Optimal media for selective isolation of entomopathogenic fungi

Tae Young Shin,Sung Min Bae,Jae Bang Choi,Ye Rim Cha,Hyun Na Koom,Soo Dong Woo 한국응용곤충학회 2009 한국응용곤충학회 학술대회논문집 Vol.2009 No.10

In agricultural fields, the entomopathogenic fungal species have been investigated for their potential as the biological control agents due to their role of natural enemies for insects. Until recent times, most of the studies for these fungi have been based on isolation from insect cadaver or soil. However, these methods, especially isolation from soil, might cause a problem involving differential isolation of the each entomopathogenic fungi. The purpose of this study is to determine the optimal isolation medium for entomopathogenic fungi using dodine, chitin, and skim milk. The growth rates of entomopathogenic fungi and non-entomopathogenic fungi were compared on dodine agar medium. The medium for this experiment was modified Veen semiselective medium which consisted of based on SDA (Sabouraund Dextrose Agar), 100 mg/ml for chloramphenicol, 50 mg/ml for streptomycin and adjusted dodine to 40, 50, 70 and 100 mg/ml. As a result, optimal concentration of dodine for isolation of entomopathogenic fungi was 50 mg/ml and 168 positive entomopathogenic fungi were isolated in 470 soil samples and 11 cadavers of insect. In addition, the isolates had significantly greater chitinase and protease activity than non-entomopathogenic fungi. The isolation method described represents a valuable tool for rapid and simple isolation of entomopathogenic fungi. These positive entomopathogenic fungi may have potential against variety pests in agriculture.

Study on Selective Media for Isolation of Entomopathogenic Fungi

( Tae Young Shin ),( Jae Bang Choi ),( Sung Min Bae ),( Hyun Na Koo ),( Soo Dong Woo ) 한국잠사학회 2010 International Journal of Industrial Entomology Vol.20 No.1

To determine the optimal isolation conditions of the entomopathogenic fungi from soil, we compared their growth characteristics with non-entomopathogenic fungi on agar media containing various concentrations of cooper (II) chloride (CuCl2) or dodine. The result showed that dodine medium is more selective, and the optimal concentration of dodine is determined with 50 μg/ml. We could isolate several putative entomopathogenic fungi from soil using this, and identify them using ITS analysis. As a result, 64% fungi were identified as typical entomopathogenic fungi. This selective medium may be useful to the rapid and simple isolation of entomopathogenic fungi from soil.

Strategy of Application of Entomopathogenic Fungi for Control of Pests

Jeong Jun Kim,Ji Hee Han,Sang Yeob Lee 한국응용곤충학회 2014 한국응용곤충학회 학술대회논문집 Vol.2014 No.04

Various insect pests infest crops including vegetables and ornamentals during crop production. Chemical pesticides have generally used until recently to control pests. Many pests are very difficult to control using organic pesticides because of the development of insecticide resistance and their rapid population increase. Entomopathogens are the promising alternative control methods. Entomopathogenic fungi are good candidates to control sucking insects such as aphid, whitefly and mite because the fungi can infect without ingestion. Conidia or blastospores of fungal entomopathogens are sprayed onto target plant and/or insect, adhered on insect surfaces, and penetrated into hemocoel through insect cuticle. Then the fungus utilize insect nutrients and kill the host insect. During this process, fungus was influenced by environmental conditions such as temperature, relative humidity and UV light. These are causing slow mortality and preventing wider application and use of mycopescitide using entomopathogenic fungi. In addition, control efficacy with fungal entomopathogen differed fungal isolate and host insect. Therefore, we need to study selection of high virulence isolate, mass production, formulation and application techniques to develop mycopesticide.

Screening and characterization of antimicrobial substances originated from entomopathogenic fungi

Shin, Tae Young,Bae, Sung Min,Woo, Soo Dong 한국응용곤충학회 2016 Journal of Asia-Pacific Entomology Vol.7 No.1

<P>To illustrate the presence of different types of antimicrobial substances derived from entomopathogenic fungi, the antimicrobial activities of 342 fungi were evaluated, and their antimicrobial substances were analyzed. The antimicrobial activities of 342 fungi isolated under various conditions from different regions of Korea were evaluated against the bacterium Bacillus cereus and the fungus Botrytis cinerea using a dual culture technique on agar plates. The results showed that 170 isolates (49.7%) and 186 isolates (54.4%) inhibited the growth of B. cereus and B. cinerea, respectively. The culture filtrates of selected fungi completely suppressed the growth of the microorganisms, indicating the presence of antimicrobial substances. Characteristics of the antimicrobial substances such as thermostability, polarity, susceptibility to proteases and molecular weight varied not only within a culture filtrate but also with the fungal isolate. Different types of antimicrobial substances with different characteristics were present in the fungal culture filtrates. These substances may be useful not only as biocontrol agents against plant diseases but also in other industrial fields. This is the first study to demonstrate various kinds of antimicrobial substances from a large number of entomopathogenic fungi. This study suggests that novel antimicrobial substances could be isolated from entomopathogenic fungi. (C) 2016 Published by Elsevier B.V. on behalf of Korean Society of Applied Entomology, Taiwan Entomological Society and Malaysian Plant Protection Society.</P>

Screening and characterization of antimicrobial substances originated from entomopathogenic fungi

신태영,배성민,우수동 한국응용곤충학회 2016 Journal of Asia-Pacific Entomology Vol.19 No.4

To illustrate the presence of different types of antimicrobial substances derived from entomopathogenic fungi, the antimicrobial activities of 342 fungi were evaluated, and their antimicrobial substances were analyzed. The antimicrobial activities of 342 fungi isolated under various conditions fromdifferent regions of Korea were evaluated against the bacteriumBacillus cereus and the fungus Botrytis cinerea using a dual culture technique on agar plates. The results showed that 170 isolates (49.7%) and 186 isolates (54.4%) inhibited the growth of B. cereus and B. cinerea, respectively. The culture filtrates of selected fungi completely suppressed the growth of the microorganisms, indicating the presence of antimicrobial substances. Characteristics of the antimicrobial substances such as thermostability, polarity, susceptibility to proteases and molecular weight varied not only within a culture filtrate but also with the fungal isolate. Different types of antimicrobial substances with different characteristics were present in the fungal culture filtrates. These substancesmay be useful not only as biocontrol agents against plant diseases but also in other industrial fields. This is the first study to demonstrate various kinds of antimicrobial substances from a large number of entomopathogenic fungi. This study suggests that novel antimicrobial substances could be isolated from entomopathogenic fungi.

Screening and Evaluation of Antibacterial Metabolites from Entomopathogenic Fungi

( Tae Young Shin ),( Seung Hyun Ko ),( Won Woo Lee ),( Sung Min Bae ),( Jae Bang Choi ),( Soo Dong Woo ) 한국잠사학회 2013 International Journal of Industrial Entomology Vol.26 No.2

Entomopathogenic fungal species have been investigated for their potential use as biological control agents owing to their natural role as insect pathogens. These fungi produce a wide range of secondary metabolites with high therapeutic values, such as antibiotics and cytotoxic substances. To evaluate the antibacterial activity of entomopathogenic fungi, 10 isolates from Korean soil were selected and tested for their activity against Escherichia coli by using fungal culture filtrates. Antibacterial activity was assessed using a two-step process: (1) a screening assay for the selection of fungal isolates and (2) a quantitative assay to evaluate the activity of select fungi. Although 4 fungal isolates were selected through the screening assay, only 3 fungal isolates, from Beauveria bassiana and Metarhizium anisopliae, showed high antibacterial activity according to the quantitative assay. The antibacterial activity of selected fungal culture filtrates was stable when exposed to heat and proteolytic enzyme treatments, which indicated that the antibacterial compound is not a protein. These entomopathogenic fungal metabolites might be useful as a source for bacterial control and in the pharmaceutical industry.

곤충병원성 진균을 활용한 해충 관리와 개발 전략

이세진,신태영,김종철,김재수 한국응용곤충학회 2022 한국응용곤충학회지 Vol.61 No.1

Entomopathogenic fungi can be used to control a variety of sucking and chewing insects, with little effect on beneficial insects and natural enemies. Approximately 170 entomopathogenic fungal insecticides have been registered and used worldwide, with the recent focus being on the mode of action and mechanism of insect-fungal interactions. During the initial period of research and development, the industrialization of entomopathogenic fungi focused on the selection of strains with high virulence. However, improvement in productivity, including securing resistance to environmental stressors, is a major issue that needs to be solved. Although conidia are the primary application propagules, efforts are being made to overcome the limitations of blastospores to improve the economic feasibility of the production procedure. Fungal transformation isalso being conducted to enhance insecticidal activity, and molecular biology is being used to investigate functions of various genes. In the fungi-based pest management market, global companies are setting up cooperative platforms with specialized biological companies in the form of M&As or partnerships with the aim of implementing a tank-mix strategy by combining chemical pesticides and entomopathogenic fungi. In this regard, understanding insect ecology in the field helps in providing more effective fungal applications in pest management, which can be used complementary to chemicals. In the future, when fungal applications are combined with digital farming technology, above-ground applications to control leaf-dwelling pests will be more effective. Therefore, for practical industrialization, it is necessary to secure clear research data on intellectual property rights. 곤충병원성 진균은 다양한 흡즙형 및 저작형 해충 방제에 적용이 가능하며, 익충과 천적에 낮은 영향을 보여, 화학농약의 대체체로서 관심이 높아지고 있다. 현재까지 전세계적으로 170여개의 제품들이 등록되어 판매되고 있으며, 최근 연구측면에서는 작용기작 및 곤충-진균 상호작 용체 구명에 집중하고 있다. 해충 방제를 위한 곤충병원성 진균의 산업화 연구는 초기 살충성이 높은 균주 선발에 집중하였으나, 최근에는 환경 스트레스 인자에 대한 저항성 확보를 포함한 생산성 향상이 해결해야 할주요 과제이다. 분생포자(conidia)가 주된 처리 형태였지만, 액체배양을 통해 생산되는 아포자(blastospore)의 한계점을 극복하여 대량생산의 경제성을 확보하려는 노력들도 진행되고 있다. 추가로 살충효과를 향상시 키기 위해, 형질전환을 비롯한 분자생물학적 연구와 유전자 및 유전체 기능 구명에 집중하고 있다. 해충방제 시장측면에서, 글로벌 작물보호제 기업들은 인수합병 또는 공동 연구개발 형태로 전문 생물농약 기업들과의 협력체계를 구축하고 있으며, 화학농약과 곤충병원성 진균의 tank-mix 전략을 주된 방향성으로 삼고 있다. 현장에서 곤충 생태에 대한 이해를 기반으로 한 생태학적 처리(ecological application)는 곤충병원성 진균의 살충효과를 향상시킬 수 있는 기회가 된다. 앞으로의 디지털팜(digital farming) 기술과 접목된다면, 지상부 해충 방제를 위한 실질적인 적용도 가능하다. 곤충병원성 진균의 산업화를 위해서는 지적재산권 분쟁 해결을 위한 명확한 비교 연구자료 확보도 필요하다. 이와 같은 곤충병원성 진균이 식량생산의 안전성과 경제성을 확보하는 중요한 미생물자원으로 활발히 활용되고 개발되길 기대한다.

Study on Selective Media for Isolation of Entomopathogenic Fungi

Shin, Tae-Young,Choi, Jae-Bang,Bae, Sung-Min,Koo, Hyun-Na,Woo, Soo-Dong Korean Society of Sericultural Science 2010 International Journal of Industrial Entomology Vol.20 No.1

To determine the optimal isolation conditions of the entomopathogenic fungi from soil, we compared their growth characteristics with non-entomopathogenic fungi on agar media containing various concentrations of cooper (II) chloride ($CuCl_2$) or dodine. The result showed that dodine medium is more selective, and the optimal concentration of dodine is determined with $50{\mu}g$/ml. We could isolate several putative entomopathogenic fungi from soil using this, and identify them using ITS analysis. As a result, 64% fungi were identified as typical entomopathogenic fungi. This selective medium may be useful to the rapid and simple isolation of entomopathogenic fungi from soil.

누에분말을 이용한 곤충기생균의 최적생장배지 개발

남성희 ( Nam Seong Hui ),정이연 ( Jung I Yeon ),지상덕 ( Ji Sang Duk ),조세연 ( Jo Se Yeon ) 한국잠사학회 2001 한국잠사곤충학회지 Vol.43 No.2

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 12 균주 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. gracilioides 등 6균주에서 6% 처리시 가장 높은 생장률을 나타내엇다. 본 시험결과 선발된 배지로부터 배양균을 누에접종 후 재배 시험한 결과 감염율, 자실체 형셩율, 분생자경수 및 분생자경의 길이는 91.3±1.5%, 88.6±2.3%, 56.6±3.2개, 33.4±2.8mm로 대조에 비해 모두 높게 나타났다. 본 시험에서 개발된 Dextrose를 첨가한 SLA-A배지의 경제성 분석결과 1ℓ 생산시 기존배지가 6,261원이 소요되는 것에 비해 총 2,386원으로 생산이 가능해 본 배지로 대체시 61.9%의 절감효과를 나타내었다. This study was carried out to investigate the optimal medium and optimal dextrose concentration of 12 entomopathogenic fungi. The colonies of cordyceps gracilioides, C. sp,(J23), Paedilomyces farinosus(J5), P. tenuipes, Paecilomyces sp.(J4), Beauveria bassiana and B. brongniartii on SLA(silkwon larva agar)medium are similar to those on PDA(potato dextrose agar) medium. On the contrary, the colonies of fungi are very various according to its medium. The optimal medium for 11 fungi was SLA-A medium, which was better than PDA medium with regard to the mycelial growth. The optimal concentration on mycelial growth was superior to 6% for 6 fungi. When silkworm larvae was injected with P. tenuipes on SLA medium for fruiting body production. Infection rate, fruiting body formation rate, synnemata number and synnemata length were 91.3±1.5%, 88.6±2.3%, 56.6±3.2and 33.4±2.8mm, respectively. In economical analysis, the prototype medium can reduce 61.9% of production cost per 1 liter compared with PDA medium.

Screening and Evaluation of Antibacterial Metabolites from Entomopathogenic Fungi

신태영,배성민,고승현,이원우,최재방,우수동 한국잠사학회 2013 International Journal of Industrial Entomology Vol.26 No.2

Entomopathogenic fungal species have been investigated for their potential use as biological control agents owing to their natural role as insect pathogens. These fungi produce a wide range of secondary metabolites with high therapeutic values, such as antibiotics and cytotoxic substances. To evaluate the antibacterial activity of entomopathogenic fungi, 10 isolates from Korean soil were selected and tested for their activity against Escherichia coli by using fungal culture filtrates. Antibacterial activity was assessed using a two-step process: (1) a screening assay for the selection of fungal isolates and (2) a quantitative assay to evaluate the activity of select fungi. Although 4 fungal isolates were selected through the screening assay, only 3 fungal isolates, from Beauveria bassiana and Metarhizium anisopliae , showed high antibacterial activity according to the quantitative assay. The antibacterial activity of selected fungal culture filtrates was stable when exposed to heat and proteolytic enzyme treatments, which indicated that the antibacterial compound is not a protein. These entomopathogenic fungal metabolites might be useful as a source for bacterial control and in the pharmaceutical industry.