• 농업과학연구
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• 제49권3호
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• pp.463-481
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• 2022

Phosphorous (P) is considered to be one of the key essential elements demanded by crop plants. Approximately 70 - 90% of phosphatic fertilizers applied to crops are fixed in soil as Ca, Fe, and Al metal cations, which are insoluble and thus not readily available for plant uptake. Therefore, most soils are deficient in plant available P. This is usually rectified by applying phosphate fertilizers continuously, although this is not economically viable or environmentally acceptable. The present paper reviews the mechanisms involved with phosphate solubilization and mineralization by phosphate solubilizing microorganisms (PSMs) with the associated factors that determine the success. PSMs are effectively involved in mediating the bioavailability of soil P. Their contribution includes mineralization of organic P solubilization of inorganic P minerals, and storing sizable amounts of P in biomass through different mechanisms such as the production of organic and inorganic acids, H₂S, siderophores, exopolysaccharides, and production of enzymes such as phosphatases, phytase, and phosphonatases/C-P lyases, which are capable of chelating the metal ions, forming complexes, and making plant available P. PSMs manifest a wide range of metabolic functions in different environments, resulting in significantly higher plant growth, enhanced soil properties, and increased biological activities. Therefore, development of bio-inoculants with efficient novel PSM strains and further investigations on exploring such strains from diverse ecological niches with multifunctional plant-growth-promoting traits are needed.

• The Plant Pathology Journal
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• 제39권5호
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• pp.430-448
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• 2023

Recently, strategies for controlling Fusarium oxysporum f. sp. lycopersici (Fol), the causal agent of Fusarium wilt of tomato, focus on using effective biocontrol agents. In this study, an analysis of the biocontrol and plant growth promoting (PGP) attributes of 11 isolates of loamy soil Bacillus spp. has been conducted. Among them, the isolates B.PNR1 and B.PNR2 inhibited the mycelial growth of Fol by inducing abnormal fungal cell wall structures and cell wall collapse. Moreover, broad-spectrum activity against four other plant pathogenic fungi, F. oxysporum f. sp. cubense race 1 (Foc), Sclerotium rolfsii, Colletotrichum musae, and C. gloeosporioides were noted for these isolates. These two Bacillus isolates produced indole acetic acid, phosphate solubilization enzymes, and amylolytic and cellulolytic enzymes. In the pot experiment, the culture filtrate from B.PNR1 showed greater inhibition of the fungal pathogens and significantly promoted the growth of tomato plants more than those of the other treatments. Isolate B.PNR1, the best biocontrol and PGP, was identified as Bacillus stercoris by its 16S rRNA gene sequence and whole genome sequencing analysis (WGS). The WGS, through genome mining, confirmed that the B.PNR1 genome contained genes/gene cluster of a nonribosomal peptide synthetase/polyketide synthase, such as fengycin, surfactin, bacillaene, subtilosin A, bacilysin, and bacillibactin, which are involved in antagonistic and PGP activities. Therefore, our finding demonstrates the effectiveness of B. stercoris strain B.PNR1 as an antagonist and for plant growth promotion, highlighting the use of this microorganism as a biocontrol agent against the Fusarium wilt pathogen and PGP abilities in tomatoes.

• 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).

• 한국응용과학기술학회지
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• 제41권2호
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• pp.199-207
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• 2024

이탄 토양으로부터 분리된 세균의 유기물 분해능, 항균 활성 및 식물생육촉진능을 확인하고 다기능성 유용 미생물을 확보하고자 하였다. 분리된 48 균주를 대상으로 β-glucosidase, cellulase, amylase, protease 생성능을 확인한 결과, SH-23, SH-26, SH-29 그리고 SH-33 균주가 우수 균주로 선발되었다. 선발된 유기물 분해 우수 세균 4 균주는 식물병원성곰팡이(Botrytis cinerea, Rhizoctonia solani, Fusarium oxysporum, Colletotrichum acutatum)에 대한 항진균 활성을 나타내었다. 유기물 분해능이 우수하고 식물병원성 곰팡이에 대해 항진균 활성을 나타낸 SH-26 균주를 최종 우수균주로 선발 하였다. 선발된 SH-26 균주의 16S rRNA 유전자 염기 서열을 결정한 결과, Pseudomonas knackmussii HG322950 B13^T, Pseudomonas citronellolis BCZY01000096 NBRC 103043^T, 그리고 Pseudomonas delhiensis jgi.1118306 RLD-1^T와 100%의 상동성을 나타내었다. Pseudomonas sp. SH-26 균주는 siderophore 생성능, 질소고정능과 Indole-3-acetic acid 생성능이 있는 것으로 확인되었다.

• 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.