USING direct-plating technique, thirty-nine species belonging to 16 fungal genera were isolated from maize and sorghum grain samples (20 samples each) on Czapek's agar (Cz) and Czapek's supplemented with 40% sucrose agar (Cz40S) media at 28 degrees C. Widest spectrum of genera and species were recorded on sorghum (16 genera and 35 species) compared with maize grains (8 and 19). The highest total count (139 CFUs/100 grains) and the number of genera (14) and species (27) were identified from sorghum grains on Cz medium. The most common fungi on the grains tested were Aspergillus flavus, A. niger, Eurotium amstelodami, E. rubrum, E. repens, Fusarium verticillioides and Rhizopus stolonifer. Among 129 isolates screened for their abilities to produce amylase enzyme, 102 isolates could produce this enzyme, of which A. terreus exhibited the highest production (EI=1.73). HPLC analysis revealed that out of 6 strains of A. flavus tested, strain No. AUMC 11311 showed the highest production of aflatoxin B-1 and B-2 while the highest value of aflatoxin G(2) was produced by strain No. AUMC 11317. It could be concluded that fungi growing on grains and have the abilities of producing enzymes and/or aflatoxins might cause deterioration and spoilage to these grains.

The present study is dealing with an ecofriendly and green biological route for extracellular biosynthesis of silver nanoparticles (AgNPs) using the endophytic fungus Cladosporium sphaerospermum F16 (KU199685). The biosynthesised AgNPs were characterised using ultraviolet-visible spectroscopy (UV-vis), transmission electron microscopy (TEM), dynamic light scattering (DLS), energy-dispersive X-ray analysis (EDX) and X-ray diffraction (XRD). The results showed the formation of stable, well-dispersed and spherical crystalline AgNPs with an average size 15.1 ± 1.0 nm and zeta potential of about −41.2 ± 0.5 mV. Optimisation of AgNPs synthesis prepared under different reaction conditions such as: pH, temperature, silver nitrate concentration and time of synthesis reaction to increase the AgNPs production. Meanwhile, the optimum conditions for maximum AgNPs production were pH (7), silver nitrate (5 mM) and incubation time (5-7 days). Interestingly, the fungal exo-metabolities were found to reduce silver ions into AgNPs within10 min after heating the reaction mixture (50-70 °C) as indicated by the developed reddish brown color compared to 30 min under room temperature.

The incidence of onion purple blotch disease was investigated at Assiut Governorate, Egypt during 2011. Lesions with typical symptoms of the disease were colonized by Alternaria porri, Stemphylium vesicarium or mixtures of the both pathogens comprising 2.6, 39.8 and 57.6 % of samples, respectively. Four isolates were selected for virulence evaluation according to the nature of isolation, whereas two isolates were individually associated with the diseased samples and two isolates were collectively recovered. Individually, A. porri AUMC9301 and AUMC10453 showed high virulence contributing 81.25 and 78.13 %, respectively. Also, S. vesicarium AUMC10512 and AUMC10519 exhibit severity comprising 37.50 and 25.00 %, respectively. On the other hand, mixture of A. porri AUMC10453 and S. vesicarium AUMC10519 exhibited highest virulence (91.50 %). In conclusion, this investigation proved that onion plants showing purple blotch symptoms mainly colonized by both A. porri and S. vesicarium. Consequently, increase in the disease may be attributed to the association between these pathogens.

Mycogenic synthesis of silver nanoparticles (AgNPs) was carried out in the present investigation using an aqueous extract of endophytic non-pathogenic Alternaria solani F10 (KT721914). The mycosynthesized AgNPs were characterized by means of spectroscopic and microscopic techniques. The surface plasmon resonance found at 430 nm confirmed the formation of stable AgNPs for several weeks at room temperature. Also, the results revealed the formation of spherical and monodispersed AgNPs with an average size of 14.8 ± 1.2 nm. The FT-IR spectrum suggested that the fungal extracellular proteins and secondary metabolites had the role in Ag reduction and AgNPs capping of which protein Ag nanoconjugates were formed. Furthermore, the mycosynthesized AgNPs exhibited potent antifungal activity against different pathogenic isolates of the same Alternaria solani fungus, the causal pathogen of tomato early blight disease. The antifungal efficiency of the AgNPs at 1, 5 and 10 ppm were evaluated for 8 days after incubation by measuring the inhibition rate of fungal radial growth. The results were further supported by investigating fungal hyphae morphology alteration by scanning and transmission electron microscopy. Treated fungal hyphae showed formation of pits and pores. Also, the mycosynthesized AgNPs were able to pass and distribute throughout the fungal cell area and interact with the cell components.

A simple new green method for the synthesis of silver nanoparticles (AgNPs) using the anti-oxidant compound curvularin isolated from the endophytic fungus Epicoccum nigrum ASU1 is reported for the first time in this article. The present work describes a one-step functionalization of AgNPs using compound curvularin as a reducing and stabilizer agent. The AgNPs capped curvularin were characterized by UV-vis spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), selected area electron diffraction (SAED), energy dispersive X-ray spectroscopy (EDX), and high-resolution transmission electron microscopy (HR-TEM). The results showed the formation of high purified spherical AgNPs with an average size of 37 nm. The FT-IR results suggested that both hydroxyl and carbonyl functional groups in curvularin are responsible for the reduction of the Ag+ ions and stabilizing AgNPs. The AgNPs showed potent antifungal activity at various extends compared to curvularin alone against the phytopathogenic fungus Alternaria solani.These findings emphasise that such biocompatible green nanoparticles, thanks to their potent antifungal activities, may be applied as new bio-fungicides against various plant pathogenic fungi in the field of plant protection and plant disease management.

ABSTRACT Although cyanobacteria are recognized as renewable sources of biomass for bioactive compounds, they have received little attention as potential biocontrol agents of foliar plant diseases. The purpose of this study was to evaluate the fungicidal efficacy of cyanobacterial extracellular products against Alternaria porri, which causes onion purple blotch disease, in vitro and under greenhouse conditions. Among the tested cyanobacteria (Anabaena oryzae, Arthrospira sp., Nostoc minutum, N. muscorum and Oscillatoria sp.), extracellular metabolites of N. muscorum and Oscillatoria sp. reduced the linear growth of A. porri by 20.37 and 36.34%, respectively. Culture filtrates of both Oscillatoria sp. and N. muscorum contained high concentrations of phenolic compounds (104.33 and 145.0 mg l−1, respectively), and alkaloids (473.31 and 378.12 mg l−1, respectively). GC-Mass analysis revealed that the most prevalent component in culture filtrates of N. muscorum and Oscillatoria sp. was beta ionone (7.21 and 7.17% of total analytes, respectively). Norharmane and α-iso-methyl ionone constituted 7.08 and 6.83% in N. muscorum and Oscillatoria sp., respectively. Components identified in the two culture filtrates included piperazine derivatives, isocyclocitral, α-trans-seequicyclocitral, phytol, oleic acid, fatty acids esters (methyl palmitate and linoleic acid mythyl ester), myristic alcohol and palmityl chloride. Application of culture filtrates of N. muscorum and Oscillatoria sp. under greenhouse conditions reduced disease severity by 55.1–66.5%. In conclusion, extracellular metabolites of N. muscorum and Oscillatoria sp. have potential as effective fungicides to control purple blotch disease of onion.

Sixty-eight fungal species belonging to 29 genera were isolated as leaf surface and endophytic fungi from healthy and purple blotch diseased onion leaves. The fungal populations associated with diseased onion leaves (1.360 × 10 CFU/g leaf in the phyllosphere, 2.614 CFU/leaf segment in the phylloplane and 1.324 CFU/leaf segment in the surface-sterilised diseased leaves) were higher than those in healthy samples (0.804 × 10 CFU in the phyllosphere, 1.184 CFU in the phylloplane, and 0.35 CFU as endophytes). Endophytic fungi of healthy leaves were represented by 12 genera and 15 species, while fungi of surface-sterilised diseased leaves included 17 species from 13 genera. The mycobiota associated with surface-sterilised diseased leaves were different from the endophytic fungi of healthy samples, whereas the disease may stimulate colonisation of opportunistic fungi causing secondary infections such as Botrytis cinerea, Penicillium aurantiogriseum, Alternaria alternata and Cladosporium spp. In contrast, healthy leaves were a source of antagonistic endophytic fungi such as Trichoderma harzianum and T. koningii. Testing the antagonistic effect of 91 fungal isolates against Alternaria porri showed that nine isolates of Trichoderma produced the highest suppressive potential (73.1%) depending on competition and mycoparasitism. Epicoccum nigrum and Penicillium oxalicum exhibited antibiosis against A. porri producing a 12 mm broad inhibition zone. In conclusion, the quantitative and qualitative compositions of fungi associated with onion leaves were distinctly influenced by A. porri infection. Mycobiota associated with asymptomatic onion leaves such as Epicoccum nigrum, Penicillium oxalicum and Trichoderma harzianum are a natural source of eco-friendly bioagents. They showed an effective antagonistic potential against A. porri, and may thus be applied as an alternative to fungicides.

One hundred halophilic and halotolerant species in addition to 3 varieties belonging to 27 genera were collccted from 25 samples of cultivated desert and saline soils from different habitats in Egypt on 5-25%. NaCl-Czapek's agar at 28°C(±2°C>. The results reveal that there were no chancteristic halophilic and halotolerant fungi of these various types of soils. The growth of all recovered fungi was tested in medi containing 5-25% sodium chloride. Almost all halophilic fungi (growing better on 5-25% than on O% sodium chloride) were Aspergillus species. Most of the highly and fairly halotolerant fungi were Aspergillus and Penicillium species. All test fungi were halophilic or halotolerant.

Fifty-two osmophilic (or osmotolerant) and halophilic (or halotolerant) species and one variety representing 24 genera were encountered from 20 combine harvester sorghum dust samples collected from four Covernorates in Upper Egypt, on 50% sucrose - and 15% NaCl-Czapck's agar at 28°C. The results obtained on the two media were basically similar, but numerous fungi could not tolerate 15% NaCl. The most frequent genera were Aspergillus Eurotium, Penicillium and Cladosporium.

Forty-nine species and 20 genera were collected irora the phyllosphere and phylloplane of wheat plants on 1% glucose and 50% sucrose-Czapek's agar at 28°C. The total counts of phyllospbere and phylloplane fungi displayed seasonal periodicities and the highest counts were found in April and May 1977, 1978. In the case of phyllosphere the most frequent species were Aspergillus niger, Penicillium corylophilum and Alternaria alternata; in the phylloplane Aspergillus niger and A. flavus.

Nine isolates of Trichoderma were collected from Assiut Governorate, Egypt, as leaf surface and endophytic fungi associated with onion flora stalks. Four isolates were identified as Trichoderma harzianum, while five isolates were belonging to Trichoderma longibrachiatum. The antagonistic activity of these isolates against onion purple blotch pathogen Alternaria porri was studied in vitro using dual culture assay. All tested Trichoderma isolates showed mycoparasitic activity and competitive capability against the mycelial growth of A. porri. Mycoparastic activity of Trichoderma was manifested morphologically by the overgrowth upon the mycelial growth of the pathogen and microscopically by production of coiling hyphae around pathogen hyphae. Isolates of T. harzianum exhibited high ability to compete on potato dextrose agar (PDA) medium causing the maximum rate of pathogen inhibition (73.12%), while isolates of T. longibrachiatum showed inhibition rate equalling 70.3%. Chitinase activity of Trichoderma was assayed, and T. harzianum Th-3013 showed the maximum value contributing 2.69 U/min. Application of T. harzianum Th-3013 to control purple blotch disease in vivo under greenhouse conditions caused disease reduction up to 52.3 and 79.9% before and after 48 h of pathogen inoculation, respectively, while the fungicide Ridomil Gold Plus caused disease reduction comprising 56.5 and 71.7%, respectively. This study proved that T. harzianum Th-3013 as a biocontrol agent showed significant reduction in onion purple blotch disease compared with the tested fungicide.

Seventeen species of Fusarium were recorded on maize (6 species) and sorghum (12 species) grains, and lentil (7 species) and sesame (7 species) seeds on Dichloran chloramphenicol peptone agar medium (DCPA) using the seed/grain-plate method. The moisture contents of most cereal grains were higher than those of seeds. Maize grains gave the highest colony forming units of Fusarium followed by sorghum, sesame and lentil. The frequency of occurrence of Fusarium species depended on the type of seeds and grains. The most frequently encountered species were F. oxysporum , F. verticillioides , F. solani and F. proliferatum on maize; F. nygamai, F. solani and F. verticillioides on sorghum, F. nygamai and F. oxysporum on lentil; and F. solani , F. chlamydosporum and F. verticillioides on sesame. Aspergillus (with A. flavus and A. niger being the most common) followed by Penicillium and Alternaria were recorded from the 4 substrates.

The results of the studies on seasonal fluctuations in number and occurrence of glucophilic, osmophilic and halophilic fungi inhabiting soils one wadi in eastern Egypt (conducted in 1985) are presented.

Density and diversity of Fusarium species and other fungi associated with rhizosphere and rhizoplane of lentil and sesame plants at three different growth stages were investigated. Sixteen species of Fusarium were isolated from rhizosphere (13 species) and rhizoplane (11) of both plants studied. In lentil, 11 species were recorded from its rhizosphere (9 species) and rhizoplane (8). Fusarium species associated with lentil rhizoplane gave highest number of propagules at the first stage of plant growth while the ones of Fusarium associated with the rhizosphere produced the highest number at the second stage of growth. F. solani was the most common in the three growth stages. In addition, of two growth stages, F. culmorum and F. tricinctum were isolated from the rhizosphere while F. nygamai and F. verticillioides from the rhizoplane. The other species were recorded from only one growth stage of lentil plant. In sesame plants, rhizosphere yielded nine Fusarium species while rhizoplane gave only six from the three stages investigated. Stage I of sesame rhizosphere possessed the highest colony forming units of Fusarium. As the case for lentil, F. solani was the most common species in sesame rhizospere and rhizoplane. F. verticillioides and F. nygamai (in three different growth stages) followed by F. oxysporum and F. tricinctum (in two growth stages) were recorded using the dilution-plate and/or soil-plate methods from sesame rhizosphere soils. Rhizoplane Fusarium species of sesame plants were isolated at the three different growth stages with almost equal number of colony forming units. F. poae came after F. solani in its frequency since it was recovered from two growth stages. Several of the isolated species are well-known as pathogens to many cultivated plants. To the best of our knowledge, three species are recorded here for the first time in Egypt from the rhizosphere (F. acutatum), rhizoplane of sesame plants (F. longipes) and from rhizosphere of both lentil and sesame and rhizoplane of lentil (F. nygamai).

The present investigation aimed to isolate the causative agents of onion purple blotch and Stemphylium blight diseases and evaluate the efficacy of certain plant extracts against the two identified pathogens, in vitro and under greenhouse condition. Fourteen isolates of S. vesicarium and two isolates of Alternaria porri were tested for pathogenicity. The results indicated that all isolates were able to produce the symptoms of Stemphylium blight and onion purple blotch diseases with different degrees of severity ranging from 10.42 to 81.25%. A. porri No. 6022 caused the highest disease severity (81.25%), while S. vesicarium No. 6003 was the best one out of the tested 14 isolates (37.5%). Antifungal activity of some aqueous plant extracts (Azadirachta indica, Cydonia oblonga, Datura stramonium, Eucalyptus globulus, Foeniculum vulgare, Ocimum basilicum, Rosmarinus officinalis and Salix mucronata) was assayed in vitro by dry weight technique. The data indicated that there were significant differences between these extracts in their effect on fungal growth of A. porri and S. vesicarium and the best were A. indica and D. stramonium. Under greenhouse conditions, application of the aqueous extract of A. indica either before or after 48 h A. porri inoculation produced the highest reduction in disease severity comprising 70 and 74.7%, respectively. On the other hand, the highest percentage of disease reduction before and after 48 h S. vesicarium inoculation was produced by Ridomil gold plus reached to 84.4 and 95.8% respectively, followed by the aqueous extract of A. indica (74.1 and 89.7, respectively). According to our results, it can be concluded that plant extracts of A. indica and D. stramonium can be used for the biocontrol of purple blotch and Stemphylium blight diseases instead of fungicides to minimise the risks and hazards of using toxic fungicides.

Two insecticides, Sparkill (25% Cypermethrin) and Tafaban (48% Chlorpyifos) were used in the treatment of maize plants. At three different doses, both Sparkill and Tafaban were toxic to total and individual fungal population of rhizosphere and non-rhizosphere soil as well as to fungi inhabiting roots and foliage of maize. The most common fungal species comprised Alternaria alternata, Aspergillus flavus, A. fumigatus, A. niger, A. terreus and Emericella nidulans. The ability of different fungal isolates to produce extracellular enzymes in solid media was tested. The effect of both Sparkill and Tafaban (at 50–400 ppm) on mycelial growth and production of amylase, cellulase, lipase and protease by certain fungi was variable. In most cases the low doses were promotive whereas the high doses were depressive.

Three native species of Zygophyllum : Z. coccinum L., Z. decumbens L. and Z. simplex L. (Zygophyllaceae) have been investigated morphologically, palynologically and mycologically. Twenty-two fungal species belonging to 11 genera were collected from leaf surfaces (11 genera and 22 species) and anthers/ pollen grains (7, 13) of Zygophyllum coccinum, Z. decumbens and Z. simplex on Czapek-Dox agar at 25 °C. Fungal diversity of the two microhabitats is basically similar and the most prevalent fungi were Alternaria alternata / A. phragmospora, Cladosporium cladosporioides / C. herbarum and Ulocladium botrytis / U. consortiale. Alternaria alternata , Cladosporium cladosporioides and C. herbarum -leaf spots were rarely recorded in the three studied plant species. Leaf lamina size and sculpture of the studied taxa almost seem to be the most reliable factors of the fungal biodiversity on the studied plant species. On the other hand, reticulate-micro reticulate pollen type is the only pollen type recorded in the present study which reflects that the very narrow range of spectrum of fungal biodiversity between the studied plant species. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Leaf surface, pollen morphology and mycobiota as well as leaf spots have been investigated in three wild medicinal plant species [ Fagonia cretica L. (Zygophyllaceae); Peganum harmala L. (Peganaceae) and Scorzonera undulata Vahl (Asteraceae)] growing in Egypt. Thirty eight fungal species belonging to 18 genera were collected from leaf surfaces (15 genera and 32 species) and anthers/pollen grains (16/26) of F. cretica , P. harmala and S. undulata on Czapek-Dox agar at 27 °C. There is basic similarity of mycobiota in the two microhabitats (leaf surface and anther/pollen grains) of the three wild medicinal plants with the most frequently encountered fungi were Alternaria alternata, Cladosporium herbarum, and Ulocladium botrytis. Also some members of Aspergillus, Fusarium and Stemphylium were only common in any of the two microhabitats. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Leaf surface, pollen morphology and fungal biodiversity as well as leaf spots have been investigated in four native species ( Cleome amblyocarpa , Cleomaceae; Haplophyllum tuberculatum , Rutaceae; Pluchea dioscoridis , Asteraceae; and Solanum elaeagnifolium , Solanaceae) of the flora of Egypt. The mycological analysis of 40 samples of each leaves and anthers/pollen grains of the above four wild plants revealed the isolation of 61 fungal species and one variety belonging to 28 genera on plates of 2 % cellulose-Czapek-Dox agar at 25 °C. The most common fungi were Alternaria alternata, Aspergillus flavus, A. niger, Cladosporium herbarum and Fusarium oxysporum or F. solani . Also, some fungi were prevalent only on a specific taxon such as Cochliobolus spicifer and Macrophoma phaseolina on leaves of Solanum elaeagnifolium , Aspergillus tamarii and A. terreus on the leaves and anthers/pollen of Pluchea dioscoridis and Chaetomium globosum, Ch. jodhurense and Humicola grisea on the anthers/pollen of Solanum elaeagnifolium . The present results revealed that the size, density of hairs and sculptures of the leaf surface almost seem to be the most reliable factors of the fungal biodiversity on the studied plant species. On the other hand, scabrate pollen surface of Solanum elaeagnifolium had a wider spectrum of fungal biodiversity and higher density of spores compared with other pollen surfaces in the examined taxa. Direct examination of leaves of the four plant species showed various degrees of Alternaria, Cladosporium, Cochliobolus, Drechslera, Pleospora and Ulocladium , leaf spots.