The antifungal activity of cork tree extract against three plant pathogenic fungi (Colletrotrichum gloeosporiodes (Penz.) Penz. & Sacc., Pythium ultimum Trow. and Botrytis cinerea Pers.) was investigated antifungal active substances were identified. Cork tree extract showed concentration-dependent antifungal activity against three plant pathogenic fungi. The cork extract had antifungal activity in a concentration-dependent manner, and in particular, showed the most vigorous antifungal activity against Botrytis cinerea. In cork tree extract, the incidence of strawberry powdery mildew fungus after 7 days of treatment was significantly lower as the treatment concentration increased. Control value against strawberry powdery mildew fungus was 49% of cork tree extract, 69% of berberine chloride, and 67% of berberine bromine, which was lower than 80.5% of Rifzol, a representative antifungal compound, but showed strong antifungal activity. The isolated compound and berberine derivative showed similar effects to Rifzol at the treatment concentration (75 μg/ml), and a concentration of at least 10 μg/ml of fresh weight showed a preventive effect against strawberry powdery mildew fungus. Fractions showing antifungal activity were obtained by TLC, and each fraction was examined for the antifungal activity to obtain fractions showing antifungal activity against three types of pathogenic fungi. The compound isolated through TLC analysis was analyzed by HPLC equipped with an ODS column to obtain the main peak presumed to be berberine, which was confirmed as a berberine through 1H NMR analysis. The results of this study are expected to be utilized as biological pesticides with strong antifungal activity against plant powdery mildew etc.
고추를 비롯한 채소작물에 심각한 피해를 야기하는 흰비단병의 생물학적 방제제를 개발하기 위하여 시설재배 토양에서 분리한 세균 중에서 흰비단병균인 Sclerotium rolfsii의 균사생장을 강하게 억제하는 균주를 선발하였다. 선발된 균주는 형태적, 생리적 분석과 16S rRNA 분석결과를 바탕으로 Bacillus amyloliquefaciens로 동정하였고 최종 선발균주를 Bacillus amyloliquefaciens KBC1009로 명명하였 다. Bacillus amyloliquefaciens KBC1009의 배양특성을 조사한 결과 배양온도 30℃, pH 7의 조건에서 72시간동안 배양했을 때 배양 효율이 가장 우수하였으며, 배양에 적정한 영양원은 탄소원 glucose, 질 소원 yeast extract를 사용했을 때 가장 높은 균수를 나타내었다. 포장에서 고추 흰비단병에 대한 Bacillus amyloliquefaciens KBC1009의 방제효과를 검정하기 위해 흰비단병원균을 토양에 접종하고 B. amyloliquefaciens KBC1009 배양액(5×108 cfu/ml)을 500배로 희석하여 10일 간격으로 3회 관주 처리한 결과 무처리대비 66.7%의 방제효과를 나타내었다.