• 한국유기농업학회지
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• 제7권1호
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• pp.137-146
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• 1998

수종의 근권세균류를 시설토양에서 분리한 후 육묘용토에 혼입처리하여 식물생장촉진효과를 측정하였다. 시설토양에서 총 125주의 단일균구를 1차적으로 순수분리하였으며, 고추에서 발생하는 위조병원균, 입고병원균, 및 묘잘록병원균 등에 대하여 항균작용이 우수한 4주의 근권세균을 최종적으로 분리하였다. 항균작용이 가장 높았던 균주로는 RB 109로서 위조병원균에 대해서는 66.0%, 입고병원균에 대해서는 65.0%, 묘잘록병원균에 대해서는 66.1% 정도의 항균작용을 나타내 전반적으로 60% 이상의 길항작용을 갖는 것으로 보였다. 길항성 균주 RB 109의 배양액을 육묘용토에 혼입처리시 고추 유묘의 초기생장이 촉진되었다. 길항성 세균 RB 109를 동정한 결과 Pseudomonas sp.와 82% 정도 유사한 균주로 동정되어 Pseudomonas sp. RB 109로 명명하였다.

• 한국토양비료학회지
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• 제49권3호
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• pp.251-258
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• 2016

A rhizobacterium LPN-2, which showed strong antifungal activity and auxin producing ability, was isolated from a farmland in North Gyeongsang Province, South Korea. Based on analysis of the 16S rDNA sequence, strain LPN-2 was identified as a novel strain of Burkholderia and was designated as Burkholderia sp. LPN-2. In vitro experiments showed that the isolated stain LPN-2 significantly produced auxin within 48 hr incubation. In order to check for PGPR function we performed in vivo growth promoting test in different crops, including mung bean, pea and cabbage. Application of Burkholderia sp. LPN-2 showed dramatic growth promoting effect on all the tested plants. We also confirmed siderophore and cellulase productions by Burkholderia sp. LPN-2 using CAS blue agar and CMC plate test. Further treatment with LPN-2 and the crude culture broth was effective in suppressing anthracnose in vitro test and also reduced incidence and severity of anthracnose in apple and pepper. Taken together, we conclude that Burkholderia sp. LPN-2 might be used as organic fertilizer for effective crop production in organic farming.

• 한국미생물·생명공학회지
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• 제40권3호
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• pp.261-267
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• 2012

본 연구에서는 경기도 궁평항 지역의 해안사구에 서식하고 있는 토착식물 6종(Rorippa islandica, Rumex crispus, Artemisia princeps var. orientalis, Lilium sp Stellaria media, and Gramineae)의 식물 뿌리와 근권토양으로부터 colony library를 구축하여 식물성장촉진 능력과 내염능을 평가하였다. 분리한 근권세균 중 4.0%의 염분이 존재하는 환경에서 50% 이상의 세균이 염분에 강한 내성을 가지고 있었다. 95개의 균주를 대상으로 식물성호르몬인 IAA생산능을 가지는 균주는 근권토양에서는 13.9%, 식물뿌리에서는 7.6%였으며, 1-aminocyclopropane-1-carboxylic acid (ACC)를 제거하는 ACC deaminase 활성을 가진 균주는 근권토양에서는 55.8%, 뿌리에서는 36.6%였다. 또한, Siderphores 합성능을 가지고 있는 균주는 근권에서 62.7%, 뿌리에서는 50%를 차지하였다. 식물성장촉진능과 내염능을 가진 세균을 대상으로 상관관계를 분석한 결과, ACC deaminase 활성과 siderphore(s) 합성능 사이에는 양의 상관관계를 형성하였고(r=0.605, p<0.037), 염분 내성능과 ACC deaminase 활성, 염분 내성능과 siderphore(s) 합성능 사이에도 양의 상관관계를 형성하였다(r=0.762, p<0.004, r=0.771, p<0.003, 각각).

• 한국환경과학회지
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• 제29권9호
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• pp.925-933
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• 2020

To develop eco-friendly microbial inoculants, siderophore-producing bacteria were isolated and identified, and their production characteristics and plant growth-promoting abilities were investigated. A strain S21 was isolated from rhizosphere of Korean perilla (Perilla frutescens) and identified as Enterobacter amnigenus by phenotypic properties and 16S rRNA gene sequencing. The highest siderophore production was obtained in a medium containing 0.5% fructose, 0.1% urea, 0.5% K₂HPO₄ and 0.1% succinic acid. By using this improved medium, siderophore production increased by 2.5 times compared to that of basal medium. The strain S21 showed insoluble phosphate solubilizing, ammonification and antifungal activities, and also produced hydrolytic enzymes (protease and lipase), indoleacetic acid and 1-aminocyclopropane-1-carboxylate deaminase. Our data suggest that E. amnigenus S21 is a potential candidate that can be used as eco-friendly biocontrol agent and biofertilizer.

• 식물병연구
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• 제22권2호
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• pp.81-93
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• 2016

식물생장촉진세균은 식물의 생장과 수확량을 촉진하고, 식물병에 대한 유도저항성을 유도하는 것으로 보고되었다. 본 논문에서 연구의 목적은 가로수와 고추의 엽면에 엽권정착 식물생장촉진세균을 처리하여, 식물생장촉진세균의 적용 범위를 확장하였다. 수목의 엽권에서 내생포자 형성 세균 1,056개 균주를 분리하여, protease, chitinase, lipase를 포함한 효소활성과 진균병인 C. graminicola와 B. cinerea에 대한 길항작용을 측정하였다. 1차 선발된 bacilli 14개 균주를 고추의 잎에 살포하여 엽권정착능을 시험하였다. 5B6, 8D4, 8G12 단독처리와 그 혼합처리군을 고추 엽면에 살포하여 생장촉진, 수확량증진, 병방제 효과를 고추 포장에서 관찰하였다. 대량배양을 통하여 선발된 균주를 대한민국 대전광역시 유성구 일대의 가로수에 살포하였을 때, 대조군과 비교하여 엽록소함량과 잎 두께가 증가하였다. 선발된 3개 균주를 수목에 엽면살포했을 때, 벚나무 진균성갈색무늬구멍병을 저해하였고 은행나무의 낙엽생성을 촉진하였다. 종합적으로 본 연구는 엽권정착세균의 엽면살포를 통하여 가로수와 고추의 생장을 촉진시키고, 식물병을 방제하는 엽권정착세균의 적용 가능성을 제시한다.

• Journal of Microbiology and Biotechnology
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• 제31권8호
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• pp.1045-1059
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• 2021

Various abiotic stressors like drought, salinity, temperature, and heavy metals are major environmental stresses that affect agricultural productivity and crop yields all over the world. Continuous changes in climatic conditions put selective pressure on the microbial ecosystem to produce exopolysaccharides. Apart from soil aggregation, exopolysaccharide (EPS) production also helps in increasing water permeability, nutrient uptake by roots, soil stability, soil fertility, plant biomass, chlorophyll content, root and shoot length, and surface area of leaves while also helping maintain metabolic and physiological activities during drought stress. EPS-producing microbes can impart salt tolerance to plants by binding to sodium ions in the soil and preventing these ions from reaching the stem, thereby decreasing sodium absorption from the soil and increasing nutrient uptake by the roots. Biofilm formation in high-salinity soils increases cell viability, enhances soil fertility, and promotes plant growth and development. The third environmental stressor is presence of heavy metals in the soil due to improper industrial waste disposal practices that are toxic for plants. EPS production by soil bacteria can result in the biomineralization of metal ions, thereby imparting metal stress tolerance to plants. Finally, high temperatures can also affect agricultural productivity by decreasing plant metabolism, seedling growth, and seed germination. The present review discusses the role of exopolysaccharide-producing plant growth-promoting bacteria in modulating plant growth and development in plants and alleviating extreme abiotic stress condition. The review suggests exploring the potential of EPS-producing bacteria for multiple abiotic stress management strategies.

• 한국환경과학회지
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• 제22권11호
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• pp.1457-1464
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• 2013

We investigated the optimal conditions for keratinase production by feather-degrading Pseudomonas geniculata H10 using one variable at a time (OVT) method. The optimal medium composition and cultural condition for keratinase production were determined to be glucose 0.15% (w/v), beef extract 0.08% (w/v), $KH_2PO_4$ 0.12% (w/v), $K_2HPO_4$ 0.02% (w/v), NaCl 0.07% (w/v), $MgSO_4{\cdot}7H_2O$ 0.03%, $MgCl_2{\cdot}6H_2O$ 0.04% along with initial pH 10 at 200 rpm and $25^{\circ}C$, respectively. The production yield of keratinase was 31.6 U/ml in an optimal condition, showing 4.6-fold higher than that in basal medium. The strain H10 also showed plant growth promoting activities. This strain had ammonification activity and produced indoleacetic acid (IAA), siderophore and a variety of hydrolytic enzymes such as protease, lipase and chitinase. Therefore, this study showed that P. geniculata H10 could be not only used to upgrade the nutritional value of feather wastes but also useful in situ biodegradation of feather wastes. Moreover, it is also a potential candidate for the development of biofertilizing agent applicable to crop plant soil.

• Applied Biological Chemistry
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• 제40권2호
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• pp.167-171
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• 1997

26종 콩과식물 종실의 메탄올 조추출물의 Bifidobacterium adolescentis, B. longun, B. bifidum, Lactobacillus casei에 대한 생육촉진 및 생육억제 활성을 탄소원 배지와 비탄소원 배지를 이용하여 in vitro 혐기조건하에서 각각 분광학적 및 여지확산법으로 검정한 결과 생육반응은 공시세균과 콩의 종류에 따라 달리 나타났다. 콩과식물 종실중, 대두(밝은 청색 종실)와 땅콩 (짙은 갈색 종실) 추출물은 유산균의 생육을 촉진하였는데, 이러한 결과로 부터 이들 콩과식물 종실에 탄소원과 비탄소원의 비피더스 인자의 존재를 알 수 있었다. 공시 유산균 중에서 L. casei에서 가장 현저한 생육측진 반응을 나타내었다. 또한, 모든 콩과식물 종실시료는 상기 유산균의 생육을 저해하지 않았다.

• 한국미생물·생명공학회지
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• 제34권2호
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• pp.180-184
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• 2006

Nineteen nitrogen-fixing bacteria were isolated from rice roots cultivated in the southern part of the Korean peninsula. Among them, three isolates - Stenotrophomonas sp. KNUC89, Pseudomonas sp. KNUC116, and Delftia sp. KNUC133 - showed antifungal activities against phytopathogenic fungi Rhizoctonia solani and Fusarium oxysporum. Besides they could produce auxin and siderophores.

• 한국균학회소식:학술대회논문집
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• 한국균학회 2018년도 춘계학술대회 및 임시총회
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• pp.49-49
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• 2018

A variety of bioactive secondary metabolites have been reported from plant-associated microorganisms. Halophytes, plants that can only grow in hypersaline area, were reported to host beneficial microorganisms such as plant growth-promoting endophytes. The microorganisms have been reported to show notable mutualistic symbiosis with halophytes to help them survive in high saline condition. Finding out bioactive secondary metabolites as well as elucidation of relationship(s) between microbes and the host halophyte has been paid attention, because of their functional diversity. Novel microbes often have associated with novel natural products. In an effort to investigate natural compounds with interesting structures from fungi, we selected plants from a distinct environmental setting which could be a promising source. Several fungi were isolated from halophyte or medicinal plants. Some strains of the fungi were cultivated on a large scale and extracted with ethyl acetate, which were subjected to a series of chromatographic methods, leading to the isolation of tens of compounds. The isolated compounds were identified by analysis of spectroscopic methods such as 1D-, 2D-NMR, and MS. Details of isolation, structure determination, and biological activities will be discussed.