Fungal fruit bodies were surveyed on a plot area of 1500 m2 from 1975–99 (excluding 1980–83) in the fungal reserve La Chaneaz in western Switzerland. Fruit bodies were identified and counted on a weekly basis. Species richness and abundances varied strongly between years. More than 400 species were encountered. Many species were transient; particularly rich years showed species occurring for only one year. This indicates that the number of species will substantially increase if the survey is continued. Within years, the species richness, abundances and periods of fruiting were tightly correlated. The abundance data of species within a year seemed symmetrically distributed over their fruiting period. The relation between species richness and abundances within years was studied by fitting species-abundance plots, known from numerical ecology. The surface area under the curves was taken as a parameter for ecological/fungal diversity. Productivity was correlated with the precipitation from June until October. The time of fruit body appearance was correlated with the temperatures in July and August. As groups, mycorrhizal and saprotrophic species behaved similarly over the years. The productivity of species was compared with their distribution in The Netherlands indicating a correlation between the level of local abundance and the geographic range of species.

The development of a transformation system is a significant technical hurdle in the study of many filamentous fungi. Recently Agrobacterium tumefaciens was shown to transform several filamentous fungi, but until now only one independent confirmation of this promising finding has been published. Fusarium circinatum (teleomorph Gibberella circinata) is an important pathogen of pine that has not been transformed previously. A. tumefaciens strain AGL1(pPK2) transformed three different isolates of F. circinatum with an efficiency of 2–150 transformants 10−5 conidia. The T-DNA was integrated into the genome and was stable through mitotic and meiotic cell divisions. Most F. circinatum transformants contained a single T-DNA copy. Half of the tested transformants also contained non-T-DNA vector sequences. These findings should facilitate future analysis of F. circinatum pathogenicity and stimulate wider use of this valuable transformation method in fungal research.

Phylogenetic relationships of Paecilomyces sect. Isarioidea species were analysed using the β-tubulin gene and ITS rDNA. Maximum parsimony analyses showed that the section does not form a natural taxonomic group and is polyphyletic within the Hypocreales. However, a group was recognized, designated as the Isaria clade, to be monophyletic comprising of the following Paecilomyces species: P. amoeneroseus, P. cateniannulatus, P. cateniobliquus, P. cicadae, P. coleopterorus, P. farinosus, P. fumosoroseus, P. ghanensis, P. javanicus and P. tenuipes. Some of these species have teleomorphs in Cordyceps.

The fly agaric is a remarkable mushroom in many respects; these are its bearing, history, chemical components and the poisoning that it provokes when consumed. The ‘pantherina’ poisoning syndrome is characterized by central nervous system dysfunction. The main species responsible are Amanita muscaria and A. pantherina (Amanitaceae); however, some other species of the genus have been suspected for similar actions. Ibotenic acid and muscimol are the active components, and probably, some other substances detected in the latter species participate in the psychotropic effects. The use of the mushroom started in ancient times and is connected with mysticism. Current knowledge on the chemistry, toxicology, and biology relating to this mushroom is reviewed, together with distinctive features concerning this unique species.

Endophytic fungi were isolated from three unidentified Licuala sp. palms in Brunei Darussalam and from three L. ramsayi palms in Australia. Endophytes were very common in both species, with overall colonisation rates of 81–89%. Taking into account a lower sampling frequency in Australia, endophyte diversity was similar in the two Licuala species. The endophyte assemblages examined were very diverse, consisting of 75 fertile species and 60 sterile morphospecies. The endophyte communities of both palms were composed of a single, dominant xylariaceous species, approximately ten less common but equally ubiquitous species and a large number of species occurring at very low frequencies. Differences were observed between the endophytic mycotas of different palm tissues and of tissues of different ages. The results presented suggest that most of the endophytes entered the petiole via the leaf and that transmission of palm endophytes is likely to be horizontal (via airborne propagules) rather than vertical (via seed). Seasonal differences were not observed in Brunei. Increased sampling effort could be expected to yield more endophyte taxa in both species investigated.

A new Phytophthora pathogen of trees and shrubs, previously informally designated Phytophthora taxon C, is formally named here as P. kernoviae. P. kernoviae was discovered in late 2003 during surveys of woodlands in Cornwall, south-west England, for the presence of another invasive pathogen, P. ramorum. P. kernoviae is self-fertile (homothallic), having plerotic oogonia, often with distinctly tapered stalks and amphigynous antheridia. It produces papillate sporangia, sometimes markedly asymmetric with medium length pedicels. Its optimum temperature for growth is ca 18 °C and upper limit ca 26 °. Currently, P. kernoviae is especially noted for causing bleeding stem lesions on mature Fagus sylvatica and foliar and stem necrosis of Rhododendron ponticum. P. kernoviae is the latest of several invasive tree Phytophthoras recently identified in the UK. Its geographical origins and the possible plant health risk it poses are discussed.

The maize endophyte Acremonium zeae is antagonistic to kernel rotting and mycotoxin producing fungi Aspergillus flavus and Fusarium verticillioides in cultural tests for antagonism, and interferes with A. flavus infection and aflatoxin contamination of preharvest maize kernels. Chemical studies of an organic extract from maize kernel fermentations of Acremonium zeae (NRRL 13540), which displayed significant antifungal activity against Aspergillus flavus and F. verticillioides, revealed that the metabolites accounting for this activity were two newly reported antibiotics pyrrocidines A and B. Pyrrocidines were detected in fermentation extracts for 12 NRRL cultures of Acremonium zeae isolated from maize kernels harvested in Illinois (4/4 cultures), North Carolina (5/5), Georgia (1/2) and unrecorded locations within the USA (2/2). Pyrrocidine B was detected by LCMSMS in whole symptomatic maize kernels removed at harvest from ears of a commercial hybrid that were wound-inoculated in the milk stage with A. zeae (NRRL 13540) or (NRRL 13541). The pyrrocidines were first reported from the fermentation broth of an unidentified filamentous fungus LL-Cyan426, isolated from a mixed Douglas Fir hardwood forest on Crane Island Preserve, Washington, in 1993. Pyrrocidine A exhibited potent activity against most Gram-positive bacteria, including drug-resistant strains, and was also active against the yeast Candida albicans. In an evaluation of cultural antagonism between 13 isolates of A. zeae in pairings with A. flavus (NRRL 6541) and F. verticillioides (NRRL 25457), A. zeae (NRRL 6415) and (NRRL 34556) produced the strongest reaction, inhibiting both organisms at a distance while continuing to grow through the resulting clear zone at an unchanged rate. Maximum colony diameters for A. zeae (NRRL 6415) and (NRRL 13540), on potato dextrose agar after 14 d, were attained within the range of 25–30 °C, with less growth recorded at 15 ° and 37.5 ° and no growth at 5 °. Potential interactions between A. zeae and other maize endophytes are considered and the significance of these interactions relative to the aflatoxin and fumonisin contamination of preharvest maize is presented. This is the first report of natural products from Acremonium zeae.

Communities of Aspergillus section Flavi resident in soils planted with cotton were compared among several areas in the southern United States. Incidence of A. flavus and A. tamarii differed among areas. A. flavus incidence increased with temperature and decreased with latitude. Less than 1% of isolates were A. nomius or A. parasiticus. A. flavus isolates were assigned to either the S or L strains on the basis of sclerotial morphology. S strain isolates produced numerous small (<400 μm) sclerotia; L strain isolates produced fewer, larger sclerotia. The S strain of A. flavus was found in all areas. Aflatoxin-producing potential of A. flavus differed among areas and was correlated with S strain incidence. L strain isolates produced only 33% as much aflatoxin B1 as S strain isolates. No S strain isolate produced both aflatoxin B1 and aflatoxin G1. Correlations indicated that L strain toxigenicity but not S strain toxigenicity varied geographically. While toxigenicities of most isolates were stable through single conidial transfer, 28% of isolates expressed altered levels of toxigenicity after transfer. The observed differences among communities may reflect geographic isolation and/or adaptation, and may cause different vulnerabilities to aflatoxin contamination among crops planted in diverse locations.

Extensive fungal growth has been detected on the walls and other building constructions in the inner parts of the Shelter of the damaged fourth Unit of the Chernobyl Nuclear Power Plant in 1997–98. The mycobiota comprised 37 species of 19 genera. Zygomycetes and ascomycetes were represented by one species each: Mucor plumbeus and Chaetomium globosum, respectively. Two mitosporic fungi commonly found were Cladosporium sphaerospermum and Penicillium hirsutum. Alternaria alternata, Aureobasidium pullulans, Aspergillus versicolor, Acremonium strictum, and Cladosporium herbarum were also encountered. Penicillium ingelheimense, Phialophora melinii, Doratomyces stemonitis and Sydowia polyspora were isolated from the Shelter and are recorded from the Ukraine for the first time. Comparison of the species growing under both severe and relatively weak radioactive contamination revealed a dominance of melanin-containing species in heavily contaminated sites; biodiversity and prevalence coefficients supported this.

To elucidate relationships among Alternaria, Ulocladium, and Stemphylium species, nuclear internal transcribed spacer (ITS) and mitochondrial small subunit (SSU) ribosomal DNA (rDNA) sequences from 18 Alternaria, four Ulocladium and four Stemphylium spp. were determined and compared. Phylogenetic analysis of the ITS and SSU rDNA sequences, performed by the neighbour joining and maximum parsimony methods, revealed that the Stemphylium spp. were phylogenetically distinct from the Alternaria and Ulocladium spp. Most Alternaria spp. and the Ulocladium spp. were placed together in a large Alternaria/Ulocladium clade. Within this large clade, the Alternaria spp. clustered into several distinct species-clades, most of which correlated with species-groups previously established based upon morphological characteristics. The Ulocladium spp. were placed into two species-clades, each of which also included Alternaria spp. A. longissima was distantly related to the other Alternaria spp., as well as the Ulocladium and Stemphylium spp. Based upon ITS and nuclear 18S rDNA sequence identities, A. longissima was most closely related to Leptosphaeria.

Aspergillus niger, a fungus capable of citric and oxalic acid production, was grown on solid medium amended with selected insoluble metal compounds (ZnO, Zn3(PO4)2 and Co3(PO4)2). While A. niger was able to grow on and solubilize all three metal compounds, a crystalline precipitate was observed to form eventually in the clear zone of solubilization under and around the colony. These crystals were extracted from the agar, examined by SEM and X-ray micro-analysis and identified as metal oxalates by performance hplc and gas chromatography–mass spectrometry. The ability of A. niger to precipitate other metal oxalates was investigated with cadmium, copper and manganese phosphates and strontium nitrate. Metal oxalates were again produced and it was found that the different metals resulted in different and characteristic crystal morphologies. A. niger is therefore capable of transforming inorganic insoluble metal compounds into organic insoluble metal compounds. The significance of this process as a means of toxic metal immobilization is discussed.

Phytophthora isolates associated with Phytophthora major ITS Clade 6 were grouped into 11 phenotypic taxa. These comprised the described morphospecies P. gonapodyides, P. megaspermas. str. and P. humicola; four previously identified but so far undescribed taxa, informally designated here P. sp. O-group, P. sp. Apple-cherry, P. taxon Pgchlamydo, and P. taxon Walnut; and four previously unknown taxa, designated P. taxon Oaksoil, P. taxon Raspberry, P. taxon Forestsoil, and P. taxon Riversoil. With the exception of P.gonapodyides, each phenotypic taxon represented an unique ITS lineage. Two isolates morphologically identical to P. gonapodyides comprised a separate lineage and probably represent another taxon, designated here P. taxon Salixsoil. P. humicola, P. sp. O-group, P. sp. Apple-cherry and P. taxon Walnut grouped together as subclade I. Within subclade II, P. taxon Oaksoil, P. taxon Raspberry, P. taxon Forestsoil, P. taxon Riversoil and P. taxon Pgchlamydo formed a cluster of closely related but phenotypically distinct lineages basal to P. gonapodyides and P. megasperma, P. taxon Salixsoil being the most basal member. The taxonomy, adaptation and breeding systems of Clade 6 taxa are discussed. They show a strong association with forests and riparian ecosystems, only a limited association with agriculture and an ability to tolerate high temperatures. Also, in contrast to most other Phytophthora clades, Clade 6 taxa are predominantly sterile or inbreeding in culture. Only one taxon, P. sp. O-group, appears classically A1/A2 heterothallic.

A recent report of an aflatoxin producing isolate of Aspergillus tamarii prompted a taxonomic re-examination of aflatoxigenic and non-aflatoxigenic isolates identified as A. tamarii as well as the closely related A. caelatus. Representatives of each species, including atypical isolates, were compared morphologically, for mycotoxin production, and for divergence in ITS, 28S, β-tubulin and calmodulin gene sequences. Because of genetic, morphological, and mycotoxin differences, the aflatoxin producing isolates of A. tamarii are given species rank as Aspergillus pseudotamarii sp. nov.

Although, oxidative stress response, which protects organisms from deleterious effects of reactive oxygen species (ROS), has been extensively studied in pro- and eukaryotes, the information about filamentous fungi is fragmentary. We investigated the effect of two ROS-generating agents (paraquat, PQ, and H2O2) on cellular growth and antioxidant enzyme induction in 12 fungal species. Our results indicate that exposure of fungal spores or mycelia to PQ and H2O2 promoted oxidative stress, as evidenced by remarkable inhibition of spore germination and biomass production; stimulation of cyanide-resistant respiration; accumulation of oxidative modified proteins. Cell responses against both superoxide and peroxide stresses include enhanced expression of superoxide dismutase (SOD) and catalase, however, the extent was different: treatment with PQ increased mainly SOD, whereas exogenous H2O2 led to enhanced catalase. We also found that G6PD has a role in the mechanism of protection against superoxide and peroxide stresses. The activation of antioxidant enzyme defence was blocked by the translation inhibitor, cycloheximide, suggesting that there was de novo enzyme synthesis.

Mycorrhizal associations, including ericoid, arbuscular and ecto-mycorrhizas, are found colonising highly metal contaminated soils. How do mycorrhizal fungi achieve metal resistance, and does this metal resistance confer enhanced metal resistance to plant symbionts? These are the questions explored in this review by considering the mechanistic basis of mycorrhizal adaptation to metal cations. Recent molecular and physiological studies are discussed. The review reappraises what constitutes metal resistance in the context of mycorrhizal associations and sets out the constitutive and adaptive mechanisms available for mycorrhizas to adapt to contaminated sites.

The only direct evidence of mycorrhizal adaptation to metal cation pollutants is the exudation of organic acids to alter pollutant availability in the rhizosphere. This is not to say that other mechanism of adaptation do not exist, but conclusive evidence of adaptive mechanisms of tolerance are lacking. For constitutive mechanisms of resistance, there is much more evidence, and mycorrhizas possess the same constitutive mechanisms for dealing with metal contaminants as other organisms.

Rhizosphere chemistry is critical to understanding the interactions of mycorrhizas with polluted soils. Soil pH, mineral weathering, pollutant precipitation with plant excreted organic acids all may have a key role in constitutive and adaptive tolerance of mycorrhizal associations present on contaminated sites.

The responses of mycorrhizal fungi to toxic metal cations are diverse. This, linked to the fact that mycorrhizal diversity is normally high, even on highly contaminated sites, suggests that this diversity may have a significant role in colonisation of contaminated sites by mycorrhizas. That is, the environment selects for the fungal community that can best cope with the environment, so having diverse physiological attributes will enable colonisation of a wide range of metal contaminated micro-habitats.

Agaricus bisporus browning is a common and economically detrimental phenomenon, in which melanogenic phenols are enzymically processed into quinones, which evolve eventually to melanins. This review deals with the two fundamental sides of this process, enzyme(s) and phenolic substrates. Mushroom tyrosinase, the main polyphenol oxidase encountered in the A. bisporus sporophore, is treated in the first part. Its overall molecular architecture, isoforms, primary sequence and genetic background are considered. The presentation of tyrosinase catalytic features, including enzyme assays, kinetic properties, substrates and inhibitors, is followed by a comprehensive description of the active site and reaction mechanisms. Because of their relevance for studies of mushroom browning during development and post-harvest storage, the occurrence and properties of latent enzyme forms, as well as the location of tyrosinase and variations of its activity during the A. bisporus life cycle, are also reviewed. The second part deals with the substrates, particularly γ-L-glutaminyl-4-hydroxybenzene (GHB) and its derivatives. Main data concerning the nature, obtention (by extraction or synthesis), spectrometric and chromatographic characteristics, chemical stabilities and biological properties of these typical Agaricaceae compounds are presented. Their distribution and levels according to the strains and flushes are described, as well as their variations during storage. Thirdly, the relationship between browning and the natural or pathogenic discolouration intensity is developed.

In a 3 year study of oak decline in Central and Southern Europe, a papillate homothallic Phytophthora species was isolated consistently, with other Phytophthora spp., from necrotic fine roots by direct plating on to selective agar medium and from rhizosphere soil samples by baiting with leaves of Quercus robur. The morphology, physiology, RAPD banding patterns and pathogenicity against apple fruits of this Phytophthora sp. are described and compared with those of other papillate Phytophthora species from Waterhouse's Group I, namely P. cactorum, P. clandestina, P. idaei, P. iranica, P. pseudotsugae and P. tentaculata, and semi-papillate Group III P. citricola. The papillate Phytophthora isolates from oak differed from all other Group I species by their uniform, dome-shaped and cottonwool-like colony growth pattern on V8 juice agar and malt extract agar, the frequent occurrence of sympodially branched primary hyphae, a high proportion of elongated, ellipsoid or ovoid oogonia, the absence of amphigynous antheridia and RAPD banding patterns. Additionally, there was no other species in Group I with as much variation in size and shape of the sporangia or large proportion of sporangia with a curved apex, hyphal projections, lateral displacement of the papilla and lateral attachment to the sporangiophore. In pathogenicity tests with infested soil, the isolates proved to be more pathogenic to Q. robur than any other Phytophthora sp. recovered from declining oaks in Central Europe. Based on their unique combination of cultural, sporangial and gametangial morphology, pathogenicity and close association with Quercus but not other trees, the papillate Phytophthora isolates from oak are described as Phytophthora quercina sp. nov.

The lipid and fatty acid compositions of Glomus intraradices and G. claroideum mycelia, extracted from quartz sand in a compartmentalized growth system, were analysed. The fungi were grown in association with Cucumis sativus and Trifolium subterraneum, respectively. For both fungi, the fatty acids 16[ratio ]1ω5 and 16[ratio ]0 dominated in the neutral lipid fraction, and 18[ratio ]1ω7 made up a significant part of the phospholipids. The fatty acids were used as estimators of the amount of neutral lipids and phospholipids of AM fungi as well as to calculate the biomass of different parts of their mycelium. The phospholipid content was higher in hyphae than in spores, whereas the opposite was observed for neutral lipids. In 3-mo-old G. intraradices mycelium, spores accounted for 90% of the external biomass, and calculations indicated that about 20% of the spore biomass consisted of neutral lipids. In both fungi the fatty acid compositions of hyphae and spores were similar regardless of the age of the mycelium.

Using the signature fatty acid 16[ratio ]1ω5 to calculate the distribution of AM biomass for a 2-mo-old mycelium of G. claroideum, we found that the fungal biomass was equally distributed between the external mycelium and the internal mycelium in the host root.

The organic soil horizons of heathland and temperate forest ecosystems are characteristically rich in phenolics, which present barriers to organic N availability to the microflora. The abilities of ectomycorrhizal (ECM), ericoid mycorrhizal and wood decomposing saprotrophic fungi to degrade model compounds representing the insoluble phenolic lignin, and soluble phenolics, which provide physical and chemical barriers respectively to organic N availability, were compared. No clear relationship was found between ability to degrade lignin and soluble phenolics. The presumptive assays indicated that most mycorrhizal fungi have only low abilities to degrade these compounds relative to the wood decomposing fungi. In general, ericoid mycorrhizal fungi were capable of greater phenolic degradation than most ECM species, and degradative ability was associated with production of phenol-oxidizing enzymes. In no case was presumptive degradation of lignin or soluble phenolic, or production of phenol-oxidizing enzymes by mycorrhizal fungi as great as that of the wood decomposing fungi. In the case of the ericoid endophyte Hymenoscyphus ericae, phenol-oxidation was associated with production of an extracellular o-polyphenol oxidase (tyrosinase) which showed optimal activity at a pH of 5–5·5 and temperature of 30°C. The ecological significance of the results is discussed.

Partial translation elongation factor 1 alpha (TEF-1α) gene and intron sequences are reported from 148 isolates of 11 species of the anamorph genus Fusarium; F. avenaceum (syn. F. arthrosporioides), F. cerealis, F. culmorum, F. equiseti, F. flocciferum, F. graminearum, F. lunulosporum, F. sambucinum, F. torulosum, F. tricinctum and F. venenatum. The sequences were aligned with TEF-1α sequences retrieved from 35 isolates of F. kyushuense, F. langsethiae, F. poae and F. sporotrichioides in a previous study, and 39 isolates of F. cerealis, F. culmorum, F. graminearum and F. pseudograminearum retrieved from sequence databases. The 222 aligned sequences were subjected to phylogenetic analyses using maximum parsimony and Bayesian Markov Chain Monte Carlo maximum likelihood statistics. Support for internal branching topologies was examined by Bremer support, bootstrap and posterior probability analyses. The resulting trees were largely congruent. The taxon groups included in the sections Discolor, Gibbosum and Sporotrichiella sensu Wollenweber & Reinking (1935) all appeared to be polyphyletic. All species were monophyletic except F. flocciferum that was paraphyletic, and one isolate classified as F. cfr langsethiae on the basis of morphology that grouped with F. sporotrichioides. Mapping of toxin profiles, host preferences and geographic origin onto the DNA based phylogenetic tree structure indicated that in particular the toxin profiles corresponded with phylogeny, i.e. phylotoxigenic relationships were inferred. A major distinction was observed between the trichothecene and non-trichothecene producers, and the trichothecene producers were grouped into one clade of strictly type A trichothecene producers, one clade of strictly type B trichothecene producers and one clade with both type A and type B trichothecene producers. Furthermore, production of the type A trichothecenes T-2/HT-2 toxins are associated with a lineage comprising F. langsethiae and F. sporotrichioides. The ability to produce zearalenone was apparently gained parallel to the ability to produce trichothecenes, and later lost in a derived sublineage. The ability to produce enniatins is a shared feature of the entire study group, with the exception of the strict trichothecene type B producers and F. equiseti. The ability to produce moniliformin seems to be an ancestral feature of members of the genus Fusarium which seems to have been lost in the clades consisting of trichothecene/zearalenone producers. The aims of the present study were to determine the phylogenetic relationships between the different species of Fusarium commonly occurring on Norwegian cereals and some of their closest relatives, as well as to reveal underlying patterns such as the ability to produce certain mycotoxins, geographic distribution and host preferences. Implications for a better classification of Fusarium are discussed and highlighted.