Three species of fossil epiphyllous coelomycetes are described from Dominican and Mexican amber in the new genera, Asteromites gen. nov., Leptostromites gen. nov. and Leptothyrites gen. nov. Characters of the pycnidia and spores most closely resemble members of their extant respective genera, Leptostroma, Asteromella, and Leptothyrium, respectively. A. mexicanus sp. nov. occurs on a petal (possibly from a caesalpinoid legume such as Peltogyne) in Mexican amber. Leptostromites ellipticus sp. nov. occurs on a dicot leaf in Dominican amber, and Leptothyrites dominicanus sp. nov. on a monocot (grass?) leaf in Dominican amber.

The suitability of random amplified polymorphic DNA for identification of Pythium aphanidermatum was investigated. Three oligoprimers were selected after testing three isolates of P. aphanidermatum and one isolate of P. ultimum with a total of 40 primers. The selected 10-mer primers were used with 20 isolates of P. aphanidermatum, four isolates of P. deliense, two isolates of P. ultimum, two isolates of P. irregulare and one isolate of P. paroecandrum. Most of the P. aphanidermatum isolates (13 of 20), were obtained from samples of Cucumis sativus, or water from cucumber greenhouses. The three selected primers gave identical fingerprints for 18 of the 20 P. aphanidermatum isolates, including all the isolates from cucumbers. Two of the primers gave fingerprints that could be used to differentiate between isolates of the Pythium species studied. The banding pattern of P. aphanidermatum given by the third primer could not easily be distinguished from the fingerprint of P. deliense. However, when used in conjunction with the other two primers, the third primer can be used to verify the identity of P. aphanidermatum.

The biological relationships of lichenicolous fungi and their hosts are studied in four members of the Dacampiaceae. Infections of the lichenicolous species Dacampia engeliana induce in its host Solorina a thallus morphology similar to that found in the lichenized D. hookeri. D. engeliana, however, differs microscopically by hyphae growing inside those of Solorina in the algal layer and the medulla. Pyrenidium actinellum develops short haustorial structures into the hyphae of the host. These haustoria are characterised by finger-like outgrowths into the host cells. Clypeococcum hypocenomycis forms dense brown mycelia in the upper cortex of the host, which is progressively destroyed. These lichenicolous parasites have a preference for the fungal symbiont of the host lichen and, in contrast to several other lichenicolous fungi, the algal partner is not primarily affected. The various types of infection modes found in the family Dacampiaceae suggest that a great variation of infection modes may exist in further groups of lichenicolous fungi. Other infection types are included in the discussion.

Teliospores, basidia, cultures, hyphal septations, cellular interactions and nucleotide sequences from the D1/D2 region of the nuclear large subunit ribosomal RNA gene of Entyloma ossifragi occurring on Narthecium ossifragum (Nartheciaceae) were examined and compared with findings in the Georgefischeriales and other Ustilaginomycetes. The data show that Entyloma ossifragi is a member of the Georgefischeriales. Among the Georgefischeriales, Entyloma ossifragi morphologically is very similar to Jamesdicksonia species, but differs from this genus and all other Georgefischeriales by the formation of dolipores without striations that become closed during teliosporogenesis. In addition, in our molecular phylogenetic analyses Entyloma ossifragi stands well apart from Jamesdicksonia, forming with some Tilletiopsis specimens a statistically supported cluster. Accordingly, the genus Gjaerumia gen. nov. and the family Gjaerumiaceae fam. nov. are proposed to accommodate Entyloma ossifragi in the Georgefischeriales. The new combination G. ossifragi (syn. Entyloma ossifragi) is made.

Fungal communities on decaying fronds of Livistona australis, Oraniopsis appendiculata (Australia), Arenga engleri, Livistona chinensis (Hong Kong), Arenga undulatifolia, Salacca affinis, and Oncosperma horridum (Brunei) were examined for fungi. In all, 288 different taxa were identified. The fungal communities on different frond parts (i.e. leaves, rachis-tips, mid-rachides and rachis-bases), on different hosts, at different sampling sites, at different stages of decay, and in different seasons were compared.

Fungal species compositions were distinct on different hosts and at different sites. Three-dimensional correspondence analysis resulted in: (a) three clusters corresponding to distinct communities on samples in Australia, Brunei and Hong Kong; (b) fungi on palms of the same genera (Arenga undulatifolia and A. engleri; Livistona australis and L. chinensis) at different sites, being more coherent than on palms of different genera at different sites; (c) fungi on palms of different genera at the same site being more coherent than on palms of the same genera at different sites. Fungal taxa on the same palm genus or species in different sampling sites were significantly different. Evidence for host specificity and fungal recurrence on different hosts and frond parts were found. No evidence of seasonal patterns of fungal communities was found on the palm hosts. Only 10% of the fungi were common to all three palm species studied in Brunei and 17% were common to the two palm species at Victoria Peak, Hong Kong.

Significant differences were found in the fungal communities colonising each of the different frond parts (leaves, rachis-tips, mid-rachides and rachis-bases). The greatest differences in most palms were found between the leaves and rachides.

When investigating fungal diversity it is recommended to examine a combination of naturally occurring fronds and frond baits throughout the decomposition process. Since a large number of forests, plant species and even types of plant tissues have yet to be explored by mycologists, we predict that there are an incredibly large number of fungi on these unexplored substrata.

This study has confirmed that fungi on palms are very diverse and suggests some reasons for this. The data has important implications towards future biodiversity studies and estimates of global fungal numbers. Future studies and estimations must reflect and incorporate these results.

We examined the phylogenetic position of Omphalina foliacea and its putative closest relative, the lichen-forming basidiomycete Lichenomphalia lobata. Both species are restricted to specific habitats in the high andine regions of tropical America. We generated nuclear ITS and LSU rDNA sequences of two collections of each species and analysed the data together with sequences of omphalinoid basidiomycetes retrieved from GenBank using a Bayesian and a maximum parsimony approach. Our analyses show that both, O. foliacea and L. lobata are lichenized basidiomycetes. L. lobata is related to other species of the genus Lichenomphalia, whereas O. foliacea is not closely related to other Omphalina or Lichenomphalia species, but probably belongs in the hymenochaetoid clade. The analysis of a nuclear LSU data set of a broader sampling of hymenochaetoid basidiomycetes supported the placement of O. foliacea in this clade, but did not reveal any close relative.

An unknown species of Ophiostoma was isolated from European larch (Larix decidua) infested by Tetropium gabrieli (Coleoptera: Cerambycidae) and Norway spruce (Picea abies) infested by Tetropium sp. in Austria. The fungus is similar to O. minus, but distinguished from it by the ecology, colony morphologies on OA and MEA, and phylogenetic analysis of aligned DNA sequences of the ITS region of the rDNA operon and the partial β-tubulin gene. It is described here as O. kryptum sp. nov. The new species readily produces perithecia with short necks and reniform ascospores, and has Hyalorhinocladiella and Leptographium-like anamorphs. Circumstantial evidence suggests that Tetropium spp. act as vectors of O. kryptum. O. minus and O. kryptum represent additional examples of morphologically similar, yet genetically and ecologically distinct species in the genus Ophiostoma. The new combination, O. crenulatum comb. nov. (syn. Ceratocystiopsis crenulata), is also made.

The green fluorescent protein gene was inserted into isolates of the endophyte Neotyphodium lolii from perennial ryegrass Lolium perenne using the method with polyethylene glycol treatment of protoplasts. The transformation rate was 3·2×10−6 of the original number of protoplasts 5 weeks after the transformation. Freshly isolated mycelium from the host plant was used in the transformation experiments, since difficulties of infecting the host plant with older isolates were observed. Isolates were identified using the universal primed (UP) PCR fingerprinting method.

The transformed mycelium readily expressed the green fluorescent protein gene. Fluorescence was observed in the cytoplasm of the mycelium cells in pure culture, both before infection and after re-isolation from the host plant. The fluorescent hyphae were easily detected in the host plant. No disturbing autofluorescence from the host plant leaf sheaths or from the wild type isolate was observed. The importance of mitotic stability is discussed, based on the transformed phenotype and southern hybridization pattern, since the Neotyphodium lolii transformants lost 1–2 copies of the integrated gene after re-isolation from the host plant without losing their GFP phenotype. This is the first report on transformation of a Neotyphodium sp. with a gfp gene. In the future, the green fluorescent protein may serve as a tool for studying gene expression and protein localization in the endophyte/host plant interaction using heterologous fusion proteins.

Fungal biomass was detected in peat soils from throughout the Everglades based on the presence of ergosterol. Ergosterol concentrations in soils were not detectably affected by the dominant plant, Cladium jamaicense or Typha domingensis, or phosphorus content of soils. In situ decomposition of decaying leaves, measured by respiration, was high (maximum 484 μl O2 h−1 g−1 dry biomass). Approximately 30% of respiration was by bacteria, and the rest was by fungi and other eukaryotes. Respiration rates were essentially the same for decomposing leaves of both plant species, with higher rates early in the decomposition process. Respiration rates were relatively unaffected by the nutrient status of the site, except for eukaryotic respiration on Cladium, which was usually higher at a high nutrient site. Ergosterol concentration increased in decaying leaves through time and was unrelated to the nutrient level except for Cladium, where it was higher at the high nutrient site. Eukaryotic respiration was not correlated with ergosterol concentration in decomposing leaves of Typha, but was positively correlated with ergosterol for Cladium.

Medusoides gen. nov. is described from North Carolina, U.S.A. The fungus reproduces sexually, with oogonia and antheridia, but no asexual stage has yet been found. The fungus has not yet been obtained in culture. The vegetative growth is mycelial but the hyphae are very narrow (<3 μm) with vesiculate nodes. The oospores are strictly plerotic. Oogonial and oospore walls are distinctive with unique ultrastructure. The peronosporomycete is a typical aero-aquatic fungus, having markedly buoyant propagules, due to the possession of long, recurved, oogonial outgrowths covering the oogonium sufficiently densely so as to retain air between them and the oogonial surface after exposure and reimmersion. Its habitat, in the lower layers of submerged deciduous leaf litter, suggests survival in an anaerobic environment and a fermentative capacity. An affinity with Pythiogeton is proposed, and Pythiogeton is made the type genus of a new family, the Pythiogetonaceae.

Seventy-one strains of fungi belonging to 53 species of Zygomycota and mitosporic fungi were isolated from soils containing different levels of 2,4,6-trinitrotoluene (TNT). Three moderately contaminated samples (500 ppm) and an uncontaminated control contained a rich diversity of species whereas few fungi were isolated from a heavily contaminated sample (1000 ppm). Most isolates were capable of biotransforming TNT into aminodinitrotoluenes and azoxy-dimers, although they differed widely in their tolerance of TNT. Spore germination was generally more strongly inhibited by TNT than hyphal growth. Among the Zygomycota, Absidia and Cunninghamella were highly TNT-tolerant and attacked the substrate even when this had precipitated at 1000 ppm, whereas 12 of the 14 Mortierella isolates were intolerant of TNT above 50 ppm. Among the mitosporic fungi, Acremonium, Cylindrocarpon, Gliocladium and Trichoderma but not Penicillium species were highly tolerant of TNT and had a high capacity to biotransform this compound. Large variations in these properties were determined between species and even strains belonging to the same species, and between different isolates from the same soil sample. Populations of soil microfungi therefore show a high natural variation of TNT tolerance and biotransformation ability, irrespective of any previous long-term exposure to this xenobiotic.

A new freshwater ascomycete genus Proboscispora is introduced to accommodate P. aquatica collected on wood submerged in streams in Australia and the Philippines. Proboscispora is characterized by having immersed, ellipsoidal, papillate ascomata, septate tapering paraphyses, cylindrical unitunicate asci with a refractive apical ring, and 3-septate, hyaline ascospores provided with coiled or proboscis-like bipolar filamentous appendages. Proboscispora aquatica is illustrated at the electron microscope level and is compared with Annulatascus, Ceratosphaeria, Ceriospora, Ceratostomella and Rivulicola, with which it shares some common characters.

Comparison of all presently available data on gasteromycetoid structure and development allows reassessment and leads to rectification of some questionable ideas about the relation of gasteromycetes to Agaricales. The gasteroid features which are dealt with are those which are particularly relevant to this subject. Some important, but specifically taxonomic, features are left out of the discussion. The loss of violent spore discharge is the only criterion to characterise basidiomycetes which have been united under the term gasteromycetes. Gasteromycetoid adaptations have probably arisen in the distant past at successive levels of basidiomycete evolution. Sometimes the shape of gasteromycetes is reminiscent of one of the groups from which they have descended and in other cases they have been subjected to an unique evolution in response to challenge by particular ecological requirements regarding spore dispersal.

Colonisation of Pinus radiata sapwood by sapstain fungi results in a permanent discoloration of the sap and is one of the major problems associated with P. radiata timber production in New Zealand. No fungicides are available that can provide a reliable level of control of sapstain for the extended time period required to export timber. A 4-year survey, commencing in 1996 revealed that the most common species which cause sapstain on radiata wood are Sphaeropsis sapinea (syn. Diplodia pinea), and two species of Ophiostoma (O. floccosum and O. ips). A total of 21 different species that cause sapstain have been identified to date. Two approaches for the control of sapstain are presented in this paper. The first relies on the ability of microorganisms to inhibit the growth of sapstain species. Such an ability has been demonstrated in laboratory trials on wood chips or wood blocks for 116 isolates of the 848 fungal and bacterial isolates initially considered. Six of the most effective isolates were further tested on sawn timber or debarked logs in field trials. Isolates of Trichoderma spp. and Trichothecium roseum were found to control sapstain as well as the standard fungicide treatments. T. harzianum was significantly better in controlling sapstain in the internal tissues of debarked logs than the fungicide. The second approach is based on inhibition of the sapstain causing fungi by secondary metabolites produced by plants or microorganisms. Massoialactone, produced by various fungi including Trichoderma spp., showed good antisapstain activity in laboratory and field trials. Twenty-nine essential oils from different plant species inhibited O. piceae in the laboratory. The most efficient oils were found to contain high levels of oxygenated monoterpenes. Oxygenated alcohol or phenolic monoterpenes proved to be extremely active against sapstain fungi preventing discoloration of sapwood for up to 9 months. A method of control for sapstain based on pine oil derivatives containing some of these compounds is now being developed for commercial use.

The first action spectrum for a photo-induced response of an arbuscular mycorrhizal fungus is reported. At low light intensity, the responsive wavelengths for light-induced hyphal branching of the primary germ tube of Gigaspora gigantea were determined to be in the blue to UV-A range. The action spectrum showed the greatest stimulation of branching occurred around 390 nm although a shoulder was observed between 360–370 nm. A second major peak of light-induced branching occurred at 430 nm. The exposure of specific areas of the germ tube to high intensity blue light for a short period led to several interesting observations. By exposing 2 mm segments (0–2, 2–4, 4–6, etc.) or 3 mm segments away from the tip, it was determined that photoinduction of hyphal branches could occur anywhere along the axis of a growing germ tube except in the apical 2 mm. When 3 mm segments were exposed at greater distances from the tip (6–9, 9–12, and up to 33–36 mm), branches frequently formed in areas not directly exposed to light. The branches were usually in clusters which were spaced approximately 3 or 6 mm apart. Since light scattering could be ruled out, these results indicated that the exposure sites and sites of hyphal branching did not necessarily coincide and suggested the probable involvement of a second messenger during this blue light-induced event.

Three isolates each, of nine different Trametes and five other wood inhabiting basidiomycetes, were collected from the indigenous forests of Zimbabwe, and the impact of temperature (20–60 °C), osmotic and matric potential (−0·5 to −8·0 MPa), and their interactions on in vitro growth compared. Generally, there was no significant difference between growth of isolates of the same species in relation to temperature. Temperature relationships of the species studied correlated well with their geographic distributions. Species occurring in hot, dry regions tolerated a wide temperature range, with some showing unusually high thermotolerance (55°, T. socotrana, T. cingulata and T. cervina). There were significant intra-strain differences for individual species in relation to solute potential on glycerol-modified media. Generally, growth of all species was better on glycerol- and KCl-modified osmotic media than on a matrically-modified medium (PEG 8000) at 25, 30 and 37°. The limits for growth on the osmotic media were significantly wider than matric medium, being −4·5 to −5·0 and −2·5 to −4·5 MPa, respectively. An Irpex sp. grew at lower water potentials than all other species, with good growth at −7·0 MPa. This study suggests that the capacity of these fungi for effective growth over a range of temperatures, osmotic and matric potentials contributes to their rapid wood decay capacities in tropical climates.

Strains (47) of 14 genera isolated from soil and woody chips were tested for their ability to oxidize dibenzofuran, a model compound for highly chlorinated dibenzofuran pollutants. Thirty strains formed one or more isomers of monohydroxylated dibenzofurans identified by chemical structure analysis with hplc and GC-MS, indicating an active monooxygenase system widely distributed in filamentous fungi. Dihydroxylated derivatives were detected in only very low amounts and some degradation products were observed. A few fungi metabolized dibenzofuran only to intermediates with hydrophilic characteristics (eight strains) and nine strains showed no transformation capability. The transformation reactions were not inducible and seemed to be strain-specific.

Sclerotinia minor accumulates β-carotene at levels dependent upon oxidative growth conditions and differentiation. β-carotene accumulation is 2.5-fold higher in differentiated mycelia at high than at low oxidative stress, and approx. 3-fold higher in differentiated than in undifferentiated mycelia. It is proposed that β-carotene may be produced by the fungus to counteract oxidative stress that develops during growth. This is shown by the finding that exogenous β-carotene at growth non-inhibiting concentrations causes a concentration-dependent reduction of oxidative stress (lipid and protein peroxidation) and sclerotial differentiation in this fungus. The data of this study support our hypothesis that sclerotial differentiation in phytopathogenic fungi may be induced by oxidative stress.

A PCR-based technique based on the ITS1-5.8s-ITS2 domain of the rRNA gene for identifying five species associated with Mycosphaerella leaf disease (MLD) of eucalypts was developed. Primer pairs MC2F and MC2R; ML1F and ML1R; MM1F and MM1R; MN1F and MN1R; and MP1F and MP1R amplified a product for DNA extracted from their single target species, those being M. cryptica, M. lateralis, M. marksii, M. nubilosa and M. parva, respectively. The possibility of false positive amplification by each primer pair was tested in reactions with DNA extracts from 16 other Mycosphaerella species associated with eucalypts and against non-infected Eucalyptus globulus leaves. Under the PCR conditions used, there were no false positive amplifications of the 16 non-target Mycosphaerella species, or from non-symptomatic E. globulus leaves for the primer pairs ML1F and ML1R; MM1F and MM1R; MN1F and MN1R; and MP1F and MP1R. The primer pair MC2F and MC2R amplified a 402 nt product from both the target M. cryptica and non-target M. nubilosa. However, these two species were differentiated by digesting the product with the restriction enzyme Sacc II which resulted in a single 402 nt product for M. cryptica, and two products of 78 and 324 nt for M. nubilosa. All of the primers were able to detect their target Mycosphaerella species from Eucalyptus globulus lesions. PCR reactions with these primers on DNA extracted from Mycosphaerella lesions confirmed the presence of all five species from leaf material collected from three plantations in Western Australia.

Following the Chernobyl accident in 1986, sporocarps of Suillus variegatus in Sweden showed a large amount of individual variation in concentration of 137Cs activity. Our aim was to determine the degrees to which this variability in sporocarp 137Cs levels could be explained by differences between (i) local populations, (ii) fungal genets and (iii) locations within genets. Five populations in a 100-yr-old Scots pine forest, located within a 1 km2 area, and two populations in Scots pine/Norway spruce forest, located 40 km north-west of Uppsala, were investigated. In total, 154 sporocarps were analysed to determine their 137Cs content. Of these, the genetic affiliations of 86 were successfully characterized using somatic incompatibility reactions. Twenty-six genets were found which, on average, consisted of 6·5 sporocarps. The genets averaged 7·5 m in size, measured as the length between the most distant sporocarps. The mean sporocarp 137Cs level was 67·1±2·8 kBq kg−1 D.W. (range between 13·6 and 182). According to analyses of variance, within-population variation accounted for 60% of the total variation in 137Cs levels, while 40% was ascribed to variation among populations. Within a population, 137Cs levels did not generally differ significantly between genets. Plausible reasons for intraspecific variation in radiocaesium content in sporocarps are discussed.