Studies on the fungus flora of three grains in Egypt

In wheat, corn and sorghum grains twenty-six genera and seventy-seven species including sixteen ofAspergillus and twenty-one ofPenicillium were identified.In grain samples adjusted to various moisture levels (up to 18.8 % on a dry-weight basis) and stored for 4 months at 8, 20 and 30 C seed-borne fungi were monthly identified and counted, and the germinability of the grains was tested. In the control samples (moisture content 7.1–8.2 %) temperature had no effect on the fungal counts and on the precentage germination. With the rise of temperature and moisture content the fungal counts markedly increased and the germinability declined.The list of fungi dominant in one or more of the experiments, included eight species ofAspergillus, six ofPenicillium, two ofFusarium and one each ofAlternaria andCurvularia. The order of dominance of these fungi varied according to the type of grain, the length of storage and the treatment.A. niger was the dominant organism in the control samples of the three grains. It could grow successfully at high moisture contents but above 15 %, it was usually overgrown by other fungi. In wheatP. citrinum andA. sydowii, in cornP. citrinum andA. terreus, and in sorghumA. terreus andA. niger were the dominant fungi at moisture contents above 15 % after four months storage at 30 C. When stored at 8 CPenicillium species tended to predominate over other fungi in grains with high moisture contents.In surface-sterilized grains adjusted to 15 % moisture content, inoculated with six dominant fungi separately and incubated at 30 C,A. niger, P. citrinum andP. variabile caused severe deterioration in the three grains;A. ochraceus in wheat only andF. moniliforme in wheat and corn;C. spicifer was slightly injurious to the three grains.     

Studies on antagonism betweenFusarium udum Butler and root region microflora of pigeon-pea

Antagonism betweenFusarium udum Butler causing wilt of pigeon-pea (Cajanus cajan (L.) Millsp.) and the saprophytic microflora of the root region of the host was studied with reference to colony interaction, hyphal interference, volatile and non-volatile metabolites and staling growth products. Studies were extended to screen potential antagonists against the wilt pathogen in soil. Aspergillus flavus, A. niger, A. terreus, Penicillium citrinum andMicromonospora globosa (an actinomycete) were antagonistic againstF. udum, whereas the pathogen parasitized and killedAspergillus luchuensis, Cunninghamella echinulata, Curvularia lunata, Mortierella subtilissima andSyncephalastrum racemosum. The pattern of growth of microorganisms on nutrient agar staled by rhizosphere soil inocula of healthy or wilted pigeon-pea plants was found to be different.F. udum colonized and grew on nutrient agar staled by the rhizosphere inoculum of the wilted plants upto 120h of incubation. However, it could not colonise and grow on the nutrient agar staled by rhizosphere microflora of healthy plants after 48h of incubation because of the presence of antagonists likeA. niger, A. flavus, A. terreus and a few species ofPenicillium in the soil inoculum. When pure cultures in soil ofF. udum was mixed with those of antagonists in different ratios,A. niger, A. flavus andM. globosa significantly suppressed the population ofF. udum, whereasA. terreus markedly reduced the population. When inoculated in soil, the antagonists exhibited a high fungistatic activity againstF. udum.     

Colonization capacity of the soil micro-organisms in relation to fungistasis

Summary Evans' tube and cellophane agar-disc techniques were used to evaluate the colonization capacity of the soil microbes and fungistasis, respectively. Spore germination ofAlternaria tenuis, Curvularia geniculata, Helminthosporium rostratum andPestalotia sp. was studied on a natural soil. Aspergillus fumigatus was the pioneer colonizer, followed in the order of decreasing colonizing capacity by,A. flavus, A. niger, A. terreus andPenicillium nigricans. Sensitivity of test spores to soil fungistasis declined in the order,C. geniculata → Pestalotia sp. →A. tenuis → H. rostratum. The fungistatic level of the soil samples decreased gradually from side arms 1 to 7 of the Evans tube, inoculated with unsterilized soil from one end. Studies conducted with an inoculum of four soil fungi (A. fumigatus, A. flavus, A. niger, andP. nigricans) as well as those involving fumigation of Evans tube by CS₂ also proved the greater colonizing capacity ofA. fumigatus. The level of fungistasis followed closely the colonization pattern of this fungus. When added individually to the soil, all fungi were able to inhibit spore germination of test fungi to some degree or other.     

Degradation of Alachlor [2-chloro-N-(methoxymethyl)-2′,6′-diethylacetanilide] by soil fungi

Summary A Penicillium sp. and a Trichoderma sp. were isolated from a soil previously treated with alachlor which is commonly used as herbicide. These fungi were found to degrade alachlor and only one degradation product was observed after 15 days of incubation. Whereas two products were noticed after 30 days with both the test organisms. re]19740913     

Persistence and degrading activity of free and immobilised allochthonous bacteria during bioremediation of hydrocarbon-contaminated soils

Rhodococcus sp. and Pseudomonas sp. bioremediation experiments were carried out using free and immobilized cells on natural carrier material (corncob powder) in order to evaluate the feasibility of its use in the bioremediation of hydrocarbon-contaminated soils. Terminal restriction fragment length polymorphism analysis was performed on the 16S rRNA gene as molecular fingerprinting method in order to assess the persistence of inoculated strains in the soil over time. Immobilized Pseudomonas cells degraded hydrocarbons more efficiently in the short term compared to the free ones. Immobilization seemed also to increase cell growth and stability in the soil. Free and immobilized Rhodococcus cells showed comparable degradation percentages, probably due to the peculiarity of Rhodococcus cells to aggregate into irregular clusters in the presence of hydrocarbons as sole carbon source. It is likely that the cells were not properly adsorbed on the porous matrix as a result of the small size of its pores. When Rhodococcus and Pseudomonas cells were co-immobilized on the matrix, a competition established between the two strains, that probably ended in the exclusion of Pseudomonas cells from the pores. The organic matrix might act as protective agent, but it also possibly limited cell density. Nevertheless, when the cells were properly adsorbed on the porous matrix, the immobilization became a suitable bioremediation strategy.     

Growth promotion ability of zoysiagrass rhizosphere fungi in consecutive plantings of wheat and soybean

Several isolates ofPhoma sp., certain nonsporulating fungi, as well asPenicillium andTrichoderma, all isolated from zoysiagrass rhizosphere, promoted growth of wheat and soybean under greenhouse conditions. However, the ability of these rhizosphere fungi to enhance plant growth varied with the crop tested. For example, most of the fungi effectively promoted the growth of wheat, whereas only a few fungi were effective on soybean. In consecutive plantings of wheat and soybean grown in soil previously infested with these zoysiagrass rhizosphere fungi, the growth promotion ability of the fungi was lowered. However, addition of fresh potting medium appeared to restore their growth-promotive effects. It appears that the activation of plant growth-promoting fungi in soil might depend on the availability of organic substrates to colonize, as evidenced by the promotion of plant growth.     

Differences in the microflora of scarified and unscarified seeds ofKarwinskia humboldtiana (Rhamnaceae)

Seeds ofKarwinskia humboldtiana obtained from a 1997 collection in the locality of Villa de García Nuevo (León, Mexico) were contaminated with spores of filamentous fungi, bacteria and yeasts. The concentration of microorganisms in unscarified seeds ranged from 3.0×10³ to 7.5×10³ CFU/g. Predominant were bacterial isolates of the generaAeromonas sp.,Bacillus, andPseudomonas; from filamentous fungi were identifiedAlternaria, Aspergillus niger, Cladosporium sp.,Fusarium sp.,Mucor sp.,Penicillium commune, Trichothecium sp.; from yeastsRhodotorula sp. andSaccharomyces cerevisiae. Seed scarification significantly reduced the microbial contamination. Of the original fungal isolates, only two were identified on scarified seeds,viz. Cladosporium sp. andSaccharomyces cerevisiae; although a relatively high incidence of a unidentifiable ofPenicillium sp. was found, the bacterial spectrum was not altered. Treatment of scarified seeds with Vitavax 200 WP and Pomarsol Forte 80 WP (3 mg/g seeds) augmented germination by 10–19% compared to treated unscarified seeds, and by 16–31% compared to untreated unscarified seeds.     

Keratinophilic fungi in the antarctic environment

Results of a study on the diffusion of keratinophilic fungi in an Antarctic environment are given. Nine soil samples collected from as many sites along the coast of Ross Sea, and six dust samples inside the Italian scientific base were examined by direct inoculation and hair baiting methods for soil samples and plate dilution method for dust samples. As regards the variety of species isolated and the counting of the numbers of colonies, plate dilution method proved to be very effective.Aspergillus spp.,Cladosporium sp., Dematiaceae,Fusarium sp.,Geomyces pannorum v.pannorum, G. pannorum v.vinaceus, Mycelia sterilia,Penicillium spp. were isolated from soil. From the dust the following moulds were isolated:Aphanoascus fulvescens, Aspergillus sp.,Beauveria sp.,Chrysosporium carmichaelii, Dematiaceae, Geomyces pannorum v.pannorum, G. pannorum v.vinaceus, Malbranchea gypsea, Mycelia sterilia, Nectria inventa, Penicillium spp.,Scopulariopsis brevicaulis, Scopulariopsis sp. andTrichophyton mentagrophytes. The presence of four colonies ofTrichophyton mentagrophytes is emphasized and correlated with the anthropization process.     

Increased Resistance to Penicillium Seed Rot in Transgenic Wheat Over‐expressing Puroindolines

Puroindolines (PINs) are the main components of the wheat grain hardness locus (Ha) and have in vitro antimicrobial activity against bacteria and fungi. Here, we examined the effect of variation in PINA and/or PINB content upon Penicillium sp. seed fungal growth inhibition. The Penicillium sp. assays were germination assays performed after incubating seeds in Penicillium sp. contaminated soil. The first set of wheat genotypes consisted of two sets of transgenic isolines created in the varieties ‘Bobwhite’ and ‘Hi‐Line’ having over‐expression of PINA and/or PINB. The second set of genotypes consisted of near‐isogenic lines (NILs) varying for mutations in PINA or PINB created in the varieties ‘Explorer’ and ‘Hank’. After incubation in Penicillium sp.‐infected soil, transgenic wheat seeds over‐expressing PINA in both ‘Hi‐Line’ and ‘Bobwhite’ and both PINs in ‘Hi‐Line’ exhibited significantly reduced fungal infection and increased germination. No significant differences in Penicillium sp. infection or germination rates were observed in seeds of the NILs. The results indicate that puroindolines native role in seeds is to increase seed viability and that when over‐expressed as transgenes, the puroindolines are effective antifungal proteins.     

Effect of fire on soil microorganisms in a meghalaya pine forest

The effect of man-made fire on soil mierobial population in a natural subtropical pine forest eco-system, was studied. A nearly fifty years old pine(Pinus kesiya Royle) forest was cut and burnt in March 1977. Another half of this pine forest was left uncut and unburnt. Microbial population was destroyed completely just after the burning and recolonization occurred after some days. Bacteria and actinomycetes were found to be the first colonizers followed by fungi. Burning initiated better growth and higher population of bacteria after two or three showers. Bacterial population was highest in July in burnt and in May in unburnt forest. Maximum fungal population in burnt site was recorded in July while it was highest in April and May in unburnt site.Penicillium spp.,Cladosporium sp. andTrichoderma sp. were found to be first colonizing fungi just after the burning. In unburnt forest eco-systemAbsidia sp.,Trichoderma sp.,Fusarium sp. andPenicillium spp. were found to be dominant.     

Variations in the cultural characteristics of Rhizoctonia solani,and its antagonists: Aspergillus terreus and Aspergillus flavus occurring in the rhizosphere of cotton

Summary Cultural studies onRhizoctonia solani, the causal agent of damping-off of cotton, as well as on two fungi of its antagonistic rhizospheric microflora, namelyAspergillus terreus andAspergillus flavus have shown coincidence of some of their cultural characteristics. However,R. solani produced mycelial growth far ahead both antagonists except at 37° C and at pH 4, at its optimum temperature. It is expected that for a successful biological control ofR. solani in the soil,A. terreus is applied at a soil-temperatured above 35° C in an acid medium.     

Some new species of Penicillium recovered from the atmosphere in Madrid and from other substrata

Six new species ofPenicillium Linkex Fries are described and illustrated. Four of them have been recovered from the atmosphere in Madrid, Spain, the other two species were isolated from must and from soil respectively. They clearly differ from all species of the genus described so far and are, therefore described and proposed as new taxa:Penicillium gerundense sp. nov.,Penicillium valentinum sp. nov.,Penicillium alicantinum sp. nov.,Penicillium malacaense sp. nov.,Penicillium tarraconense sp. nov., andPenicillium vasconiae sp. nov.     

Keratinophilic fungi and other moulds associated with air-dust particles from Egypt

One-hundred and eleven species and three species varieties belonging to 39 genera were collected from 50 dust samples on the five media used at 28°C. Using the hair-baiting technique with horse hair, 10 species ofChrysosporium were isolated:C. asperatum, C. state ofArthroderma tuberculatum, C. indicum, C. inops, C. keratinophilum, C. merdarium, C. pannorum, C. queenslandicum, C. tropicum andC. xerophilum. True dermatophytes were isolated:Trichophyton verrucosum andTrichophyton sp. Also, numerous fungi tolerating high levels of cycloheximide were encountered, such as members ofAcremonium, Aspergillus andPenicillium. On plates of glucose or cellulose Czapek-Dox agar (free from sucrose) the most frequent fungi were:Alternaria alternata, Aspergillus flavus, A. flavus var.columnaris, A. fumigatus, A. niger, A. ochraceus, A. sydowii, A. terreus, Chaetomium globosum, Cladosporium herbarum, Emericella nidulans, Fusarium oxysporum, Mucor hiemalis, Penicillium chrysogenum, P. oxalicum, Scopulariopsis brevicaulis andUlocladium atrum. On plates of 50% sucrose or 10 and 20% NaCl-Czapek's agar, some interesting species were frequently encountered:Eurotium amstelodami, E. chevalieri, E. halophilicum, E. montevidensis, E. repens, E. rubrum andScopulariopsis halophilica. The isolated, fungi have been tested for osmophilicity and halophilicity, they showed different rates of growth on sucrose and sodium chloride-Czapek's medium of various osmotic potential.     

Mycoflora of mangrove mud

Summary Thirty-nine species and four varieties of fungi are reported from mangrove mud collected from Kagh Island, Port Canning and Diamond Harbour, West Bengal, India. Of these forms twelve species and two varieties belonged to genusAspergillus and three species belonged, each toMucor, Penicillium andPreussia. Two species both ofFusarium andTrichoderma were also isolated. Two new species,Cladosporium indicum andPaecilomyces indicus and five other interesting fungi are described in detail.     

Studies on the distribution of alkalophilic and alkali-tolerant soil fungi I

Soil fungi were isolated from two different soil types using alkaline and slightly acidic media (alkaline cornmeal agar (AC-MA), pH 9.7; cornmeal agar (CMA), pH 6.0) to study their distribution. Different species were obtained on each isolation medium. The number of species ofAcremonium andFusarium increased on ACMA, though many species growing well in acidic conditions were not detected on ACMA. Most of the fungi isolated on ACMA, especially from the alkaline soils, were alkalophiles or alkali-tolerants that can grow at pH 10.Acremonium alternatum, A. furcatum, Acremonium sp. 6,Gliocladium cibotii (YBLF 575),Phialophora geniculata, Stachylidium bicolor andStilbella annulata were alkalophilic, of whichAcremonium sp. 6 was the most pronounced alkalophile. Ability to grow under alkaline conditions, as well as under acidic conditions, was common in manyAcremonium species. The use of alkaline medium facilitates the isolation of alkalophilic soil fungi.     

Three new species ofPenicillium isolated from soil

Three new species ofPenicillium Linkex Gray nom. cons. prop. are described and illustrated. These species have been recovered from samples of sandy soil under pine trees. They differ from all species of theGenus described so far and are, therefore, considered and proposed as new taxa:Penicillium rubefaciens sp. nov.,Penicillium vaccaeorum sp. nov. andPenicillium michaelis sp. nov.     

Microbial mineralization of organic phosphate in soil

Summary Phosphate-dissolving microorganisms were isolated from non-rhizosphere and rhizosphere of plants. These isolates included bacteria, fungi and actinomycetes. In broth cultures, Gram-negative short rod,Bacillus andStreptomyces species were found to be more active in solubilizing phosphate thanAspergillus, Penicillium, Proteus, Serratia, Pseudomonas andMicrococcus spp. The sterile soils mixed with isolated pure culture showed slower mineralization of organic phosphate than that of non-sterile soil samples at all incubation periods. Maximum amount of phosphate mineralization by isolated microorganisms were obtained at the 60th and the 75th day of incubation in sterile and non-sterile soils respectively. The mixed cultures were most effective in mineralizing organic phosphate and individuallyBacillus sp. could be ranked next to mixed cultures. Species ofPseudomonas andMicrococcus were almost the same as that of the control under both sterile and non-sterile conditions.     

Vesicular-arbuscular mycorrhizal fungi in coastal dune plant communities I. Spore formation ofGlomus spp. predominates under a patch ofElymus mollis

Vesicular-arbuscular (VA) mycorrhizal fungi in pure patches of coastal dune plantsElymus mollis, Wedelia prostrata andZoysia macrostachya were examined for frequency of occurrence and number of spores of VA mycorrhizal fungi over one year. Six species in three genera of VA mycorrhizal fungi were recovered. Under a patch ofE. mollis, spores ofAcaulospora sp. 1,Glomus tortuosum, Glomus sp. 1,Glomus sp. 2 andScutellospora gregaria were recovered. Spores ofGlomus spp. were most common. In patches ofW. prostrata andZ. macrostachya spores ofAcaulospora sp. 1,G. tortuosum, Glomus sp. 1,Glomus sp. 2,S. gregaria andScutellospora sp. 1 were found.Contribution No. 112, Laboratories of Plant Pathology and Mycology, Institute of Agriculture and Forestry, University of Tsukuba.     

Antifungal activity of berberine iodide, a constituent ofFumaria indica

Berberine iodide, an isoquinoline alkaloid was isolated fromFumaria indica and its efficacy was tested against spore germination of some plant parasitic as well as saprophytic fungi. The alkaloid significantly curbed spore germination ofCurvularia lunata, Erysiphe cichoracearum, E. pisi, Fusarium udum andPenicillium species. Complete inhibition (100%) of spore germination was observed inE. cichoracearum andPenicillium species at 1.5 g/L.Albugo candida andAlternaria species were not affected by the chemical.     

The antibiotic effect of culture filtrates of some soil fungi on rhizobial growth in cultures

Summary Four strains ofRhizobium sp. from peanut (Arachis hypogaea L.) root nodules were tested for their sensitivity to metabolites (culture filtrates) of more than ten common soil inhabiting fungi, in yeast extract mannitol agar and broth cultures. Among the rhizobial strains tested strain CB-530, BU-1 and BU-2 were not sensitive to metabolites ofMyrothecium roridum andFusarium moniliforme whereas CB-1024 was sensitive. Culture filtrates ofGliocladium roseum, Thielavia basicola andDrechslera pedicellata inhibited the strains CB-530 and BU-2 but not CB-1024. Most of the soil inhabiting fungi tested were inhibitory to rhizobial growthin vitro and very few were stimulatory, their effect in either case being strain specific.