• Journal of Microbiology and Biotechnology
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• 제22권3호
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• pp.326-330
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• 2012

Antifungal metabolites were isolated from a culture of Pseudomonas aurantiaca IB5-10. Chemical structures of the metabolites were elucidated as phenazine-1-carboxylic acid (PCA; 1), 2-hydroxyphenazine (2-OH-PHZ; 2), and cyclo-(L-Pro-L-Val; 3), respectively, based on spectroscopic methods. Among them, 3 was isolated for the first time from this strain. The antifungal activities of 1-3 were evaluated against a variety of plant pathogens. To the best of our knowledge, the antifungal activities of 3 against plant fungal pathogens have been evaluated for the first time in this work. PCA (1) showed the most potent antifungal activities against Phytophthora capsici, Rhizoctonia solani AG-1(IA), and Pythium ultimum with MICs (${\mu}g/ml$) of less than 1.0, 1.3, and 2.0, respectively. On the other hand, 2-OH-PHZ (2) showed potent antifungal activity against R. solani AG-1(IA) with the MIC (${\mu}g/ml$) of 2.0, whereas it showed moderate antifungal activity against P. ultimum with the MIC (${\mu}g/ml$) of 50.0. In addition, 3 showed antifungal activity against only R. solani AG-1(IA).

• Mycobiology
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• 제51권3호
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• pp.186-194
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• 2023

In July 2021, wilting symptoms were observed in adult and seedling hemp (Cannabis sativa L. cv. Cherry Blossom) plants grown in a greenhouse. As the disease progressed, yellowing and wilting symptoms on the leaves developed, resulting in whole plant death. In seedling plants, typical damping-off symptoms were observed. To identify the pathogen, the roots of diseased plants were sampled, surface sterilized, and cultured on potato dextrose agar (PDA) media. From the culture, 4 different fungal isolates were recovered and purely cultured. Each fungal isolate showed distinct growth shapes and color development on malt extract agar, oatmeal agar, sabouraud dextrose agar, and PDA media. Microscopic observation and molecular identification using ribosomal DNA internal transcribed spacer sequencing identified them as 3 Fusarium spp. and 1 Thielaviopsis paradoxa. Additional sequencing of elongation factor 1-alpha and b-tubulin regions of 3 Fusarium spp. revealed that 2 of them are Fusarium solani, and the other one is Fusarium proliferatum. To examine which isolate can act as a causal agent of wilt disease of hemp, each isolate was tested for their pathogenicity. In the pathogenicity test, F. solani AMCF1 and AMCF2, and F. proliferatum AMCF3, but not T. paradoxa AMCF4, were able to cause wilting disease in hemp seedlings. Therefore, we report that F. solani AMCF1 and AMCF2, and F. proliferatum AMCF3 as causal agents of Fusarium wilt of hemp plants. To our knowledge, this is the first report of the wilt disease of C. sativa L. caused by Fusarium spp. in Korea.

• The Plant Pathology Journal
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• 제40권2호
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• pp.192-204
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• 2024

In this study, the efficacy of the essential oil of Mentha longifolia, Achillea arabica and Artemisia absinthium plants were evaluated against important soil-borne fungal pathogens as Verticillium dahliae, Rhizoctonia solani, and Fusarium oxysporum. Essential oils were obtained from plants by hydrodistillation method and the chemical components of essential oils were determined by analyzing by gas chromatography-mass spectrometry. The main components found as piperitone oxide (13.61%), piperitenone oxide (15.55%), pulegone (12.47%), 1-menthone (5.75%), and camphor (5.75%) in M. longifolia, á-selinene 13.38%, camphor 13.34%, L-4-terpineneol 8.40%, (-)-á-Elemene 7.01%, 1,8-cineole 4.71%, and (-)-spathulenol 3.84% in A. arabica, and á-thujone (34.64%), 1,8-cineole (19.54%), pulegone (7.86%), camphene (5.31%), sabinene (4.86%), and germacrene-d (3.67%) in A. absinthium. The antifungal activities of the oils were investigated 0.05, 0.1, 0.25, 0.5, 1.00, and 2.00 μl/ml concentrations with the contact effect method. M. longifolia oil (1.00 and 2.00 μl/ml) has displayed remarkable antifungal effect and provided 100% inhibition on mycelial growth of V. dahliae, R. solani and F. oxysporum. The results obtained from this study may contribute to the development of new alternative and safe methods against soil-borne fungal pathogens.

• 한국미생물·생명공학회지
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• 제27권6호
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• pp.427-432
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• 1999

농산물의 증산을 위한 과도한 농약 사용으로 인한 토양 생태계의 파괴를 줄이기 위하여 맹독성 농약을 대신할 수 있는 생물학적 방제제 개발의 일환으로 식물병원성 진균의 생육을 억제하는 siderophore를 생산하는 생물학적 방제균을 선발하여, 이를 동정하고 근부병균억제기작을 연구하여 향후 다기능 생물학적 방제제 개발의 기초자료를 활용하고자 하였다. 이를 위해 저병해 경작지 토양에 장기간 우점화 되어 있는 siderophore 생산 가능성이 높은 토착 길항미생물을 전국 각지의 저병해 경작지에서 분리하였고, 이들 중 siderophore 생산능이 높은 길항미생물 4종의 균주를 chrome azurol S(CAS) agar를 이용하여 선발하였다. 그 중 최고의 길항성을 나타내는 GL7 균주를 최종 선발하였고, API diagnostic test와 지방산 분석, 그리고 각종 생리학적 특성 및 형태학적 특성을 통해 동정한 결과 Pseudomonas fluoresceus의 한 균주임을 확인하였다. 최종 선발된 siderophore 생산균주 P. fluorescens GL7의 길항기작을 병원성 진균인 Fusarium solani를 대상으로 균사 생장과 포자 발아 등의 억제율을 조사한 결과 균사 생장 억제율은 75% 이상이며, 포자 발아억제율은 97% 이상으로 우수한 방제능을 확인할 수 있었다. 선발된 siderophore 생산능이 높은 길항균주 P. fluo-rescens GL7을 대상으로 토양 내에서 실제로 근부병에 방제력이 있는가를 조사하기 위해 강낭콩 종자(Phaseolus vulgaris L.)를 발병 기주식물로 사용하여 방제시험을 한 결과 F. solam만 처리한 경우는 30%의 성장율을, P. fluorescens GL7 균주와 F. solani와 함께 처리한 경우는 95% 정도의 성장율을 나타내어 약 65% 정도의 발병율을 줄일 수 있었다. 또한 F. solani와 P. fluorescens GL7을 처리하지 않은 무처리구에 비해 식물 물게가 147% 정도로 증가하여 식물의 생육도와 뿌리의 발육상태가 양호하였고, 근부병 발생도 거의 볼 수 없었으므로 아주 우수한 siderophore 생산성 생물학적 방제균을 선발할 수 있었다.

• 농업생명과학연구
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• 제43권3호
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• pp.35-44
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• 2009

알로에 껍질과 육질 추출물이 Collectrichum gloeosporioides, Fusarium oxysporum, and F. solani의 세 가지 식물병원균에 대한 알로에 추출물의 용매 및 농도별 항균활성을 분석하였다. 용매의 종류에 따른 알로에 추출물의 항진균 활성은 C. gloeosporioides, F. solani에 대하여 물>메탄올>에탄올의 순서로 항균활성이 높았다. 알로에 껍질과 육질추출물의 항균활성에 있어서 F. oxysporum은 껍질 추출물에서, C. gloeosporioides와 F.sloani는 육질 추출물이 활성이 높아 껍질 보다는 육질에서 우수한 항균활성을 보였다. 알로에 육질의 물 추출물 농도에 따른 항균활성은 F. oxysporum는 $100{\mu}l/L$의 농도에서는 항균활성이 나타나지 않았으나 $100,000{\mu}l/L$의 농도에서 9.5%의 항균율을 보인 반면, C. gloeosporioides $100{\mu}l/L$의 농도에서 활성반응을 시작하여 $100,00{\mu}l/L$의 농도에서 최고 29.3%의 항균율을 나타내었다. F. oxysporum에 대한 알로에 육질 추출물 엽면살포 처리의 방제효과는 육질 추출물 농도가 증가할수록 방제효과가 증가하는 경향이었으며, 10g/L 농도 엽면살포 처리는 대조구에 비하여 62%의 방제효과를 나타내어 추출물의 농도가 증가함에 따라 In vivo에서도 F. oxysporum에 대한 항균활성이 강하게 나타내어 예방차원에서의 알로에 육질 추출물 엽면살포 처리는 F. oxysporum에 의한 시들음병 방제에 효과적인 수단이 될 수 있다고 사료된다.

• 한국작물학회지
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• 제44권4호
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• pp.382-390
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• 1999

In order to identify the responses of Korean soybean cultivars to sudden death syndrome (SDS), forty-two Korean cultivars and three check cultivars (Hartwig and PI 520733 are resistant; Hartz 6686 is susceptible) were tested with sorghum seed inoculum infested with Fusarium solani f. sp. glycines isolate 171 in the greenhouse. This isolate has blue pigment cultural shape on potato dextrose agar (PDA) medium. All Korean cultivars inoculated with F. solani isolate 171 showed the typical SDS symptoms and disease severity on soybean leaves in each cultivar varied at 4 weeks after inoculation. Nine cultivars were included in the most SDS susceptible group and six cultivars were included in the most susceptible group based on Duncan＇s multiple range tests (P$\leq$0.05). In results of the LSD analysis for SDS the resistant group, a total of twenty-five Korean cultivars were included in the same SDS resistant group as PI 520733 or Hartwig and fourteen Korean cultivars were included in the same SDS susceptible group as Hartz 6686. In the second experiment, ten Korean cultivars, ten U.S. cultivars, and one introduced line were compared in the same way as the first experiment Disease severity ranking of check cultivars, Hartwig, PI 520733, and Hartz 6686, were the same as in the first experiment. Within Korean cultivars, seven cultivars showed the consistent severity proportions of leaf symptoms. Disease rankings of these cultivars in this experiment were the same as those in the first experiment. Three US cultivars: Hartwig, Hartz 5454, and Forrest, three Korean cultivars： Keunolkong, Myeongjunamulkong, and Jinpumkong 2, and one introduced line, PI 520733, were included in the highest SDS resistant group. Shinphaldalkong 2, Milyang 87, and Samnamkong consistently showed the highest SDS susceptibility in both experiments. Average disease severity in the first and the second experiment were 49.56% and 45.39%, respectively.

• 한국균학회지
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• 제47권4호
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• pp.407-416
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• 2019

A common post-harvest disease of sweetpotato tuber is root rot caused by Fusarium solani in Korea as well as the other countries. Storage root rot disease was monitored earlier on sweetpotato (Ipomoea batatas) in storehouses of different locations in Korea. In the present study, an isolate SPL16124 was choosen and collected from Sweetpotato Research Lab., Bioenergy Crop Research Institute, NICS, Muan, Korea, and confirmed the identification as Fusarium solani by conidial and molecular phylogenetic analysis (internal transcribed spacer ITS and translation elongation factor EF 1-α gene sequences). The isolate was cultured on potato dextrose agar, and conidiation was induced. The fungus was screened for Fusarium root rot on tuber of 14 different varieties. Among the tested variety, Yenjami, Singeonmi, Daeyumi, and Sinjami showed resistant to root rot disease. Additionally, the pathogen was tested for pathogenicity on stalks of these varieties. No symptom was observed on the stalk, and it was confirmed that the disease is tissue specific.

• 한국미생물·생명공학회지
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• 제19권4호
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• pp.356-361
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• 1991

식물근부병의 방제균으로 선발된 Bacillus subtilis YBL-7의 식물부균 Fusarium solani에 대한 길항력을 유전공학적 조작에 의해 다목적으로 증강시킬 수 있는지를 타진하기 위해 외부유전자인 Bacillus pasteurii의 urease 유전자를 생물방제균 B.subtilis YBL-7내 도입자하고자 시도하였다. 외부 urease 유전자는 B.pasteurii의 urease gene을 shuttle vector인 pGR71의 HindII site에 삽입하여 E.coli내에서 발현시킨 pGU66을 사용하여 형질전환시켰으며 이때의 최적 형질전환조건과 도입된 urease 유전자의 발현을 조사해 보았다.

• The Plant Pathology Journal
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• 제32권2호
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• pp.85-94
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• 2016

Studies were conducted to determine the role of 3-methylthioproprionic acid (MTPA) in the pathogenicity of potato stem canker, Rhizoctonia solani, and the concentrations required to inhibit growth of R. solani under laboratory and plant house-based conditions. The experiments were laid out in a completely randomized design with five treatments and five replications. The treatments were 0, 1, 2, 4, and 8 mM concentrations of MTPA. The purified toxin exhibited maximal activity at pH 2.5 and $30^{\circ}C$. MTPA at 1, 2, 4, and 8 mM levels reduced plant height, chlorophyll content, haulm fresh weight, number of stolons, canopy development, and tuber weight of potato plants, as compared to the control. MTPA significantly affected mycelial growth with 8 mM causing the highest infection. The potato seedlings treated with MTPA concentrations of 1.0-8.0 mM induced necrosis of up to 80% of root system area. Cankers were resulted from the injection of potato seedling stems with 8.0 mM MTPA. The results showed the disappearance of cell membrane, rough mitochondrial and cell walls, change of the shape of chloroplasts, and swollen endoplasmic reticulum. Seventy-six (76) hours after toxin treatment, cell contents were completely broken, cytoplasm dissolved, and more chromatin were seen in the nucleus. The results suggested that high levels of the toxin concentration caused cell membrane and cytoplasm fracture. The integrity of cellular structure was destroyed by the phytotoxin. The concentrations of the phytotoxin were significantly correlated with pathogenicity and caused damage to the cell membrane of potato stem base tissue.

• Journal of Microbiology
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• 제38권2호
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• pp.66-73
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• 2000

To investigate the genetic relationship among 12 species belonging to the Fusarium section Martiella, Dlaminia, Gibbosum, Arthrosporiella, Liseola and Elegans, the internal transcribed spacer(ITS) regions of ribosomal DNA (rDNA) were amplified with primer pITS1 and pITS4 using the polymerase chain reaction(PCR). After the amplified products were digested with 7 restriction enzymes, restriction fragment length polymorphism (RFLP) patterns were analyzed. The partial nucleotide sequences of the ITS region were determined and compared. Little variation was observed in the size of the amplified product having sizes of 550bp or 570bp. Based on the RFLP analysis, the 12 species studied were divided into 5 RFLP types. In particular, strains belonging to the section Martiella were separated into three RFLP types. Interestingly, the RFLP type of F. solani f. sp. piperis was identical with that of isolates belonging to the section Elegans. In the dendrogram derived from RFLP analysis of the ITS region, the Fusarium spp. examined were divided into two major groups. In general, section Martiella excluding F. solani f. sp. piperis showed relatively low similarity with the other section. The dendrogram based on the sequencing analysis of the ITS2 region also gave the same results as that of the RFLP analysis. As expected, 5.8S, a coding region, was highly conserved, whereas the ITS2 region was more variable and informative. The difference in the ITS2 region between the length of F. solani and its formae speciales excluding F. solani f. sp. piperis and that of other species was caused by the insertion/deletion of nucleotides in positions 143-148 and 179-192.