Randomly amplified polymorphic DNA (RAPD) markers were used to assess the genetic diversity of isolates of grey snow mould (‘gray snow mold’), Typhula incarnata, taken from infected turfgrasses from 40 different locations in the northern USA. Data from 115 markers using 37 RAPD primers showed 48% polymorphism. The distance coefficients between isolates indicate the wide genetic diversity of T. incarnata across the sample area. Dendrograms generated using neighbour-joining (NJ) bootstrap analyses showed three clades and suggest possible recent colonization from common founder groups. Partitioning of the genetic variance using analysis of molecular variance (AMOVA) of four groups based on geographic locations (Michigan, lower and upper peninsula; Minnesota; Wisconsin) showed that genetic variation attributable among groups and within groups was 12.67 and 87.33%, respectively. No correlation was found between geographic distance and pairwise genetic distance of the groups. High outcrossing and sexual recombination of T. incarnata may well be key factors explaining the genetic variability as shown with the low Fixation index (FST) and high average of genetic diversity per locus within groups.

The production and properties of Agaricus bisporus endoxylanase and β-xylosidase were studied in compost and liquid cultures. A. bisporus was grown on minimal medium with solka floc BW40, oat spelt xylan, Whatman CC41 microcrystalline cellulose, D-xylose and D-glucose as carbon sources. Endoxylanase activity and β-xylosidase activity were found during growth with complex carbon sources such as cellulose or xylan and no activity was present with sugars such as glucose or xylose. In compost culture endoxylanase activity increased during and after the button stage of fruit body development and decreased after fruit body harvest. The production of β-xylosidase differed in that it was only detectable during the button stage of development. Using activity staining and preparative IEF, three endoxylanase activities were separated from liquid cultures and three principal endoxylanase activities were separated from compost extract. The pH optima and IEF profiles of these activities were similar. Only one β-xylosidase activity was found in liquid culture, whereas two were found in compost culture; the IEF profiles of the compost activities differed markedly from those of the β-xylosidase found in liquid culture.

Two new species of Unguiculariopsis are described from tropical Guangxi and the Changbai Mountains in northeastern China. Unguiculariopsis changbaiensis and its anamorph Deltosperma oblongum occurs on a pyrenomycete and U. damingshanica is lichenicolous.

Ultrastructure of the marine, bitunicate, ascomycete Julella avicenniae is presented and compared with the marine Pleospora gaudefroyi. Asci of J. avicenniae possess an ocular chamber, a thick endoascus, and a thinner ectoascus. Pseudoparaphyses are enveloped by mucilage (hyphal sheath) which stains with ruthenium red. The mucilage appears to be an extension of the pseudoparaphysis cell wall and internally these cells contain an array of vesicles. Muriform ascospores are surrounded by an exosporial sheath, an electron-dense episporium and a bilamellate mesosporium. Optimum conditions for growth are 25–30°C in 100% artificial seawater glucose- yeast extract-tryptone media, but the fungus also is able to grow at 35° and at higher salinities. The ability of the fungus to withstand extremes of environmental conditions is discussed.

We visualised rDNA of two ascomycetes, Cochliobolus heterostrophus and Haematonectria haematococca, by fluorescence in situ hybridisation (FISH) and analysed the condensation state of rDNA during mitosis. Both fungi showed a similar course of change in rDNA condensation corresponding to different mitotic stages. rDNA was decondensed in its entire length at interphase, and became increasingly condensed during prophase. The condensation reached a maximum at metaphase, remaining in that state through anaphase. Metaphase observation revealed the single distal location on a chromosome of rDNA in each fungus. This study provides the first visual evidence of the cyclic change of the condensation/decondensation state of rDNA during mitosis in filamentous fungi by FISH.

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 diversity of the family Trichocomaceae, which includes the major anamorph genera Aspergillus and Penicillium, was studied in the Katandra Nature Reserve, Central Coast, NSW, Australia. Soil, living leaves, leaf litter and detritus were examined by both direct and dilution plating techniques. Fungi were isolated on dichloran Rose Bengal chloramphenicol agar, and dichloran 18% glycerol agar, media suitable for cultivation of many species within this family. Species of Trichocomaceae were isolated from all sites and all substrates examined. A high diversity was found, with more than 50 known species identified, and an equal number of undescribed species detected. More species of Penicillium were recovered than other genera, with Aspergillus species the next most common. Most of the species recovered were anamorphs, though 16 known and unknown ascosporic species were also isolated from heated and unheated soil. Soils, leaf litter, a scat from a native herbivore and leaves of living native plants yielded higher diversity than insects, worms or introduced plants. More species belonging to the family were isolated from soil in dry sclerophyll forest than in rainforest. Conversely, native rainforest plants harboured more diversity than the dry sclerophyll forest plants examined.

Ascogenous hyphae of foliicolous members of the Arthoniaceae, including the genera Arthonia, Eremothecella, Amazonomyces, and Cryptothecia, were studied by epifluorescence microscopy. Two additional representatives of Opegrapha were included. The ascogenous hyphae in Arthonia, Eremothecella, Amazonomyces, and Opegrapha arise from a central region of the ascoma and form a dense and branched tree-like structure. The asci of Cryptothecia are not connected by such structures and arise singly. Differences of measurements, structures and branching patterns of ascogenous hyphae indicate that these are species-specific characters. Typical ascogones were not observed. The fusion of tips or croziers of ascogenous hyphae and haploid mycelium were seen in several species. The systematic significance of the observations is discussed.

Transmission electron microscopy was used to study the development and structure of resting spores and sporosori of Polymyxa graminis. Osmiophilic bodies generally distributed in the cytoplasm moved to the periphery as spores matured. The spore wall consisted of four or five layers, two of which extended into spines linking adjacent spores. An unstained plug in the wall, faced towards the outside of the sporosorus. Some spores germinated in situ by producing primary zoospores. Bundle-like structures in some spores may have been barley yellow mosaic virus particles.

Growth in Neurospora proceeds by the highly polarised extension of hyphal tips and the formation of new tips (branches). While much attention has been devoted to tip growth, the mechanisms responsible for the decision to form a branch are unknown. One important issue is the degree to which the decision to branch is made independently by each tip, or is under the control of proximal regions of the colony. We address this question by comparing the lengths of branch intervals growing from one branch point. We find significant correlations between such intervals under nearly all circumstances tested. In contrast, we find no significant correlation between branch intervals adjacent in series. The strength of the correlation depends on the qualitative nature of the branches surveyed. Dichotomous/apical branching shows a high degree of correlation while lateral branching shows a weaker but still statistically significant correlation (this difference cannot be explained either by differences between the growth rates or distributions of lengths of branch intervals). We interpret the observed correlations to mean that the decision to form a branch is not independently controlled by the tip where the branch forms. Instead it is determined, at least in part, by factors at or close to the previous branch.

Penicillium virgatum sp. nov. is described from the soil of a soybean field in New Caledonia. Its delimitation from P. daleae, isolated from forest soils in Poland and Germany, is discussed. The species are differentiated on the basis of morphological features of their cultures in vitro, comparison of the PCR-RFLP profiles with DdeI, HpaII, Sau3A1, and TagI restriction endonucleases, and nucleotide sequences.

Two unusual species of Acremonium sect. Acremonium, A. borodinense sp. nov. and A. cavaraeanum, are described and illustrated. They were isolated in Japan from rhizosphere soil of sugarcane and an outer wall of a wooden house respectively. A. borodinense is characterized by forming two kinds of conidia, ellipsoidal rough-walled and cylindrical smooth-walled. Of A. cavaraeanum a second isolate has become available; it forms long chains of fusiform conidia, has a luteous reverse and exudes a livid-red pigment into the medium.

We report an investigation into the relationship between Aspergillus nidulans mutations sltA1 and agaA50, conferring salt sensitivity and arginase deficiency, respectively, and the ability of spores to swell and commence germination. Spores from both mutant strains exhibited uncontrolled swelling at pH 5.5 in the presence of arginine as the nitrogen source. The controlled swelling of spores from a salt tolerant strain under these conditions was disrupted by the Na+/H+ exchange inhibitor amiloride. Swelling in the presence of amiloride was associated with an elevation in the concentration of arginine within the spores of each strain tested. The possible consequences of alterations in the arginine economy of the spore for colony establishment in osmotically challenged habitats are discussed.

A new Hypocrella species with white pulvinate stromata collected in Puerto Rico and Costa Rica is described as H. zhongdongii sp. nov. Morphological and molecular evidence confirms that the new species of Hypocrella is the teleomorph of Aschersonia incrassata. It most closely resembles H. andropogonis; both A. incrassata and A. andropogonis are common yellow-spored species. The relationships of H. zhongdongii with other species in the genus are elucidated through phylogenetic analyses of three different genetic loci (LSU, RPB2, and mtSSU). Our analysis also sheds light on current subgeneric concepts in Aschersonia, in which the presence or absence of conidiomatal paraphyses is a major character to separate the genus into two subgenera. The present phylogenetic tree suggests that paraphyses have been lost or gained multiple times during evolutionary history, and do not define monophyletic groups.

Fungal endophytes of the genera Neotyphodium and Epichloë are important mutualistic symbionts and pathogens of many cool-season grass species. Here we report the characterization of a secreted N-acetylglucosaminidase from the Neotyphodium sp. endophyte that infects the grass Poa ampla. The enzyme was expressed at low levels within the host, and activity could be detected in the apoplastic protein fraction. Low-level expression could also be detected in endophyte-infected perennial ryegrass (Lolium perenne), Chewings fescue (Festuca rubra subsp. fallax), and tall fescue (L. arundinaceum). The enzyme may function in the recycling of chitin oligomers generated from turnover of the fungal cell wall. This is the first report of a secreted N-acetylglucosaminidase expressed by an endophytic fungus in the infected host plant.

Genetic relationships among the violet root rot fungi were studied by hyphal anastomosis and sequencing of the ITS-5·8S rDNA regions. Twelve isolates of Helicobasidium mompa, one isolate each of H. purpreum and H. compactum, two isolates of Helicobasidium sp., eight isolates of Rhizoctonia crocorum, and three isolates of R. violacea anastomosed in most combinations, resulting in the death of fused cells and adjacent cells. Phylogenetic analyses of the ITS-5·8S rDNA regions separated 31 violet root rot fungal isolates into five lineages: H. mompa from Japan and Korea; R. crocorum from Europe and New Zealand; H. purpureum, R. crocorum, and R. violacea from Europe; Helicobasidium sp. from Japan; and H. compactum from the USA. Within each lineage there was no more than one nucleotide substitution, and similarity ranged from 81·8% to 98·2% between lineages. The discrepancy between the results from the two methods are discussed in terms of the biological species concept in the complex.

Twenty-four strains of six Cylindrocladiella spp. were compared with respect to their morphology, nuclear ribosomal DNA (nuclear rDNA) polymorphisms, and restriction fragment length polymorphisms of A+T-rich DNA (AT-DNA). Two distinct DNA profiles were observed for the ten strains of C. camelliae/peruviana-complex studied. One profile corresponded with the type strain of C. peruviana, which was earlier regarded as a synonym of C. camelliae. Based on Southern analyses and AT-DNA, C. parva, C. elegans and C. lageniformis were confirmed to be distinct species with little intraspecific variation. Although C. infestans was shown to have some variation among the four strains studied, they could not clearly be distinguished as separate taxa. Based on general morphology, nuclear rDNA and AT-DNA polymorphisms, seven species of Cylindrocladiella are recognized.

Investigations of corticolous fungi in Patagonia have revealed the existence of a new species of Hysterium. H. andinense sp. nov. is described and compared to the related species. H. andicola is synonymized with H. insidens.

Ophiostoma piceaperdum and O. europhioides are well-known, first described from conifers in Canada. They have been considered to be synonymous. After studying the type material, as well as a collection of isolates of O. piceaperdum and O. europhioides, we have concluded that they cannot be distinguished from each other, so we support the synonymy of O. europhioides and O. piceaperdum and provide a description for the Leptographium anamorph of O. piceaperdum. Ceratocystis pseudoeurophioides has previously been distinguished from O. europhioides based on differences in anamorph morphology. This species has also been reduced to synonymy with O. penicillatum, which was reported to have cucullate ascospores. Later descriptions of O. penicillatum reported it to have allantoid ascospores. We conclude that C. pseudoeurophioides cannot be distinguished from O. piceaperdum and is, therefore, reduced to synonymy with that species.

Two new species of Inonotus, I. chihshanyenus sp. nov. and I. formosanus sp. nov. found growing saprotrophically on the decayed stems of Melicope merrillii and Persea zuilhoensis, respectively, in Taiwan are described and illustrated. Their cultural characters are described.