• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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• pp.101.2-102
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• 2003

The ability of P. chlororaphis O6 to induce resistance to Erwinia carotovora subsp. carotovara SCCI and to promote growth in tobacco was demonstrated in microtiter assays on plants pre-inoculated at the root level with the bacteria before challenge with the leaf pathogen. To identify th bacterial determinants involved in induced systemic resistance and plant growth promotion, cell culture of O6 grown in King's medium B was fractionated with organic solvents and purified using various columns. in vivo and in vitro assays with samples from successive fractionation steps of the O6 supernatant led to the conclusion that antibacterial compounds were observed in aqueous layer, and to the isolation of fractions containing metabolites that retained most of the resistance-inducing activity (70：30, methanol：water) and the plant growth promotion (80：20 and 90：10, methanol：water) after ODS column chromatography. Although these molecules remain to be purified further and structurally characterized, its isolation is an addition to the range of determinants from plant growth-promoting rhizobacteria known to stimulate plant defence.

• 한국미생물·생명공학회지
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• 제34권1호
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• pp.78-82
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• 2006

Since there could be more and rather various diazotrophs in rhizosphere of wild crops than those in rhizosphere of cultivars, some wild gramineous crops grown in Korea were collected for isolating nitrogen-fixing bacteria. Six diazotrophs were purified from their roots using nitrogen-free media. The isolated bacteria were partially identified as 4 genera by 16S rDNA sequence analysis: Stenotrophomonas sp., Bosea sp., Klebsiella sp., and Azorhizobium sp. By PCR amplification and sequence analysis, DNA fragments extracted from all isolates turned out to have an individual nifH homologous gene. Five isolates (KNUC163, KNUC165, KNUC169, KNUC170, and KNUC171) showed auxin activity and four isolates (KNUC163, KNUC166, KNUC170, and KNUC171) produced siderophores. Especially,3 strains of S. maltophilia showed both auxin and siderophore activities. In conclusion, the isolated nitrogen-fixing bacteria might have capabilities for plant growth promotion.

• 식물병연구
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• 제24권3호
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• pp.221-232
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• 2018

근권세균은 식물 생육과 건강 증진에 중요한 역할을 하며 생물학적 스트레스뿐만 아니라 저온, 고온, 건조 및 염과 같은 비생물적 스트레스에도 내성을 부여한다. 본 연구는 토마토에 생물적 및 비생물적 스트레스를 완화시키는 기능을 가진 식물생장촉진 근권세균(plant growth promoting rhizobacteria, PGPR)을 선발하는 것을 목표로 하였으며 토마토 근권에서 Variovorax sp. PMC12균주를 분리하였다. PMC12균주는 in vitro에서 PGPR의 특성으로 알려진 암모니아, IAA, 시드로포아 및 ACC 탈아민효소를 생성하였다. PMC12 균주를 처리한 토마토는 대조구에 비해 염, 저온 및 건조 스트레스 조건에서 지상부 생체중이 유의적으로 높았다. 또한 PMC12 균주를 처리한 토마토는 Ralstonia solanacearum에 의한 세균성 시들음병에 대한 저항성이 증가되었다. 결과적으로 PMC12 균주는 식물의 비생물적 스트레스 및 생물적 스트레스에 대한 감수성을 감소시키는 유망한 생물학적 방제제 및 생물활성제로 사용될 수 있을 것으로 전망된다.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2006년도 한국약용작물학회 공동춘계학술발표회
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• pp.482-483
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• 2006

• 한국식물병리학회지
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• 제14권1호
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• pp.13-18
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• 1998

The use of bioluminescence as a sensitive marker for the detection of Pseudomnas sp. in the rhizosphere was investigated. Transposon Tn4431 which contains a promoterless luciferase operon and tetracycline resistant gene was used. This transposon, present on a suicide vector (pUCD623) in E. coli HB101, was mated with spontaneous rifampicin mutant of Pseudomonas fluorescens B16, a plant growth promoting rhizobacteria (PGPR), and then rifampicin and tetracycline resistant survivors were isolated. Twenty tow mutants wer isolated from the conjugants between E. coli HB101 and P. fluorescens B16. One of these, B16::Tn4431 (L22) recombinant which glowed brightly in the dark was selected for analysis. The cucumber seeds inoculated with L22 were grown in moisten two layers of filter paper and nonsterile soil contained in half cut PVC pipe. The roots were removed from the filter paper and PVC pipe, then placed on the 1/2 LB media plates. The plates were incubated at room temperature for 16 hr. L22 could successfully be detected in the rhizoplane by using the ordinary negative camera film (ASA100-400) with 30 minutes exposure under dark condition. The root colonizing ability and the plant growth promoting effect of L22 were not reduced compared to the untreated bacteria and wild type. L22 was superior to will type.

• Journal of Applied Biological Chemistry
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• 제66권
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• pp.394-403
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• 2023

지속 가능하고 친환경적인 농업 관행을 추구하기 위해 우리는 40년이 넘는 장기간 동안 화학 비료를 사용하지 않은 토양에 서식하는 근권 박테리아에 대한 광범위한 연구를 수행하였다. 이번 조사를 통해 식물생장촉진 근권박테리아 총 80종을 분리하고 이들의 식물생장 증진 가능성을 평가했다. 이러한 분리균중에서 Burkholderia cepacia CD2는 가장 우수한 식물 성장촉진 활성과 생장능을 나타내어 추가 분석을 위한 최적의 후보균주로 선정되었다. Burkholderia cepacia CD2는 인 가용화 능력, 사이드로포어 생산, 탈질화 능력, 아질산 이온 활용능력 및 요소분해효소 활성을 포함하여 식물 성장에 도움이 되는 다양한 유익한 특성을 나타내었다. 이러한 특성은 식물의 성장과 발달에 긍정적인 영향을 미치는 것으로 잘 알려져 있다. 균주의 분류학적 분류를 검증하기 위해 16S rRNA 유전자 서열분석을 통해 Burkholderia 속 내 위치를 확인하여 계통발생 관계에 대한 추가 통찰력을 제공하였다. 식물 생장 촉진 특성의 기본 메커니즘을 더 깊이 조사하기 위해 우리는 CD2에서 식물 생장촉진과 관련된 특정 유전자의 존재를 확인하려고 하였다. 이를 달성하기 위해 옥스포드 나노포어를 활용하여 전장 유전체 시퀀싱을 수행하였다. CD2 게놈에 대한 전장유전체 분석을 통해 식물 생장 개선에 중추적 요인으로 생각되는 하위 시스템 기능을 확인하였다. 이러한 발견을 바탕으로 Burkholderia cepacia CD2는 미생물 비료로 작용하여 화학 비료에 대한 지속 가능한 대안을 제공할 수 있는 잠재력을 가지고 있다는 결론을 내릴수 있다.

• 식물병연구
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• 제29권2호
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• pp.174-183
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• 2023

관행적 화학농약의 식물병 관리 및 치료의 한계적인 효과는 유익한 세균이나 미생물을 이용한 식물병 제어 방법 개발의 필요성을 나타낸다. 지속 가능한 농업은 특히 다양한 항생물질과 이차 대사 생성물을 생산하는 방선균의 농업적 중요성을 시사하며, Streptomyces globiosporus SP6C4균주와 Streptomyces sp. S8은 강력한 항균 작용을 가지고 있으며, 지속가능한 농업에서 작물 생장을 개선하기 위한 우수한 균주로 인정되고 있다. 본 연구에서는 다양한 질소원과 탄소원을 활용하여 대상 미생물 Streptomyces 두 균주의 생장을 촉진시키는 방법을 조사하였다. L-글루타민과 L-시스테인이 첨가된 조건에서 S. globiosporus SP6C4와 Streptomyces sp. S8 균주의 포자 생성 능력이 증가하였으며, 각 균주의 생장이 촉진되었다. 이러한 결과는 유용 미생물의 대량배양 기술의 범위 확장과 농업미생물의 실용화에 기여할 것으로 생각된다.

• Mycobiology
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• 제36권4호
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• pp.236-241
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• 2008

The colonization of an arbuscular mycorrhizal fungus Glomus intraradices BEG110 in the soil caused a decrease in disease severity in cucumber plants after fungal inoculation with Colletotrichum orbiculare. In order to illustrate the resistance mechanism mediated by G. intraradices BEG110, infection patterns caused by C. orbiculare in the leaves of cucumber plants and the host cellular responses were characterized. These properties were characterized using transmission electron microscopy on the leaves of cucumber plants grown in soil colonized with G. intraradices BEG110. In the untreated plants, inter- and intra-cellular fungal hyphae were observed throughout the leaf tissues during both the biotrophic and necrotrophic phases of infection. The cytoplasm of fungal hyphae appeared intact during the biotrophic phase, suggesting no defense response against the fungus. However, several typical resistance responses were observed in the plants when treated with G. intraradices BEG110 including the formation of sheaths around the intracellular hyphae or a thickening of host cell walls. These observations suggest that the resistance mediated by G. intraradices BEG110 most often occurs in the symplast of the host cells rather than in the apoplast. In addition, this resistance is similar to those mediated by biotic inducers such as plant growth promoting rhizobacteria.

• Journal of Microbiology and Biotechnology
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• 제31권10호
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• pp.1373-1382
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• 2021

Plant growth promoting rhizobacteria (PGPR) are a group of bacteria that can increase plant growth; but due to unfavorable environmental conditions, PGPR are biologically unstable and their survival rates in soil are limited. Therefore, the suitable application of PGPR as a plant growth stimulation is one of the significant challenges in agriculture. This study presents an intelligent formulation based on Bacillus velezensis VRU1 encapsulation enriched with nanoparticles that was able to control Rhizoctonia solani on the bean. The spherical structure of the capsule was observed based on the Scanning Electron Microscope image. Results indicated that with increasing gelatin concentration, the swelling ratio and moisture content were increased; and since the highest encapsulation efficiency and bacterial release were observed at a gelatin concentration of 1.5%, this concentration was considered in mixture with alginate for encapsulation. The application of this formulation which is based on encapsulation and nanotechnology appears to be a promising technique to deliver PGPR in soil and is more effective for plants.

• 원예과학기술지
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• 제35권1호
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• pp.11-20
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• 2017

The objective of this study was to determine whether inoculation with Bacillus licheniformis MH48 as a plant growth-promoting rhizobacterium (PGPR) could promote nutrient uptake of seedlings of the ornamental plant Camellia japonica in the Saemangeum reclaimed coastal land in Korea. B. licheniformis MH48 inoculation increased total nitrogen and phosphorus content in soils by 2.2 and 20.0 fold, respectively, compared to those without bacterial inoculation. In addition, B. licheniformis MH48 produced auxin, which promoted the formation of lateral roots and root hairs, decreased production of growth-inhibiting ethylene, and alleviated salt stress. Total nitrogen and phosphorus uptake of seedlings subjected to bacterial inoculation was 2.3 and 3.6 fold higher, respectively, than the control. However, B. licheniformis MH48 inoculation had no significant effect on the growth of seedlings. Our results suggest that inoculation with B. licheniformis MH48 can be used as a PGPR bio - enhancer to stimulate fine root development, promote nutrient uptake and alleviate salt stress in ornamental plant seedlings grown in the high-salinity conditions of reclaimed coastal land.