Strains of Colletotrichum species derived from diseased strawberry plants from a wide geographical range were studied using mitochondrial and ribosomal DNA RFLPs, and acetyl and propionyl esterase isoenzymes. Two major species aggregates were detected, centred on C. acutatum and C. gloeosporioides respectively, with significant further subdivision. There were apparent discrepancies in the hierarchical nesting of some taxon groups based on the different molecular techniques. Strains assigned to C. acutatum fell into several rDNA RFLP groups, but there was less variation in mtDNA RFLP band patterns. There appears to be at least one probably clonal population in the U.S.A. which is also present in Europe, and a less well-defined series of groups which are at least sometimes sexually reproducing. Strains assigned to C. fragariae were found not to have distinct rDNA band patterns from the teleomorph linked strains studied, which had been referred to as C. gloeosporioides. They did vary in this respect from C. gloeosporioides associated with Citrus, its type host. It was, therefore, concluded that all the strains studied with cylindrical conidia should be placed within C. fragariae, which is confirmed as separate from C. gloeosporioides and recognized as a holomorphic taxon. Nevertheless, a separate asexually reproducing infraspecific group was distinguishable using mtDNA information. An epitype is designated for C. fragariae.

The extracellular subtilisin-like protease activity of several fungal pathogens of nematodes, insects and plants was recorded after batch cultivation. Nematophagous and entomophagous isolates of Verticillium, Paecilomyces, Beauveria and Metarhizium produced Suc-(Ala)2-Pro-Phe-pNA hydrolysing enzymes that differed in serological properties based on Western blot analysis with polyclonal antibodies. The antibodies used were raised against the main subtilisin-like proteases from one species from each of the four genera. From each strain of V. chlamydosporium tested, between one and four isoforms with different pI values were separated by isoelectric focusing and visualized by enzymoblots. The occurrence of multiple isoforms with unique N-terminal sequences in single strains might suggest the presence of subtilisin gene families. Using as a probe a fragment of the Pr1 gene from M. anisopliae, RFLPs were observed that confirmed qualitative differences between subtilisin-like genes within and between species. In contrast to these pathogens of invertebrates, plant-pathogenic species of Verticillium did not produce subtilisin-like proteases, nor were homologous genes detected. Such activity, however, and the corresponding genes, were detected in species weakly pathogenic to plants, or saprotrophs.

The objective of the study was to develop methods for the specific and rapid identification of Tuber spp. to aid ecological and taxonomical investigations of Tuber spp. and ectomycorrhizal fungi in general. Antisera raised against Tuber melanosporum, T. magnatum, Boletus edulis and Tricholoma matsutake and monoclonal antibodies produced against T. melanosporum were used to develop various immunological assays such as ELISA, Dot-blot and Western blot. A simple squash Dot-blot was used to visualize mycorrhizal infection of inoculated host plants grown in tube cultures and experimental truffières.

Most antisera reacted strongly with homologous antigens from ascomata or mycelia and mycorrhizal root-tips. Their specificity allowed differentiation between Tuber spp. and other ectomycorrhizal fungi. Differentiation among Tuber spp. was possible by Western blot but not by ELISA or Dot-blot assay. The results suggested that specificity of the antisera was confined to genus level. In two cases specificity was increased by absorption with cross-reactive antigens.

Eleven monoclonal antibodies were produced against T. melanosporum. Two were directed against proteinaceous material, the others probably against various carbohydrate determinants. Unfortunately they could not be used for differentially recognizing T. melanosporum as they all cross-reacted at least with extracts of four other ectomycorrhizal fungi.

During growth of Agaricus bisporus fruit bodies the amount of active tyrosinase increased. The amount of active tyrosinase can be related to the degree of browning, as opposed to the fully activated tyrosinase level. Isoelectric focusing revealed that active and latent tyrosinase isoforms having different isoelectric points could be distinguished. The isoform composition was dependent on the tissue and developmental stage. In the later developmental stages new active isoforms appeared.

Leaves of members of the Cruciferae influence the germination of the entomogenous fungus Metarhizium anisopliae. The percentage germination of conidia on reconstituted epicuticular waxes of oilseed rape, Chinese cabbage, and turnip was influenced by the solvent used, the plant species, and the age of the leaf. The epicuticular waxes contain a mixture of stimulatory and inhibitory compounds. Germination was more rapid and greater on the surfaces of dewaxed than intact leaves suggesting that epicuticular waxes contain fungistatic compounds and/or act as a barrier to the leaching of nutrients. Surface leachates and soluble extracts of leaves increased percentage germination of conidia and the virulence of M. anisopliae to the mustard beetle, Phaedon cochleariae. Plant extracts stimulated germination more than yeast or starch extract. Formulation of conidia in leachates or leaf extracts increased the virulence of M. anisopliae. Germination increased on insect cuticle that were pretreated with leaf extracts/leachates, suggesting that the insect cuticle will adsorb or sequester nutrients.

Similar small-statured, frequently excentrically stipitate species of Gymnopilus and Galerina occurring in the same habitat in Australia appear to form a continuum morphologically. As a result of detailed examination of field and microscopic characters, and an analysis of their styrylpyrone pigment content by thin layer chromatography, a satisfactory distinction can be made between similar species of the two genera. Three new species of Gymnopilus subgenus Gymnopilus, G. corticophilus, G. tomentulosus and G. tasmanicus are described and compared with G. eucalyptorum, G. tyallus and G. moabus. These six species are also compared and contrasted with three excentrically stipitate Galerina species, Ga. eucalyptorum and two new species Ga. incrustata and an unusual pink Ga. bulliformis.

This paper describes the use of a monoclonal antibody-based ELISA for the quantification of the effects of Trichoderma harzianum on the saprotrophic growth dynamics of Rhizoctonia solani in unsterile compost-based microcosms. Quantification of R. solani was based on the immunological detection of a constitutive, extracellular, water soluble glycoprotein antigen (the copper-containing enzyme catechol oxidase) which is secreted by actively growing mycelium of the fungus only. Extracts derived from lyophilized mycelium (FDM) were used as a quantifiable and repeatable source of the antigen in order to prepare calibration curves that accounted for incomplete extraction of the antigen from compost samples. These curves were used to convert the absorbance values of extracts in ELISA to FDM biomass equivalents, which allowed comparisons of the saprotrophic growth dynamics of R. solani to be made in the presence and absence of T. harzianum. The high pH (9·6) of the buffer used to extract the antigen from microcosm samples also resulted in the extraction of humic components of the compost which interfered with the sensitivity of the assay. A protocol, based on the determination of optimal ELISA absorbance[ratio ]extract dilution ratios, was used in order to reduce the interference and improve the sensitivity of the quantitative assay.

Isolates of Pisolithus and Scleroderma species from different northern temperate and tropical geographical regions were subjected to analyses of pure culture morphology, colony growth rates, isozyme (allozyme) variation and ribosomal DNA (rDNA) restriction fragment length polymorphisms (RFLPs). Cultural characteristics enabled clear species separation of isolates and together with growth rates suggested geographically-linked intraspecific variability in the Pisolithus populations. Combined or method-specific hierarchical cluster analyses of allozyme polymorphisms and RFLPs of the fungal internal transcribed spacer (ITS) and intergenic spacer (IGS) sequences confirmed the Scleroderma species groupings and considerable geographical and host-linked variation in the Pisolithus population. Isolates of Pisolithus from the Philippines were genetically very homogeneous and distinct from less related isolates from Europe, Scandinavia and North America. Based on the ITS–RFLP and isozyme polymorphism data, the isolates investigated probably represent four different ‘species groupings’ which supports similar findings from recent taxonomic and genetic studies of Australian Pisolithus species.

Recent field work on smut fungi in Cuba yielded one new species and, among many new records, several poorly known species which are described and illustrated. The new species, Cintractia cubensis on Rhynchospora microcephala, is characterized by rather large, dark, and finely foveolate teliospores which can germinate with basidia of only two basidial cells. The poorly known C. samanensis was found on the new host Rhynchospora fascicularis ssp. fascicularis. Entyloma guaraniticum on Bidens pilosa differs from E. bidentis on the same host by thick-walled teliospores embedded in the mesophyll of leaves deforming them. Spores of E. bidentis are smaller and do not deform the leaf. Sphacelotheca everhartii on Andropogon virginicus, S. microspora on Paspalum notatum, and S. panici-leucophaei on Trichachne insularis are transferred into Sporisorium.

The endophytic mycobiota of healthy twigs and the assemblage of species associated with twig lesions of Eucalyptus globulus and E. grandis planted at the same site in the central west region of Uruguay was examined. Twig segments from E. grandis and E. globulus were plated on 2% malt agar. The diversity of endophytes isolated was low, as was the number of host-specific species. E. globulus endophytes of healthy xylem were different from the colonizers of cracked lesions and healthy bark. Conversely, in E. grandis characterized by black spots, the main difference in species composition was between xylem and bark. Cytospora chrysosperma was isolated from healthy bark and symptomatic twigs of E. globulus, suggesting that symptomatic tissues, such as cracks produced under drought were favourable to saprotrophic expansion.

The ability of six fungi to solubilize natural-occurring gypsum was tested in vitro. The solubilization process was monitored by the production of a clear zone (halo) around or underneath the growing colony on Czapek–Dox agar containing 0·5% (w/v) gypsum (CaSO4.2H2O). Aspergillus niger, Penicillium bilaii, P. simplicissimum and Paxillus involutus displayed differential solubilization activities depending on the supplemented nitrogen source. Colonies grown on nitrate-containing medium showed the ability to solubilize gypsum, but when ammonium (at equivalent nitrogen) was used there was a significant reduction in solubilization. It was found that liquid cultures of nitrate-grown fungi produced substantial amounts of oxalic acid, whereas in ammonium-containing medium oxalic acid was only detected in small amounts. The production of citric and gluconic acid under these experimental conditions was low in both media, although the involvement of citric acid in gypsum solubilization is possible. Coriolus versicolor and Phanaerochaete chrysosporium did not exhibit any solubilization activity in nitrate- or ammonium-containing medium. Additionally these two fungi excreted small quantities of oxalic acid in both media with no citric acid being produced in liquid medium. Concomitant with the solubilization process and inside the clear solubilized zone, A. niger, Pax. involutus and P. bilaii produced crystals of differing shapes and abundance depending on the fungal strain. No crystals were produced by P. simplicissimum. These crystals were identified as calcium oxalate based on HPLC analysis and energy-dispersive X-ray microanalysis. Abundance of these crystals was found to be correlated with both oxalic acid production and the acidity of the medium. It is concluded that gypsum solubilization was predominantly achieved by both oxalic acid, which was accompanied by formation of calcium oxalate crystals, and citric acid production rather than the acidity of the medium. The results are discussed in relation to the significance of such an activity in agricultural applications, e.g. land reclamation, as well as the possible roles played by these fungi in mineral cycling.

The responses of a number of wood-rotting fungi to culture filtrates of Phellinus contiguus strain GWR, which contained a factor active in self-induction of precocious fruiting, were tested by means of a bioassay. Fruiting of a second isolate of P. contiguus was stimulated by active filtrate and the responses of single basidiospore progeny of GWR ranged from nothing to full fruiting. In similar bioassays culture filtrates from 13 out of 16 single spore progeny stimulated fruiting in GWR but production of active filtrate did not correlate with capacity to respond. Other wood-rotting fungi (two other strains of P. contiguus, P. occidentalis, P. ferruginosus, P. igniarius and P. pini, Phylloporia ribis and Trametes versicolor) produced filtrates capable of inducing fruiting in P. contiguus strain GWR. P. pomaceus, lacked inducing activity and the inactive filtrate of Coniophora puteana was also inhibitory to mycelial growth. It is concluded that production of the factor inducing fruiting in P. contiguus is not species specific.

Anastomoses between hyphae, leading to both successful cell fusions and death of fused cells (vegetative incompatibility) were observed by video microscopy. Anastomosis was seen only to occur between tip cells from side branches, never main runner hyphae, and tip to side fusion was never observed. Perfect hyphal fusion was only observed following pre-contact tropism between the hyphae involved. The time taken for the process of cell wall dissolution and reformation following contact was 15 min.

In experimental microcosms, three Glomus spp. were subjected to heating to over 200°C at the soil surface and 70° at 5 cm to determine the effect of fire on survival of arbuscular mycorrhizal fungi. Heating reduced the quantity of propagules surviving at the soil surface and the effect declined with depth. While all propagules are likely to be affected by heat, we argue that the hyphal network is most severely disturbed and probably responsible for declines in density of fungi observed in the field following fire.

Species of Gondwanamyces are unusual amongst the ophiostomatoid fungi in that they are associated with the infructescences of Protea in South Africa. These fungi are distinguished from other ophiostomatoid genera by their Knoxdavesia anamorphs. Knoxdavesia spp. are peripherally similar, but distinct from Stachybotrys and Phialocephala. They are, however, morphologically identical to Custingophora. Custingophora olivaceae, was isolated from compost in Germany, a niche very different from that associated with fungi from Protea spp. The similarity of Custingophora and Knoxdavesia is such that they cannot be distinguished morphologically. The notion that Gondwanamyces might represent a teleomorph for Custingophora is intriguing. To determine whether an anamorph–teleomorph connection exists between Knoxdavesia and Custingophora, we determined the sequence of approximately 1100 nucleotides from the large subunit (LSU) ribosomal RNA gene. Results suggest that species of Gondwanamyces and C. olivaceae are phylogenetically related. This, as well as their morphological similarity suggests that Gondwanamyces and C. olivaceae have a shared ancestry. They are, however, sufficiently different that Gondwanamyces is probably not a teleomorph for Custingophora olivaceae.

The aim of this study was to compare the ectomycorrhizal community structure in spruce stands treated with different levels of dolomite lime. ITS-typing of randomly sampled mycorrhizas, without prior morphotyping, was used. Sixteen different ITS-RFLP patterns were found. By comparison with the available reference material, nine of these could be identified at least to genus level. Variation within treatments was large and statistically there were no significant differences between treatments with respect to specific taxa. A similarity assessment did, however, show less similarity between control and high dolomite (HD) than between low dolomite (LD) and either control or HD, suggesting a shift in the community structure as a result of the treatment. The fruitbody production at Hasslöv had been recorded in a different study during 1985–92 and 28 ectomycorrhizal species had been found in the treatments examined in the present study. Except for three species, all were present in the reference material used for identification of the ITS-types. Only three species, Russula ochroleuca, Lactarius necator and Boletus chrysenteron were found as both mycorrhizas and fruitbodies. There were five taxa which occurred on over 5% of the screened roots. These were Thelephora terrestris, 21.5%; Tylopilus felleus, 13%; Tylospora fibrillosa, 13%; and two unidentified taxa, 10% and 6%. Together these five taxa colonized over 60% of the mycorrhizal roots investigated, yet none of them was found among the fruitbodies recorded in the above-ground study. Despite the differences in taxa found below and above ground, similarity tests between treatments using the fruitbody data also revealed a shift in community structure.

Using leaf disc techniques, nine isolates of the mycoparasite Sphaerellopsis filum were examined for pathogenicity to Melampsora epitea, the most important species of rust in renewable energy willow plantations. Five isolates were derived from Melampsora spp. on willows and poplar, one from Puccinia coronata on couch grass, two from Phragmidium violaceum on blackberry and one from Triphragmiopsis laricinum on larch. Two inoculation experiments were carried out. In the first, S. filum and rust were applied simultaneously on to leaf discs of Salix burjatica cv. Korso. In the second, leaf discs were inoculated with rust initially, then the resulting rust uredinial pustules were inoculated with S. filum. In both experiments, all S. filum isolates from Melampsora spp., and that from P. coronata, developed pycnidia on willow rust. No pycnidia were produced from the other three isolates. Among isolates which produced pycnidia, the frequency of rust pustules colonized by S. filum and suppression of rust spore production differed markedly. In the first experiment, 55–99% pustules were colonized and rust spore production was suppressed by 64–98%. In the second, the proportions were 33–97% and 53–73%, respectively. Suppression of rust sporulation was closely correlated with the frequency of rust pustules bearing S. filum pycnidia. The results suggest that S. filum is composed of pathogenically specialized populations differing widely in their virulence.