Showing papers in "Mycologia in 1991"
TL;DR: A number of critical reviews by internationally recognized experts on the microbial ecology of leaves are presented in this paper, including methods of assessment of microbial populations on leaf surfaces, leaves as reservoirs of ice nucleation phenomenon, and leaves as microbial habitats in both aquatic and terrestrial environments.
Abstract: The leaf surface of phyllosphere is a major habitat for micro-organisms. Microbes on or within leaves play important roles in plant ecology, and these microbes can be manipulated to enhance plant growth or reduce plant disease. This book presents a number of critical reviews by internationally recognized experts on the microbial ecology of leaves. Topics include methods of assessment of microbial populations on leaf surfaces, leaves as reservoirs of ice nucleation phenomenon, and leaves as microbial habitats in both aquatic and terrestrial environments. The book will be of interest to students and scientists in numerous disciplines, inlcuding botany, aerobiology, meteorology, ecology, agriculture and microbiology.
417 citations
TL;DR: This work presents a meta-analyses of the molecular Basis of Candida Pathogenicity and its relationships with Virulence in the Early Stages of Phaeohyphomycosis, and the role of cuticle-Degrading Enzymes in Fungal Pathogenesis in Insects.
Abstract: I. Spore Attachment and Invasion.- 1. Adhesion of Fungi to the Plant Surface: Prerequisite for Pathogenesis.- 2. Signaling for Infection Structure Formation in Fungi.- 3. The Plant Cell Wall as a Barrier to Fungal Invasion.- 4. Rust Basidiospore Germlings and Disease Initiation.- 5. Attachment of Mycopathogens to Cuticle: The Initial Event of Mycoses in Arthropod Hosts.- 6. The Fate of Fungal Spores in the Insect Gut.- 7. Candida Blastospore Adhesion, Association, and Invasion of the Gastrointestinal Tract of Vertebrates.- 8. Infectious Propagules of Dermatophytes.- II. Fungal Spore Products and Pathogenesis.- 9. Melanin Biosynthesis: Prerequisite for Successful Invasion of the Plant Host by Appressoria of Colletotrichum and Pyricularia.- 10. The Plant Cuticle: A Barrier to Be Overcome by Fungal Plant Pathogens.- 11. Appearance of Pathogen-Related Proteins in Plant Hosts: Relationships between Compatible and Incompatible Interactions.- 12. The Role of Cuticle-Degrading Enzymes in Fungal Pathogenesis in Insects.- 13. Potential for Penetration of Passive Barriers to Fungal Invasion in Humans.- 14. Dihydroxynaphthalene (DHN) Melanin and Its Relationship with Virulence in the Early Stages of Phaeohyphomycosis.- III. Host Response to Early Fungal Invasion.- 15. Invasion of Plants by Powdery Mildew Fungi, and Cellular Mechanisms of Resistance.- 16. Induced Systemic Resistance in Plants.- 17. The Plant Membrane and Its Response to Disease.- 18. The Fungal Spore: Reservoir of Allergens.- 19. Conidia of Coccidioides immitis: Their Significance in Disease Initiation.- 20. Cell-Mediated Host Response to Fungal Aggression.- 21. Suppression of Phagocytic Cell Responses by Conidia and Conidial Products of Aspergillus fumigatus.- IV. Molecular Aspects of Disease Initiation.- 22. Molecular Approaches to the Analysis of Pathogenicity Genes from Fungi Causing Plant Disease.- 23. Current Status of the Molecular Basis of Candida Pathogenicity.- Taxonomic Index.
417 citations
TL;DR: This high degree of specialization may help explain why vesicular-arbuscular mycorrhizal fungi are so efficient in their beneficial role of nutrient and water transport to the host plant.
Abstract: Different forms of vesicular-arbuscular mycorrhizal fungal inoculum are found in soil patches with differing histories. These inoculum types include spores, infected root fragments, and extramatric...
349 citations
TL;DR: Identification of the mycotoxins produced by different species of Fusarium can serve to verify their classification or to relate the variation of toxigenic potential within a species.
Abstract: Identification of the mycotoxins produced by different species of Fusarium can serve to verify their classification or to relate the variation of toxigenic potential within a species. Strains of Fu...
285 citations
TL;DR: The mycelium of higher fungi is portrayed as a developmentally versatile collective in which an initially dendritic pattern of branching is converted, by hyphal anastomosis, into a communication network as mentioned in this paper.
Abstract: The mycelium of higher fungi is portrayed as a developmentally versatile collective in which an initially dendritic pattern of branching is converted, by hyphal anastomosis, into a communication network. Spatial and functional patterns in the mycelium depend on the establishment of gradients allowing flow of protoplasmic resources and organelles via radial or tangential routes between source and sink regions. (...)
252 citations
TL;DR: The following are some examples of wheat diseases that have been recorded in recent years:
197 citations
TL;DR: A pathogenic species of marine slime mold, Labyrinthula, has been identified as the etiological agent of the present recurrence of wasting disease of eelgrass, Zostera marina, and proposed for this pathogen based on its host specificity, cytology, characteristic growth patterns in culture, cell size, color in mass, and aggregation structures.
Abstract: A pathogenic species of marine slime mold, Labyrinthula, has been identified as the etiological agent of the present recurrence of wasting disease of eelgrass, Zostera marina. It is also implicated...
167 citations
TL;DR: The viability rate of Saccharomyces cerevisiae cells is increased from 30% to 96-98% and the stability of properties of Penicillium expansum is demonstrated with the improved method.
Abstract: Two parameters of a one step freeze-drying process, cooling rate and protecting media, are studied in an effort to improve the viability and the stability of the preserved fungal strains. Cooling rates of 1.6 C, 3 C and 40 C/min are applied on cells of Saccharomyces cerevisiae and Brettanomyces bruxellensis and on spores of Trichoderma viride and Arthrobotrys arthrobotryoides preserved in 93 suspending media containing polymers, sugars, albumin, milk, honey, polyols, amino acids alone or in combination. The viability rate of Saccharomyces cerevisiae cells is increased from 30% to 96-98% by using an appropriate protecting medium containing 10% skim milk with 2 compounds among honey, sodium glutamate, trehalose or raffinose in the freeze-drying process carried out at a 3 C/min cooling rate. In the same conditions Arthrobotrys arthrobotryoides spores, the most sensitive strain among the four tested, provides 60-65% viability, while this strain does not survive a classical freeze-drying in 10% skim milk. Moreover, with the improved method the stability of properties of Penicillium expansum is demonstrated.
118 citations
TL;DR: Analysis of sample value distributions indicated that samples of small total area (<800 m2) tended to overestimate sporocarp biomass, because biomass was strongly skewed toward high values.
Abstract: Hypogeous sporocarps of ectomycorrhizal fungi were harvested from 10 Douglas-fir stands representing a variety of natural habitats. Calculated over all stands, total dry standing biomass equaled 1....
118 citations
TL;DR: A medium with 2 mg/L benomyl permitted virtually uninhibited growth of hymenomycetes while strongly inhibiting many non-hymenomyCetes, but members of the Mucorales and several other species still grew well.
Abstract: The growth rates of 32 hymenomycetes and non-hymenomycetes were compared on five media that have been devised for isolation of hymenomycetes. A medium with 2 mg/L benomyl permitted virtually uninhibited growth of hymenomycetes while strongly inhibiting many non-hymenomycetes, but members ofthe Mucorales and several other species still grew well. Testing of various combinations and concentrations of ingredients led to the use of 2 mg/L benomyl and 2 mg/L dichloran as antifungal ingredients. This was tested in isolations from various field materials and in every case performed as well as or better than other commonly used media.
TL;DR: A detailed description is provided of the coelomycetous fungus causing dogwood anthracnose on Cornusflorida, C. kousa and C. nuttallii in North America, described as a new species of Discula, Discula destructiva.
Abstract: A detailed description is provided of the coelomycetous fungus causing dogwood anthracnose on Cornus florida, C. kousa and C. nuttallii in North America. Conidiomata are acervular and subcuticular ...
TL;DR: In this paper, the Phytophthora Megasperma Complex was identified and classified as a species of the phyto-pathogen and the species was identified as follows:
Abstract: (1991). Species of the Phytophthora Megasperma Complex. Mycologia: Vol. 83, No. 3, pp. 376-381.
TL;DR: There is some morphological resemblance between P. nishigaharanas and Arachnophora fagicola Hennebert, which forms conidia of complex shape with a central body which is usually 1-septate, bearing several inwardly curved, brown lateral protuberances, terminally on well-developed conidiophores with percurrent proliferations.
Abstract: (1991). Expression of Antifungal Activity in Agar Culture by Isolates of Grass Endophytes. Mycologia: Vol. 83, No. 4, pp. 529-537.
TL;DR: Fungus/host interactions during primary stroma formation were investigated for Acremonium ty?
Abstract: Fungus/host interactions during primary stroma formation were investigated for Acremonium ty? phinum in Agrostis hiemalis and Elymus canadensis and found to be essentially the same in both grasses. In Festuca obtusa, where no primary conidial stroma or perithecial Epichloe typhina stroma are formed, A. typhinum is seed transmitted and has a similar habit to A. coenophialum in Festuca arundinacea. Experiments were conducted to determine the possible role of sugar utilization capacity in regulating stromata formation.
TL;DR: Grain samples of sorghum were collected from Nigeria, Lesotho, and Zimbabwe from grain sold in markets, left unharvested in the field, and stored in home storage units to identify Fusarium species isolated.
Abstract: Grain samples of sorghum were collected from Nigeria, Lesotho, and Zimbabwe from grain sold in markets, left unharvested in the field, and stored in home storage units. The most prevalent Fusarium species isolated was F. moniliforme which accounted for 65.2% of the total Fusarium species recovered. Other species isolated were F. equiseti (8.9%), F. semitectum (8.4%), F. nygamai (7.5%), F. chlamydosporum (4.5%), and F. graminearum (3.7%). Other species isolated infrequently were F. compactum, F. solani, F. proliferatum, F. dimerum, F. avenaceum, F. sporotrichioides, F. lateritium, F. sambucinum, F. napiforme, F. oxysporum, and F. subglutinans, these species accounting for 1.8% of those recovered. Fusarium moniliforme, F. equiseti, F. nygamai, and F. semitectum were recovered from samples from all three countries. Fusarium graminearum was recovered from samples from Nigeria and Zimbabwe but not from samples from Lesotho. Fusarium moniliforme and F. nygamai are known to produce fumonisins, some of which are carcinogenic. The recovery of isolates of F. sporotrichioides from a sample from Nigeria was unexpected since this species is usually found only in temperate to cold regions.
TL;DR: The results suggest that Lentinus is paraphyletic and, therefore, that lamellae have been found to be intermediate between the Polyporaceae and Tricholomataceae and could not be clearly assigned to either family.
Abstract: Evolutionary relationships of Lentinus to the Tricholomataceae and Polyporaceae were studied using restriction analysis of nuclear-encoded ribosomal RNA genes (rDNA). Five species of Lentinus, three species in the Polyporaceae and two species in the Tricholomataceae were examined. Ribosomal DNA phenotypes were determined by restriction endonuclease digestion of enzymatically amplified rDNA (PCR fingerprinting). This method generates restriction fragment length polymorphism data without Southern blotting or autoradiography. With five different four-base restriction enzymes, one hundred and one unique restriction fragments were resolved. Among the 16 individuals studied, there were twelve different rDNA types. A similarity matrix based on presence or absence ofcomigrating restriction fragments was analyzed with UPGMA, complete and single-linkage analysis (using the NTSYS computer package), and Fitch-Margoliash and KITSCH analysis (using the PHYLIP computer package). Results of all analytical approaches were highly consistent and strongly suggest that Lentinus tigrinus is more closely related to the Polyporaceae than to the Tricholomataceae. Morphological characters (dimitic hyphae and hyphal pegs) also support this hypothesis. The other species of Lentinus appear to be intermediate between the Polyporaceae and Tricholomataceae and could not be clearly assigned to either family. The results also suggest that Lentinus is paraphyletic and, therefore, that lamellae have
TL;DR: A method for Rapid Small-Scale Preparation of Fungal Dna is described in this article, where the authors present a method for rapid small-scale preparation of fungal DNA.
Abstract: (1991). A Method for Rapid Small-Scale Preparation of Fungal Dna. Mycologia: Vol. 83, No. 6, pp. 835-838.
TL;DR: Mating compatibility studies show that all members of the C. dryophila complex have a heterothallic tetramer and this indicates that species concepts for species separation andciation were investigated were incorrect.
Abstract: Speciation and species concepts were investigated for the Collybia dryophila complex. Mating compatibility studies show that all members of the C. dryophila complex have a heterothallic tet...
TL;DR: Ultrastructural aspects of ccyclcpmcnt of hat-shaped ascospore and centrum organization in O. cucullawm were studied and compared with other species in Ceratocystis sensu/ala apparently having similar ascospores.
Abstract: Ultrastructural aspects of ccyclcpmcnt of hat-shaped ascospores and centrum organization in O. cucullawm were studied and compared with other species in Ceratocystis sensu/ala apparently having similar ascospores. The ascospore wall consisted of a reniform primary and ornamented secondary wall. Secondary wall ornamentation incorporated three cqual1y spaced and parallel ridges along the length of the ascospore that gave the ascospore a triangular outline in transverse section. Brim appendages developed on the secondary wall at the rounded ends of the primary \Va]}resulting in the hatshaped appearance of the ascospores in side vie\\-'. These appendages differed considerably from those of the symmetrically shaped and hemispherical bowler-hat ascospores previously obsen'ed in C. IllOlIilifarmis and C. fimbria/a. Centrum organization in 0, cucuffalUHl was, however, similar to that previously illustrated of O. dm'idsollii. In both of the latler species, young asci were arranged in a cluster at the ascomatal base. This was different to that in C. mOlliliformis where young asci lined the inner ascomatal \vall.
TL;DR: Embedding specimens in plastic resin requires timeconsuming preparation of the tissues and resulting sections often are not thin enough to show wall structures clearly, but plastic resin offers the advantage of being transparent which allows for proper orientation of the ascocarps, something which may be difficult to do in paraffin.
Abstract: (1991). A Method for Sectioning Ascomycete Herbarium Specimens for Light Microscopy. Mycologia: Vol. 83, No. 4, pp. 520-524.
TL;DR: Esti?
Abstract: Measurements of competitive saprophytic colonization were used to evaluate the activity of Tricho? derma harzianum in non-sterile soil under conditions of varying soil moisture and temperature. Esti? mates of activity based on levels of colonization, determined after homogenization of substrate pieces, were more discriminating than those based on the number of colonized pieces. T. harzianum was found to be most active at soil matric potentials from -0.5 to -1.0 bar, with activity declining at matric potentials of 0.0, -7.5, and -15.0 bars. The saprophytic activity of T. harzianum was greatest at temperatures from 15 to 21 C. The optimum temperature for competitive colonization was several
TL;DR: The DNA content in the mature RS (4C) was found to be twice the highest level of DNA in the zoosporangium (2C) which suggested that there was a diploidization during RS formation.
Abstract: Evidence of several kinds was sought to confirm that structures thought to be resistant sporangia (RS) in Neocallimastix sp. shared characteristics with RS of other zoosporic fungi. In liquid medium, Neocallimastix formed a chytrid-like thallus made up of a system of intramatrical anchoring rhizoids and an extramatrical sessile or stalked zoosporangium on fiber pieces. As the culture aged, there was a shift from the development of zoosporangia to the production of RS. RS were first observed 36 h after zoospores were inoculated into fresh basal anaerobic medium. Encysted zoospores often developed into elongate thalli that branched monopodially near the tip. During RS formation, the tip of each branch enlarged and the nuclei and cytoplasm migrated towards this enlarged region. A septum was then formed to delimit the developing RS which became pigmented as it matured. The mature RS were dark brown and the pigment in their walls was identified as melanin using histochemical tests. Zoospores had the 1C level of DNA with 1C and 2C levels being observed in developing zoosporangia. The DNA content in the mature RS (4C) was found to be twice the highest level of DNA in the zoosporangium (2C) which suggested that there was a diploidization during RS formation. Additional studies needed to characterize the RS are discussed.
TL;DR: The hypothesis that distinct species of Leptostroma, which are morphologically almest indistinguishable from each other, colonize apparently healthy needles of A. alba, A. balsamea, and P. abies is supported.
Abstract: Growth on different media, substrate utilization patterns, water-soluble protein electrophoretic pro fi.les, as well as pectinase and amylase multilocus enzyme analyses were used to characterize thirty seven endophytic strains of Leptastroma isolated from needles of Picea abies, Abies alba, and A. ?alsamea. Among substrate utilization tests, only proteolytic activity, almest absent in the spruce 1solates but usually present in the others, could be used for characterization of strains. All isolates tested positive for the Bavendamm reaction and were able to utilize soluble starch and cellulose. Electropho resis of water soluble proteins provided a reliable method to distinguish isolates from different hosts because electromorphs were host-specific. Electrophoresis of pectic enzymes allowed a more accurate differentiation of strains within host, but, on the whole, host-specificity of electromorphs was confirmed. Amylolytic activity was absent in ca 50% of the strains tested and the same electromorph was shared by roughly 80% of the remaining isolates. The results of this study support the hypothesis that distinct species of Leptostroma, which are morphologically almest indistinguishable from each other, colonize apparently healthy needles of A. alba, A. balsamea, and P. abies. Ecophysiologically all isolates showed biochemical attributes associated with needle penetration and long-term residence within needles. Key W ords: conifers, endophytes, fungi, substrate utilization, taxonomy
TL;DR: It was determined that the conidia produced by iterative germination also undergo an additional series of microcyclic conidiations, which may be a fundamentally important aspect of the life history of E. typhina and a variety of other fungi.
Abstract: Germination of ascospores in Epichloe typhina was described earlier as iterative germination in which each part spore of an ascospore germinated and produced conidia without an intervening mycelial phase. In the present study it was determined that the conidia produced by iterative germination also undergo an additional series of microcyclic conidiations. Thus, conidia produced from the ascosporic microcyclic structure germinated and produced other conidia, which also germinated producing yet another microcyclic structure. It was only after the third stage of microcyclic conidiations that mycelial development occurred. Microcycle conidiation in E. typhina is viewed as an obligate developmental sequence since no alternative process was observed. This distinguishes it from microcycle conidiation reported in other fungi where microcycle conidiation is facultative, being inducible only under certain laboratory conditions. Although unexplored, microcyclic conidiation may be a fundamentally important aspect of the life history of E. typhina and a variety of other fungi.
TL;DR: There has been no growth stimulation using the synthetic lipid triacetin, but this may have been the result of acetate inhibition (Lindeberg and Lindeberg, 1974) or the inability to use acetate as a sole carbon source.
Abstract: Several reports have indicated the stimulating effeet of fatty acid-containing materials on the growth of ectomycorrhizal fungi. Growth of dif? ferent ectomycorrhizal fungi can be stimulated by lipids (Schisler and Volkoff, 1977; Fries et al, 1985), Tween 80 (Straatsma and Bruinsma, 1986), or certain free fatty acids (Lindeberg and Lin? deberg, 1974). Palmer and Hacskaylo (1970) re? ported no growth stimulation using the synthetic lipid triacetin, but this may have been the result of acetate inhibition (Lindeberg and Lindeberg, 1974) or the inability to use acetate as a sole carbon source.
TL;DR: Using Electron Microscopy to Study Plant Pathogenic Fungi: Vol. 83, No. 1, pp. 1-19, 1991 as discussed by the authors, was the first attempt to use electron microscopy to study plant pathogenic fungi.
Abstract: (1991). Using Electron Microscopy to Study Plant Pathogenic Fungi. Mycologia: Vol. 83, No. 1, pp. 1-19.