• 한국균학회소식:학술대회논문집
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• 한국균학회 2016년도 춘계학술대회 및 임시총회
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• pp.13-13
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• 2016

Insects constitute the largest and most diverse group of animals in the world. They also serve as the hosts or nutrient sources for an immense assemblage of pathogens, parasites, and predators. More than 700 fungal species from 100 genera have adopted an entomopathogenic lifestyle. Although entomopathogenic fungi were studied as only biocontrol agents against a variety of pests in various countries, it has been recently focused their additional roles in nature. They are antagonists to/against plant pathogens, endophytes, and possibly even plant growth promoting agents. The potential antimicrobial effect against fungal plant pathogens by an isolate of entomopathogenic fungi including Beauveria bassiana, Lecanicillium spp., and Isaria fumosorosea have been reported since late 1990s, but wasn't reported pathogenicity of the isolate against pests. Later, a Canadian Lecanicillium sp. isolate and L. longisporium isolated from Vertalec$^{(R)}$ showed simultaneous control effect against both aphid and cucumber powder mildew. Therefore, the antimicrobial activities of 342 fungi isolates collected from various regions and conditions in Korea were evaluated against plant pathogenic fungus Botrytis cinerea using dual culture technique on agar plate. As a result, 186 isolates (54.4%) shown the antifungal activity against B. cinerea. The culture filtrates of selected fungi completely suppressed the growth of the microorganisms, indicating that suppression was due to the presence of antimicrobial substances in the culture filtrate. Mode of action of these fungi against insect involves the attachment of conidia to the insect cuticle, followed by germination, cuticle penetration, and internal dissemination throughout the insect. During infection process, secreted enzymes, proteinous toxins, and/or secondary metabolites secreted by entomopathogenic fungi can be used to overcome the host immune system, modify host behavior, and defend host resources. Recently, secondary metabolites isolated from entomopathogenic fungi have been reported as potential bioactive substances. Generally, most of bioactive substances produced by entomopathogenic fungi have reported low molecular weight (lower than 1,000 g/mol) as peptide and, in contrast the high molecular weight fungal bioactive substances are rare. Most substances based on entomopathogenic fungi were shown antimicrobial activity with narrow control ranges. In our study we analyzed the antimicrobial substances having antagonistic effects to B. cinerea. Antimicrobial substances in our fungal culture filtrates showed high thermostability, high stability to proteolytic enzymes, and hydrophilicity and their molecular weights were differed from substance. In conclusion, entomopathogenic fungi showed pathogenicity against insect pests and culture filtrate of the fungi also shown to antimicrobial activity. In the future, we can use the entomopathogenic fungi and its secondary metabolites to control both insect pest control and plant pathogenic fungi simultaneously.

• 한국잠사곤충학회지
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• 제43권2호
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• pp.83-87
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• 2001

현재까지 곤충기생균 고유배지가 개발되어 있지 않아 식물기생균 배지를 대체 이용해 옴에 따라, 본 시험에서는 고단백질원으로써 이용가치가 있는 누에분말을 이용하여 곤충기생균 최적배지를 개발코자 하였다. 그 결과 사면배지상에서 균 배양시 12종의 배양형태는 현상, 융기, 주변형태가 균종 및 배지에 따라 배양 상이 동일 혹은 다양하게 형성되었다. 균주별 생장율은 12균주 중 C. militaris를 제외한 11 균주가 SLA배지에서 PDA에 비해 대부분의 균생장이 양호하였으나 C. militaris는 기존배지와 비교해 생장률이 78.6%로 감소하였다. Dextrose 첨가시 최적 농도는 C. gracilioides등 6균주에서 6% 처리시 가장 높은 생장률을 나타내었다. 본 시험결과 선발된 배지로부터 배양균을 누에접종 후 재배 시험한 결과 감염율, 자실체 형성을, 분생자경수 및 분생자경의 길이는 91.3$\pm$1.5%, 88.6$\pm$2.3%, 56.6$\pm$3.2개, 33.4$\pm$2.8mm로 대조에 비해 모두 높게 나타났다. 본 시험에서 개발된 Dextrose를 첨가한 SLA-A배지의 경제성 분석결과 1ι생산시 기존배지가 6,261원이 소요되는 것에 비해 총 2,386원으로 생산이 가능해 본 배지로 대체시 61.9%의 절감효과를 나타내었다.