A total of 374 Pythium isolates were isolated and identified from the rhizosphere soils of maize plants grown in 100 different agricultural fields in nine provinces at El-Minia Governorate, Egypt. Five Pythium spp. of P. deliense, P. graminicola, P. irregulare, P. oligandrum and P. splendens were obtained P. deliense and P. oligandrum were predominant in all of the locations with 48.1% and 41.4% of total counts, respectively. P. graminicola, P. irregulare and P. splendens were not isolated in 4, 2 and 4 provinces out of 9 provinces with 5.3%, 3.5%, and 1.6% of isolation percentage from total counts, respectively. Number of Pythium isolates in each were 34, 31, 34, 33, 34, 96, 37, 37 and 38 out of 374, for locations of El-Edwa, Maghagha, Beni-Mazar, Matai, Samalout, El-Minia city, Abou-Querquas, Mallawi and Der Mawas, respectively. Pre- and post-emergence pathogenicity tests indicated that only P. deliense was highly pathogenic to germinating grains and seedlings of maize whereas P. oligandrum was non-pathogenic.
Edible Grain ; Ecosystem* ; Egypt* ; Pythium* ; Rhizosphere* ; Seedlings ; Soil ; Virulence* ; Zea mays*

Ginseng damping-off, caused by the fungal pathogens Rhizoctonia solani and Pythium sp., is a critical disease in ginseng seedling. In a continuing effort to find microorganisms with the potential of acting as a biocontrol agent against Rhizoctonia damping-off, we found that a Streptomyces sp. A501 showed significant antifungal activity against Rhizoctonia solani. In field experiment to test the efficacy of Streptomyces sp. A501 in controlling ginseng damping-off, the incidence of damping-off disease was meaningfully reduced when ginseng seeds were soaked in the culture broth of Streptomyces sp. A501 before sowing. To perform characterization of the antifungal compound, we isolated it from the culture broth of strain A501 through Diaion HP-20 and silica gel column chromatographies and preparative high-performance liquid chromatography. The structure of the antifungal compound was assigned as fungichromin by spectroscopic methods, mainly nuclear magnetic resonance and electrospray ionization-mass analysis.
Chromatography ; Chromatography, Liquid ; Incidence ; Magnetic Resonance Spectroscopy ; Panax* ; Pythium ; Rhizoctonia ; Seedlings ; Silica Gel ; Streptomyces*

Twenty-five isolates of Pythium species were identi6ed and classified on the basis of RFLP(restriction fragment length polymorphism) of ITS(internal transcribed spacer) region in ribosomal DNA. and M-13 PCR markers. Eight restriction endonucleases were used to investigate the genetic relatedness among isolates P. graminicola and P. arrhenomanes as well as P. aphanidermatum and P. delience produced identical band patterns with all restriction endonucleases used and M-13 markers. P. myriotylum and P. catenulatum also formed tight cluster on the basis of RFLP of ribosomal DNA but produced distinct band pattern with M-13 PCR markers. No intraspecitic variations were observed with RFLP of ITS region in ribosomal DNA. Molecular analysis based on M-13 marker demonstrated that each species produced distinct band patterns. Intraspecific variation of P. ultimum and P. torulosum was observed with M-13 markers.
DNA Restriction Enzymes ; DNA, Ribosomal* ; Polymerase Chain Reaction* ; Polymorphism, Restriction Fragment Length* ; Pythium*

A severe damping-off disease of bush okra caused by Pythium aphanidermatum, was diagnosed in plastic houses in Der Attia village, 15 km southwest of El-Minia city, Egypt, during the winter of 2001. Bush okra seedlings showed low emergence with bare patches inside the plastic houses. Seedlings that escaped pre-emergence damping-off showed poor growth, stunting and eventually collapsed. Examination of the infected tissues confirmed only Pythium aphanidermatum, showing its typical intercalary antheridia, and lobulate zoosporangia. P. aphanidermatum was shown to be pathogenic on bush okra under pot and field experiments. Bacteria making inhibition zones against the damping-off fungus P. aphanidermatum were selected. Agar discs from rhizosphere soil of bush okra containing colonies were transferred onto agar plate culture of P. aphanidermatum. After 2 days of incubation, colonies producing clear zones of non-Pythium growth were readily detected. The two bacteria with the largest inhibition zones were identified as Pseudomonas fluorescens. Bush okra emergence(%) in both pot and plastic houses experiments indicated that disease control could be obtained by applying P. fluorescens to the soil or coating the bacteria to the bush okra seeds before sowing. In the plastic houses, application of the bacteria onto Pythium-infested soil and sowing bush okra seeds dressed with bacteria gave 100% emergence. In addition, This was the first reported disease of bush okra by this oomycete in Egypt.
Abelmoschus* ; Agar ; Bacteria ; Egypt ; Fungi ; Oomycetes ; Plastics ; Pseudomonas fluorescens* ; Pseudomonas* ; Pythium* ; Rhizosphere* ; Seedlings ; Soil ; United Nations

Epicoccum purpurascens stain 5615 AUMC was investigated for its biocontrol activity against root rot disease caused by Pythium irregulare. E. purpurascens greenhouse pathogenicity tests using three leguminous plants indicated that the fungus was nonpathogenic under the test conditions. The germination rate of the three species of legume seeds treated with a E. purpurascens homogenate increased significantly compared with the seeds infested with P. irregulare. No root rot symptoms were observed on seeds treated with E. purpurascens, and seedlings appeared more vigorous when compared with the non-treated control. A significant increase in seedling growth parameters (seedling length and fresh and dry weights) was observed in seedlings treated with E. purpurascens compared to pathogen-treated seedlings. Pre-treating the seeds with the bioagent fungus was more efficient for protecting seeds against the root rot disease caused by P. irregulare than waiting for disease dispersal before intervention. To determine whether E. purpurascens produced known anti-fungal compounds, an acetone extract of the fungus was analyzed by gas chromatography mass spectrometry. The extract revealed a high percentage of the cinnamic acid derivative (trimethylsiloxy) cinnamic acid methyl ester. The E. purpurascens isolate grew more rapidly than the P. irregulare pathogen in a dual culture on potato dextrose agar nutrient medium, although the two fungi grew similarly when cultured separately. This result may indicate antagonism via antibiosis or competition.
Acetone ; Agar ; Antibiosis ; Cinnamates ; Fabaceae ; Fungi ; Gas Chromatography-Mass Spectrometry ; Germination ; Glucose ; Pythium ; Seedlings ; Seeds ; Solanum tuberosum ; Sprains and Strains

Seventy-three fungal species belonging to forty-three genera were isolated from 40 samples of Saccharrum officinarum (collected from Naage-Hamadi canal in Qena Governorate, Egypt). Aspergillus, Trichoderma, Mucor and Pythium were the most common genera on the two isolation media. The dominant species of Aspergillus were A. niger, A. flavus, A. ustus, A. terreus and A. wentii. Some species were dominant on 40 g/l sucrose such as Aspergillus niger, A. flavus, Emericella nidulans, Trichoderma viride, Torula herbarum and Mamaria echinoeotryoides, while the dominant species on 10 g/l glucose were Mucor circinelloides, Aspergillus niger, Torula herbarum and Trichoderma viride. Mycotoxins including aflatoxins B1, B2, G1 and G2, zearalenone and diacetoxyscirpenol were detected in the examined samples of Saccharrum officinarum. The mycelial growth of A. flavus, A. niger, Fusarium moniliforme and Torula herbarum decreased with the increase in Dimethoate concentrations, although 25 ppm was less effective than the higher levels of the insecticide (75~200 ppm). Dimethoate stimulated the activity of Go-T in A. niger, F. moniliforme and T. harbarum, while the Go-T activity was inhibited in A. flavus with the Dimethoate treatments.
Aflatoxins ; Aspergillus ; Aspergillus niger ; Cryptococcus ; Dimethoate ; Egypt* ; Emericella ; Fusarium ; Glucose ; Mucor ; Mycotoxins* ; Niger ; Pythium ; Saccharum* ; Sucrose ; Trichoderma ; Zearalenone

During a continuing search for antimicrobial substances from Korean native wild mushroom extracts, we found that the methanolic extract of the fruiting body of Clitocybe nebularis exhibited mild antifungal activity against pathogenic fungi. Therefore we evaluated the antifungal substances and other chemical components of the fruiting body of Clitocybe nebularis, which led to the isolation of nebularine, phenylacetic acid, purine, uridine, adenine, uracil, benzoic acid, and mannitol. Nebularine showed mild antifungal activity against Magnaphorthe grisea and Trichophyton mentagrophytes, and phenylacetic acid potently inhibited the growth of Pythium ultiumand displayed moderate antifungal activity against Magnaphorthe grisea, Botrytis cinerea, and Trichophyton mentagrophytes. The other isolated compounds showed no antimicrobial activity.
Adenine ; Agaricales ; Benzoic Acid ; Botrytis ; Fruit ; Fungi ; Mannitol ; Methanol ; Phenylacetates ; Purine Nucleosides ; Purines ; Pythium ; Ribonucleosides ; Trichophyton ; Uracil ; Uridine