• Title/Summary/Keyword: Phytotoxin

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Studies on Phytotoxin in Intensively Cultivated Upland Crops -I. Identification of phytotoxin in soil and effects of phytotoxin application to the toxicity of hot-pepper plant (연작재배지토양(連作栽培地土壤)의 식물독소(植物毒素)에 관(關)한 연구(硏究) -제(第)1보(報) 토양중(土壤中) 식물독소(植物毒素)의 분리정량(分離定量) 및 식물독소(植物毒素) 첨가(添加)가 고추 유식물(幼植物)에 미치는 영향(影響))

  • Lee, Sang Kyu;Suh, Jang Sun;Kim, Young Sig;Park, Jun Kyu
    • Korean Journal of Soil Science and Fertilizer
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    • v.20 no.1
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    • pp.63-67
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    • 1987
  • A laboratory experiment was conducted to find out the concentration of phytotoxin in intensively cultivated hot-pepper, garlic and chinese cabbage, and effects of these phytotoxin to the germination and growth of young hot-pepper plant. Also this experiment presents describes of the bio-assay method and results of phytotoxin application to the toxicity of hot-pepper plant. The results obtained were summarized as follows; 1. A series of non-volatile (aromatic) phenolic compounds such as hydroquinone, benzoic-, p-hydroxybenzoic, and vanillic acid were quantitatively and qualitatively analysed using BSA(N, O-bis(trimethylsilyl)acetamide) by means of gas chromatography method. 2. Phytotoxin as hydroquinone, benzoic-, p-hydroxybenzoic- and vanillic acid were determined in intensively cultivated hot- pepper, garlic and chinese cabbage. Highest concentration of phytotoxin was obtained in hot-pepper cultivated soil. 3. Direct toxic action of the applied phytotoxin to the germination and young hot-pepper plant growth was observed at the levels of 200 ppm. Benzoic acid was obtained the highest toxicity to the young hot-pepper plant growth. 4. Mode of actions of phytotoxins to the young hot-pepper plant growth were observed as stunting of stem elongation, discoloration of leaf and oxygen depletion from consideration as causes of symptom.

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Identification and Biological Activity of Two New Phytotoxins Isolated from Botrytis cinerea (Botrytis cinerea로부터 분리한 두 개의 새로운 phytotoxin의 구조 결정 및 생물활성)

  • Kim, Geum-Jung;Yoon, Mi-Young;Kim, Heung-Tae;Choi, Gyung-Ja;Jang, Kyoung-Soo;Choi, Yong-Ho;Park, Myung-Soo;Cha, Byeong-Jin;Kim, Jin-Cheol
    • Research in Plant Disease
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    • v.15 no.2
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    • pp.112-119
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    • 2009
  • We discovered two novel phytotoxins produced by the pathogenic fungus, Botrytis cinerea. Among the twenty-five B. cinerea isolates, which were obtained from various host plants in 1994 and 1996, twenty-two showed strong or moderate pathogenicity on five plants such as cucumber, tomato, red pepper, tobacco and Chinese cabbage. The culture filtrate of the B. cinerea 2-16 strain showed the most potent phytotoxic activity in a tobacco leaf-wounding assay. Two novel phytotoxins were isolated from the liquid cultures of B. cinerea 2-16 by ethyl acetate extraction, flash silica gel column chromatography, silica gel column chromatography, Sephadex LH-20 column chromatography, preparative TLC and subsequently preparative HPLC. Their chemical structures were determined to be 3-O-acetyl botcinol and 3-O-acetyl botcinolide, respectively, by mass and NMR spectral analyses. These two phytotoxins caused leaf necrosis in a leaf-wounding bioassay, and significant electrolyte leakage from leaf tissues of tobacco. In the two bioassays tested, 3-O-acetyl botcinol exhibited stronger phytotoxic activity than 3-O-acetyl botcinolide. This is the first report on the production of both 3-O-acetyl botcinol and 3-O-acetyl botcinolide from B. cinerea.

Phytotoxins of Pseudomonas syringae and PCR Primers for Detection of Phytotoxin-Producing Strains (Pseudomonas syringae의 식물독소와 독소 생산 균주의 검출을 위한 PCR Primer)

  • 정재성;한효심;고영진
    • Research in Plant Disease
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    • v.7 no.3
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    • pp.123-133
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    • 2001
  • Many pathovars of the species Pseudomonas syringae are known to produce different phytotoxins as secondary metabolites. Although phytotoxins generally enhance the virulence of P. syringae, they are not required for pathogenesis. Among the phytotoxins produced by P. syringae, lipodepsipeptides, coronatine, phaseolotoxin, and tabtoxin are the most well-known toxins which have been intensively studied for their structure, mode of action, biosynthesis, and regulation. A polymerase chain reaction (PCR) technique that amplifies a segment of the phytotoxin gene cluster using a primer set has been developed in recent years. This method offers the advantages of speed and sensitivity compared to the approaches based on physiological and biochemical methods. PCR detection of genes involved in the production of toxins could be exploited for early diagnosis of plant diseases caused by P. syringae pathovars.

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Role of Two New Phytotoxins in the Pathogenicity of Botrytis cinerea (두 개의 새로운 phytotoxin의 Botrytis cinerea 병원성에시의 역할)

  • Kim, Geum-Jung;Yoon, Mi-Young;Kim, Heung-Tae;Choi, Gyung-Ja;Jang, Kyoung-Soo;Choi, Yong-Ho;Park, Myung-Soo;Cha, Byeong-Jin;Kim, Jin-Cheol
    • Research in Plant Disease
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    • v.15 no.2
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    • pp.120-126
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    • 2009
  • In the course of study on the roles of phytotoxins in the pathogenicity of Botrytis cinerea, we isolated two novel phytotoxins. They were identified as 3-O-acetyl botcinol and 3-O-acetyl botcinolide. In this study, we investigated correlation between the two phytotoxins and the pathogenicity of B. cinerea. In liquid cultures, the two phytotoxins were not produced by three low pathogenic isolates out of 25 B. cinerea isolates. Among strong or moderate pathogenic isolates, some produced the two phytotoxins, but the others did not. On the other hand, the ethyl acetate extracts of fermentation broths of 10 out of 25 isolates showed phytotoxic activity against various plants tested in a whole plant assay. The phytotoxins were detected in all of the 10 phytotoxic ethyl acetate extracts. In planta, the two phytotoxins were detected in all of the plant tissues infected with strong pathogenic isolates. However, there was no correlation between the ability of B. cinerea isolates to produce the two phytotoxins and their pathogenicities. The two phytotoxins began to detect in tomato plant tissues infected with B. cinerea 2-16 at 3 days after inoculation, increased gradually till 4 days after inoculation, and then decreased. The above results suggest that 3-O-acetyl botcinol and 3-O-acetyl botcinolide are one of pathogenicity factors for B. cinerea, but not a primary determinant of its pathogenicity.

Role of a Phytotoxin Produced by Fusarium oxysporum f. sp. raphani on Pathogenesis of and Resistance to the Fungus (무 시들음병균이 생산하는 Phytotoxin의 병원성 및 저항성에서 역할)

  • Shim, Sun-Ah;Kim, Jin-Cheol;Jang, Kyoung Soo;Choi, Yong Ho;Kim, Heung Tae;Choi, Gyung Ja
    • Horticultural Science & Technology
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    • v.31 no.5
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    • pp.626-632
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    • 2013
  • In the course of a developing screening method for resistant radish to Fusarium oxysporum f. sp. raphani, we found that the fungus produces phytotoxic compound against Raphanus sativus. The culture filtrate of F. oxysporum f. sp. raphani KR1 represented the strongest phytotoxicity when the fungus was incubated in the malt extract broth with 150 rpm at $25^{\circ}C$ for 14 days. Under bioassay-guided purification, we isolated a substance from liquid culture of F. oxysporum f. sp. raphani KR1, with phytotoxic effect against R. sativus. The compound was identified as fusaric acid by mass and nuclear magnetic resonance spectral analyses. Phytotoxicity of the compound against cruciferous vegetable crops, including radish, cabbage, and broccoli, was investigated. Fusaric acid represented phytotoxicity on radish seedlings by concentration dependant manner. And the phytotoxin demonstrated strong phytotoxicity on the resistant cultivars as well as susceptible cultivars of radish to F. oxysporum f. sp. raphani. In addition, fusaric acid isolated from the fungus also showed a potent phytotoxic efficacy against non-host Brassicaceae crops of the fungus such as cabbage and broccoli. The results demonstrate that fusaric acid produced by F. oxysporum f. sp. raphani is non-host-specific toxin and for screening of resistant radish to the fungal pathogen, spore suspension of the fungus without the phytotoxin has to be used.

Construction of Transformation Method for Streptomyces scabiei ATCC 49173 Producing Phytotoxin (식물독소를 생산하는 Streptomyces scabiei ATCC 49173의 형질전환법 구축)

  • Jang, Bo-Youn;Ha, Heon-Su;Choi, Sun-Uk
    • KSBB Journal
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    • v.25 no.2
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    • pp.167-172
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    • 2010
  • Streptomyces scabiei producing phytotoxin called thaxtomin, which cause scab disease on economically important crops such as potato. For molecular genetics study of S. scabiei an effective transformation method was established based on conjugal transfer from Escherichia coli ET12567 (pUZ8002) using a phiC31-derived integration vector, pSET152, containing oriT and attP fragments. The high frequency was obtained on MS medium containing 50 mM $MgCl_2$. In addition, the sequence and location of the chromosomal integration attB site of S. scabiei was identified for the first time in the strains producing thaxtomin by the southern blot analysis of exconjugants and the sequencing of plasmid containing DNA flanking the insertion sites from exconjugant chromosome. Similar to the case of Streptomyces species, a single phiC31 attB site of S. scabiei is present within an ORF encoding a pirin-homolog.

Phytotoxin Production of Nigrospora sphaerica Pathogenic on Turfgrasses

  • Park, Gyung-Ja;Kim, Jin-Cheol;Shon, Mi-Jeong;Kim, Heung-Tae;Cho, Kwang-Yun
    • The Plant Pathology Journal
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    • v.16 no.3
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    • pp.137-141
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    • 2000
  • A causal fungus of turfgrass blight was isolated from the infected leaves of zoysiagrass (Zoysia japonica Steud.) and identified as Nigrospora sphaerica (Sacc.) Mason by using a light misroscope. Its conidia are large (14-20 ${\mu}{\textrm}{m}$ diameter), shiny, black, aseptate, and smooth-walled spheres. The fungus caused typical blighting symptoms on the two turfgrass plants of bermudagrass (Cynodon dactylon (L.) Pers.) and bentgrass (Agrostis palustris Huds.). The fungus was found to produce a phytotoxic subtance to be associated with the pathogenic mechanism. A phytotoxin was isolated from the liquid cultures of N. sphaerica by repeated silica gel column chromatography and its structure was determined to be 5, 6-dihydro-5-hydroxy-6-propenyl-2H-pyr-2-one (T-3 compound). It was not a host-specific toxin showing phytotoxic effects to various plants inclusing turfgrasses in the leaf-wounding assay, the whole plant test, and the cellular leakage test. The compound caused leaf tip dieback symptoms in turfgrass plants similar to those caused by the pathogen. Thus, T-3 compound is thought to be involved in the development of Nigrospora blight.

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Production of a Phytotoxic Substance by Exserohilum monoceras, the Causal Fungus of Barnyardgrass Leaf Blight, and its Response on Host Plants (논피잎마름병균(Exserohilum monoceras)의 독소생산과 그 기주반응)

  • 조재민;홍연규;엄재열
    • Korean Journal Plant Pathology
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    • v.13 no.2
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    • pp.132-137
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    • 1997
  • Phytotoxicity of the culture filtrate and culture conditions for the production of the phytotoxin by Exserohilum monoceras 92-044 were examined. The necrotic lesions were developed on the leaves of Echinochloa crus-galli within 48 hrs after inoculation of the culture filtrate, and the leaves were completely blighted within 5∼7 days. Maximum toxicity was found in the culture broth containing 20% V-8 juice. Phytotoxin accumulation and fungal growth reached their highest peak at around 11 days. Typical symptom appeared on the leaf of E. crus-galli within 48 hrs. Only a weak chlorosis appeared on rice, Arundinella hirta (THUNB) and henry crabgrass (Digitaria sanguinalis SCOP.), but no further symptom developed.

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Effects of phytotoxins on Change of pH in the Continuous Cropping Soil (연작지(連作地) 토양(土壤)의 독소물질(毒素物質)이 토양(土壤) pH 변화(變化)에 미치는 영향(影響))

  • Jeong, Ji-Ho;Lee, Kap-Sang;So, Jae-Don
    • Korean Journal of Soil Science and Fertilizer
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    • v.24 no.1
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    • pp.17-21
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    • 1991
  • The experiment was conducted to investigate the origin of pH changes in a continuous cropping soil. The results obtained were as follows : 1. The concentration of phytotoxin increased and at the same time the soil pH decreased with the prolonged practice of continuous cropping. 2. The decrease of soil pH by the phytotoxin materials was higher in the distilled water and tap water than in the soil. 3. The effect of phytotoxin on plant germination was higher in benzoic acid than in p-hydroxybenzoic acid. 4. The treatment of acetone to the continuous cropping soil recovered the initial soil pH and sesame growth was normal in the soil.

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3-Methylthiopropionic Acid of Rhizoctonia solani AG-3 and Its Role in the Pathogenicity of the Fungus

  • Kankam, Frederick;Long, Hai-Tao;He, Jing;Zhang, Chun-hong;Zhang, Hui-Xiu;Pu, Lumei;Qiu, Huizhen
    • The Plant Pathology Journal
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    • v.32 no.2
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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.