The presence of the 1,8-dihydroxynaphthalene (DHN) melanin biosynthesis pathway was demonstrated in several sapstain fungi including Ceratocystis and Ophiostoma, using both chemical inhibitors and molecular techniques. The inhibitor compounds tricyclazole and carpropamid effectively reduced pigmentation at low concentrations in all tested fungal species, but also lead to growth inhibition at higher concentrations. The inhibitor cerulenin prevented fungal growth in all tested fungi at all tested concentrations, likely due to its inhibitory effect on another enzyme, the metabolically critical fatty acid synthase. Partial DNA sequences for the gene encoding scytalone dehydratase (SD) were obtained from species of Ceratocystis and Ophiostoma and found to have homology with known respective DHN-SD gene sequences. Sequence analysis of the partial SD amino acid sequences showed greater than 80% similarity among the sapstain species, and corresponded well with known phylogenies of sapstain fungi based on rDNA sequences. Aside from the work carried out on the isolate O. floccosum 387N, this is the first known documentation of the melanin pigmentation pathway used by species of the sapstain fungi Ceratocystis, Leptographium and Ophiostoma. Furthermore, since no fungus has ever been found, to our knowledge, to have more than one melanin synthesis pathway, we can state that these species are likely only to use the DHN pathway for melanin production.

A new ascomycete Ascomauritiana lignicola gen. et sp. nov. is described and illustrated from a specimen collected on submerged wood in Mauritius. The taxon is compared with species of Arnium, Melanospora and Pustulipora, unitunicate ascomycetes having brown ascospores with germ pores and with species of Argynna, Caryospora, Lepidopterella and Zopfia. Ascomauritiana is characterized by large 5-septate, brown ascospores with polar germ pores and clavate, 4-spored asci that lack an apical ring and deliquesce early. Its taxonomic placement in the Ascomycetes incertae sedis is discussed.

Cercospora caricis is being considered as a bioherbicide agent for use against purple nutsedge (Cyperus rotundus), one of the world's worst weeds. However, first its efficiency must be improved, for example by genetic transformation. By optimizing physical and biological parameters, the particle gun acceleration method (biolistics) has been adapted to transform mycelial cells of C. caricis. Two genes were expressed in C. caricis by biolistic transformation. The β-glucuronidase gene (GUS) fused to the GDP1 promoter of Cochliobolus hetrostrophus and the hygromycin B resistance gene under control of the PtrpC promoter of Aspergillus nidulans. Although the transformation frequency was not high, all transformants were stable when they were propagated on a selective medium after eight subsequent transfers.

Ascotricha hispanica sp. nov. is described and illustrated. It is characterized by ostiolate ascomata with a translucent peridium and subdichotomously branched setae, cylindrical asci and oblate ascospores with an equatorial germ slit. It is compared with related species.

Sixteen highly branched (colonial) mutants of Fusarium graminearum A3/5 were isolated at the end of 11 Quorn® myco-protein production fermentations. These ranged from the highly branched C134-3 to the sparsely branched C145, which was similar to A3/5 in liquid culture. Although allelic complementation was observed to occur between some of the mutants, heterokaryon analysis revealed that all the highly branched mutants belonged to a single complementation group. Mixed cultures of A3/5 and six of the colonial mutants were grown in glucose-, ammonium-, magnesium- and sulphate-limited chemostat culture. One mutant (C153) had a selective advantage over A3/5 in all nutrient limitations tested; four mutants (C134-1, C134-3, C137-1, and C135) had a selective advantage over A3/5 in all except one nutrient limitation; and one mutant (C139) had a selective advantage over A3/5 in magnesium-limited chemostat culture only. Four mutants (C134-3, C139-1, C153 and C135) had a selective advantage over A3/5 when the dilution rate was increased above the critical dilution rate (0·22 h−1) and nutrients were present in excess. These results suggest that the growth conditions in the Quorn® production plant (which is operated as a glucose-stat) favour mutations that confer general growth rate advantages, but these mutations may result in growth disadvantages when nutrient limitations are imposed. As all of the mutations appear to occur in one gene or gene cluster, the differing patterns of selective advantage/disadvantage for the six mutants studied suggests that regulatory genes may also be involved or that different sites of mutation can lead to a variety of pleiotropic effects.

3- and 7-hydroxyflavone and their acetic acid esters were tested against Cladosporium herbarum and Penicillium glabrum for antifungal activity. The effect of the hydroxylated flavones was relatively low whereas the ester derivatives were substantially more active.

Prosthemium betulinum and Pleomassaria siparia are found in the same sites on birch branches. Single spore cultures of P. siparia produced conidia similar to those of P. betulinum. Restriction analysis of 18S rDNA did not differentiate between P. betulinum and P. siparia. Random amplified microsatellite fingerprints showed a high amount of variation, which was not explained by the origin of cultures. We conclude that P. betulinum is the anamorphic state of P. siparia.

We isolated ascospores and conidia of fungi associated with leaf spots common in birch leaves, and prepared mycelial cultures from them. The taxonomic positions of the fungi were determined by analysing morphological characteristics with photomicroscopy. The relationship between the teleomorph and anamorph was tested using random amplified microsatellite fingerprints, in which the variation was not explained by the origin of isolates (e.g. ascospores or conidia). This suggested that the ascospores and conidia would have been produced by the same biological species. In pathogenicity tests birch leaves inoculated with mycelia derived from ascospores developed spots showing that the fungus could be the cause of the leaf spots. The anamorph was isolated from the developing spots. Based on these results and on review of the literature we concluded that the causative agent of the leaf spot disease of birch in Finland is Pyrenopeziza betulicola, the anamorph of which belongs to Cylindrosporium.

A microsatellite-enriched library was constructed from genomic DNA of Phialophora gregata f. sp. sojae, the causal agent of soybean brown stem rot. Specific oligonucleotide primer pairs were designed to flank individual microsatellite loci, and used in PCR to detect polymorphisms among 118 contemporary and archival isolates of P. gregata from several countries, which represent two distinct, but sympatric populations delineated by rDNA genotypes. In general, low levels of genetic variation were observed and manifested in two ways. First, the number of polymorphic loci was low. Among 24 microsatellite loci screened, four polymorphic loci were detected, and two of them were located on the same clone. Second, the number of alleles in the polymorphic loci was low. Only two alleles were observed in each polymorphic locus. Alleles of the polymorphic microsatellite loci were invariant within, but different between, the two populations of P. gregata. From all evidence available, P. gregata f. sp. sojae exhibits several genetic features characteristic of clonal genetic structure, namely widespread distribution and stability of identical genotypes, absence of recombinant genotypes, and correlation of independent genetic traits including three sets of molecular markers, defoliating and nondefoliating pathotypes, and differential pathogenic fitness.

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.

Melanographium palmicolum sp. nov. is described and illustrated based on a specimen collected on a decaying rachis of Archontophoenix alexandrae in Hong Kong. It differs from other previously described species of Melanographium by its moderately dense and widely divergent conidiophore fascicles, and the shape and size of its conidia. A key to the eight species currently accepted in the genus is provided, based on the literature.

Eight new species of Anthostomella, A. acuminata, A. applanata, A. caffrariae, A. colligata, A. meerensis, A. palmae, A. raphiae and A. spiralis, are described from South Africa. They are compared with similar species and illustrated with differential interference contrast photomicrographs.

Puccinia menthae is highly variable, with several varieties and variants within varieties. Two principal groups of races, nominated spearmint rust and peppermint rust, have been recognized according to their host range on commercially-important Mentha species, yet both belong to the same variety, P. menthae var. menthae. Ten collections of P. menthae teliospores from four Mentha species in Victoria, Australia, were examined using light microscopy and SEM. The teliospores from M. spicata, M.×cordifolia and M. suaveolens, all hosts to spearmint rust, were verrucose with two equally-sized cells, whereas those from M.×piperita, host to peppermint rust, were generally smooth-walled, and the apical cell was larger and thicker-walled than the basal cell. Fifteen isolates of P. menthae collected from four Mentha species in Victoria were assessed for genomic variation using RAPD analysis and PCR-generated length polymorphism of the ITS region of rDNA. Six out of 113 RAPD primers amplified reproducible marker profiles, 58 polymorphic bands were scored and simple matching distances were computed between the isolates. UPGMA cluster analysis was used to produce a dendrogram and non-metric multi-dimensional scaling to produce a two-dimensional map of the isolates. The spearmint rust and peppermint rust isolates clustered into two non-overlapping groups, providing good evidence that there is limited gene flow between them. All isolates had the same sized ITS fragments. The taxonomic implications of these results are discussed and it is suggested that the peppermint and spearmint rusts should be accorded separate varietal or specific status.

Species of Gloniella, Glonium and Gloniopsis from southern South America were studied. A new fungus Glonium colihuae sp. nov., with hysterothecia is described from Argentina, Patagonia; Glonium chusqueae is synonymized with Gloniella typhae; Gloniopsis argentinensis and Glonium costesi are validated, and some comments on the taxonomy and occurrence of Gloniopsis araucana, G. praelonga, Glonium abbreviatum and G. cumingii are presented.

Ephelis japonica and E. oryzae are biotrophic fungi that form systemic epiphytic associations with warm-season grasses. Ephelis has been recognized as the anamorph of Balansia and Myriogenospora, and a synanamorph of Atkinsonella; all three genera belong to Clavicipitaceae (Ascomycota). The teleomorphs have not been detected for E. japonica and E. oryzae. Balansia oryzae had been regarded as the teleomorph of Ephelis oryzae, however, this teleomorphic name is not validly published for the teleomorph alone (Art. 59·6). We analyzed the sequences of the ITS1, ITS2 and 5·8S rDNA regions of 33 Ephelis isolates from Japan, Korea, China, Nepal and India. Phylogenetic relationships of these isolates were analyzed, together with other clavicipitaceous fungi for which sequences were obtained from GenBank. All Asian Ephelis isolates formed a single cluster, which comprised two subgroups. One subgroup had strong affinity with B. andropogonis, an epibiont of grasses in tropical regions of Asia. The second subgroup had strong affinity with B. discoidea, an epibiont of grasses in the Americas. A close relationship was also shown to B. asperata, another epibiont of grasses of tropical regions of Asia. Our results do not justify the separation of Asian Ephelis epibionts into E. oryzae and E. japonica. E. japonica, established in 1904, ten years prior to the name E. oryzae, is the appropriate name for the asexual Ephelis epibionts of warm season grasses of Asia.

A numerical taxonomic analysis of 272 specimens and strains of Leptoxyphium, Caldariomyces and Aithaloderma was undertaken. Analysis was carried out on two data sets: characters from the form of the hyphal cells, shape of conidiomata and the presence of ascospores were coded and 34 binary variables encoded for all strains; 29 living cultures of Leptoxyphium and Caldariomyces were characterized for colony morphology, micromorphology and physiological characters encoded as 168 binary variables. Cluster analysis, principal components analysis and discriminant analysis was carried out. Three main groups are identified. A group comprising mainly Aithaloderma specimens is most clearly resolved. Another group comprises a mixture of Caldariomyces and Leptoxyphium specimens. The third group comprised mainly Leptoxyphium specimens with some Aithaloderma specimens. Physiological characters provide no evidence for the separate recognition of Caldariomyces and Leptoxyphium.

Five murine hybridoma cell lines secreting monoclonal antibodies (MAbs) with similar binding specificities were raised to extracts from cyclamen leaves colonized with Ulocladium atrum, a saprotrophic fungus used for biological control of Botrytis cinerea. One of the cell lines produced a MAb, UA–PC3, which was used to develop a quantitative ELISA to determine the biomass of U. atrum in extracts from colonized leaves. The antigen, which is water soluble, was present on the surface of conidia and hyphae and was secreted into culture fluids. Production of the antigen was much greater in vivo than in vitro. Germination of conidia took place in saline buffers at 4 °C after 6 h. To avoid amplification of the antigen in biomass assays of the fungus in extracts from sporulating tissues, coating of microtitre wells in ELISA was reduced to 1 h.

Many small (temporary) collections of fungi maintained by plant pathologists during their research receive inadequate attention to ensure stability. Maintaining collections of fungi in pure and viable conditions, minimising physiological and morphological changes is, however, a necessity. The objective of this study was to find preservation techniques for three Rosellinia isolates used in our plant pathogenic research. Various inert and nutritious carriers, solid as well as liquid, were used to test their suitability for conserving these Rosellinia isolates. Different cryoprotectants, cooling rates and thawing rates were tested to optimise liquid nitrogen storage procedures. Survival and/or growth rate were assessed over time. Rosellinia bunodes was the most difficult to store with survival not exceeding six to nine months using traditional storage methods in mineral oil and silica gel. Storage of Rosellinia necatrix and Rosellinia pepo was successful for periods up to at least 16 months in several carriers and for up to two years for R. necatrix in silica gel. Storage in liquid nitrogen proved no problem for R. necatrix or R. pepo with a 100% survival in all cases, although radial growth rates after recuperation were affected by cryoprotectant and thawing rates. Storage of R. bunodes was more difficult and survival as well as growth rates were affected by cryoprotectant and thawing rates. Cooling rates did not affect radial growth in any of the isolates. The results showed that development of a generalised procedure for storage of our Rosellinia species was not possible and successful storage protocols had to be developed for individual isolates.

We analysed 40 isolates of species Armillaria. borealis, A. cepistipes, A. gallica, A. mellea, A. ostoyae and A. tabescens, mostly collected in the Czech Republic, by PCR-RFLP of the ITS rRNA genes using the restriction endonucleases AluI, HinfI and MboI. Restriction fragments were analysed by ion-exchange high performance liquid chromatography which proved to be more useful informative, and less time-consuming than classical electrophoresis on agarose gel. The HPLC method enabled detection of some heterozygous strains. HinfI discriminated between all six species. Ten isolates were sequenced to confirm changes in restriction sites found by restriction analysis. Cluster analysis based on the restrictions patterns of restriction endonucleases AluI and HinfI divided the analysed species into three groups. The first and the most distant group contained all A. mellea isolates, the second group was formed by A. tabescens and the third group contained species A. borealis, A. cepistipes, A. gallica and A. ostoyae. The A. tabescens group was very homogenous regardless of the origin of isolates (Czech Republic, France and Finland).

The effect of carbon source on the production of a single extracellular β-glucosidase by Acremonium persicinum was investigated using fast protein liquid chromatography. The enzyme was detected in the medium during growth of the fungus on a wide range of β-glucans, particularly those containing a high proportion of (1→6)-β-linkages. While growth of A. persicinum on gentibiose, cellobiose and laminari-oligosaccharides moderately increased β-glucosidase production, growth on sophorose provoked 10-fold greater levels of this enzyme in the culture medium. Levels of the β-glucosidase were minimal in the presence of even low concentrations of glucose, sucrose, fructose or galactose. The results are consistent with the extracellular A. persicinum β-glucosidase being an inducible enzyme, subject to carbon source control by readily metabolizable sugars, with sophorose possibly directly inducing its synthesis.