Few studies have examined faeces as a substratum for nematophagous fungi, and no information is available about colonisation of faeces in tropical regions. Sheep faeces were deposited on a Brachiaria decumbens pasture in the Mata Region of Minas Gerais, Brazil. Up to 2 wk after deposition, samples were collected and cultivated on water agar (2 %) with free-living nematodes as bait. From 150 samples, 130 isolates were recovered after 3 wk. More than 70% were predators and Arthrobotrys and Monacrosporium spp. predominated. Endoparasitic species of Drechmeria, Harposporium, Myzocytium, Nematoctonus and Verticillium were also isolated.

The aim of this study was to test the usefulness of direct PCR-amplification in analysing fungal diversity in stumps. The analysis was conducted on stumps treated against Heterobasidion spp. using a commercial formulation of Phlebiopsis gigantea (Rotstop), and carried out using denaturing gradient gel electrophoresis (DGGE) of small subunit (SSU) ribosomal DNA (rDNA) fragments PCR-amplified directly from wood DNA samples using two separate fungus-specific primer pairs. On average, two (range 0–9) different amplification products were observed by DGGE in single wood samples of approximately 500 mm3. The PCR products were classified into operational taxonomical unit (OTU) groups based on their DGGE mobility. Six OTUs could be affiliated with a known species based on a reference fungal collection of 37 species: Heterobasidion annosum, H. parviporum. Hypholoma capnoides, P. gigantea, Resinicium bicolor and Stereum sanguinolentum. Sequence analyses did not give further identifications. OTU profiles from old (6 yr-old) and fresh (1-year-old) Scots pine and Norway spruce stumps from treated and untreated forest plots were compared statistically, and some significant differences were observed in the species composition between the treated and untreated plots. However, the frequency of most of the OTUs did not seem to be affected, and the treatment did not seem to have reduced the overall level of fungal diversity. Based on these results, direct PCR-amplification seems to be useful in analyses of fungal communities in decaying conifer stumps.

A monoclonal antibody (MAb), UB31, is described that binds to the extracellular matrix (ECM) surrounding germ-tubes and appressoria, but not conidia, of the bean anthracnose fungus, Colletotrichum lindemuthianum. Comparative localisation studies with MAb UB26, which has the same cell type specificity, suggest that the ECM is heterogeneous in composition. Immunofluorescence showed that UB31 labelled appressoria more intensely than germ-tubes, whereas UB26 labelled these structures to a similar extent. Immunofluorescence and TEM-immunogold labelling showed that UB31 antigens were located close to the appressorial wall, while UB26 antigens extended further away from the wall. MAb UB31 bound to the ECMs of all six Colletotrichum species tested. Western blotting and ELISA indicated that the antibody recognises a high Mr glycoprotein (>200000) that may be linked to melanin. The glycoprotein recognised by UB31 was not removed from substrata by ultrasonication, suggesting it may contribute to germling adhesion.

Two species of Haptoglossa isolated from nematodes from cow manure from N.E. England are described. H. erumpens sp. nov., infecting Bunonema nematodes, is aplanosporic, the cysts being released after rupture of the nematode cuticle in the absence of an evacuation tube. H. dickii sp. nov. is zoosporic, infecting several species of rhabditid nematodes. Aplanospores and zoospore cysts germinated to produce secondary spores (gun cells) with which to infect further nematode hosts. Some key ultrastructural features in both species have been included.

The name Agaricus subfloccosus (J. E. Lange) Pilát, based originally on Danish specimens, has been applied to mushrooms growing in coastal northwestern Europe as well as to mushrooms associated with Picea (and Abies) at higher elevations in western Europe. Corresponding populations are also found in these two habitat zones in western North America. Material of both lowland and highland forms from Europe and North America was studied using morphological, cultural, and genotypic approaches. Homothallism was consistently observed in those isolates studied. Individual and population level genetic data are also consistent with homothallic reproduction. Dissimilarity analysis of multilocus nuclear and mitochondrial genotypes based on allozyme and DNA RFLP markers provided strong evidence that, within either ecologically distinct group, the amphiatlantic populations were genotypically very similar. Conversely, there were large genotypic differences between the two ecologically distinct groups, whether within or between continents. Supported by cultural and morphological evidence, these data indicate that two ancient, phylogenetically distinct entities exist within current concepts of A. subfloccosus. A formal taxonomic resolution is complicated by the lack of a holotype for Lange's species.

Two new species of Helicoon, H. myosuroides and H. dendroides, are described and illustrated, and their characteristics are outlined in comparison with similar species. Both species belong to the ecological group of the aero-aquatic fungi and are even more specialized as they only inhabit raised bogs. Their ecological characteristics are discussed in detail.

Mycoëmilia scoparia gen. sp. nov. is described as a new member of Kickxellales. It is characterized by lageniform sporocladia produced acrogenously in mass and bears wet and fusiform spores on the sporocladia. Ramicandelaber brevisporus sp. nov. is distinguished from the type species of the genus, R. longisporus, by producing much shorter asexual spores, (3–)8(–13) long fertile branches arising from a globose body, and lateral branches.

Development of mushrooms is driven by genetic and epigenetic factors in a continuous interaction with the environment. It is assumed that each successive stage of morphogenesis depends on specific sets of signals arising at the appropriate time and place during the growth process. Morphogenetic dynamism proceeds in a time dimension through a cascade of signal-effect associations. Developmental errors may occur when such signals originate in the wrong place and/or at the wrong time. As a result various abnormalities such as ectopic tissues can develop and morphogenesis can be severely disturbed. Both endogenous genetic disturbances and exogenous factors can cause developmental errors. Lamellar dysplasia, which is a pore-like proliferation of the gills, forms an example; it may be induced experimentally. Both lamellar dysplasia and rosecomb disease of Agaricus bisporus result from endogenous genetic instability, whereas the developmental errors observed in wet bubble disease, which is caused by the infection of Mycogone perniciosa, originate from an exogenous factor. Morphogenesis normally leads to a symmetrical form of primordia of A. bisporus. Asymmetry is very frequently associated with an underlying pathological situation. Defining exact criteria of and sharp borderlines between normal and abnormal development seems infeasible. Fungi may readily tolerate morphogenetic imprecision. In this report, various macro- and microscopic features of normal and pathological development are illustrated; the dilemma of normal versus abnormal fruit body development has been discussed.

A mathematical model is presented which qualitatively describes the growth kinetics of the aphid-pathogenic Erynia neoaphidis in liquid culture. An essential feature of the model is that it allows for the presence of a toxic component within the growth medium which may be broken down by an extracellular enzyme released by the biomass. In this investigation, the toxin was oleic acid which had previously been shown to be essential for the growth of E. neoaphidis, but only at low concentration.

The model reproduces a number of unusual features of the kinetics of growth of E. neoaphidis in liquid culture. These include: the requirement for a high inoculum concentration to successfully initiate growth in liquid culture; failure to grow in continuous culture under conditions similar to those supporting successful batch culture; a reduced growth yield in continuous culture compared to batch culture; a depressed apparent specific growth rate in continuous culture compared to batch culture and, deviation from the usual exponential decrease of biomass concentration during washout. Through the development of the model, and the application of predictions derived from it to the laboratory situation, continuous culture of E. neoaphidis was achieved for the first time.

A 909 bp region containing a genomic clone encoding for hydrophobin (ssgA) from the entomopathogenic fungus Metarhizium anisopliae has been sequenced and the regulatory motifs analysed against those recognized in other fungi. The genomic clone was also compared with the open reading frame of the hydrophobin ssgA (starvation stress gene) cDNA sequence. The genomic clone contained a 291 bp coding sequence with one intron of 64 nucleotides. From this sequence primers were established that could be used to amplify the hydrophobin. Restriction fragment polymorphism analysis of hydrophobin amplified by the polymerase chain reaction from 80 isolates of M. anisopliae showed no variability. Analysis of the potential regulatory elements 313 bp upstream from the transcriptional start site revealed typical TATAA and CCAAT boxes. CT or GC motifs were not found. Upstream regulatory elements were also found with sequence homologies to the AREA, CREA, CRE (cAMP response element) and BRLA regions of Aspergillus nidulans as well as the CYS3 and AmyB regions of Aspergillus oryzae. The promoter regions of other fungal hydrophobins were also assessed for the presence of regulatory elements. Upstream regulatory elements are also present for the gene encoding a cuticle-degrading protease (Pr1) from M. anisopliae. We suggest that nutrient levels and cAMP mediation of thigmotropic signals in the entomopathogenic fungus, M. anisopliae, co-ordinate the regulation of the gene products required for morphological development and secretion of ‘penetration’ enzymes.

Investigation of Phaeocollybia in British Columbia, Washington, Oregon and California has led to a better understanding of the characters and biology of the genus as a whole. Generically significant characters – pseudorhizas, pellicular veil, tibiiform diverticula, and sarcodimitic tissues – are examined in depth with four variations of branched and unbranched pseudorhizal patterns outlined. Basidiome development is traced from subterranean initiation to fully mature emergent basidiomes. Hypotheses on the ontogeny of Phaeocollybia basidiomes and biological associations are developed based on extensive observations of primordia and numerous field excavations. Comparisons between rhizomorphs and the thread-like pseudorhizal extensions of certain species are made and the term ‘rhizomorphic pseudorhiza’ is introduced. Possible biological strategies are explored and evidence for consideration of Phaeocollybia as a mycorrhizal genus is presented.

Silver scurf is an important postharvest disease affecting potato tubers worldwide, caused by Helminthosporium solani. In the present study, key steps of infection of potato tubers (cv. ‘Dark Red Norland’) by H. solani were described using transmission (TEM) and scanning electron microscopy (SEM). The fungus entered potato tubers mainly via hyphae, although germ tubes were also able to directly penetrate the tubers. An extracellular sheath was observed around hyphae growing over the surface of tubers and the host cell wall appeared lyzed at the point of penetration. Observations suggested that both mechanical and enzymatic processes are involved in periderm penetration. Hyphae of H. solani, 9 h after tuber inoculation, were present intracellularly mostly in the periderm and in some cortical cells. Two days after inoculation, host cells were invaded and both infected and neighbouring host cells showed signs of necrosis (disrupted cytoplasm, absence of typical organelles or endomembrane systems, collapsed peridermal cells) that were not observed in healthy control tubers. Four days after inoculation, completing the infection cycle, conidiophores emerged from peridermal cells directly by erupting through the host cell walls.

Faecal samples collected from the Mountain brushtail possum (Trichosurus caninus) at several sites in eastern Australia showed the presence of spores from at least 21 hypogeous fungi, and several epigeous species. Most were found in faeces of animals at one site, where samples were collected in different seasons. Further collections are needed from the other sites at different times of the year to clarify how widespread the mycophagous habits of T. caninus are. Many of the hypogeous fungi identified are either known or presumed to form mycorrhizal relationships with the roots of forest trees and shrubs and T. caninus may disperse their spores in its faeces.

Four ascomycete species with brown 1-septate ascospores with wall ornamentation were identified from palms in Ecuador and Brunei. Asci were long cylindrical, relatively thick-walled, bitunicate with non-fissitunicate dehiscence, and the hamathecium was composed of trabeculae. These fungi are referred to Roussoëlla, and are described and illustrated in this paper, including two new species. A key to accepted species of Roussoëlla is provided.

Collybia fusipes is the cause of a root rot of oak trees. We studied the structure of C. fusipes populations in two infected oak stands by using somatic incompatibility and DNA amplification. Isolates were obtained from different oak root systems or from within the same root system and somatic incompatibility groups (SIG) were identified. Many small SIGs that seldom encompassed more than one root system were present in both stands. More than one SIG was usually present on an individual root system: there were 3·1±1·3 SIGs on the pedunculate oaks and 2·2±0·6 on the red oaks. The largest SIG contained more than 70% of the isolates obtained from the root system of 14 of the 20 trees studied. Isolates that belonged to the same SIG usually had the same ribosomal intergenic spacer. It is concluded that C. fusipes spreads poorly from tree to tree by vegetative means.

Laetiporus sulphureus causes heart-rot in deciduous trees and conifers. European isolates were examined using nuclear DNA markers as well as somatic and sexual compatibility. Pairing tests for somatic compatibility with isolates from 20 different host individuals revealed that each tree is normally colonized by a different genet. The hyphae are multinucleate, basidiospores are binucleate, and conidia contain 2–6 nuclei. Basidiospore germination was erratic, and no clear mating pattern was observed. In one case all single spore isolates from the same basidioma were compatible with each other. Single spore isolates from coniferous and from broadleaf trees were incompatible. The nuclear ribosomal DNA ITS regions from six isolates of different origin revealed nucleotide distances of up to 14·6%. Phylogenetic analysis resulted in a single clade for all isolates. Within this clade, a subclade including only the isolates from gymnosperm hosts was present, indicating that these isolates were derived from ancestral lines from broadleaf hosts. While there is evidence that more than one species or ecotype is represented within the current definition of L. sulphureus, circumscription of additional taxa, and separations within this taxon, remain unclear.

The causal agent of a patch disease of buffalo grass (syn. St Augustine grass) is determined and described as a new species, Gaeumannomyces wongoonoo sp. nov. Glasshouse experiments have shown that it is pathogenic to buffalo grass (cultivar ST 1191) but not to maize or wheat. The pathogen is different to the varieties of G. graminis in having shorter ascospores (36–75 μm) and producing numerous perithecia readily on malt extract and potato dextrose agars. The disease is named ‘wongoonoo patch’ to distinguish it from take-all patch of turf grasses caused by G. graminis.

Entoleuca mammata (syn. Hypoxylon mammatum) is a damaging pathogen of Populus tremuloides and P. grandidentata in North America and P. tremula in Europe, where the fungus occurs only sporadically in alpine regions and Scandinavia. It has been hypothesized that E. mammata was introduced to Europe from North America. In this study, E. mammata isolates collected from Europe and North America were compared by a sequence analysis of two DNA markers derived from DNA fingerprints. The objective of the study was to elucidate the relationship between North American and European E. mammata populations by testing two hypotheses: (1) North American and European isolates are conspecific; and (2) the fungus was introduced between continents causing both a founder effect and a genetic bottleneck. North American populations were found to be more polymorphic, but no major phylogenetic differences between fungal isolates collected from different continents were found. This result combined with the historical observations of the disease in Europe implies that E. mammata was introduced to Europe several centuries ago.

Rust is reported for the first time in North America on tansy (Tanacetum vulgare), a widespread and invasive Eurasian plant that was introduced into North America in the 17th century. Morphologically, the rust fungus corresponds exactly to Gäumann's description of Puccinia tanaceti, and to European specimens of P. tanaceti on T. vulgare. An inoculation study confirmed the narrow host specialization of P. tanaceti that Gäumann described, in that T. vulgare was successfully inoculated whereas four other species of the tribe Anthemidae of the Asteraceae were entirely resistant, i.e. Leucanthemum maximum (Shasta daisy), L. vulgare (ox-eye daisy), Artemisia absinthium (wormwood), and A. tridentata (sagebrush). This confirmation of a specialized P. tanaceti invalidates P. tanaceti s. lat. The latter complex has resulted from synonymies, and compilation of host records of rust fungi resembling P. tanaceti on at least 105 species representing 19 genera from six tribes of the Asteraceae from both New and Old Worlds.

Spongospora nasturtii is a plasmodiophorid pathogen of watercress (Rorippa nasturtium-aquaticum), causing crook root disease. In the past, some authors have considered the plasmodiophorids as protists, and others have considered them as true fungi. This study was performed with the aims of elucidating both the relationship of S. nasturtii to other plasmodiophorids, and also the placement of the plasmodiophorids as a group when compared to other organisms. Analysis of partial 18S ribosomal DNA sequences of a range of plasmodiophorids by phylogenetic techniques including parsimony, neighbour-joining, and principal co-ordinate analysis, indicated that there was a close relationship between S. nasturtii, S. subterranea and Plasmodiophora brassicae. However, analyses incorporating 1.2 kb of 18S rDNA sequence from S. subterranea cast doubt over the long-held view that S. subterranea and S. nasturtii are more closely related to each other than to other genera of plasmodiophorids. Consideration of the entire 18S rDNA of both S. nasturtii and P. brassicae showed that they are not closely related to a range of protists and true fungi examined.