• Proceedings of the Korean Environmental Sciences Society Conference
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• 2006.05a
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• pp.411-413
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• 2006

애기장대에 카드뮴을 5가지 농도(1, 5, 15, 30, 50 mg/L)로 처리하였을 때 식물의 생장에 미치는 영향을 조사하였다. 환경부고시 오염물질 배출기준농도(0.1 mg/L)의 50배 높은 카드뮴농도로 처리한 식물의 줄기 생장은 정상식물보다 어느 정도 촉진되었으나,오염물질 배출기준농도의 150배 이상의 높은 농도에서는 농도에 비례하여 생장이 감소되었다. 뿌리 생장에서는 줄기 생장과 유사한 경향을 나타냈지만 오염물질 배출기준농도의 50배 이상의 높은 카드뮴농도에서부터 뿌리생장이 점진적으로 감소하였다. 잎 생장에서는 줄기 생장과 비슷한 경향을 나타내어 오염물질 배출기준농도의 50배 높은 카드뮴농도까지는 엽신이 크고 표면적이 증가하여 생장이 정상식물보다 오히려 촉진되었으나 150배 이상의 높은 농도부터는 농도에 비례하여 생장이 감소되었다 카드뮴을 처리한 식물들의 생중량은 줄기와 잎 생장의 결과와 거의 유사한 결과를 나타내었다.

• Journal of Plant Biotechnology
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• v.47 no.4
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• pp.337-344
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• 2020

Plant growth-promoting microorganisms promote plant growth by supplying nutrients to roots and interacting with the intrinsic factors in plants through volatile organic compounds (VOCs). In this study, we evaluated the effect of UOS, plant growth-promoting fungi (PGPF) isolated from previous study, on the growth of Nicotiana tabacum L. var Xanthi nc. Phylogenetic analysis and GC-MS were used to identify the fungal species and the VOCs emitted by the UOS, respectively. The fresh weight of UOS-treated Nicotiana tabacum L. was 3.8 and 4.2-fold higher than that of the control groups grown in vertical and I-plates, respectively. Moreover, in the UOS-treated plants, the length of the primary root was half and the number of lateral roots were twice compared to those in control plants. The UOS was identified as Phoma sp. by studying spore and mycelial morphology and using phylogenetic analysis. GC-MS revealed that the VOC emitted by the UOS was hexamethylcyclotrisiloxane (D3). These results suggest that the UOS of Phoma sp. influences plant growth and root development through D3. We expect this UOS and its VOC, D3 to be utilized in the future to increase growth and enhance yield for other plants.

• Journal of Life Science
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• v.3 no.1
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• pp.2-8
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• 1993

천연화합물과 합성화합물은 모두 합쳐서 식물생장조절제라 부르고 이들 화합물은 경우에 따라 식물의 기간들의 생장율을 촉진하거나 억제한다. 호르몬이란 용어는 천연적으로 발생하는 색물생장 조절제에 국한되는 것이다. 실제의 응용에 있어서 합성된 생장조절제가 사용되는 것은 이 물질이 생체내에서 안정도가 더 크기 때문이다. 따라서, 합성물질은 식물 호르몬의 구조적인 유사성으로 흉내를 내거나 내생 호르몬들의 생합성, 전류, 및 대사를 조정해서 그 수준을 조절하게 된다. 그래서, 식물생장 조절물질들의 기능과 가능력을 이해하기 위해서 분자수준에서 식물호르몬들의 작용의 양상을 고찰한다.

• The Korean Journal of Mycology
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• v.33 no.1
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• pp.30-34
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• 2005

Fifteen PGPF (plant growth promoting fungi) isolates were selected from 728 fungal isolates collected from rhizosphere of zoysiagrass in Korea. Identification of the 15 isolates was based on their morphological characteristics. They were classified as Gliocladium sp. (n=1), Penicillium sp. (n=5), Trichoderma sp. (n=3), Fusarium sp. (n=3), and unidentifed species (n=3). Of the 15 isolates, six (PF-31, PF-136, PF-238, PF-255, PF-395, PF-420) significantly promoted the growth of tomato seedlings, and three (PF-31, PF-101, PF-255) also promoted the growth of hot pepper and two (PF-31, PF-225) also promoted the growth of cucumber, The 15 PGPF isolates were divided into 4 groups based on root colonizing ability. Isolates PF-17, PF-101 and PF-225 were included in the group 1, which had high root colonizing ability.

• Microbiology and Biotechnology Letters
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• v.49 no.3
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• pp.413-424
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• 2021

In order to enhance rhizoremediation performance, which remediates contaminated soils using the interactions between plants and microorganisms in rhizosphere, it is required to develop effective microbial resources that simultaneously degrade contaminants and promote plant growth. In this study, heavy metal-resistant rhizobacteria, which had been cultivated in soils contaminated with heavy metals (copper, cadmium, and lead) and diesel were isolated from rhizospheres of maize and tall fescue. After that, the isolates were qualitatively evaluated for plant growth promoting (PGP) activities, heavy metal tolerance, and diesel degradability. As a result, six strains with heavy metal tolerance, PGP activities, and diesel degradability were isolated. Strains CuM5 and CdM2 were isolated from the rhizosphere soils of maize, and were identified as belonging to the genus Cupriavidus. From the rhizosphere soils of tall fescue, strains CuT6, CdT2, CdT5, and PbT3 were isolated and were identified as Fulvimonas soli, Cupriavidus sp., Novosphingobium sp., and Bacillus sp., respectively. Cupriavidus sp. CuM5 and CdM2 showed a low heavy metal tolerance and diesel degradability, but exhibited an excellent PGP ability. Among the six isolates, Cupriavidus sp. CdT2 and Bacillus sp. PbT3 showed the best diesel degradability. Additionally, Bacillus sp. PbT3 also exhibited excellent heavy metal tolerance and PGP abilities. These results indicate that the isolates can be used as promising microbial resources to promote plant growth and restore soils with contaminated heavy metals and diesel.

• Journal of Life Science
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• v.29 no.11
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• pp.1281-1293
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• 2019

The rhizosphere is the active zone where plant roots communicate with the soil microbiome, each responding to the other's signals. The soil microbiome within the rhizosphere that is beneficial to plant growth and productivity is known as plant growth-promoting rhizobacteria (PGPR). PGPR take part in many pivotal plant processes, including plant growth, development, immunity, and productivity, by influencing acquisition and utilization of nutrient molecules, regulation of phytohormone biosynthesis, signaling, and response, and resistance to biotic- and abiotic-stresses. PGPR also produce secondary compounds and volatile organic compounds (VOCs) that elicit plant growth. Moreover, plant roots exude attractants that cause PGPR to aggregate in the rhizosphere zone for colonization, improving soil properties and protecting plants against pathogenic factors. The interactions between PGPR and plant roots in rhizosphere are essential and interdependent. Many studies have reported that PGPR function in multiple ways under the same or diverse conditions, directly and indirectly. This review focuses on the roles and strategies of PGPR in enhancing nutrient acquisition by nutrient fixation/solubilization/mineralization, inducing plant growth regulators/phytohormones, and promoting growth and development of root and shoot by affecting cell division, elongation, and differentiation. We also summarize the current knowledge of the effects of PGPR and the soil microbiota on plants.

• Journal of Applied Biological Chemistry
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• v.66
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• pp.394-403
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• 2023

In the pursuit of sustainable and environmentally-friendly agricultural practices, we conducted an extensive study on the rhizosphere bacteria inhabiting soils that have been devoid of chemical fertilizers for an extended period exceeding 40 years. Through this investigation, we isolated a total of 80 species of plant growth-promoting rhizosphere bacteria and assessed their potential to enhance plant growth. Among these isolates, Burkholderia cepacia CD2 displayed remarkable plant growth-promoting activity, making it an optimal candidate for further analysis. Burkholderia cepacia CD2 exhibited a range of beneficial characteristics conducive to plant growth, including phosphate solubilization, siderophore production, denitrification, nitrate utilization, and urease activity. These attributes are well-known to positively influence the growth and development of plants. To validate the taxonomic classification of the strain, 16S rRNA gene sequencing confirmed its placement within the Burkholderia genus, providing further insights into its phylogenetic relationship. To delve deeper into the potential mechanisms underlying its plant growth-promoting properties, we sought to confirm the presence of specific genes associated with plant growth promotion in CD2. To achieve this, whole genome sequencing (WGS) was performed by Plasmidsaurus Inc. (USA) utilizing Oxford Nanopore technology (Abingdon, UK). The WGS analysis of the genome of CD2 revealed the existence of a subsystem function, which is thought to be a pivotal factor contributing to improved plant growth. Based on these findings, it can be concluded that Burkholderia cepacia CD2 has the potential to serve as a microbial fertilizer, offering a sustainable alternative to chemical fertilizers.

• Microbiology and Biotechnology Letters
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• v.48 no.4
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• pp.399-422
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• 2020

Remediating soils contaminated with heavy metals due to urbanization and industrialization is very important not only for human health but also for ecosystem sustainability. Of the available remediation technologies for heavy metal-contaminated soils, phytoremediation is a relatively low-cost environment-friendly technology which preserves biodiversity and soil fertility. The application of plant growth-promoting bacteria (PGPB) during the phytoremediation of heavy metal-contaminated soils can enhance plant growth against heavy metal toxicity and increase heavy metal removal efficiency. In this study, the sources of heavy metals that have adverse effects on microorganisms, plants, and humans, and the plant growth-promoting traits of PGPB are addressed and the research trends of PGPB-assisted phytoremediation over the last 10 years are summarized. In addition, the effects of environmental factors and PGPB inoculation methods on the performance of PGPB-assisted phytoremediation are discussed. For the innovation of PGPB-assisted phytoremediation, it is necessary to understand the behavior of PGPB and the interactions among plant, PGPB, and indigenous microorganisms in the field.

• Korean Journal of Microbiology
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• v.46 no.1
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• pp.33-37
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• 2010

Rhizobacterial strain isolated from barren soil, Bacillus subtilis RFO41 exhibits a high level of phosphate solubilizing activity and produces some phytohormones. Its promoting effect on the growth of Xanthium italicum Moore, a wild plant growing at lakeside barren land and thus a good candidate plant for revegetation of barren lakeside was evaluated in the in situ test for 19 weeks at Lake Paro, Kangwon-do. Strain RFO41 could enhance the dry weight of X. italicum by 67.7%. It also increased the shoot length of X. italicum plant by 21.1% compared to that of uninoculated control. Both growth enhancements had statistical significance. However, the inoculation did not show any effect on the root growth, which might be due to the breakage of tiny root. Denaturing gradient gel electrophoresis analysis showed that the inoculated bacteria were maintained in the soils, and the indigenous bacterial community did not exhibit any significant change. This plant growth promoting capability may be utilized as an environment-friendly and low cost revegetation method, especially for the sensitive areas such as barren lakeside lands.

• Research in Plant Disease
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• v.22 no.2
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• pp.81-93
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• 2016

Out of plant-associated bacteria, certain plant growth-promoting bacteria (PGPB) have been reported to increase plant growth and productivity and to elicit induced resistance against plant pathogens. In this study, our objective was to broaden the range of applications of leaf-colonizing PGPB for foliar parts of road tress and pepper. Total 1,056 isolates of endospore-forming bacteria from tree phylloplanes were collected and evaluated for the enzymatic activities including protease, lipase, and chitinase and antifungal capacities against two fungal pathogens, Colletotrichum graminicola and Botrytis cinerea. Fourteen isolates classified as members of the bacilli group displayed the capacity to colonize pepper leaves after spraying inoculation. Three strains, 5B6, 8D4, and 8G12, and the mixtures were employed to evaluate growth promotion, yield increase and defence responses under field condition. Additionally, foliar application of bacterial preparation was applied to the road tress in Yuseong, Daejeon, South Korea, resulted in increase of chlorophyll contents and leaf thickness, compared with non-treated control. The foliar application of microbial preparation reduced brown shot-hole disease of Prunus serrulata L. and advanced leaf abscission in Ginkgo biloba L. Collectively, our results suggest that leaf-colonizing bacteria provide potential microbial agents to increase the performance of woody plants such as tree and pepper through spray application.