본 연구는 국외토양으로부터 분리한 400여개의 군주에서 agar plug assay를 이용하여 식물병원균에 대한 항진균성물질을 생산하는 방선균 (I-8)을 분리하였다. 항진균 물질 생산의 최적 조건을 검토한 결과 공시균 I-8은 pH 8로 조정된 ISP No. 2 배지에서 항진균물질 생산성이 가장 우수한 것으로 입증되었다. 공시균 I-8의 식물병원균의 생육저해 기구를 규명하기 위한 기초 연구로서 공시균 I-8이 세포벽 구성성분인 cellulase, chitinase와 같은 가수분해효소를 생산하는 것을 확인하였다. I-8의 배양액은 ethyl acetate추출물에서 식물병원균 14개 균주에 항진균 활성을 나타내었고 ethyl ether추출액에서는 식물병원균 10개 균주에 항진균 활성을 나타내었다. I-8의 ethyl acetate추출물은 공시균인 13-16의 추출물과 혼합사용시 식물병원균인 Monosporascus cannonballus KACC 40940에 대한 항진균력의 상승효과를 확인할 수 있었다. I-8균주 배양체는 고체배지상에서 16개의 식물병원균에 대해 강한 생육저해 효과를 보여, 광범위한 항진균 활성을 나타내는 것을 확인하였다.
For the production of an antifungal compound, one strain (I-8) was selected from approximately 400 strains isolated from various soil samples. The optimum carbon source, nitrogen source and pH culture conditions for the production of the antifungal compound were investigated. ISP No. 2 medium (yeast extract 0.4%, malt extract 1% and dextrose 0.4%, at pH 8) was determined to be the optimum medium. Strain I-8 showed broad antifungal activity against the plant pathogenic fungi tested, including Sclerotinia sclerotiorum KACC 41065, as well as cellulase and chitinase activities in an agar plate assay. The extraction of antifungal compounds was performed using ethyl ether and ethyl acetate. In a culture broth of strain I-8, the ethyl acetate extract exhibited effective growth inhibition against 14 of the 20 phytopathogenic fungi tested. By mixing the ethyl acetate extract from I-8 with the ethyl ether extract from the fungus 13-16, which shows specific antifungal activity against Colletotrichum orbiculare KACC 40808, the antifungal activity of I-8 against phytopathogenic fungi was confirmed to be slightly increased. Strain I-8 showed strong growth inhibition against 16 phytopathogenic strains in agar plate tests.
