This issue of Mycological Research News features altruism within Dictyostelium colonies, and questions whether lichens protect or damage stonework.

This month's Mycological Research includes 16 papers. The first is a major contribution to knowledge of the diversity and ecology of coprophilous fungi, the most detailed to have appeared since 1972. Molecular studies focus on the Auriculariales and related orders, family and generic concepts in the Georgefischeriales, the Galerina marginata complex, Serpula lacrymans and S. himantioides, and lichenicolous fungi referred to Hobsonia and Marchandiomyces. A hydroxynaphthalene reductase gene from Ophiostoma floccosum has been cloned which complements a phenotype of Magnaporthe grisea, and chitin synthase sequences are reported in different arbuscular mycorrhizal fungi.

Fungi able to grow on toluene have been investigated, the potential of Rhynchosporium alismatis chlamydospores in weed biocontrol explored, and the behaviour of the conidia of the entomopathogen Erynia neoaphidis in air studied.

Systematic papers concern Leptographium species on pines, novel fungi on Juncus roemerianus, a new homothallic Mortierella, and Sphaerella species described from filmy ferns.

The following new scientific names are introduced: Eballistraceae fam. nov.; Eballistra, Hobsoniopsis, Illosporiopsis, Phragmotaenium, and Pycnodallia gens. nov.; Hymenopsis chlorothrix, Leptographium alethinum, L. euphyes, L. pityophilum, Mortierella tsukubaensis, and Pycnodallia dupla spp. nov.; Eballistra brachiariae (syn. Entyloma brachyariae), E. lineata (syn. Melanotaenium lineata), E. oryzae (syn. Entyloma oryzae), Hobsoniopsis santessonii (syn. Hobsonia santessonii), Illosporiopsis christiansenii (syn. Hobsonia christiansenii), Jamesdicksonia dactylis (syn. Thecaphora dactylidis), J. eleochartis (syn. Ustilago eleochartis), J. irregularis (syn. Entyloma irregulare), J. ischaemianum (syn. Melanotaenium ischaemianum), J. scirpicola (syn. E. scirpicola), Phragmotaenium indicum (syn. Melanotaenium indicum), and Trichothelium assurgens (syn. Sphaerella assurgens) combs. nov.

Fungi developing on dung samples, from a wide range of locations and incubated in moist chambers, were recorded. Highly significant differences were found among the mycobiota of different dung types, from different latitudinal ranges, and collected at different seasons. Sheep, cattle, deer, rabbit, hare and grouse provided 86 % of the 425 samples. Highly significant differences in the community composition of the mycobiota of these six dung types were observed. Coprinus stercoreus was the commonest basidiomycete, and most frequent on sheep, cattle, deer and rabbit; C. miser was the only common species, of any taxonomic group, which showed no significant difference in its frequency on different dungs. Apothecial fungi comprised about a quarter of the records, with Ascobolus, Saccobolus and Thelebolus spp., Iodophanus carneus and Lasiobolus cuniculi the commonest. A. carletonii occurred uniquely, but frequently, on grouse. Perithecial species, especially of Schizothecium, Podospora, Coniochaeta and Sporormiella, accounted for ca 50% of all records. The grouse dung mycobiota was markedly different, with a lower species richness (mean 3.2 per sample), from that of the mammalian herbivores, which had means of 9–12 spp. per sample. In temperate latitudes more species were recorded on samples in winter. Species richness was greater in samples from lower latitudes. Significant differences in the composition of different dung types are discussed in relation to their fungal communities. The usefulness of studying the fungi of the dung microcosm as a means of rapid biodiversity assessment is considered, by comparing the results with those of a similar, but smaller, study 30 years earlier, and by examining the diversity of a sample from a subjectively poor habitat in Morocco. There was no indication of any major change in the coprophilous mycobiota that might be associated, e.g. with climatic change or changed farming practice over the last three decades. The Moroccan samples had a much lower diversity (80 spp./50 samples) than would be expected of samples from that latitude (146 spp./50 samples) based on the worldwide data set.

In order to estimate phylogenetic relationships in the Auriculariales sensu Bandoni (1984) and allied groups we have analysed a representative sample of species by comparison of nuclear coded ribosomal DNA sequences, applying models of neighbour joining, maximum parsimony, conditional clustering, and maximum likelihood.

Analyses of the 5′ terminal domain of the gene coding for the 28 S ribosomal large subunit supported the monophyly of the Dacrymycetales and Tremellales, while the monophyly of the Auriculariales was not supported. The Sebacinaceae, including the genera Sebacina, Efibulobasidium, Tremelloscypha, and Craterocolla, was confirmed as a monophyletic group, which appeared distant from other taxa ascribed to the Auriculariales. Within the latter the following subgroups were significantly supported: (1) a group of closely related species containing members of the genera Auricularia, Exidia, Exidiopsis, Heterochaete, and Eichleriella; (2) a group comprising species of Bourdotia and Ductifera; (3) a group of globose-spored species of the genus Basidiodendron; (4) a group that includes the members of the genus Myxarium and Hyaloria pilacre; (5) a group consisting of species of the genera Protomerulius, Tremellodendropsis, Heterochaetella, and Protodontia. Additional analyses of the internal transcribed spacer (ITS) region of the species contained in group (1) resulted in a separation of these fungi due to their basidial types.

To obtain an understanding of the phylogenetic relationships among the Georgefischeriales, septation, cellular interactions, teliospores, basidia, cultures and nucleotide sequences from the 5′ terminal domain of the nuclear large subunit rRNA gene were studied. Analyses of both morphological and molecular characters yield similar phylogenetic conclusions. The Georgefischeriales are divided into three groups, corresponding to the Eballistraceae, Georgefischeriaceae, and Tilletiariaceae. The basal dichotomy is between the Eballistraceae and the branch uniting the Georgefischeriaceae and Tilletiariaceae. The Tilletiariaceae are phragmobasidiate, whereas the Eballistraceae and the Georgefischeriaceae are holobasidiate. The Eballistraceae differ from the Georgefischeriaceae and Tilletiariaceae in the lack of the ballistospore mechanism. The systematic position of Tilletiopsis minor is unclear. The Eballistraceae, Eballistra and Phragmotaenium are proposed as new taxa. The descriptions of the Tilletiariaceae and Jamesdicksonia are emended. Except for Entyloma majus, E. parvum, Georgefischeria, Jamesdicksonia brunkii, J. obesa, Tilletiaria anomala, and Tolyposporella chrysopognis, the teleomorphic species of the Georgefischeriales are presented as new combinations.

Species of Mycosphaerella and their anamorphs are commonly found on the leaves of Myrtaceae, many of which are defoliated by these pathogens. The taxonomy of these fungi has been based on minute morphological differences, and virtually nothing is known regarding their relatedness to each other. In this study, we present a phylogeny of 30 species of Mycosphaerella or their anamorphs from myrtaceous hosts, based on sequence data from the ITS regions of the ribosomal RNA operon. Fifteen of the species were also analysed for the 5′ end of the large subunit (28S), which produced a phylogeny similar to that obtained for the ITS data set. The Mycosphaerella species included in this analysis are all regarded as representatives of section Plaga, and appear to represent a monophyletic assemblage. Mycosphaerella lateralis was the only species shown to have a wide host range. In general, species clustered together based on their anamorph genera. Species with Colletogloeopsis and Stenella anamorphs always grouped in two respective clusters. However, species with Mycovellosiella, Phaeophleospora, Pseudocercospora and Uwebraunia anamorphs occurred separately, suggesting that they have evolved more than once within Mycosphaerella. Based on the ITS data set, all morphospecies were also shown to be phylogenetic species, although too few isolates were available to address questions relating to intraspecies variation. Nevertheless, ITS sequence data proved sufficient to distinguish morphologically similar taxa that have hitherto only been distinguished based on ascospore germination patterns and anamorph characteristics. Sequence data presented in this study should facilitate the identification of Mycosphaerella species occurring on Myrtaceae in the future.

The distinctiveness of the European Galerina marginata and the American G. autumnalis is tested with analyses of DNA sequences from the internal transcribed spacer (ITS-2) of the nuclear ribosomal repeat and RFLP analysis of the entire ITS region. European and North American material from six taxa described in Galerina subgenus Naucoriopsis are included along with out-group material of six taxa representing two other subgenera of Galerina. The results do not indicate any genetic difference between species by Smith & Singer (1964) referred to the two ‘stirpes’ Marginata and Autumnalis of Naucoriopsis, i.e. G. autumnalis, G. marginata, G. oregonensis, G. pseudomycenopsis, G. unicolor, and G. venenata and all except G. pseudomycenopsis are considered later synonyms of G. marginata. Galerina badipes (syn. G. cedretorum var. bispora of ‘stirps’ Cedretorum is well supported as a distinct species. Subgenus Naucoriopsis appears as a distinct infrageneric unit well separated from the infrageneric units represented by the out-group species.

Rhynchosporium alismatis, a pathogen of several Alismataceae species, is being studied in Australia as a potential weed biocontrol agent for Alisma lanceolatum, A. plantago-aquatica and Damasonium minus. Chlamydospores of R. alismatis are described for the first time. Large numbers (5.34×105 cm−2) were produced on potato dextrose agar within 8–15 d and range in size from 4.7 to 14 μm. There was variability between isolates in mean diameter but size was not related to the host of origin. Within 24 h at 30 °C 60% of chlamydospores, 8 d to 3 months old, germinated. Each germinated chlamydospore produced up to four germ-tubes. Chlamydospores were detected in leaf lesions on naturally-infected A. plantago-aquatica. One-month-old chlamydospores were pathogenic to leaf discs cut from mature leaves of A. lanceolatum and Damasonium minus. The relative robustness of chlamydospores is an advantage over conidia for the future production of a biological control agent if they can be produced and harvested in broth culture.

Relationships between Serpula lacrymans and S. himantioides isolates of ‘wild’ Himalayan woodland and building (European and Australian) origin were examined using RAPD–PCR and ITS rDNA sequence comparison. GelCompar analysis of the genetic fingerprints of eighteen isolates using four RAPD-primer combinations clearly distinguished S. lacrymans and S. himantioides. Little intraspecific variation was observed in S. lacrymans (including isolates of Himalayan woodland origin), relative to S. himantioides. Despite previously reported differences in growth rates and decay capabilities of ‘wild’ Himalayan woodland S. lacrymans isolates and those from buildings, RAPD fingerprints and ITS sequences indicated they were genetically similar. Interspecific ITS sequence polymorphisms were consistent with other studies and clearly demonstrated S. himantioides and S. lacrymans were distinct taxa. Evolutionary questions regarding the origins of S. lacrymans are discussed.

The genera Hobsonia, Illosporium, and Marchandiomyces include several common lichenicolous (lichen-inhabiting) species that have been taxonomically linked in the past. These mitosporic genera are frequently misidentified because of a paucity of morphological characters, which has led to some confusion about their relationships. We examined the phylogenetic positions of species in these genera using complete sequences of the small subunit (SSU) and internal transcribed spacer (ITS) ribosomal DNA (rDNA), and portions of the mitochondrial (mt) SSU rDNA obtained from isolated cultures of freshly collected specimens. Phylogenetic analysis of the sequence data indicated that Marchandiomyces corallinus and M. aurantiacus are closely related members of a basidiomycete clade. In addition, the clade includes an undescribed non-lichenicolous species that is morphologically similar to M. corallinus. Another undescribed species with marchandiomyces-like sclerotia, appears to be in a separate basidiomycete clade. The three recognized species of Hobsonia are unrelated, with H. christiansenii appearing to be a hypocrealean ascomycete closely related to a sample of Illosporium carneum, H. santessonii an ascomycete of unknown affinity, and H. mirabilis a basidiomycete. The latter, a plant pathogen, is the type species of Hobsonia. The new generic names Illosporiopsis and Hobsoniopsis gens. nov. are described for the lichenicolous species H. christiansenii and H. santessonii, respectively, and the necessary new combinations made.

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.

The arbuscular mycorrhizal (AM) fungus Glomus intraradices was grown in vitro with RIT-DNA transformed Daucus carota roots on plates divided into two compartments. One side of the plates contained only fungal hyphae and spores while the other contained mycorrhizal roots. Using this technique, the limitations of insufficient biological material available for molecular analysis of this obligate symbiont were overcome. Fungal material from the first compartment was used as a pure source of G. intraradices for genomic DNA extraction. PCR amplification as well as southern hybridization were conducted using this DNA. Sufficient pure genomic DNA and mRNA was obtained to carry out Southern analysis, achieve optimum PCR results with 25–35 cycles and conduct RT-PCR. Differential expression of chitin synthase class I and II was detected in G. intraradices. Using degenerate primers specific to fungal chitin synthase sequences, a single amplification product obtained after 25 cycles of PCR was cloned. Sequencing of this fragment revealed similarity to other fungal chitin synthase genes. PCR with these primers and additional primers allowed the amplification of chitin synthase fragments from spores of different isolates of G. intraradices as well as from G. mosseae, Gigaspora margarita, Acaulaspora scrobiculata, Scutellospora calospora and Entrophosphora colombiana. A total of 21 chitin synthase sequences from different species and isolates of various AM fungi were successfully amplified. Sequencing of these fragments permitted their classification into class I and II of the chitin synthase groups.

Five fungal strains that are able to grow on toluene were isolated from enrichment cultures. Three different techniques were used: solid state-like batches, air biofilters and liquid cultures. Fungal growth in the latter systems was favoured by combining low pH and low water activity. Soil and groundwater samples from gasoline-polluted environments were used as inocula. The isolates were identified as deuteromycetes belonging to the genera Cladophialophora, Exophiala and Leptodontium and the ascomycete Pseudeurotium zonatum. The previously isolated toluene-degrading fungus Cladosporium sphaerospermum was included in the present study. Results showed that fungi grew on toluene with doubling times of about 2 to 3 days. Some of the strains also grew on ethylbenzene and styrene. The apparent half-saturation constant (Km) for toluene oxidation ranged from 5 to 22 μM. Degradation activity was inhibited by 50% at toluene concentrations ranging from 2.4 to 4.7 mM. These kinetic parameters are comparable to analogous data reported for toluene-degrading bacteria. The ability of fungi to grow at low water activities and low pH suggest that they may be used for the purification of gas streams containing aromatic hydrocarbons in air biofilters.

The temporal pattern of release and dispersal of inoculum of plant and insect pathogenic fungi play an important role in the spread of disease. Airborne concentrations of primary and secondary conidia of Erynia neoaphidis released from the rose-grain aphid Metopolophium dirhodum were monitored at the edge of two winter wheat crops on IACR-Rothamsted Experimental Farm between May and September in 1996 and 1997. Hourly average temperature and humidity were recorded at each spore trap site and daily totals of rain and sunshine hours and daily average wind speed recorded about 1.6 km from the monitoring sites. No airborne conidia were found in 1996, but large numbers were trapped at the two sites in 1997. They were present from mid-June until early August, reaching peak concentrations on 17–18 July. Concentrations were usually highest during the night and in the early morning (01:00–07:00 h GMT) and were generally low during the day. On the 3 days when significant numbers of conidia were caught in the afternoon, daytime relative humidity was high (about 89%) and day-time temperature low (about 16 °C). Night-time conditions nearly always favoured the production of conidia. This suggests day to day variation in airborne conidium concentrations may be affected more by underlying biological factors than environmental conditions.

Leptographium species are common inhabitants of fresh conifer logs and lumber that are known for their ability to cause blue-stain and, in some cases, their association with disease. L. procerum has been associated with a root disease although controversy surrounds its role in tree death. During the course of the past two decades, a relatively large number of isolates tentatively identified as L. procerum have been collected in various parts of the world. Some of these display morphological characters unlike those of L. procerum s. str. and this has prompted us to re-examine them. Four groups of morphologically distinct isolates were identified, of which L. procerum s. str. represented one. The remaining isolates of Leptographium are newly described as L. alethinum, L. pityophilum and L. euphyes spp. nov.

Pycnodallia dupla gen. sp. nov. and Hymenopsis chlorothrix sp. nov. are described from saltmarsh Juncus roemerianus in North Carolina. Conidiomata of P. dupla develop on senescent inflorescences and involucral leaves, between 40 and 60 cm above the rhizome, therefore, the species can be considered as facultative marine. Conidiomata of H. chlorothrix are found on dead culms, 16–43 cm above the rhizome. This species is classified as obligately marine. Dwayaangam junci, the anamorph of Orbilia junci, has been found for the first time in nature. Conidia develop on the medulla of leaves, in lesions caused by grasshoppers.

Mortierella tsukubaensis sp. nov., isolated from uncultivated soil at Tsukuba, Japan, is described and illustrated as a new homothallic species. Simple, large sporangiophores with terminal, many-spored sporangia, large chlamydospores and naked zygospores are characteristic of M. tsukubaensis. A key of the 13 known homothallic species is provided.

The two Mycosphaerella and Sphaerella species described from filmy ferns (Hymenophyllaceae) turned out to be lichenized and to belong to different ascomycete orders, the Trichotheliales and Pyrenulales. As one epithet antedates the names currently in use for the taxon, the following new combination is proposed: Trichothelium assurgens (syn. Sphaerella assurgens Cooke, Trichothelium marianense Harada, T. nanum Malcolm & Vězda). These unexpected redispositions serve as an example of the current state of knowledge about the taxonomy of foliicolous ascomycetes, both non-lichenized and lichenized. They also show that type studies are essential to evaluate the identity of Mycosphaerella and Sphaerella species, and that the resulting number of accepted species in the huge genus Mycosphaerella, and consequently in the ascomycetes as a whole, might be lower than currently thought. Strigula phyllogena and Porina albicera are reported as new for Samoa.