A new description and illustration of Polydesmus elegans, the type species of Polydesmus, is given. It was formerly considered as congeneric with Sporidesmium. Two new genera, Imimyces to accommodate I. aquaticus, I. bambusae, I. carrii, I. densus, I. heterocateniformis and I. hollowayensis, and Linkosia to accommodate the single species L. coccothrinacis, are proposed. A key to species of Imimyces is provided, and a new species and six new combinations are proposed.

DNA was extracted from dried specimens of nine taxa of the Cantharellaceae. Approximately 325 bases near the 5′ end of the nuclear 28S ribosomal gene were sequenced, and the sequences were compared. Sequence analyses demonstrated that Cantharellus and Craterellus should be treated as distinct genera. The phylogeny generated using parsimony suggests that Cantharellus tubaeformis and Pseudocraterellus sinuosus should be considered species of Craterellus. As a result of this study, we recognize the first placement of these two species in Craterellus by Fries and Quélet. A reassessment of the morphological characters used to separate Cantharellus and Craterellus is indicated.

Three hypotheses of the phylogeny of the lichenized Parmeliaceae are constructed, using sequences of the nuclear ribosomal gene cluster (SSU, ITS, 5·8S rDNA) from Bryoria capillaris, Cetraria islandica, Evernia prunastri, Hypogymnia physodes, Parmelia saxatilis, Platismatia glauca, Pleurosticta acetabulum, Usnea florida, Vulpicida juniperina, V. pinastri and Xanthoparmelia conspersa. The first analysis, based on SSU sequences, shows the representatives of the Parmeliaceae to form a monophyletic group within the order Lecanorales. Usnea florida and Bryoria capillaris, sometimes classified in the families Usneaceae and Alectoriaceae, respectively, are also members of the Parmeliacceae. Cetraria and Vulpicida form a well-supported monophyletic group together with Usnea, but there is little support for any other groupings within Parmeliaceae. The second analysis is based on ITS an 5·8S sequence data of the representatives of the Parmeliaceae included in the first analysis, and supports the close relation of Cetraria and Vulpicida. Other groupings are not supported, and the topology also varies greatly with minor alignment changes. This is attributed to the included taxa being too distantly related to each other, causing alignment difficulties of the variable ITS region when a relatively small number taxa are included. It is predicted that a larger sample of phylogenetically intermediate taxa will overcome this problem. When combining the two datasets, the results are similar to the ITS results. The present study is one of the first phylogenetic studies utilizing the information in more than one gene alone in lichenized ascomycetes.

Mycology is changing as an era of extensive genome sequencing comes of age and provides vital information that enables questions to be addressed about fungi in all the major taxonomic groups. As technology transfer facilitates what was once only possible for a very small number of model species, it becomes possible to explore the biology and biodiversity of fungi as a whole. The availability of genome sequence information and reverse genetic technologies allows hypotheses that emerge from biological observations to be tested. Genomic and post-genomic technologies will underline the importance of fungi as excellent models for the study of fundamental biological phenomena. Two enduring areas of research in my own laboratory are described that are now being extended using post-genomic approaches. These projects relate to how fungal hyphae extend and guide their tips and secondly how plant pathogenic oomycete zoospores are guided on their journey to the plant surface.

The ergocalciferol (vitamin D2) content of individual fruit bodies of the edible mushroom Cantharellus cibarius (chanterelle) was measured with HPLC 2–6 years after drying. The concentrations of ergocalciferol in different fruit bodies varied between 0·12 and 6·30 μg g DW−1, with a mean of 1·43 μg g DW−1. This result indicates that dried and stored chanterelles contain significant amounts of ergocalciferol. The huge range in concentration challenges the validity of food tables based on means from pooled samples. The range may reflect differences in exposure to sun light, as fruit bodies within the same cluster showed little variation. Our study indicates that mycelial cultivation for ergocalciferol production is an interesting prospect if strains and incubation conditions are selected carefully. No significant difference in ergocalciferol concentration between pigmented and albino forms was found.

Green moulds caused by Trichoderma harzianum biotypes Th2 and Th4 are responsible for important economic losses on mushroom farms producing Agaricus bisporus, whereas other biotypes present in farms have only slight effects on the cultivated mushroom. Adaptation of Th2 and non-Th2 strains of Trichoderma to grow in compost prepared for mushroom cultivation was compared through extracellular enzyme activities and competition with bacteria isolated from compost. No specific differences between Th2 and non-Th2 strains were observed for the activities of the 17 secreted enzymes tested. Confrontations of 27 bacterial isolates with 4 Trichoderma strains revealed that the aggressive Th2 strains were affected by a lower number of bacterial isolates than the non-Th2 strains. Capacities of T. harzianum, biotype Th2, to colonise mushroom compost are not due to a specific ability to produce enzymes necessary for compost degradation but to their tolerance to the inhibitory effect of bacteria present in compost.

The entomopathogenic fungus Pandora neoaphidis is an important natural enemy of aphids. ISSR, ERIC (Enterobacterial Repetitive Intergenic Consensus) and RAPD PCR-based DNA fingerprint analyses were undertaken to study intra-specific variation amongst 30 isolates of P. neoaphidis worldwide, together with six closely related species of Entomophthorales. All methods yielded scorable binary characters, and distance matrices were constructed from both individual and combined data sets. Neighbour-joining was used to construct consensus phylogenetic trees which showed that although P. neoaphidis isolates were highly polymorphic they separated into a monophyletic group compared with the other Entomophthorales tested. Three distinct subclades were found, with UK isolates occupying two of these. No specific correlation with aphid host species was established for any of the isolates apart from those in one cluster which contained isolates obtained from nettle aphid, Microlophium carnosum. ERIC, ISSR and RAPD analysis allowed the rapid genetic characterisation and differentiation of isolates with the generation of potential isolate- and cluster specific- diagnostic DNA markers.

Pleurotus pulmonarius is a species of the oyster mushroom which has become the second most popularly cultivated mushroom in the world. In this study, we show that renewed fruiting from excised stipes can be used as a simple and rapid in vitro bioassay system to detect fruiting modulators. We used this and conventional cultivation techniques to examine the effects of cadmium, a potential contaminant from industrial sources, calcium, which is an ingredient in mushroom compost, and manganese, which has been claimed to improve the yield of P. ostreatus. All the three metallic salts did not affect sporulation. Calcium chloride addition shortened the time taken for the mushroom to fully cover the cultivation compost and improved yield. Insoluble calcium salts at higher concentrations had a similar though less pronounced effect. The calcium and total amino acid contents of fruit bodies also increased. Compost supplementation with calcium is desirable for cultivation of the oyster mushroom but not indispensable since the straw-based cultivation substrate is itself able to provide the required minerals. By contrast, manganese chloride retarded mycelial growth and decreased yield but increased the total amino acid content in the stipe whilst manganese sulphate did not enhance accumulation of manganese into fruit bodies. Excess manganese induced browning of vegetative tissues. Cadmium ions did not kill the oyster mushroom at 4·5 mM but reduced yield by 50%. At this concentration cadmium decreased the total amino acid content and affected the amino acid profile but did not affect the form and shape of the fruit bodies. Pleurotus pulmonarius concentrated cadmium to such an extent that consumption of as little as 20 g (D.W.) of the most contaminated samples would exceed the weekly limit tolerated by humans and thus pose a health hazard. Monitoring the heavy metal contents of mushrooms marketed for food is, therefore, advised as the source of the substrate for cultivation is usually not known.

Coarse woody debris is important for mycodiversity in forest ecosystems, but its availability in managed stands is reduced. Leaving dead wood during felling is suggested as an option to sustain and restore the diversity. However, little is known what fungi would colonise freshly cut wood left on managed sites, and how the colonisation process is influenced by ecological factors. During summer and autumn, 120 freshly cut Picea abies stem sections over 8 cm in diameter were placed upright in mapped locations over two discrete plots separated by 100 m in a north-temperate forest. After seven weeks the sections were collected, and isolation and identification of fungi was done from their upper surfaces. In all 943 fungal strains were isolated, representing 97 species. Species richness in the summer survey was 42.5% higher than during the autumn survey. Low species similarity characterized the different seasons (Sorensen indices: SS=0.36 and SN=0.34) and for 21 species (22%) observation frequency was significantly affected by season. As a result, community structures in summer and autumn differed notably (z-test; P<0.001). Species richness between the two plots differed by less than 10%, but there were 64 species (66%) found only in one of them, thus qualitative similarity was low (SS=0.49). Quantitative similarity was higher (SN=0.63), indicating that the dominant species colonised wood to a similar extent in both areas. Fungal community structure differed significantly among the two plots (z-test; P<0.001). Our data showed that freshly cut CWD contributed to mycodiversity in managed north-temperate forest, providing habitats for numerous individuals from over 100 species. The fungal community within a single stand differed markedly both across small distances and over the seasons. In order to sustain and enhance mycodiversity in managed stands, coarse wood should always be left during harvesting. This study also demonstrates the importance of molecular identification and ITS sequence databases for exploring fungal diversity in natural communities.

Analysis of Amplified Fragment Length Polymorphisms (AFLP) in a sample population of Epichloë and Neotyphodium was conducted to evaluate the usefulness of this technique in estimating phylogenetic relationships among these fungi. A total of 963 unique restriction fragments were identified with 13 selective primer combinations. Neighbour-joining and parsimony analysis produced phylogenetic trees with high bootstrap support. All Epichloë festucae isolates were monophyletic, and clades of E. festucae were identified that correspond to the host species from which they were isolated. These groups may indicate the importance of coevolution in the development of the fine fescue-E. festucae symbiosis. The grouping of E. festucae isolates from hard fescue and Chewings fescue into one clade conflicts with the current taxonomy of these host grasses. Sequencing of ribosomal DNA spacer regions ITS1 and ITS2 was conducted for comparisons to the phylogenetic relationships estimated by AFLP. Using the maximum likelihood test, a significant difference was detected between AFLP and rDNA trees due to discrepancies in the association of anamorphs (Neotyphodium) and teleomorphs (Epichloë). This discrepancy may be due to some mechanism of genetic recombination, such as hybridization or parasexual recombination, that occurs in Neotyphodium populations. It is concluded that AFLP markers are useful for producing meaningful phylogenies among a diverse group of fungi and for identifying groups of closely related individuals that are genetically and biologically similar. Further investigation is needed to determine how AFLP markers change over short periods of time in populations and over evolutionary time.

This work tested the hypothesis that the abundance of fungal species on coniferous needles is correlated to climatic factors at a regional scale. The proportions of Pinus sylvestris needles colonised by Lophodermium pinastri, Cyclaneusma minus and Verticicladium trifidum were examined along two altitudinal transects in 2 successive years. L. pinastri and C. minus colonisation increased with altitude, whereas that of V. trifidum decreased. The data are discussed in relation to the importance of climatic controls on species distributions.

The ability of two non-aflatoxin producing strains of Aspergillus flavus to interfere with aflatoxin production by a toxigenic A. flavus strain was examined using a replacement series with suspended disc culture method. Individual glass fiber discs, affixed to a pin suspended from the caps of scintillation vials, were inoculated with medium containing A. flavus conidial mixtures in different proportions (aflatoxin producer[ratio ]non-producer=100[ratio ]0, 80[ratio ]20, 60[ratio ]40, 20[ratio ]80 and 0[ratio ]100 by vol) at a constant total density (1×105 spores ml−1). Reductions in the total conidial density of these strains when grown alone, had little effect on fungal growth (mycelium dry weight) or aflatoxin production. Significant (P<0.0001) reductions in aflatoxin B1 were recorded when non-toxigenic strains represented any proportion of the inoculum mixture. Aflatoxin yield values were less than (P<0.0001) expected from the input ratios for toxigenic vs. non-toxigenic conidial inoculum within the replacement series. Aflatoxin yields were also reduced (P<0.001), with a corresponding increase in fungal growth (P<0.001), when conidia from aflatoxin producing strains were mixed in equal proportions. This suggests that the substantial inhibition of aflatoxin yield for inoculum mixtures results from the failure of spore germlings to establish a cooperative mycelial network.

Molecular, morphological, and cytological evidence show that the arbuscular mycorrhizal fungus Glomus scintillans is more closely related to the genera Gigaspora and Scutellospora (Gigasporaceae) than it is to Glomus s. str., and consequently it contributes to the non-monophyly of the genus Glomus. We transfer the species to Gerdemannia gen. nov., with consequent autonymy of an appropriate family, Gerdemanniaceae fam. nov. Small subunit (SSU) rDNA analysis places Gerdemannia in a clade sharing common ancestry with the Gigasporaceae, and therefore within the Diversisporales (Glomeromycota). Glomus dominikii is considered to be conspecific with G. scintillans, and these species are synonymised. Glomus chimonobambusae is also transferred to the new genus as Gerdemannia chimonobambusae comb. nov.

A morphological and molecular analysis was performed on 25 individuals of Phaeoacremonium isolated from diseased European and Californian grapevines (Esca disease). An unexpectedly high intra-generic molecular divergence was evidenced by partial rDNA sequencing between P. chlamydosporum isolates on one hand and an aggregate including P. angustius and P. aleophilum isolates and some undescribed ones on the other. These two groups show 26% nucleotide differences within the 26S rDNA fragment sequenced and were unalignable within the ITS2, suggesting distant phylogenetic relationships. Moreover, P. chlamydosporum appeared more closely related to Phialophora verrucosa (supposed to be an anamorph of the Herpotrichiellacae), than to the type species of the genus, P. parasiticum (more related to Magnaporthaceae).

The β-1,3-glucanase system of the mycoparasitic T. harzianum, isolate T-Y, was found to be composed of at least five different enzymes. Their migration distance in acrylamide gels corresponded to peptides with molecular masses of 30–200 kDa, and they were named accordingly. The largest enzyme – Gβ-1,3–200, was the most abundant when T-Y was grown with no carbon source. Its secretion was almost eliminated when T-Y was grown on media containing a high concentration of carbon sources such as N- acetylglucosamine (GlcNAc) or malic acid. Several isolates of T. harzianum were found to have a β-1,3-glucanase secretion system, controlled by catabolite repression. Each isolate exhibited a different β-1,3-glucanase profile. Gβ-1,3–200 was isolated and purified: its molecular mass was approximately 75 kDa, and its activity was of the exo-type, specific to β-1,3-glucan linkages. Four short peptides resulting from proteolysis of this enzyme were sequenced, and their sequences were most homologous to LAM1.3, a previously isolated β-1,3-glucanase.

Experimental systems were established for the molecular analysis of different developmental stages of Glomus mosseae. RNA and DNA were simultaneously extracted from ectocarpic spores, chlamydospores, dormant and germinating sporocarps and extraradical hyphae. A β-tubulin gene fragment was obtained by PCR from spore genomic DNA and further analysed. β-tubulin RNA expression could be monitored during the fungal life cycle with a gene-specific primer by RT–PCR using an internal cRNA standard.

Close relationship between the Sphaerophoraceae and Austropeltum and Neophyllis, is established by phylogenetic analysis of nuclear SSU rDNA sequences, including newly produced sequences of Austropeltum glareosum, Neophyllis melacarpa and Sphaerophorus globosus. Anatomical, chemical, and ontogenetical characters, and support for this relationship, are discussed, as is the suitability of the nuclear SSU rRNA gene for phylogenetic analyses at this taxonomic level. The analysis gives no support for regarding Austropeltum (presently classified in the Stereocaulaceae) and Neophyllis (presently in the Cladoniaceae) to be closely related to either Stereocaulon ramulosum and Pilophorus acicularis (Stereocaulaceae), or Cladonia bellidiflora (Cladoniaceae), and it is pointed out that the delimitation of all three families needs further investigation. The homology of podetial and pseudopodetial structures is discussed.

Genetic divergence among 57 isolates of Colletotrichum lindemuthianum collected in north, central and south America and The Netherlands was assessed on the basis of PCR-RFLP analysis and sequencing of the nuclear rDNA region of the two internal transcribed spacers (ITS 1 and ITS 2) and the 5·8S rRNA gene. A reproducible 0·58 kb fragment was amplified in all 57 isolates. Races of C. lindemuthianum formed two groups based on the restriction of the PCR-amplified ITS regions. Group I consisted mainly of Middle American races (65%), whereas 85% of Andean races belonged in group II. Genetic distances calculated from the sequence polymorphism in the rDNA region ranged from 0·2 to 1·8% among 14 isolates of C. lindemuthianum. The neighbour-joining and parsimony analyses of the sequence data showed no association of any particular ITS genotype with host gene pool, virulence or geographic origin of races. These data suggest that virulence can arise in different geographic areas at different times, independent of genetic background. Molecular polymorphism among isolates of races 7, 17, 31 and 73 collected in different countries was demonstrated by RFLP analysis of the ITS regions. A similar lack of agreement was observed in the sequence data between isolates of race 73 from Mexico and the United States and the Jukes–Cantor genetic distance between the isolates was large (0·9%). These findings support a level of molecular variability within C. lindemuthianum greater than the variability previously characterized by virulence analysis and suggest independent evolution of specific virulence patterns.

The entomopathogenic fungus Alternaria alternata grew equally well on potato dextrose agar (PDA) and also on potato extract agar (PEA). The latter was excellent for sporulation. The fungus grew at a wide temperature range of 15–35 °C with an optimum at 25 °. On PDA sporulation was much reduced as compared to that on PEA. The spores of the fungus germinated only at 100% relative humidity (rh). Darkness significantly increased the germination percentages in the early stages of germination at all temperatures tested. Differences in germination percentages between light and dark conditions were mostly levelled 24 h post incubation. The germ tubes formed distinct appressoria, both on glass slides and on the aphid host Anuraphis nerii, on which appressoria were formed on all parts of the insect bodies, even on the hardest ones, such as the head and thorax. Most appressoria were single globose and formed terminally on hyphal branches. Few were subapical and still fewer compound and multilobed. Detachment of appressoria from their original position revealed an exceedingly smoothened appression area, around which a mucilagenous material was secreted, apparently cementing them onto the host epicuticle. Optimum temperature for appressorium formation was 20–25 °. At these temperatures more than 80% of the emerging germ tubes formed appressoria. The factors affecting spore germination and appressorium formation are discussed in relation to the prevailing environmental conditions in the mediterranean area as well as their role in influencing the spread and activities of the pathogen and the infection of aphids under field conditions.

In Fusarium section Liseola, the teleomorph is used to identify mating populations that represent different biological species when distinguishing morphological characters are absent in the anamorph. The Gibberella fujikuroi mating populations to which strains of Fusarium section Liseola belong were determined for isolates from sorghum grown at Ifakara, Ilonga and Kachiri, Tanzania. Representatives of all of the mating populations (A–F) were recovered at Ilonga, but C and E were absent at Ifakara and C was absent from Kachiri. The frequency of the different mating populations was similar at all three sites with A (21%) and F (49%) being the most frequent and C and E the least frequent, if they were recovered at all. The relative proportions of mating populations A and F in the population were significantly different from each other at Ilonga, but were not significantly different at Ifakara or Kachiri. Female fertile strains were more common within mating population A than within mating population F. The inbreeding effective population sizes for the A and F mating populations, respectively, were 69 and 91% of count based on mating type, and 88 and 53% of count based on male/hermaphrodite ratios.