Tropical xylariaceous taxa in the genera Biscognauxia, Hypoxylon and Xylaria were evaluated for their ability to produce wood-decay enzymes and effect mass loss and lignin solubilization in angiosperm and gymnosperm wood. All xylariaceous taxa were capable of cellulose and xylan hydrolysis, but few produced enzymes involved in lignin breakdown. Xylariaceous fungi were incapable of causing mass loss in gymnosperm wood, but several caused significant mass loss in angiosperm wood during a six month in vitro exposure. Mass loss values obtained were low at approx. 20% of those obtained for basidiomycetes. Lignin was solubilized at similar rates to mass loss by Hypoxylon and Xylaria species, resulting in indices of lignin solubilization between 0.88 and 1.11, which were similar to those obtained for white-rot basidiomycetes and higher than those previously reported for any other xylariaceous fungi.

Conocybe lactea was examined as part of a larger study on the distribution of amatoxins and phallotoxins in fungi, and the taxonomic relationships between these fungi. As amatoxins are present in the congener C. filaris, the locally abundant C. lactea was examined using HPLC and mass spectroscopy. Amatoxins were not found in C. lactea, but the related phallotoxins were present in small quantities making it the first fungus outside of the genus Amanita in which phallotoxins have been detected. Despite the presence of a related toxin, C. lactea was found not to be taxonomically close to C. filaris. Phylogenetic analyses using nuclear ribosomal RNA genes indicated that North American specimens of C. lactea were conspecific with North American specimens of C. crispa in Conocybe sect. Candidae. European C. crispa was a distinct taxon. The implications of the use of the name C. albipes for these taxa are discussed. Nucleotide data confirmed placement of the sequestrate taxon Gastrocybe lateritia in sect. Candidae, but as a distinct taxon. It is hypothesized that the unique sequestrate morphology of G. lateritia may be caused by a bacterial infection.

The lichens Usnea florida and U. subfloridana have since long been recognised as distinct species. They show many similarities in morphology, but have different reproductive strategies. Usnea florida is always provided with many apothecia and produces no specialised asexual propagules. Usnea subfloridana has soralia, isidiomorphs and occasionally apothecia. Phylogenetic analyses based on continuous sequences of the ITS and LSU regions of the nuclear ribosomal DNA and the gene coding for β-tubulin, show that specimens of the two species form one monophyletic group of intermixed specimens, and not two groups corresponding to morphology, which would have been expected if two species were at hand. The ‘species pair’ concept in lichenology is discussed. Other Usnea species included in the study are: U. articulata, U. barbata, U. ceratina, U. filipendula, U. hirta, U. rigida and U. wasmuthii.

Aspergillus flavus and A. parasiticus are closely related species belonging to the Aspergillus section Flavi. Both species can produce aflatoxins, but not all isolates of either species do so. We examined the genetic relationship between toxigenic and non-toxigenic isolates using RAPD and Neighbour Joining analysis. Twenty-four RAPD amplifications using a combination of 17 primers discriminated between 20 isolates of A. flavus and 15 isolates of A. parasiticus. A. flavus isolates divided into two distinct groups with both toxigenic and non-toxigenic isolates occurring in each group. No association was seen between RAPD genotype and the ability to produce toxin. Five non-toxigenic isolates of A. parasiticus separated into two groups, in which the isolates were similar but not identical. These groups of non-toxigenic isolates occurred on branches in which toxigenic isolates also occurred. This study suggests that either multiple losses of toxigenicity in A. flavus and A. parasiticus have occurred, or that recombination has reassorted this phenotype into a variety of different genetic backgrounds.

Elicitins, holoproteins which act as inducers of hypersensitivity on tobacco, were considered as a characteristic of Phytophthora. They are also produced, along with glycosylated isoforms, by three species belonging to the related genus Pythium, Py. vexans, Py. oedochilum and Py. marsipium, while other Pythium species do not possess such proteins. Various elicitin-like sequences were determined, bringing novel features to the elicitin family, such as an histidine residue and C-terminal extensions on the deduced peptide sequences. As the unique elicitin content of these species supports a distinct location among Pythiaceae, we suggest the separation of vexans, Py. oedochilum and Py. marsipium from Pythium and consider them as linking species between Phytophthora and Pythium.

Filamentous fungi and yeasts control cytoplasmic osmotic pressure through ion accumulation and synthesis of compatible osmolytes including polyhydric alcohols (polyols), proline, and trehalose. Authoritative data on the osmotic effects of these compounds were obtained using vapour pressure deficit osmometry. All osmolytes tested were characterised by nonlinear relationships between concentration and osmotic pressure. At high concentrations larger polyols generated higher osmotic pressures than smaller ones, though differences between the osmotic effects of polyols with three, four, five and six carbon atoms were not pronounced at lower (physiological) concentrations. Proline shared a similar relationship between concentration and osmotic pressure with polyols with five carbon atoms, while at concentrations above 0.5 M trehalose generated higher osmotic pressures than any of the polyols tested. Mixtures of trehalose and glycerol boosted osmotic pressure in a synergistic rather than additive fashion. These data provide new clues to the adaptive significance of glycerol accumulation, and also suggest that complex patterns of osmolyte synthesis are not due to differences between the osmotic effects of these compounds.

Three A. bisporus strains (U1, C45 and B62) with different resistance towards bacterial blotch were infected with Pseudomonas tolaasii or with a partly purified toxin extract. In the two susceptible strains (U1 and B62), the total tyrosinase level decreased upon treatment with bacteria or the toxin-containing extract. The amount of active tyrosinase increased, suggesting an activation of tyrosinase upon infection. In the resistant strain (C45), the tyrosinase activity remained unchanged. Protease levels were found to be increased in regions of the sporocorp that were infected with the pathogenic bacterium, but not when treated with the toxin preparation, suggesting an activation of tyrosinase by a non-proteolytic mechanism. This observation was confirmed with in vitro experiments in which tyrosinase was found to be activated by a protease-free tolaasin-containing preparation.

Based on ITS and β-tubulin sequence data of 33 isolates, the newly introduced genus, Phaeomoniella was confirmed as being distinct from Phaeoacremonium (Pm.). Phylogeny inferred from DNA sequences and cultural characteristics also confirmed the species status of Pm. aleophilum and Pm. angustius, which were recently reduced to synonymy. Pm. aleophilum has an optimum growth rate at 30 °C and the ability to grow at 35°, whereas Pm. angustius has an optimum growth rate at 25 °C and does not grow at 35°. Furthermore, ITS and β-tubulin sequence data showed Pm. viticola to be indistinguishable from Pm. angustius, while a new species, Pm. mortoniae, could be distinguished from this complex.

Results of an investigation into the fungi associated with submerged wood in Lake Barrine, north Queensland, Australia are reported. Thirty-nine fungi were identified, 15 ascomycetes, 23 deuteromycetes and one basidiomycete. The frequency of occurrence and the effect of the incubation period on the recovery of fungi has also been investigated and is presented. The new species Massarina lunispora and Dactylaria lakebarrinensis, and some other notable species, are described and illustrated.

Cordyceps sinensis, the caterpillar fungus in traditional Chinese medicine, has been intensively collected from nature in recent years. As a result, the establishment of the anamorph of this species has become important for large-scale culture to meet increasing demand for medicinal use and to ease exploitation of natural populations. To establish a reliable connection between the teleomorph and anamorph stages, the ITS nrDNA sequences were sequenced from both the stroma of the telemorph and cultures of the anamorph. Observations of microcyclic conidiation were also made on germinated ascospores and compared with the anamorph in culture. Hirsutella sinensis was confirmed as the anamorph of C. sinensis by both DNA sequences and microcyclic conidiation. Two recently described species, C. multiaxialis and C. nepalensis, were shown to share identical or almost identical ITS sequences with C. sinensis. These minor variations were considered to be within the range of variation exhibited within a species, but representing different populations. Sequences from other Cordyceps species included in this study exhibited considerable differences from each other. Therefore, these three entities are probably conspecific, and the names should be regarded as synonymous. The morphological characters used in the description of the two new species are discussed. It is suggested that ITS sequences provided useful information on establishing the anamorph–telemorph connection and assisting in the delimitation of species within Cordyceps.

The formation of oxidases and peroxidases by newly isolated ectomycorrhizal fungi was examined with agar spot tests for tyrosinase, laccase, polyphenol oxidase and peroxidase as well as with the Bavendamm test. Extracellular peroxidase was released by virtually all isolates. Tyrosinase (taken as cresolase) was presumably intracellular and occurred in the majority of isolates. The strong laccase reaction was predominantly extracellular, although in some ectomycorrhizal genera the intracellular laccase seemed to dominate. Polyphenol oxidase, as the catecholase/monophenol monooxygenase complex, was found in all isolates although its detection was complicated in the presence of laccase. Lactarius and Russula and the possibly more saprotrophic Morchella showed the most intense enzyme reactions. A comparison with wood and litter decaying fungi indicated that at least some species of several ectomycorrhizal genera possess extracellular oxidative enzymes that are normally characteristic of white rot fungi. It is concluded that mycorrhizal fungi grown asymbiotically can release extracellular enzymes capable of oxidizing a wide range of aromatic compounds.

Fungi isolated from the leafy liverwort Cephaloziella exiliflora collected in Australia and continental Antarctica were compared with Hymenoscyphus ericae using internal transcribed spacer (ITS) region DNA sequences. The isolates displayed <2·1% sequence divergence within the ITS region, indicating that the endophytes from C. exiliflora are probably H. ericae. The data significantly extend the known host range and geographical distribution of H. ericae and indicate that the fungus has a global distribution.

Lignin peroxidase and laccase gene-specific PCR primers were used to screen 38 diverse basidiomycetes and xylariaceous fungi. Lignin peroxidase gene-specific sequences were obtained for basidiomycetes only and were highly divergent. Possession of laccase genes was relatively widespread among basidiomycetes, and is shown for the first time in Xylariaceae. All sequences were highly conserved with no variation resulting in changes to predicted amino acid sequence. Those basidiomycetes shown to possess lignin peroxidase and laccase genes also produced the enzyme in vitro. Conversely none of the xylariaceous fungi shown to possess laccase genes were able to do so, whilst others decolorized Poly R yet yielded no PCR amplicons.

The saprotrophic fungus Fusarium culmorum, Penicillium hordei, Rhizoctonia solani and Trichoderma harzianum and the arbuscular mycorrhizal fungus Glomus intraradices were examined for content of phospholipid fatty acids (PLFA) and neutral lipid fatty acids (NLFA). The AM fungus differed from the saprotrophic fungi especially by its content of the fatty acid 16[ratio ]1ω5 which was absent in the saprotrophs. The fatty acid 18[ratio ]2ω6,9 was the dominant fatty acid of the saprotrophic fungi while it was negligible in mycelium of G. intraradices. Specificity in content of fatty acids made it possible to quantify G. intraradices and F. culmorum simultaneously in soil. Furthermore, a compartmented growth system made it possible to study mycelial interactions in the absence of roots. We measured hyphal spread of both fungi, hyphal 33P transport of G. intraradices and sporulation of F. culmorum. The two fungi did not interact according to the parameters used in this study. We conclude that fatty acid signatures may be a valuable tool when studying interactions between AM fungi and other fungi in root-free soil.

We report the development of two new transformation systems, polyethylene glycol (PEG)-mediated transformation of protoplasts and Agrobacterium tumefaciens-mediated transformation of mycelium, for the filamentous ascomycete Venturia inaequalis. New binary vectors have been created for the latter. Although transformation was initially achieved using a PEG-mediated method, this was superseded by the A. tumefaciens-mediated approach. The advantages of the latter include: ease of the protocol, no requirement for protoplasts; higher transformation efficiency; and single-site integration. A comparison between the two transformation methods is presented.

Esteya vermicola gen. et sp. nov. isolated from infected pinewood nematodes, Bursaphelenchus xylophilus, is described and illustrated. The new species is characterized by the production of two types of conidiophores, conidiogenous cells, and conidia. The first type of conidiophore is subhyaline to greyish green, flask-shaped, apex tapering at the apex into a thin neck, sometimes crooked; the conidiogenous cells are integrated, phialidic, rarely percurrent; the conidia are hyaline, one-celled, lunate, concave, containing an endospore-like apparatus, adhesive. The second type of conidiophore is subhyaline to greyish green, cylindrical, subulate, septate, the base somewhat swollen; conidiogenous cells integrated, phialidic; conidia hyaline, one-celled, bacilloid, often forming an aggregate droplet at the apex, non-adhesive. Esteya vermicola exhibits high infectivity towards the pinewood nematode, and the potential for its development as a biocontrol agent against the pinewood nematode is briefly discussed.

Two distinct groups (A and B) of the conifer shoot blight and canker pathogen Sphaeropsis sapinea have been recognized on pine hosts in the northcentral United States. Their occurrence in a collection of isolates from much more diverse hosts and locations was studied by analysis of RAPD markers and isozymes. Seventy-nine isolates were used for RAPD marker analysis, and 37 for isozyme analysis, with 33 isolates in common. Hosts included 19 species in Pinus and species of Cedrus, Larix, Picea, Pseudotsuga, located in Africa, Australasia, Europe, and North America. Relationships among these isolates were determined using cluster analyses of presence or absence data for each amplification product or isozyme. Analyses of either RAPD marker or isozyme data placed most isolates in a group that contained previously characterized RAPD marker group A isolates. There was no strong indication of either host or geographic clustering within this highly similar, widely distributed group. Analysis of RAPD marker data placed several other isolates in a separate group that contained previously characterized RAPD marker group B isolates. This is the first report of isolates from hosts other than Pinus banksiana or P. resinosa, and from outside Michigan, Minnesota, or Wisconsin, that have been characterized as members of the RAPD marker group B.

Beauveria spp. from New Zealand were compared with isolates from other countries using morphological and genetic methods. The New Zealand isolates could be divided into B. bassiana and B. brongniartii based on conidial dimensions; isolates with conidia longer than 3 μM were classified as B. brongniartii, isolates with shorter, spherical conidia were B. bassiana. RAPD analyses using 10 random primers and scoring 330 bands divided isolates into four large groups: a heterogeneous B. bassiana/B. brongniartii group from New Zealand and other countries, a group containing only New Zealand B. bassiana, a group of only B. brongniartii from both New Zealand and overseas, and a group of other Beauveria species (B. velata, B. caledonica, B. amorpha and B. vermiconia). Restriction digestion of the internal transcribed spacer regions of the nuclear rDNA supported the existence of a genetically distinct New Zealand group of B. bassiana isolates, separating these from a heterogeneous group of B. bassiana and B. brongniartii.

Partial rDNA sequences were obtained from 26 isolates representing species of Cercospora, Passalora, Paracercospora, Pseudocercospora, Ramulispora, Pseudocercosporella and Mycocentrospora. The combined internal transcribed spacers (ITS) including the 5·8S rRNA gene and 5′ end of the 25S gene (primer pairs F63/R635) on rDNA were amplified using PCR and sequenced directly. The ITS regions including the 5·8S varied in length from 502 to 595 bp. The F63/R635 region varied from 508 to 519 bp among isolates sequenced. Reconstructed phylogenies inferred from both regions had highly similar topologies for the taxa examined. Phylogenetic analysis of the sequences resulted in four well-supported clades corresponding to Cercospora, Paracercospora/Pseudocercospora, Passalora and Ramulispora, with bootstrap values greater than 92% for each clade. Based on the results of the analysis, a new combination for Pseudocercosporella aestiva is proposed in Ramulispora, and Paracercospora is reduced to synonymy with Pseudocercospora.