Auxarthron conjugatum (Onygenaceae) and Myxotrichum deflexum (Myxotrichaceae) are distantly related cleistothecial (gymnothecial) ascomycetes that form ascomata with strikingly similar peridia in which rigid, branched and anastomosed, thick-walled hyphae create a cage- or mesh-like enclosure (reticuloperidium). We tested the hypothesis that the reticuloperidium plays a role in dispersal mediated by arthropods by enclosing ascomata of these fungi together with flies from the family Sarcophagidae. Gymnothecia of both fungi were picked up easily when the stiff hairs of the flies impaled the ascomata by passing through the interhyphal spaces of the reticuloperidium. Ascospore release from the gymnothecia then occurred during grooming activities during which the limbs of the flies caught the ascoma appendages causing the peridium to be torn apart. This adaptation to arthropod morphology and behaviour is interpreted as the driving force behind the evolution of reticuloperidia in unrelated groups of cleistothecial ascomycetes.

Immunogold labelling and electron microscopy were used to investigate β-1,3-glucanasesecretion by Claviceps purpurea during ergot disease of rye in situ. Molecularcytology allowed us to explore the hypothesis that this enzyme might degrade host phloem callose tomaintain flow of assimilates for fungal nutrition and therefore β-1,3-glucanase could play a rolein pathogenicity. An extracellular endo-β-1,3-glucanase was purified from axenic culture and anantibody was raised. Enzyme activity staining and immunoblotting showed that the antibody wasmonospecific for β-1,3-glucanase present in fungal protein populations. Mycelia printings ofplate-grown cultures displayed spot-like and streaky immuno-signals suggesting a secretion ofβ-1,3-glucanase at hyphal tips and young hyphae. The enzyme was immuno gold localizedpredominantly in cell walls of mycelia from axenic culture. In Western blots of honeydew fractions,one β-1,3-glucanase was immunoreactive. In inoculated plants, immunogold labelling was found inall infection stages and limited to the host-pathogen interface. Gold labelling was detected overfungal protoplasts in vacuoles and in tubular-vesicular complexes and multivesicular bodies, whichfused with the fungal plasma membrane, indicating that they are part of the secretion pathway. Thelabelling of the fungal secretory organelles and lack of labelling in any host area apart from theinterface verified the fungal origin of β-1,3-glucanase immuno-detected in infected ovaries.Antigenic sites were located in external, subcuticular, penetrating and intercellular hyphae,indicating that the enzyme was secreted throughout the colonization process in planta.Intense labelling regularly associated with fungal cell walls extended into adjacent host walls,indicating a migration of the fungal β-1,3-glucanase into the host apoplast. The gold labellingover host periplasmic spaces showed that the enzyme reached the deposition sites of callose, pointingto an enzymatic suppression of putative plant defense reactions. The host phloem was colonized inter-and intracellularly. Hyphae penetrated into the pectic middle lamella of sieve plates and intenseimmuno-labelling for β-1,3-glucanase in this area supports a phloem unblockinghypothesis.

Two specimens of a new species of Hypocrella with large stromata were collected in Bolivia and Costa Rica. The morphology of the new species, H. macrostroma sp. nov., was compared with that of other species with large stromata, i.e. H. africana, H. gaertneriana, and H. schizostachyi. In addition, phylogenetic analyses of partial sequences from three genes, large subunit nuclear ribosomal DNA (LSU), translation elongation factor 1-α (EF1-α), and RNA polymerase II subunit 1 (RPB1), were conducted to determine the relationships of the new species to other species of Hypocrella/Aschersonia. Phylogenetic analyses show that H. macrostroma belongs to a strongly supported clade that includes H. africana, H. schizostachyi, and Aschersonia insperata, whereas other Hypocrella species belong to two sister clades. Hypocrella macrostroma is described and illustrated, and a lectotype is designated for H. gaertneriana.

Two dark-spored agaric species from Asia are placed in the genus Anamika (Agaricales or euagarics clade). This result is supported by ITS and nLSU-rDNA sequences with strong measures of branch support, in addition to several morphological and ecological similarities. An inclusive ITS study was performed using a mixed model Bayesian analysis that suggests the derived status of Anamika within Hebeloma, thereby rendering Hebeloma a paraphyletic genus. However, the monophyly of Hebeloma cannot be rejected outright given ITS and nLSU-rDNA data. Thus, we propose two new Asian species in Anamika: A. angustilamellata sp. nov. from dipterocarp and fagaceous forests of southwestern China and northern Thailand; and A. lactariolens comb. nov., a Japanese species originally described in the genus Alnicola. A complete description of A. angustilamellata, including illustrations, is provided.

The nematophagous fungus Pochonia chlamydosporia is a potential biocontrol agent against root knot and cyst nematodes. Genetic transformation of the fungus to introduce visual marker genes, novel traits, or changes in expression levels of endogenous genes, would greatly enhance understanding of its behaviour on nematode-infested roots and of its interactions with other soil and rhizosphere microorganisms. A transformation system for the introduction of novel genes into P. chlamydosporia has been developed. Methods to generate protoplasts, introduce DNA and regenerate transformed viable fungal mycelium have been optimised, using plasmids carrying the green fluorescent protein marker gene gfp and the hygromycin resistance gene hph. Cultures of P. chlamydosporia were resistant to high levels of a range of fungal inhibitors, including hygromycin, that are commonly used with dominant selectable marker genes in the transformation of other fungi. However, regenerating protoplasts transformed with hph could be selected by their ability to grow through an agar overlay containing 1 mg ml−1 hygromycin. Green fluorescence was observed in protoplasts and regenerating mycelium after transformation with gfp, but the GFP phenotype was lost on subculture. Maintenance of introduced genes was not stable, and during subculture, PCR assays indicated that the transformants lost both hph and gfp. When these genes were introduced on the same plasmid, segregation of hph and gfp was observed prior to their loss. It was unclear whether the introduced plasmids were able to replicate autonomously in P. chlamydosporia, or if they integrated transiently into the fungal genome. Possible reasons for the instability of the transformants are discussed.

A transformation system is described for the edible mushrooms Pleurotus ostreatus and Volvariella volvacea. The system developed is based on a positive selection strategy using the trp3iar gene from Coprinus cinereus, which confers resistance to the antimetabolite 5-fluoroindole. Transformation frequencies were low in both species. Southern blot analysis confirmed the integration of transforming DNA into the genome of transformants and indicated the presence of tandemly duplicated copies of the plasmid in some of these transformants. The system has potential for introducing beneficial traits such as enhanced substrate bioconversion and faster sporophore development.

Nine isolates of a Colletotrichum sp. collected in North America on yellow water-lily (Nuphar luteum subsp. polysepalum) at five locations in the Pacific Northwest (PNW) and one isolate from Nymphaea odorata in Rhode Island were compared to three isolates of C. nymphaeae occurring on Nymphaea alba and Nuphar luteum in Europe. The appressoria of all North American isolates were significantly wider than those of C. nymphaeae. Conidia of the nine PNW isolates were significantly wider than those of both the Rhode Island isolate and C. nymphaeae isolates. All isolates were compared using random amplified polymorphic DNA (RAPD) and restriction fragment length polymorphism of the ITS region (RFLP-ITS). Two distinct clusters were differentiated in the dendrogram based on the RAPD analysis. The ten North American isolates formed one cluster and the European isolates of C. nymphaeae formed a second cluster. The separation of the North American isolates from the European isolates was supported by distinct restriction digest phenotypes of the ITS region. Based on morphological and molecular characterization the North American fungus is proposed as a new species, C. nupharicola.

A study on the mangrove leaf litter fungi of two tropical mangroves in Singapore was carried out. Five Halophytophthora species and four isolates which did not fit the descriptions of known species were isolated from leaves of Avicennia alba, A. rumphiana, Rhizophora apiculata and R. mucronata. Halophytophthora exoprolifera, H. kandeliae, H. operculata, H. spinosa var. lobata and H. vesicula are new records for Singapore; the first three also being new records for tropical mangroves. The isolate of H. exoprolifera sporulated at 28 °C and may be a tropical strain. H. operculata is reported for the first time outside of Australia. The results of this study contribute to the little known distribution of the Halophytophthora in the Indian Pacific region. Thirteen deuteromycetes were also isolated from the mangrove leaf litter and represented both phylloplane fungi as well as possible marine fungi.

The relationship between hyphal growth and branching of the grape pathogen Botrytis cinerea was determined on solid media containing either glucose, fructose, sucrose, tartaric acid or malic acid. The concentration of the carbon source had little effect on specific growth rate or the specific rate of tip formation, but growth was inhibited at high concentrations of tartaric and malic acids. Hyphal growth unit length and hyphal extension rate increased with increasing sugar concentration and were always significantly greater than values on tartaric or malic acids. The data provide an explanation for colonization patterns of grape berries. Growth will be poor during the period from setting to the onset of ripening, when organic acids are the main carbon source produced by the berry. Following the onset of ripening, the production of sugars provides more favourable carbon sources for the fungus, enabling achievement of higher specific growth rates, greater hyphal extension rates and, hence, greater colonizing potential.

To test the validity of R. tauricus as a separate species, its carbon source utilization, isoenzyme patterns and PCR-coupled RFLP of the ITS of its rDNA were analysed. Whilst R. tauricus differed considerably from R. pusillus and R. miehei in morphological traits as well as its ability to row on single carbon sources, the results obtained from all other experimental approaches suggest extensive similarity between R. tauricus and R. pusillus. These findings lead us to believe that R. tauricus is a mutant heterothallic strain of R. pusillus.

Cladistic analysis was performed on partial sequences from the nuclear-encoded small subunit ribosomal DNA. Four Halosarpheia spp., Lignincola laevis and Nais inornata were examined to determine the placement of these genera within the unitunicate ascomycetes. Two equally most parsimonious cladograms resulted from the analysis of the data. In a strict consensus of the two cladograms the taxa sampled did not form a monophyletic group, and Halosarpheia was shown to be polyphyletic. The marine Halosphaeriales formed a subclade with taxa from the Microascales. Data indicate that L. laevis and N. inornata may be congeneric, but other species of both genera require further study.

The phylogenetic relationships of several smut fungi parasitic on dicotyledons were analysed. Parsimony analysis was performed based on the sequences of the ITS regions of the rDNA genes. Three genera were considered: Microbotryum, Sphacelotheca and Ustilago. The cladogram showed a dichotomy: the species of Microbotryum and Ustilago parasitic on dicotyledons (dicot Ustilago) were found to be divided into two independent taxa among the Microbotryaceae. A divergent mechanism of evolution of the species of each of these two clades with their respective hosts could be involved in this dichotomy. According to our results, Microbotryum appears monophyletic and restricted to the anthericolous smuts on Caryophyllaceae. However, no morphological characters have yet been found to support this distinction, and we refute the denomination Bauhinus as defined by Moore to describe the group of ‘dicot Ustilago’ as it leads to controversial determinations. Sphacelotheca belongs to Microbotryales, but could not be synonymised with Microbotryum as S. polygoni-persicariae is in an independent clade. Lastly, U. duriaeana is independent of the ‘dicot Ustilago’ clade; the position of this species among Microbotryales is still uncertain.

The succession of microfungal communities on Myrtus communis leaf litter was monitored from Jan. 1993 to Nov. 1994 using the litter bag method. Three main groups of fungal colonizers were identified, whose presence is correlated with the successive decomposition stages of the substrate and with seasonal variations.

The occurrence of an undescribed ergot species, Claviceps citrina, on the halophytic chloridoid grass Distichlis spicata, in the Texcoco region of central Mexico, is reported. RAPD and ITS1 sequences of this fungus were compared with other Claviceps species and the morphological uniqueness of the fungus was reinforced. Its sclerotia do not contain any alkaloids of the ergoline type. Germination of sclerotia occurred immediately after placing them on humid sand. After removal of the capitula, the remaining stipe was able to regenerate the capitulum.

The development of a PCR assay for the detection of the poplar pathogenic fungi Septoria musiva (teleomorph Mycosphaerella populorum), S. populicola (M. populicola) and S. populi (M. populi) is described. Three pairs of species-specific PCR primers were designed using interspecific polymorphisms in the internal transcribed spacer (ITS) of nuclear ribosomal RNA gene (rDNA) repeats. The specificity of the three primer pairs was successfully tested on a collection of 40 S. musiva, 39 S. populicola and six S. populi isolates. Using stringent PCR conditions, no cross-reaction was observed with any of the isolates tested. The specificity of the PCR assay was further confirmed with DNA extracted from 12 additional Septoria species and 17 other fungal species obtained from stems or leaves of poplars. Specific amplification of the fragments for S. musiva and S. populicola was sensitive relatively to the technique used, detecting as low as 1 pg template DNA, and 10 pg of DNA of the target species in a background of 1 ng of DNA of the other species. Moreover, using DNA purified directly from disrupted conidia, it was possible to detect with a probability of 90%, using one unique PCR assay, the DNA equivalent of 166 conidia per μl of S. musiva and 156 conidia per μl of S. populicola. The procedures developed in this work can thus be applied for rapid and accurate detection and identification of Septoria species from poplars.

The broad spectrum fungicide mancozeb was applied to monocultured sugarcane soils affected by the growth constraint known as sugarcane yield decline. The constraint is associated with the long-termmonoculture of sugarcane and has been shown to decrease sugarcane growth by 20% in commercial crops in Queensland. The fungicide was shown to decrease root colonization by soil fungi, particularly dematiaceous sterile fungi. Higher doses of mancozeb (up to 400 mg kg−1) sometimes led to increased populations of Penicillium spp. The fungicide greatly improved plant growth and root health when applied at doses of 100 mg kg−1 and above. Results suggest that the role of dematiaceous sterile fungi in sugarcane yield decline should be further examined.

Dichomitus is re-examined in Africa and six species are accepted. Dichomitus citricremeus and D. kirkii are described as new species. Megasporoporia is reduced to synonymy with Dichomitus, and the new combinations D. carvernulosus, D. delicatulus and D. setulosus, are proposed. An emended description of Dichomitus is provided, to accommodate species with hyphae with a dextrinoid reaction. A key to all accepted species in Dichomitus is given.

Mycoëmilia scoparia gen. sp. nov. is described as a new member of Kickxellales. It is characterized by lageniform sporocladia produced acrogenously in mass and bears wet and fusiform spores on the sporocladia. Ramicandelaber brevisporus sp. nov. is distinguished from the type species of the genus, R. longisporus, by producing much shorter asexual spores, (3–)8(–13) long fertile branches arising from a globose body, and lateral branches.

Three species of fungi endoparasitic in nematodes were obtained in pure culture for the first time. The fungi belong to Harposporium and Verticillium. Morphology of the fungi on corn meal agar was studied and infectivity proving Koch's postulates was achieved for each species. The infection method for Harposporium cycloides was shown to be by spore ingestion. Whilst all species were found to produce infection conidia in pure culture, both species of Harposporium produced accessory conidia and, in H. lilliputanum, arthroconidia were also formed.

Several hyaline-spored coelomycetes placed in Ascochyta, Phoma and Phyllosticta have been recorded from spots on leaves and pods of soybean. Comparison of herbarium material, pathogenicity tests and in vitro studies have demonstrated that Phoma sojicola comb. nov. (syn. Ascochyta sojicola) was predominantly involved as a pathogen of soybean. The diagnostic characters and history of this fungus and other hyaline-spored coelomycetes occurring on soybean are described.