Three polypeptides with manganese superoxide dismutase (MnSOD) activity were found in mycelium, zoospores and germinated cysts of Phytophthora nicotianae. Their relative molecular weights in non-denaturing gels were approximately 34.5, 36 and 50 kDa. No evidence for the presence of either iron or copper/zinc SODs was detected at any of the developmental stages examined. The level of activity of the MnSOD polypeptides was similar in mycelia and spores. Degenerate PCR was used to amplify partial genes of two different MnSODs, designated PnMnSOD1 and PnMnSOD2, from P. nicotianae. Southern blot analysis indicated that there are two PnMnSOD1 genes in the P. nicotianae genome. Full length sequence was obtained for one of these genes, PnMnSOD1a, from a P. nicotianae bacterial artificial chromosome (BAC) library. RNA blots probed with PnMnSOD1 showed similar levels of expression in vegetative and sporulating hyphae, lower levels in germinated cysts and no detectable expression in zoospores. PnMnSOD1a had 96%, 97% and 99% amino acid identity with homologous genes from P. ramorum, P. infestans and P. sojae, respectively. The second gene cloned from P. nicotianae, PnMnSOD2, had only 38% amino acid identity with PnMnSOD1a and was homologous to MnSODs that possessed an N-terminal mitochondrial targeting sequence in Phytophthora species and other eukaryotes. Southern blots indicated that there is one copy of PnMnSOD2 in the P. nicotianae genome. PnMnSOD2 was expressed at similar levels in mycelia and germinated cysts but PnMnSOD2 transcripts were not detectable in zoospores.

Two main taxa of Phomopsis associated with Phomopsis cane and leaf spot disease of grapevine have been recognized in Australian vineyards. The present investigation identifies Diaporthe viticola, recorded for the first time since 1867 on grapevines, as the teleomorph of Taxon 1. Perithecia of D. viticola were found on 1 and 2 year old canes of cvs Chardonnay, Shiraz, Riesling, Cabernet and Pinot Noir in many vineyards in southern Australia. The teleomorph was induced in vitro on oatmeal agar and on sterilised segments of grapevine cane inoculated with isolates of Phomopsis Taxon 1.

To understand the mechanism of wood discolouration employed by the staining fungus Ophiostoma floccosum, a gene involved in dihydroxynaphthalene (DHN) melanin biosynthesis was cloned from this organism and its function was examined. Degenerate oligonucleotide primers were designed according to conserved regions of hydroxynaphthalene (HN) reductases and used to PCR-amplify a 380 bp fragment from genomic DNA of O. floccosum. The amplified product was used as a probe to screen an O. floccosum genomic phage library. A genomic clone containing a full-length HN reductase gene was retrieved and a total of 1681 bp of its nucleotide sequence was determined. The determined sequence contained 673 bp of 5′ untranslated sequence, 807 bp of putative open reading frame (ORF) encoding a protein of 269 amino acids and 197 bp 3′ untranslated sequence. The ORF contained a 76-bp intron. Based on the similarity of the inferred amino acid sequence to other known fungal HN reductases, the cloned O. floccosum gene was considered an HN reductase gene. Disruption of the O. floccosum reductase gene was unsuccessful due to integration anomalies during homologous recombination. As an alternative, we complemented an HN reductase deficient buf mutant of the rice blast fungus Magnaporthe grisea by introducing the cloned O. floccosum reductase gene using hygromycin B resistance plasmid pCB1004. The complemented M. grisea buf mutants produced a black pigment like a wild type strain, indicating that the O. floccosum reductase is functionally homologous to other fungal HN reductases. These results suggest that O. floccosum uses the DHN pathway for pigmentation.

Conioscypha is reviewed, with a discussion on generic concepts and conidiogenesis. A new genus, Conioscyphopsis, is described from submerged wood in Australia, and a key to species in both genera is provided. Conioscyphopsis australiensis sp. nov. is similar to species of Conioscypha in lacking conspicuous conidiophores, but its dematiaceous, unicellular conidia are produced from ampulliform conidiogenous cells borne on semi-immersed hyphae. Conioscyphopsis differs from Conioscypha mainly in its conidiogenesis. Conidiogenesis in Conioscypha is intermediate between ‘annellidic’ and ‘phialidic’, single conidia being produced endogenously within indeterminate, percurrently proliferating conidiogenous cells. In Conioscyphopsis, conidiogenesis is ‘enteroblastic-phialidic’, solitary conidia being produced exogenously from determinate, but percurrently regenerating conidiogenous cells.

DsRNAs were detected in 36 of 49 Monilinia fructicola isolates from stone fruit orchards in New Zealand. The dsRNA profiles were highly variable, even between isolates from a single tree. Comparison of pathogenicity on detached fruit, in vitro growth rate, and sporulation of 14 isolates showed no obvious correlation with presence of dsRNAs. Partially purified extracts from four isolates were examined for the presence of virus-like particles by transmission electron microscopy. One isolate contained 45 nm isometric particles similar in appearance to totiviruses and partitiviruses. A second isolate contained 200–250×25 nm rigid rods similar in appearance to the plant pathogenic tobraviruses and furoviruses. This is the first report of the presence of viral-like agents in the brown rot fungus Monilinia fructicola.

A new species of Ascobotryozyma, A. cognata sp. nov. (anamorph Botryozyma cognata), was isolated from beetle galleries in Idaho, USA. A. cognata was found on the surface of free-living nematodes, Panagrellus dubius, collected from galleries created by the long-horned beetle Saperda calcarata in Populus (aspen), and the weevil Cryptorhynchus lapathi in Salix (willow). A. cognata isolates were collected from similar habits and in relatively close proximity to those of A. americana, the only species described from North America. The recognition of A. cognata as a distinct species was supported by morphological and molecular data. Thallus cells of A. cognata were significantly shorter than those of A. americana. Low DNA reassociation values, notably different randomly amplified polymorphic DNA (RAPD), inter-sequence simple repeat (ISSR), and amplified fragment-length polymorphic (AFLP) fingerprints, and sequence divergence in both the D1/D2 domain of the nuc-LSU rDNA and an additional unidentified region were all consistent with the recognition of a new species.

The ultrastructure of the septal pore cap (SPC) of Asterodon, Asterostroma and Coltricia were examined to establish the taxonomic position of these genera. Asterostroma has dolipores with perforate SPCs and is classified in the Lachnocladiaceae. In contrast, Asterodon and Coltricia have dolipores with imperforate SPCs and belong to the Hymenochaetaceae. Other selected species of genera belonging to the Hymenochaetaceae like Hydnochaete, Coltriciella, Inonotus, Onnia, and Cyclomyces also contained imperforate SPCs. Coltriciella, Inonotus and Cyclomyces moreover presented a lamella of endoplasmic reticulum above the imperforate SPC after chemical fixation. Such a lamella could rarely be observed in Coltricia only after high-pressure freezing and freeze substitution. Cryofixed fungal cells of Cyclomyces and Coltricia showed differences in the architecture of the matrix of the SPC. Coltricia showed a more layered matrix structure than the SPC of Cyclomyces. In addition, transmission- and scanning electron microscopy revealed an indent in the centre of the imperforate SPC of Cyclomyces, indicating a reduced thickness, and resulting into a tented profile in cross-sections.

Single-strain biocontrol agents often look promising when tested against single-strain pathogens. When confronted with a biodiverse field population, however, biocontrol is inconsistent. This study implies that biodiversity of the crown rot pathogen Colletotrichum musae leads to strain discrimination by antagonists which results in variable biocontrol of the disease. Broad host-range mycoparasites of fungi of the crown rot disease complex of banana (C. musae, Fusarium moniliforme and Botryodiplodia theobromae) which attacked at least two of the pathogen genera, exhibited significant differences in aggression against different strains of C. musae, the main pathogen. Antagonists acted via several different mechanisms, i.e. parasitism, antibiosis or competition, simultaneously. The relative importance of each mechanism differed with the individual mycoparasites. Strain discrimination was correlated to differential susceptibility to one or more minor mechanism(s). When as many as four antagonists were combined into one inoculum, they complemented rather than antagonised each other. Biocontrol efficiency increased with the number of antagonist strains combined. Therefore, strain mixtures should be sought to control the crown rot disease complex of banana.

Stipe elongation in fruit bodies of Coprinopsis cinerea (syn. Coprinus cinereus) was examined from a biomechanical perspective. Two strains were studied: the self-compatible Amut Bmut homokaryon that produces normal fruit bodies with relatively short stipes, and mutant B1918 that produces abnormally elongated stipes. Measurements of the pressure exerted by developing mushrooms were made using strain gauges, and these data were compared with measurements of the pressures exerted by vegetative hyphae of the same strains. The experiments demonstrate that AmutBmut hyphae elongating within stipe tissue push with the same pressure (approx. 0.5 atmosphere) as vegetative hyphae growing through their food sources. In purely biomechanical terms, the fruit body may therefore be viewed as a relatively uncomplicated sum of its parts. Analysis of the mutant strain B1918 demonstrated that hyperelongation of the stipe is not associated with any difference in the pressure exerted by the fruit body. The fault in the mechanism of stipe extension in B1918 may be reflected in the increased fluidity of the cell wall of vegetative hyphae of this strain, but further work is necessary to resolve this.

Species of Leptographium are well-known inhabitants of conifers in the Northern Hemisphere, in which they cause a blue-stain. They are also known to be associated with insects, especially bark beetles (Coleoptera: Scolytidae). Surveys of dying stands of Siberian fir (Abies sibirica) have resulted in the consistent isolation of an unknown Leptographium from the galleries of the fir sawyer beetle, Monochamus urussovi (Coleoptera: Cerambycidae). This fungus is responsible for the blue-stain in living trees. Comparison with known species of Leptographium led to the conclusion that it had not been previously described, and the name Leptographium sibiricum sp. nov. is introduced here.

Twenty-six fungi associated with leaf spots of palms in north Queensland have been identified, including 12 ascomycetes, one basidiomycete and 13 deuteromycetes. Eight were identified as species new to science. A new species of Pseudospiropes is described and descriptions of two unnamed species of Glomerella are also given.

Several isolates of the entomopathogenic Metarhizium anisopliae that harboured dsRNA viruses of similar electrophoretic band sizes (1.8 and 2.0 kbp) were assessed for homologies of the dsRNA by Northern analysis. The isolates were also characterised genetically by RAPD and VCG. Similarly sized dsRNA, as visualised by electrophoresis, were not always homologous, suggesting that the comparison of dsRNA based solely on electrophoretic banding patterns is an unreliable method of dsRNA characterisation. Several isolates, but not all, harbouring multiple dsRNA patterns, including a 1.8 and 2.0 kbp doublet, also showed homologies to strains harbouring only the dsRNA banding doublet. This suggests that mixed infections of different dsRNA elements are found in M. anisopliae. Genetically similar fungi, based on RAPD banding patterns and vegetative compatibility, were more likely to harbour genetically related dsRNA. The findings suggested that dsRNA elements in M. anisopliae are horizontally transferred to genetically related isolates or are maintained through clonal lineages.

The phylogenetic relationships of Tholurna dissimilis were investigated in relation to a phylogeny of twenty-three species in Caliciaceae and eighteen species from Physciaceae. ITS and LSU regions of the nuclear ribosomal DNA were used for the reconstruction of phylogenies by maximum parsimony methods. Calicium adaequatum was shown to be the closest relative of and possibly congeneric with Tholurna. Calicium is thus not monophyletic unless Tholurna is included. Calicium in the molecular phylogeny contains several distinct clades, which to some extent can be characterized morphologically. Cyphelium in a traditional sense is probably not monophyletic. Cyphelium s. str. has immersed apothecia, large smooth spores and a very thin excipulum throughout. C. inquinans and C. karelicum, which form a distinct and highly supported clade, may be accommodated in Acolium, possibly along with other Cyphelium and Calicium species. The phylogenies presented here do not support the recognition of neither Physciaceae nor Caliciaceae in a narrow sense, but they also do not exclude this. Numerous spliceosomal and unclassified insertions were found in the LSU sequences. They to some extent offered phylogenetic information both with respect to location and by their sequence similarities.

Phomopsis cucurbitae is a latent infection fungus which causes muskmelon fruit decay only after harvest. It can cause severe losses during fruit storage and marketing in the U.S.A., Japan and some Central American countries. Previous studies showed that P. cucurbitae produced polygalacturonase (PG) in both culture and muskmelon fruit tissue. In this study, a prominent PG isozyme (PG1) produced by P. cucurbitae in decayed fruit was purified to homogeneity by a procedure of extraction, ultrafiltration, preparative isoelectric focusing, anion exchange, and gel filtration chromatography. The isozyme had a primary endo-activity, a relative molecular weight of 54 kD according to SDS-PAGE, and a pI of 4·2 based on IEF-PAGE. The isozyme was active in a low pH range from 2 to 6, and was optimum at pH 5. Optimum temperature for the activity of PG1 was 40–45°C. The Km and Vmax on polygalacturonic acid were 44·7 μg ml−1 and 0·14 U μg−1 enzyme, respectively. The purified PG1 effectively macerated mature fruit tissue, suggesting that the isozyme may be involved in the pathogenesis of Phomopsis fruit rot of muskmelon.

The 29 spore-ball-forming smut fungus genera (of the total 58 recognized genera) are analysed, grouped, briefly characterized and illustrated. Problems within the genera, similarities, possible relationships and differences between genera are discussed. The following groups and genera are treated: genera with spores in pairs (Schizonella, Mycosyrinx, Geminago), genera with permanent spore balls composed of colourless spores and sterile cells and/or modified mycelia (Burrillia, Doassansia, Doassansiopsis, Heterodoassansia, Nannfeldtiomyces, Narasimhania, Pseudodoassansia, Tracya), genera with permanent spore balls composed of pigmented spores and sterile cells (Urocystis, Moesziomyces, Dermatosorus, Testicularia), and genera with spore balls containing only spores and lacking sterile cells between the spore balls. Within the latter group, the two sub-groups were distinguished: one with light, brownish spores (Sorosporium, Thecaphora, Glomosporium, Fulvisporium), and another one with dark, blackish spores (Tolyposporium, Tolyposporella, Clintamra, Orphanomyces). Heterotolyposporium has small, hyaline spores between the pigmented spore balls. Sporisorium and Macalpinomyces have sterile cells between the true or pseudo spore balls. Odd genera are: Ustacystis, Mundkurella and Uleiella. A key to the spore-ball-forming genera of smut fungi is given. The value of the spore balls in the taxonomy of the Ustilaginales is discussed. The arrangement of the genera in groups is based on the most important characters of the spore balls. It has a practical, didactic purpose and in many cases the groups do not reflect natural relationships.

A new species of Zoophagus, Z. cornus, capturing loricate rotifers on short peg-like traps, was isolated from paddy field mud in Ibaraki, Japan. The fungus produced long, narrow, cylindrical, aseptate conidia. Azygospores containing a large vacuole were produced directly from the hyphae.

As part of an inventory of mycodiversity in the Brazilian Cerrado new coelomycetes were collected and are herein described: Phyllosticta xylopiae-sericeae sp. nov., Dinemasporium duguetiae sp. nov., Harknessia salvertiana sp. nov., Harknessia qualeae sp. nov. on living leaves of Xylopia sericea, Duguetia furfuracea, Salvertia convallariodora, and Qualea grandiflora, respectively. Pseudothiopsella hirtellae is reported on a new host, Hirtella gracilipes, and for the first time illustrated in detail.

A 3193 bp contiguous sequence has been cloned from the oleaginous fungus Mucor circinelloides, that contains a full-length gene encoding a putative NADP+[ratio ]dependent malic enzyme (EC. 1.1.1.40). The cloned DNA contains a 2154 bp putative open reading frame containing five introns and encoding a protein of 616 amino acids. The gene encoded what appeared to be an anaerobic isoform of malic enzyme (isoform II); this conclusion is supported by transcript analysis and by the fact that the ORF contains an N-terminal mitochondrial target sequence (a similar cellular location was identified for the anaerobic malic enzyme in Saccharomyces cerevisiae; Boles et al. 1998). The cloned gene did not encode either isoform III (the isoform associated with active growth) or isoform IV (associated with lipid accumulation) previously identified. M. circinelloides therefore must possess (at least) two structural genes for malic enzyme.

The objectives of this study were to examine genetic variation, physiological dissimilarities and diversity in pathogenicity between Verticillium fungicola var. aleophilum and var. fungicola and within a population of six V. fungicola var. fungicola strains responsible for dry bubble outbreaks on mushroom farms. Genetic variability was investigated using random amplification of polymorphic DNA (RAPD). Mycelial growth rate, extracellular enzyme production and susceptibility to hydrogen peroxide were used to examine physiological dissimilarities. Variation in pathogenicity was studied both in vitro and during mushroom cultivation. All the physiological properties studied indicated that var. aleophilum isolates were potentially more efficient than var. fungicola isolates for rapid colonisation of the mushroom cultivation medium. They could then interact more efficiently with Agaricus bisporus to produce dry bubble disease. RAPD analysis confirmed that all the French isolates belonged to var. fungicola, and two isolates were distinguishable from the homogeneous group constituted by the others. These isolates had a higher mycelial growth rate and lower extracellular enzyme activities in liquid media, except for chitinases. Their spores were more susceptible to germination inhibition by hydrogen peroxide, and they were responsible for higher levels of affected mushrooms. The two varieties might be regarded as pathotypes that are geographically isolated, and variation in isolates of var. fungicola might have consequence for mushroom growers.

A new species of Boerlagiomyces is described from submerged wood collected from a freshwater river in the Philippines. Boerlagiomyces grandisporus is compared with previously described species in the genus and is shown to possess greatest similarity with B. websteri. Selected ultrastructural characteristics of the ascospores of B. grandisporus are illustrated and discussed in relation to other fungi. The taxonomic relationship of the genera Boerlagiomyces and Garethjonesia are reassessed and shown to be congeneric; the new combination B. lacunosispora is accordingly validated.