• 한국균학회지
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• 제45권1호
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• pp.74-82
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• 2017

꽃도라지(Eustoma grandiflorum)는 국내에서 장식용 화훼류로 널리 이용되는 절화류이다. 2015년 경기도 여주와 경남 김해 지역에서 꽃도라지가 시들고, 지제부가 잘록해지면서 위축되고, 뿌리가 썩는 증상이 나타났다. 병든 식물체는 포장이나 육묘상자에서 황화되고, 뿌리 발육이 저해되었고, 진전되면 전체적으로 황화되면서 시들고, 위축되며, 결국 2~3개월 안에 완전히 말라 죽는다. 병든 식물체 지제부에서 Fusarium균이 분리되었고, 9개 균주를 단포자 분리하여 형태적 특성을 조사한 결과, Fusarium solani로 동정되었다. 대형포자는 통통하고, 직선형이거나 약간 굽은 초승달 모양이고, 소형분생포자는 긴mono형태의 분생포자원세포에서 false head상으로 형성되었다. 후벽포자는 균사 중간 혹은 끝부분에 풍부하게 형성되었다. 이와 같은 동정 결과는 translation elongation factor 1 alpha (TEF)와 RNA polymerase II subunit (RPB2) 유전자의 염기서열 분석으로 재확인되었다. 그 결과, 분리 균주는 NCBI GenBank에 등록된 F. solani와 TEF 유전자는 99.2~99.9%, RPB2 유전자는 98.0~98.1%의 상동성을 나타내었다. 건전한 꽃도라지 유묘의 뿌리를 포자현탁액에 침지 접종하여 병원성 검정을 수행한 결과, 접종 7일 이내에 접종한 식물체에서만 병징이 관찰되었다. 따라서 이 병을 F. solani에 의한 꽃도라지 뿌리썩음병으로 명명하며, 병의 발생을 국내에서 처음으로 보고한다.

• 한국미생물·생명공학회지
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• 제49권3호
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• pp.374-383
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• 2021

Rhizoctonia solani is one of the major pathogens that cause sheath blight disease in rice. Sheath blight is one of the most difficult diseases to control. Biological control (with the use of rhizobacteria) is one of the ways to control this disease. Plant Growth Promoting Rhizobacteria (PGPR) is a rhizosphere bacterium that can be used to enhance plant growth. The composition of the rhizobacteria in organic and nonorganic soil is affected by the chemical characteristics of the soil - which influences plant physiology and root exudation patterns. This study aimed to obtain a species of rhizobacteria which shows PGPR activity, from organic and nonorganic rice fields and test their capability to suppress R. solani growth. Out of 23 isolates screened for PGPR activity, the following isolates showed high PGPR activity and were selected for in vitro antagonistic activity testing against R. solani: ISO6, ISO11, ISO15, ISN2, ISN3, and ISN7, The six isolates produced 43,42-75,23 ppm of IAA, possessed phosphorus solubilization capability, and chitinase-producing activity. ISO6 (54.88%) and ISN7 (83.33%) displayed high inhibition capacities against R. solani, in vitro. ISO6 and ISN7 inhibited the growth of R. solani lesions on rice leaves by 89% and 100% (without lesion), respectively, after 7 days of incubation. Analysis of their 16S rRNA sequences revealed that the ISO6 isolate was Citrobacter freundii and ISN7 isolate was Pseudomonas aeruginosa.

• Mycobiology
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• 제28권1호
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• pp.17-26
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• 2000

The orchid symbiotic fungi were isolated from the roots of Korean native orchid (Cymbidium goeringii) collected and Chinese orchid (C. sinense) obtained from greenhouses. They were identified as a species of Rhizoctonia, based on the sequences of 18r rDNA, the microscopic observations of mycelia, and the symbiotic relationships with commercial orchids. The isolate collected from Chinese orchids was revealed to be a species of Ceratobasidium endophytica, and to be different from the other isolates at the thickness of the mycelia stained in the root cells of Korean native orchids. The other isolates collected from the Korean native orchids were considered to be a species of Tulsanella repens (anamorphic: Epulorhiza repens) or its related one. The physiologic or microscopic variations were oftenly observed among them, but the tendency of grouping these in the 18s rDNA sequences were observed to be consistent with those of the localities collected. The further taxonomical segregating for Korean symbiotic fungi was not made because the information concerned were limited in this moment, but was recognized as based on the sequences of 18s DNA.

• 한국균학회지
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• 제47권4호
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• pp.427-435
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• 2019

최근 경남 산청, 함양의 딸기 재배지역의 육묘하우스에서 딸기 묘목의 뿌리와 관부를 썩게 하고 지상부의 생육을 저해하며 최종적으로 식물체를 시들게 하는 뿌리썩음병(가칭)증상이 발생하였다. 이러한 병반을 나타내는 딸기 식물체 뿌리와 관부로부터 병원균을 분리하고 균학적 특성을 조사하였으며, 유전자 염기서열 분석과 계통학적 분석을 수행하였다. 그 결과, 딸기 육묘과정에서 발생한 뿌리썩음병(가칭)의 병원균은 Neopestalotiopsis clavispora로 확인되었으며, 건전한 딸기 식물체를 대상으로 접종실험을 수행한 결과 딸기에 대한 병원성을 확인하였다. 지금까지 국내에서 N. clavispora에 의한 딸기 뿌리썩음병이 보고되지 않았으므로 본 연구결과를 바탕으로 이병을 딸기뿌리썩음병으로 국내 최초로 보고한다.

• The Plant Pathology Journal
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• 제39권6호
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• pp.575-583
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• 2023

Fusarium root rot is an increasingly severe problem in soybean cultivation. Although several Fusarium species have been reported to infect soybean roots in Heilongjiang province, their frequency and aggressiveness have not been systematically quantified in the region. This study aimed to investigate the diversity and distribution of Fusarium species that cause soybean root rot in Heilongjiang province over two years. A total of 485 isolates belonging to nine Fusarium species were identified, with F. oxysporum and F. solani being the most prevalent. Pot experiments were conducted to examine the relative aggressiveness of different Fusarium species on soybean roots, revealing that F. oxysporum and F. solani were the most aggressive pathogens, causing the most severe root rot symptoms. The study also assessed the susceptibility of different soybean cultivars to Fusarium root rot caused by F. oxysporum and F. solani. The results indicated that the soybean cultivar DN51 exhibited the most resistance to both pathogens, indicating that it may possess genetic traits that make it less susceptible to Fusarium root rot. These findings provide valuable insights into the diversity and distribution of Fusarium species that cause soybean root rot and could facilitate the development of effective management strategies for this disease.

• 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.

• 미생물학회지
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• 제12권2호
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• pp.94-98
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• 1974

This study was conducted from April 1 to September 31, 1973. Ten strains of Fusarium spp. were isolated from the diseased ginseng in two local areas at Kangwha-Gun nad Kumsan-Gun in Korea. Among of them, 2 strains ($G_1$, $G_4$) did not have virulence to ginseng in reinoculation. Their cultural, morphological characteristic and hose virulence to pea seedling were examined. Taxonomical identification of 8 isolates followed by the method of Wollenweber, Snyder nad Toussoun, Booth, Matuo and Snyder. All of eight strains were identified as the Fusarium solani f.sp.pisi(Jones) Synd. et Hans.

• Mycobiology
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• 제49권2호
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• pp.196-200
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• 2021

In May to July 2019, ovate-leaf atractylodes seedling and plant with Damping-off symptoms were observed in farmer field at Sangju and Mungyeong, Korea. Seven fungal isolates have been retrieved from diseased root tissue and identified as Rhizoctonia solani AG-5 based on morphological and molecular characteristics. To the best of our knowledge, this is the first report on damping-off of ovate-leaf atractylodes caused by R. solani AG-5 in South Korea.

• 한국양식학회:학술대회논문집
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• 한국양식학회 2003년도 추계학술발표대회 논문요약집
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• pp.134-135
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• 2003

The geographic expansion of the toxic dinoflagellates genus Alexandrium has been shown to be world wide ranging. The members of the genus Alexandrium ocnstituted of 20-30 species did not show substantial differences in their morphology, which is mostly referred in the 'tamarensis species complex', except some species. Though rDNA sequences variations are very few and pseudogene types are so diverse that it is difficult to use them as the specific markers. In this study, we outlined Korean and Japanese A, tamarense and A. catenella regional isolates by phylogenetic analysis inferred from no cutting alignments of LSU rDNA D1-D2 and SSU rDNA sequences to group these regional isolates. The results were compared to RFLP patterns of PCR products targeted chloroplast DNA. Lastly screening of highly repeated microsatellite DNA which is frequently used for population analysis in eukaryotes was conducted. A. catenella regional strains identified by the sequencing of rDNA D1-D2 domain were divided into at least 3 groups of type E, CMC and Chinese type, divergence root may not be deep comparing with that of A. tamarense whose pseudogenes are very variable. Results of RFLP pattern and the phylogeny of the unknown gene targeting chloroplast showed that Korean and Japanese A. catenella regional isolates were divided into 3 types: Korean, Japanese and the third CMC types. Population-specific PCR amplification with Japanese A. catenella type-specific PCR primers was useful method for population analysis of A. catenella. Various types of satellite sequences such as 5 nucleotides repeats were obtained from A. tamarense and A. catenella. The 5 nucleotides repeats were primed at the both 3'and 5' ends, and these repeats were prominent as longer repeated motifs. This repeated DNA was intercalated as internal sequences containing various types subrepeats. It is expected that these satellite DNA would be a useful molecular population marker through detail comparison among Alexandrium regional isolates to trace their transferring pathway and to prevent their human-associated their regional extents.

• 한국토양비료학회지
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• 제23권1호
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• pp.67-72
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• 1990

수종(數種)의 비두과식물(非荳科植物)의 뿌리로 부터 질소고정균(窒素固定菌)을 분리(分離)하여 분리(分離)된 균(菌)에 대(對)해서 숙주식물(宿主植物)의 접종실험(接種實驗)을 하여 유효균(有效菌)의 선발(選拔)을 한 결과(結果) 1. 9개(個)의 식물(植物)에 대(對)해서는 시금치, 배추, 오이, 갓 및 가지에서 비교적(比較的) 높은 아세칠렌 환원능(還元能)을 가진 균주(菌株)를 얻었고 2. 그 중(中)에서 아세칠렌 환원능(還元能)이 큰 4개(個)의 숙주식물(宿主植物)중 시금치, 배추, 오이에서 양호(良好)한 생육(生育)을 하는 균주(菌株)를 찾았다. 특(特)히 시금치에서 접종효과(接種效果)가 현저(顯著)하였다. 3. 이상(以上)의 결과(結果)로 부터 비두과식물(非荳科植物)의 뿌리에도 약한 협생(協生)을 하는 질소고정균(窒素固定菌)이 생육(生育)되고 있어 뿌리의 생장(生長) 및 분화(分化)를 촉진(促進)시켜 지상부(地上部)의 생육(生育)을 왕성하게 하는 것으로 판단(判斷)된다.