNA. Practical and simple media for the strain S. griseofuscus CNU-A91231 was developed at the conditions ($28^{\circ}C$ and pH 6 with aeration) for efficient bacterial growth. Alanine, glutamine, proline and ammonium ion were good nitrogen sources for the bacterium. Addition of the major salts including Na, Cl, Ca, P, K, and Mg into molasses did not increase the growth of S. griseofuscus. Addition of fertilizers containing amino acids significantly enhanced growth of the bacterium. The optimal medium was formulated as molasses + 1% of glutamate fermentation waste powder. All the conditions and components used in this study did not affect the antifungal activity of S. griseofuscus. The bacterium and the medium in this study can be used as a bio-antifungal agent for plant farming.