• Toxicological Research
• /
• v.29 no.2
• /
• pp.143-147
• /
• 2013

Cyanogenic glycosides are HCN-producing phytotoxins; HCN is a powerful and a rapidly acting poison. It is not difficult to find plants containing these compounds in the food supply and/or in medicinal herb collections. The objective of this study was to investigate the distribution of total cyanide in nine genera (Dolichos, Ginkgo, Hordeum, Linum, Phaseolus, Prunus, Phyllostachys, Phytolacca, and Portulaca) of edible plants and the effect of the processing on cyanide concentration. Total cyanide content was measured by ion chromatography following acid hydrolysis and distillation. Kernels of Prunus genus are used medicinally, but they possess the highest level of total cyanide of up to 2259.81 $CN^-$/g dry weight. Trace amounts of cyanogenic compounds were detected in foodstuffs such as mungbeans and bamboo shoots. Currently, except for the WHO guideline for cassava, there is no global standard for the allowed amount of cyanogenic compounds in foodstuffs. However, our data emphasize the need for the guidelines if plants containing cyanogenic glycosidesare to be developed as dietary supplements.

• Korean Journal of Agricultural Science
• /
• v.29 no.2
• /
• pp.91-97
• /
• 2002

Two phytotoxic compounds, 3-methoxybenzoic acid (MBA) and 3-hydroxy benzoic acid methyl ester (HBAME), were purified and structurally characterized by instrumental analyses from a culture of a phytopathogenic fungus, Bipolaris sorokiniana. During the isolation procedure, the toxic components were monitored by the assay using rice (Echinochloa crusgalli) and Italian ryegrass (Lolium multiflorum). These compounds had a molecular formula of $C_8H_8O_3$ and inhibited the root growth of the plant seedlings over 90% at a level of 1000 ppm. This is the first report of herbicidal activity of MBA and HBAME purified from B. sorokiniana.

• Korean Journal of Weed Science
• /
• v.14 no.3
• /
• pp.192-198
• /
• 1994

Zeaenol isolated from the culture filtrate of a fungal weed pathogen Drechslera portulacae, which causes necrosis on the leaves and stem of purslane (Portulaca oleracea). Its structure was determined by single-crystal x-ray diffraction method together with assignments of $^1H$ and $^{13}C$-NMR experiments. Zeaenol inhibited root length of Echinochloa crus-galli and Abutilon avicennae by 22.8% and 54.8% at $3{\times}10^{-6}M$, respectively.

• Applied Biological Chemistry
• /
• v.39 no.3
• /
• pp.241-244
• /
• 1996

A bicyclic sesterterpene from Drechslera siccans was purified and structurally characterized. During the isolation procedure, the toxic component was monitored by the assay using Italian ryegrass (Lolium multiflorum Lam.), one of the host plants of the pathogen. Siccanol (1) named arbitrarily was shown to have a molecular formula of $C_{25}H_{38}_{4}$. Siccanol completely inhibited the root growth of the Italian regrass seedlings at a level of 100 ppm.

• The Plant Pathology Journal
• /
• v.27 no.1
• /
• pp.14-19
• /
• 2011

Early blight of potato, caused by Alternaria solani, is a ubiquitous disease in many countries around the world. Our previous screening of several Iranian potato cultivars found that significant variation in resistance phenotypes exists between two cultivars: resistant 'Diamond' and susceptible 'Granula'. Our previous analysis of five different pathogen isolates also identified varying degrees of aggressiveness regardless of the host cultivar. Here, a bioassay was used to study the role of liquid culture exudates produced in vitro on pathogenicity and elicitation of disease symptomology in seedlings as well as detached leaves. Responses of host genotypes to the exudates of the two A. solani isolates were significantly different. Detached leaves of the resistant cultivar 'Diamond' elicited fewer symptoms to each isolate when compared to the susceptible cultivar 'Granula'. Interestingly, the phytotoxicity effect of the culture filtrate from the more aggressive isolate A was higher than from isolate N suggesting an increased concentration or strength of the toxins produced. Our results are significant because they indicate a correlation between symptoms elicited by A. solani phytotoxins and their aggressiveness on the host.

• ALGAE
• /
• v.36 no.2
• /
• pp.91-109
• /
• 2021

The occurrence of benthic dinoflagellates, many of which are known to be toxic, is a critical concern for scientists, government officers, and people in the aquaculture, dining, and tourism industries. The interest in these dinoflagellates in countries with temperate climate is increasing because tropical or subtropical species introduced into temperate waters by currents are able to survive the winter season in the new environment owing to global warming. Recently, several species from the benthic dinoflagellate genera Amphidinium, Coolia, Ostreopsis, Gambierdiscus, and Prorocentrum have been reported in the waters of the South and East Sea of Korea. The advent of the benthic dinoflagellates in Korean waters is especially important because raw or slightly cooked seaweeds, which may harbor these benthic dinoflagellates, as well as raw fish, which can be potentially intoxicated by phytotoxins produced by some of these benthic dinoflagellates, are part of the daily Korean diet. The recent increase in temperature of Korean coastal waters has allowed for the expansion of benthic dinoflagellate species into these regions. In the present study, we reviewed the species, distribution, and toxicity of the benthic dinoflagellates that have been reported in Korean waters. We also provided an insight into the ecological and socio-economic importance of the occurrence of benthic dinoflagellates in Korean waters.

• The Plant Pathology Journal
• /
• v.31 no.3
• /
• pp.245-251
• /
• 2015

Alternative hosts increase the difficulty of disease management in crops because these alternate hosts provide additional sources of primary inoculum or refuges for diversity in the pathogen gene pool. Agropyron cristatum (crested wheatgrass), Bromus inermis (smooth bromegrass), Pascopyrum smithii (western wheatgrass), Stipa viridula (green needlegrass), and Thinopyrum intermedium (intermediate wheatgrass), commonly identified in range, prairie, verge, and soil reclamation habitats, serve as additional hosts for Pyrenophora tritici-repentis, the cause of tan spot in wheat (Triticum aestivum L.). A. cristatum (five lines), B. inermis (seven lines), P. smithii (four lines), S. viridula (two lines), and T. intermedium (six lines) were tested for their reactions to 30 representative P. tritici-repentis isolates from races 1-5. Plants were grown until the two-three-leaf stage in a greenhouse, inoculated individually with the 30 isolates, held at high humidity for 24 h, and rated after 7 days. All lines developed lesion types 1-2 (resistant) based on a 1-5 rating scale. Also, leaves from an additional plant set were infiltrated with two host selective toxins, Ptr ToxA as a pure preparation and Ptr ToxB as a dilute crude culture filtrate. All lines were insensitive to the toxins. Results indicate that these grass hosts have a limited or nonsignificant role in tan spot epidemiology on wheat in the northern Great Plains. Additionally, the resistant reactions demonstrated by the grass species in this research indicate the presence of resistance genes that can be valuable to wheat breeding programs for improving wheat resistance to P. tritici-repentis.

• Korean Journal of Soil Science and Fertilizer
• /
• v.24 no.1
• /
• pp.17-21
• /
• 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.

• Korean Journal of Weed Science
• /
• v.14 no.3
• /
• pp.184-191
• /
• 1994

A zearalenone derivative, methyldihydroxyzearalenone has been isolated from a plant pathogenic fungus, Drechslera portulacae which causes necrosis on the leaves and stem of Portulaca oleracea. It was characterized as 3, 4, 5, 6, 9, 10-hexahydro-8, 9, 16-trihydroxy-14-methoxy-3-methyl-1H-2-benzoxacyclotetradecine-1, 7(8H)-dione on the basis of spectral analysis. Methyldihydroxyzearalenone treatment at $3{\times}10^{-5}M$ inhibited root length of Echinochloa crus-galli and Abutilon avicennae by 35.7% and 72.6% as compared with the control, respectively.

• The Plant Pathology Journal
• /
• v.39 no.1
• /
• pp.88-107
• /
• 2023

In the present investigation, bacterial isolates from infected apple trees causing apple canker during winter were studied in the northern Gyeongbuk Province, Korea. The pathogen was identified as Pseudomonas syringae pv. syringae (Pss) through various physiological and biochemical characterization assays such as BIOLOG, gas chromatography of fatty acid methyl esters, and 16S rRNA. Bioassays for the production of phytotoxins were positive for syringopeptin and syringomycin against Bacillus megaterium and Geotrichum candidum, respectively. The polymerase chain reaction (PCR) method enabled the detection of toxin-producing genes, syrB1, and sypB in Pss. The differentiation of strains was performed using LOPAT and GATTa tests. Pss further exhibited ice nucleation activity (INA) at a temperature of -0.7℃, indicating an INA⁺ bacterium. The ice-nucleating temperature was -4.7℃ for a non-treated control (sterilized distilled water), whereas it was -9.6℃ for an INA^- bacterium Escherichia coli TOP10. These methods detected pathogenic strains from apple orchards. Pss might exist in an apple tree during ice injury, and it secretes a toxin that makes leaves yellow and cause canker symptoms. Until now, Korea has not developed antibiotics targeting Pss. Therefore, it is necessary to develop effective disease control to combat Pss in apple orchards. Pathogenicity test on apple leaves and stems showed canker symptoms. The pathogenic bacterium was re-isolated from symptomatic plant tissue and confirmed as original isolates by 16S rRNA. Repetitive element sequence-based PCR and enterobacterial repetitive intergenic consensus PCR primers revealed different genetic profiles within P. syringae pathovars. High antibiotic susceptibility results showed the misreading of mRNA caused by streptomycin and oxytetracycline.