• The Plant Pathology Journal
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• 제34권3호
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• pp.208-217
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• 2018

In this study, samples were collected from the leaves and stems of healthy wild Pistachio trees (Pistacia atlantica L.) from various locations of Baneh and Marivan regions, Iran. In total, 61 endophytic bacteria were isolated and grouped according to phenotypic properties. Ten selected isolates from each group were further identified by partial sequencing of the 16S rRNA gene. Based on the results, isolates were identified as bacteria belonging to Pseudomonas, Stenotrophomonas, Bacillus, Pantoea and Serratia genus. The ability of these isolates was evaluated to phytohormone production such as auxin and gibberellin, siderophore production, phosphate solubilization, atmospheric nitrogen fixation, protease and hydrogen cyanide production. All strains were able to produce the plant growth hormone auxin and gibberellin in different amounts. The majority of strains were able to solubilize phosphate. The results of atmospheric nitrogen fixation ability, protease and siderophore production were varied among strains. Only Ba66 could produce a low amount of hydrogen cyanide. The results of biocontrol assay showed that Pb78 and Sp15 strains had the highest and lowest inhibition effects on bacterial plant pathogens, Pseudomonas syringae pv. syringae Pss20 and Pseudomonas tolaasii Pt18 under in vitro condition. Pb3, Pb24 and Pb71 strains significantly promote root formation on carrot slices. To our knowledge this is the first report of the isolation of endophytic bacterial strains belonging to Pantoea, Bacillus, Pseudomonas, Serratia and Stenotrophomonas genus from wild pistachio trees with plant growth promoting potential and biocontrol activity.

• 한국미생물·생명공학회지
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• 제49권4호
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• pp.576-586
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• 2021

본 연구는 근권 토양 및 뿌리에 존재하는 미생물 중 미생물 제제로 적합한 Bacillus sp.을 선별하기 위하여 10종의 식물 병원성 곰팡이에 대한 항진균 활성, 식물 생장 촉진 활성 및 미네랄 가용화능을 평가하였다. 식물 병원성 곰팡이에 대한 항진균 활성은 Bacillus sp.에 따른 차이를 보였으며, 선별된 균주 중 DDP4, DDP16, DDP148, SN56, SN95는 9종 이상의 식물 병원성 곰팡이에 대해 항진균 활성을 나타내었다. 질소고정능과 1-aminocyclopropane-1-carboxylic acid deaminase 생성능에서는 Bacillus sp. 모두 비슷한 수준으로 활성을 나타냈으며, siderophore 생성능은 ANG42와 DDP427에서 비교적 높게 나타났다. Indole-3-acetic acid 생성능은 1.83-67.91 ㎍/ml으로 확인되었으며, Bacillus sp.에 따른 활성 차이를 나타내었다. 이후 각 species마다 활성이 높은 1 균주씩 선정하여 미네랄 가용화능을 확인한 결과, 대부분의 Bacillus sp.에서 인산과 탄산칼슘 가용화능을 확인할 수 있었으며, DDP148과 SN56은 각각 규소 가용화능과 아연 가용화능도 나타내었다. 따라서, 본 연구에서 분리한 Bacillus sp.의 항진균 활성, 식물 생장 촉진 활성 및 미네랄 가용화능 결과를 통해 다목적 기능을 가진 미생물 제제로써 활용이 가능할 것으로 판단된다.

• Journal of Applied Biological Chemistry
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• 제55권2호
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• pp.129-133
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• 2012

비식량 바이오매스 대상작물인 억새의 생육을 촉진하는 균주를 선발하기 위하여 충북 청원군 대청호 주변에서 서식하는 물억새 뿌리로부터 64균주를 분리하였다. 분리균의 식물생육촉진 활성을 확인하기 위하여 옥신, 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase 생선능 및 기타 배양조건에 따른 생육 특성을 조사한 결과, 8균주가 선발되었으며 Agrobacterium sp. BE516 균주가 억새 줄기의 생육을 2배 이상 증가시켜 가장 활성이 뛰어난 균주로 선발되었다. Agrobacterium sp. BE516 균주는 식물호르몬 indole acetic acid를 64 ${\mu}g/mL$ 생산하고, 염 및 건조 등의 환경 스트레스 저항성 ACC deaminase 를 생산하며, $4-15^{\circ}C$, pH 4.0 및 4% NaCl 농도에서 생육하였다. 따라서, Agrobacterium sp. BE516 균주가 간척지와 같은 조건불리지역에서 비식용 바이오매스 대상작물인 억새의 생육을 촉진시키기 위한 미생물비료제 개발에 유용한 균주임을 확인하였다.

• 한국유기농업학회지
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• 제26권3호
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• pp.463-475
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• 2018

국내 일부 시설재배지는 장기간 과도한 양분 투입 등에 의한 염류 집적 현상이 문제가 되어왔으며, 최근 이상기온에 따른 온도장해에 의한 피해도 발생하고 있다. 이러한 현상에 대해 친환경적으로 대처하기 위하여 고염류와 온도 스트레스에 대해 작물에 내성을 증강시키는 미생물을 선발하였다. 국내 토양에서 분리한 1,944균주중 고염류 또는 온도 스트레스 조건에서 세균의 생장과 식물생장촉진 관련 특성(IAA 생성, ACC deaminase 활성, 인산가용화능)을 고려하여 20균주를 1차 선발(전체 균주의 1.03%)하였다. 1차 선발한 20균주 중 토마토 식물검정을 통해 고염류 또는 온도스트레스에 대한 내성을 유도하는 7세균(1차 선발균주의 35%, 전체 균주의 0.36%)을 단계적으로 선발할 수 있었다. 선발된 세균은 16S rRNA 유전자의 염기서열 분석을 통해 모두 Bacillus 속에 속하는 것으로 확인되었다. 이러한 결과로 선발된 7균주는 토마토의 고염류 또는 온도 스트레스에 대한 효과적인 미생물 제제로 활용이 가능한 것을 확인할 수 있었다.

• Journal of Applied Biological Chemistry
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• 제64권4호
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• pp.333-341
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• 2021

본 연구는 근권 토양 및 뿌리에 존재하는 근권 미생물 중 미생물 제제로 적합한 균주를 선별하기 위해서 미네랄 가용화능, 10종의 식물 병원성 곰팡이에 대한 항진균 활성 및 식물 생장 촉진 활성을 평가하였다. 결과적으로 불용성 인산, 탄산칼슘, 규소 및 아연 가용화능과 질소고정능, siderophore, indole-3-acetic acid와 aminocyclopropane-1-carboxylate deaminase 생성능 및 7종의 식물 병원성 곰팡이에 대해 항진균 활성을 갖는 DDP346을 선별하였다. 선별된 DDP346은 Acinetobacter pittii DSM21653 (NR_117621.1)와 99.9% 이상의 높은 상동성을 보였으며, 16S rRNA 염기서열을 바탕으로 계통도를 분석한 결과에서도 Acinetobacter pittii와 높은 유연관계를 나타내었다. DDP346의 생장 조건은 온도(10-40 ℃), pH (5-11) 염농도(0-5%) 범위로 확인하였다. 또한 pH 변화와 가용화된 인산 함량 간에 음의 상관계수(r²= -0.913, p <0.01)를 나타내는 것을 확인하였는데, 이는 배양 중에 생성되는 유기산에 의한 것으로 추정된다. 결과적으로 미네랄 가용화능, 식물 병원성 곰팡이에 대한 항진균 활성 및 식물 생장 촉진 활성 평가를 통해 Acinetobacter sp. DDP346을 다목적 미생물 제제로써 활용 가능성을 제시한다.

• Journal of Applied Biological Chemistry
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• 제48권2호
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• pp.79-83
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• 2005

While screening for nematicidal activity of bacterial origins, various pseudomonads strains were inhabited in tomato rhizosphere. One isolate designated as $PE_{10}$ was selected for studies on nematicidal properties and plant growth-promoting (PGP) activity and was identified as Pseudomonas aeruginosa based on morphological features, biochemical and physiological tests, and carbohydrate utilization. To investigate nematicidal activity, Meloidogyne incognita juvenile mortality was determined using $PE_{10}$ culture filtrate. Inhibition of strain $PE_{10}$ against Fusarium oxysporum was observed using dual culture technique. Strain $PE_{10}$ showed good siderophore activity, HCN and IAA production abilities, and growth and development enhancement of tomato.

• The Plant Pathology Journal
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• 제39권1호
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• pp.108-122
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• 2023

Fusarium oxysporum f. sp. lycopersici (Fol) and Fusarium oxysporum f. sp. cubense (Foc), are the causal agent of Fusarium wilt disease of tomato and banana, respectively, and cause significant yield losses worldwide. A cost-effective measure, such as biological control agents, was used as an alternative method to control these pathogens. Therefore, in this study, six isolates of the Streptomyces-like colony were isolated from soils and their antagonistic activity against phytopathogenic fungi and plant growth-promoting (PGP) activity were assessed. The results showed that these isolates could inhibit the mycelial growth of Fol and Foc. Among them, isolate STRM304 showed the highest percentage of mycelial growth reduction and broad-spectrum antagonistic activity against all tested fungi. In the pot experiment study, the culture filtrate of isolates STRM103 and STRM104 significantly decreased disease severity and symptoms in Fol inoculated plants. Similarly, the culture filtrate of the STRM304 isolate significantly reduced the severity of the disease and symptoms of the disease in Foc inoculated plants. The PGP activity test presents PGP activities, such as indole acetic acid production, phosphate solubilization, starch hydrolysis, lignin hydrolysis, and cellulase activity. Interestingly, the application of the culture filtrate from all isolates increased the percentage of tomato seed germination and stimulated the growth of tomato plants and banana seedlings, increasing the elongation of the shoot and the root and shoot and root weight compared to the control treatment. Therefore, the isolate STRM103 and STRM104, and STRM304 could be used as biocontrol and PGP agents for tomato and banana, respectively, in sustainable agriculture.

• Journal of Microbiology and Biotechnology
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• 제27권10호
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• pp.1790-1797
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• 2017

In the present study, we demonstrate that the growth of salt-stressed pepper plants is improved by inoculation with plant growth-promoting rhizobacteria (PGPR). Three PGPR strains (Microbacterium oleivorans KNUC7074, Brevibacterium iodinum KNUC7183, and Rhizobium massiliae KNUC7586) were isolated from the rhizosphere of pepper plants growing in saline soil, and pepper plants inoculated with these PGPR strains exhibited significantly greater plant height, fresh weight, dry weight, and total chlorophyll content than non-inoculated plants. In addition, salt-stressed pepper plants that were inoculated with B. iodinum KNUC7183 and R. massiliae KNUC7586 possessed significantly different total soluble sugar and proline contents from non-inoculated controls, and the activity of several antioxidant enzymes (ascorbate peroxidase, guaiacol peroxidase, and catalase) was also elevated in PGPR-treated plants under salt stress. Overall, these results suggest that the inoculation of pepper plants with M. oleivorans KNUC7074, B. iodinum KNUC7183, and R. massiliae KNUC7586 can alleviate the harmful effects of salt stress on plant growth.

• Mycobiology
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• 제43권1호
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• pp.87-91
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• 2015

Eighteen endophytic fungi with different colony morphologies were isolated from the roots of Nymphoides peltata growing in the Dalsung wetland. The fungal culture filtrates of the endophytic fungi were treated to Waito-c rice seedling to evaluate their plant growth-promoting activities. Culture filtrate of Y2H0002 fungal strain promoted the growth of the Waito-c rice seedlings. This strain was identified on the basis of sequences of the partial internal transcribed spacer region and the partial beta-tubulin gene. Upon chromatographic analysis of the culture filtrate of Y2H0002 strain, the gibberellins (GAs: $GA_1$, $GA_3$, and $GA_4$) were detected and quantified. Molecular and morphological studies identified the Y2H0002 strain as belonging to Aspergillus clavatus. These results indicated that A. clavatus improves the growth of plants and produces various GAs, and may participate in the growth of plants under diverse environmental conditions.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2010년도 정기총회 및 추계학술발표회
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• pp.18-18
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• 2010

Molecular insights on the role of plant growth promoting rhizobacteria (PGPR) in potato tuberization are reported in the present study. The PGPRwere isolated from the soil collected from potato fields of Highland Agricultural Research Centre, Pyeongchang, Korea and they were identified to the genus level based on the 16S rRNA sequence analysis. These PGPR were heat-killed, filtered and the filtrates were addedindividually at a concentration of $10^7\;cfu\;mL^{-1}$ in MS (Murashige and Skoog's) medium supplemented with 7% (w/v) sucrose to study their influence on in vitro potato tuberization. Tuber initiation occurred early in untreated control, while tuber growth was pronounced in case of PGPR treatments. The control explants showed tuber formation as a result of sub-apical swelling of stolons while several sessile tubers formed directly in the axils of nodal cuttings in case of PGPR treatments, which is an indication of strong induction for tuberization. Theexplants cultured on MS medium supplemented with bacterial isolate 6 (Bacillus firmus strain 40) showed highest average tuber yield (Ca. 12.56 g per treatment) after 30 days of culture, which was 3 folds increase over the untreated control. A significant increase in lipoxygenase (LOX1) mRNA expression and activity of LOX enzyme were also detected in the tubers induced on PGPR treatments as compared to untreated control. This LOX expression level correlated with increased tuber growth and tuber yield. Further studies focused on the role of bacteria cell wall components, growth regulators and signal molecules released by PGPR are under investigation to elicit clues for PGPR-mediated signal pathway controlling potato tuberization.