• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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• pp.100.1-100
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• 2003

A dctA gene encoding a protein with identity to a C4-dicarboxylate/H+ was cloned from a beneficial biocontrol bacterium, P. chororaphis O6. Expression of the dctA was induced in minimal medium by several organic acids and was repressed by glucose. Highest expression was observed in early-log cells grown on fumarate and succinate with decline as cells approached late-log phase. The dctA transcript accumulated weakly when cells were grown on malate but strong expression was observed with benzoate. Expression of the dctA transcript was repressed in early-log cells upon addition of glucose to fumarate, but was detected as the cell culture aged. A dctA-deficient mutant of O6, constructed by marker exchange mutagenesis, did not grow on minimal medium containing succinate, benzoate, or fumarate, and growth on malate was delayed. The dctA mutant and wild type grew equally on glucose. The dctA mutant on cucumber roots in sterilized potting soil was colonized at levels comparable to those of the wild type, but induction level of disease resistance by the mutant against target leaf spot disease was decreased. These results may indicate that the dctA is essential for utilization of certain organic acids and its expression is controlled by the availability of sugars. In addition, the dctA is not essenitial for cucumber root colonization, but important for induction of disease resistance.

• 한국환경복원기술학회지
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• 제19권5호
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• pp.47-57
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• 2016

In the recent years, the incidence of abandoned concrete roads have been increasing rapidly due to road improvements and facilities route construction, these abandoned expressway and unused roads are scattered throughout the country but the management system is not clear, they does not be an effectively managed because there is no maintenance cost. In response to these social concern and expectation, the Korea Expressway Corporation that is management authority of the expressway is developing policy initiatives and various projects to restore the closed road to ecological for eco-friendly projects of the existing expressway. And as part of these projects, Hwanggan IC unmanaged abandoned concrete roads restoration project was done and it was conducting monitoring for ecological restoration that is not one-off but sustainable. After test construction over seven years at the time, test construction of four ways enforced but the boundaries have become blurred over time. And Pinus koraiensis, Callicarpa dichotoma and Sorbaria stellipilla var. typica planted in the site are dominating, else Amorpha fruticosa and Indigofera pseudotinctoria sowed are dominating. Invasive species is that Robinia pseudoacacia was growing in the colony. Over monitoring result time, the vegetation was taking root and the ecosystem was being restore. But the disturbance of vegetation happens due to planting of tree species that doesn't fit in the restoration area and advent of ecosystem Disturbing Species. The study will be providing a basic data that identify change of plant environment by monitoring of the site and soil environment during June to November 2016 and secure an objective evaluation data by analyzing the effects of ecological restoration for revegetation test bed evaluation for ecological restoration of expressway in ecological restoration construction in later.

• 한국토양비료학회지
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• 제45권4호
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• pp.582-592
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• 2012

Microorganisms present in the rhizosphere soil plays a vital role in improving the plant growth and soil fertility. Many kinds of fertilizers including chemical and organic has been approached to improve the productivity. Though some of them showed significant improvement in yield, they failed to maintain the soil properties. Rather they negatively affected soil eventually, the land became unsuitable for agricultural. To overcome these problems, microorganisms have been used as effective alternative. For past few decades, plant growth promoting rhizobacteria (PGPR) and arbuscular mycorrhizal fungi (AMF) have been used as effective inoculants to enhance the plant growth and productivity. PGPR improves the plant growth and helps the plant to withstand biotic and abiotic stresses. AM fungi are known to colonize roots of plants and they increase the plant nutrient uptake. Spore associated bacteria (SAB) are attached to spore wall or hyphae and known to increase the AMF germination and root colonization but their mechanism of interaction is poorly known. Better understanding the interactions among AMF, SAB and PGPR are necessary to enhance the quality of inoculants as a biofertilizers. In this paper, current knowledge about the interactions between fungi and bacteria are reviewed and discussed about AMF spore associated bacteria.

• Journal of Ginseng Research
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• 제36권2호
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• pp.211-217
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• 2012

Endophytic fungi were isolated from various tissues (root, stem, petiole, leaf, and flower stalk) of 3- and 4-year-old ginseng plants (Panax ginseng Meyer) cultivated in Korea. The isolated endophytic fungi were identified based on the sequence analysis of the internal transcribed spacer (ITS), 1-5.8-ITS 2. A morphological characterization was also conducted using microscopic observations. According to the identification, 127 fungal isolates were assigned to 27 taxa. The genera of Phoma, Alternaria and Colletotrichum were the most frequent isolates, followed by Fusarium, Entrophospora and Xylaria. Although 19 of the 27 taxa were identified at the species level, the remainder were classified at the genus level (6 isolates), phylum level (Ascomycota, 1 isolate), and unknown fungal species (1 isolate). Endophytic fungi of 13 and 19 species were isolated from 3- and 4-year-old ginseng plants, respectively, and Phoma radicina and Fusarium solani were the most frequently isolated species colonizing the tissues of the 3- and 4-year-old ginseng plants, respectively. The colonization frequency (CF%) was dependant on the age and tissue examined: the CFs of the roots and stems in the 3-year-old ginseng were higher than the CF of tissues in the 4-year-old plants. In contrast, higher CFs were observed in the leaves and petioles of 4-year-old plants, and endophytic fungi in the flower stalks were only detected in the 4-year-old plants. In conclusion, we detected diverse endophytic fungi in ginseng plants, which were distributed differently depending on the age and tissue examined.

• 한국균학회지
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• 제38권1호
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• pp.1-4
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• 2010

광릉요강꽃(Cypripedium japonicum)과 복주머니란(C. macranthum)의 뿌리에서 난 균근균이 확인되었다. 두 종의 난 뿌리에서 균근의 형태적인 특성을 관찰하였다. 분자적인 분석을 통하여 두 종의 뿌리로부터 난균근균을 확인하였다. 뿌리에서 DNA를 추출하여, 담자균류 ITS 지역에 특이적인 프라이머인 ITS1-OF와 ITS4-OF를 사용하여 ITS 지역을 증폭한 후 염기서열을 분석하여 두 식물의 뿌리에 공생하는 난균근균을 동정하였다. 광릉요강꽃의 뿌리에는 3종류의 Tulasnellaceae와 1종의 담자균류가 발견되었고, 복주머니란의 뿌리에서는 2종류의 Tulasnellaceae에 속하는 균이발견되었다.

• Journal of Ginseng Research
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• 제43권1호
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• pp.77-85
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• 2019

Background: Glomus intraradices is a species of arbuscular mycorrhizal fungi that, as an obligate endomycorrhiza, can form mutually beneficial associations with plants. Panax ginseng is a popular traditional Chinese medicine; however, problems associated with ginseng planting, such as pesticide residues, reduce the ginseng quality. Methods: In this experiment, we studied the effect of inoculating G. intraradices on several physiological properties and microbial communities of ginseng. UV-Visible Spectrum method was used to detect physical properties. Denaturing gradient gel electrophoresis method was used to analyze microbial communities. Results: The results indicated that inoculation with G. intraradices can improve the colonization rate of lateral ginseng roots, increase the levels of monomeric and total ginsenosides, and improve root activity as well as polyphenol oxidase and catalase activities. We also studied the bacterial and fungal communities in ginseng rhizospheric soil. In our study, G. intraradices inoculation improved the abundance and Shannon diversity of bacteria, whereas fungi showed a reciprocal effect. Furthermore, we found that G. intraradices inoculation might increase some beneficial bacterial species and decreased pathogenic fungi in rhizospheric soil of ginseng. Conclusion: Our results showed that G. intraradices can benefit ginseng planting which may have some instructive and practical significance for planting ginseng in farmland.

• Journal of Microbiology and Biotechnology
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• 제15권6호
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• pp.1286-1298
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• 2005

The genus Paenibacillus is a new group of bacilli separated from the genus Bacillus, and most of species have been isolated from soil. In the present study, we collected 450 spore-forming bacilli from the roots of winter crops, such as barley, wheat, onion, green onion, and Chinese cabbage, which were cultivated in the southern part of Korea. Among these 450 isolates, 104 Paenibacillus-like isolates were selected, based on their colony shape, odor, color, and endospore morphology, and 41 isolates were then finally identified as Paenibacillus spp. by 16S rDNA sequencing. Among the 41 Paenibacillus isolates, 23 were classified as P. polymyxa, a type species of the genus Paenibacillus, based on comparison of the 16S rDNA sequences with those of 32 type strains of the genus Paenibacillus from the GenBank database. Thirty-five isolates among the 41 Paenibacillus isolates exhibited antagonistic activity towards plant fungal and bacterial pathogens, whereas 24 isolates had a significant growth-enhancing effect on cucumber seedlings, when applied to the seeds. An assessment of the root-colonization capacity under gnotobiotic conditions revealed that all 41 isolates were able to colonize cucumber roots without any significant difference. Twenty-one of the Paenibacillus isolates were shown to contain the nifH gene, which is an indicator of $N_{2}$ fixation. However, the other 20 isolates, including the reference strain E681, did not incorporate the nifH gene. To investigate the diversity of the isolates, a BOX-PCR was performed, and the resulting electrophoresis patterns allowed the 41 Paenibacillus isolates to be divided into three groups (Groups A, B, and C). One group included Paenibacillus strains isolated mainly from barley or wheat, whereas the other two groups contained strains isolated from diverse plant samples. Accordingly, the present results showed that the Paenibacillus isolates collected from the rhizosphere of winter crops were diverse in their biological and genetic characteristics, and they are good candidates for further application studies.

• Journal of Microbiology and Biotechnology
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• 제24권9호
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• pp.1149-1161
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• 2014

Cotton plants were sampled and ranked according to their resistance to Verticillium wilt. In total, 642 endophytic fungi isolates representing 27 genera were recovered from Gossypium hirsutum root, stem, and leaf tissues, but were not uniformly distributed. More endophytic fungi appeared in the leaf (391) compared with the root (140) and stem (111) sections. However, no significant difference in the abundance of isolated endophytes was found among resistant cotton varieties. Alternaria exhibited the highest colonization frequency (7.9%), followed by Acremonium (6.6%) and Penicillium (4.8%). Unlike tolerant varieties, resistant and susceptible ones had similar endophytic fungal population compositions. In three Verticillium-wilt-resistant cotton varieties, fungal endophytes from the genus Alternaria were most frequently isolated, followed by Gibberella and Penicillium. The maximum concentration of dominant endophytic fungi was observed in leaf tissues (0.1797). The evenness of stem tissue endophytic communities (0.702) was comparatively more uniform than the other two tissues. Eighty endophytic fungi selected from 27 genera were evaluated for their inhibition activity against highly virulent Verticillium dahliae isolate Vd080 in vitro. Thirty-nine isolates exhibited fungistasis against the pathogen at varying degrees. Seven species, having high growth inhibition rates (${\geq}75%$), exhibited strong antifungal activity against V. dahliae. The antifungal activity of both volatile and nonvolatile metabolites was also investigated. The nonvolatile substances produced by CEF-818 (Penicillium simplicissimum), CEF-325 (Fusarium solani), CEF-714 (Leptosphaeria sp.), and CEF-642 (Talaromyces flavus) completely inhibited V. dahliae growth. These findings deepen our understanding of cotton-endophyte interactions and provide a platform for screening G. hirsutum endophytes with biocontrol potential.

• Applied Biological Chemistry
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• 제47권2호
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• pp.182-186
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• 2004

아바스큘라 내생균근(arbuscular mycorrhizae, AM) 균은 대부분의 육상식물 뿌리와 공생하며, 식물의 성장에 도움을 주는 균이다. 인삼은 다년생 식물로서 뿌리를 약재로 사용하는 대표적인 약재 중 하나이다. 본 연구에서는 우리나라 8개 지역에서 인삼을 채집하여 AM 균을 염색을 통하여 형태적으로 관찰하고, 분자생물학적인 방법을 사용하여 뿌리내에 공생하는 다양한 AM 균을 확인하였다. 인삼의 뿌리에 감염되어 있는 AM 균을 염색하여 형태적으로 관찰한 결과 감염률이 낮고 흐리게 염색되었다. 또한 균사와 vesicle 이 발견되었고 이들은 Arum type 으로 판단되지만 arbuscule을 관찰하지 못했기 때문에 Arum-type으로 단정하기는 어려웠다. 식물 내에 공생하는 AM균들의 종류를 확인하기 위하여 채집된 인삼의 뿌리에서 내생균근 균의 DNA를 AM균에 특이적인 18s rDNA primer를 이용한 nested PCR을 수행하여 AM 균의 18S rDNA중 일부를 확보하였다. 증폭된 DNA는 클로닝을 통해서 개별 내생균근 균 종의 염기서열들로 분리하였고, 이들은 AluI, HinfI과 같은 제한 효소를 사용하여 RELP하였다. RELP 패턴에 따라 그룹을 나누어, 각 그룹에서 1개씩 염기서열 분석을 수행하였다. 염기서열은 기존의 서열과의 유사성과 계통 관계의 분석을 통하여 모두 AM균인 것으로 확인되었고, 다음 2개의 종과 가장 유사한 것으로 판단되었다; Paraglomus brasilianum, Glomus spurcum이 중 Paraglomus에 속하는 종인 P. brasil-ianum. 이 인삼의 뿌리에서 공통적으로 관찰되어 이들 균과 인삼과의 특이적 관계에 관하여 추측할 수 있었고, G. spurcum은 유사한 것으로 분석된 염기서열들이 계통도 상에서 특이한 분지를 형성하는 것으로 나타났는데, 이들 분지에 대해서는 확충된 염기서열들과 비교 분석과 같은 연구가 필요한 것으로 생각된다.

• Journal of Microbiology and Biotechnology
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• 제14권3호
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• pp.553-562
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• 2004

To investigate protective activity in pepper plants, which were pre-inoculated with arbuscular mycorrhizal (AM) fungi Glomus intra radices (Gi), against pathogenic strain Phytophthora capsici (Pc), pathogenesis-related (PR) proteins and antioxidant enzymes were examined. The growth of root and shoot was the highest in peppers inoculated with G. intraradices, compared with non-inoculated control plants and those challenged by the pathogen with and without mycorrhizae after nine days of infection. Mycorrhizal colonization rate was reduced by about 10% in pathogen-challenged plants, but disease pressure was reduced. The activities of PR proteins, $\beta$-1- 3-glucanase and chitinase, were increased in Pc-treated plants compared to Gi+Pc-treated plants in leaves, but those in roots were suppressed. Superoxide dismutase activity and $H_2O_2${/TEX> content in Gi+Pc and Pc-treated plants were gradually increased in leaves. However, those in roots continuously increased up to 5 days, and then decreased dramatically. Peroxidase activity in leaves and roots increased after P. capsici infection both in plants inoculated with or without G. intraradices. These results suggest that AM fungi, G. intra radices, potentially act as one of the protective agents against plant pathogens. Changes of PR proteins and antioxidative enzymes in mycorrhizae-inoculated pepper appear to be regulated differently in leaves and roots by pathogen infection.