The 5′ end of the large subunit (LSU) region and the entire internal transcribed spacer (ITS) region of ribosomal DNA were sequenced from 11 species or special forms of Melampsora on Salix, and three species on Populus. For all the species, except for M. larici-epitea and M. coleosporioides, the sequences in both the examined regions were identical within a species. Within M. larici-epitea, f. sp. larici-epitea typica and f. sp. larici-retusae shared the same sequences which slightly differed from that of f. sp. larici-daphnoides. In the LSU region, M. larici-epitea, M. capraearum and the stem-infecting form on S. viminalis shared the same sequence and the Far-Eastern species M. epiphylla differed from them only slightly (p distance 0.006), indicating that they may share a common ancestral lineage. M. amygdalinae and M. coleosporioides formed a distict group (bootstrap value 100% for combined ITS and LSU data). M. larici-epitea and M. ribesii-purpurea, both belonging to the M. epitea complex, appeared to be distinct. The molecular data also suggest that the differences in certain characteristics, such as the thickness of teliospore walls and host specificity, may have evolved relatively recently.

Datronia caperata, a basidiomycete fungus, is one of the dominant polypore species found in neotropical mangrove forest fragments, where it is locally specialized on Laguncularia racemosa. We examined the genetic structure of D. caperata populations from four Panamanian mangrove forests using AFLP markers. Using five primer pair combinations, 145 loci were detected, 98.6% of which were polymorphic. Each of the populations showed a high degree of genetic diversity (Nei's h ranging from 0.146 to 0.223). Results from minimum spanning trees and Mantel tests showed little evidence for small-scale spatial structure within sites. A significant amount of total genetic variation was partitioned among populations (ΦST=0.21) separated by 10s to 100s of km, a considerably greater amount than has been detected in other mushroom and wood-decaying fungi sampled at equal or greater geographic distances. These results suggest that despite production of copious basidiospores capable of long distance dispersal, some homobasidiomycete fungi may be susceptible to genetic isolation due to habitat fragmentation.

Genetic relationships were investigated among several populations of Pleurotus tuberregium from Nigeria, Papua New Guinea and New Caledonia. Intrastock mating compatibility studies using progeny from two collections demonstrated a tetrapolar mating system for P. tuberregium. Interstock matings among the geographically distinct populations were compatible. All isolates were found to be intersterile with tester strains of other Pleurotus species, showing that P. tuberregium represents a unique intersterility group in Pleurotus. Nucleotide sequences of the ITS region of the rDNA gene were determined for 30 isolates and used to infer phylogenetic structure of populations. Phylogenetic analysis shows that African and Australasian-Pacific isolates form at least two distinct evolutionary lineages. Higher genetic divergence was observed among ITS sequences from the Australasian-Pacific region than among African isolates, which suggests a possible origin of P. tuberregium in the Australasian-Pacific region.

The arbuscular mycorrhizal (AM) fungus Scutellospora reticulata (CNPAB11) was characterized using morphological, ontogenetic and molecular approaches. Spore ontogenesis was studied using Ri T-DNA transformed carrot roots and observations were compared with those published for eight other, pot-cultured, Scutellospora species. The sporogenesis of S. reticulata exhibited an unreported pattern of outer spore wall differentiation. In addition, Denaturing Gradient Gel Electrophoresis (DGGE), targeting the V9 region of the SSU nrDNA, was used to differentiate S. reticulata from 16 other Scutellospora species and results were confirmed by sequencing analysis. Phylogenetic analyses, using nearly full length SSU nrDNA sequences, grouped S. reticulata in a cluster together with S. cerradensis and S. heterogama, species that share similar spore wall organization and also possess ornamented external walls. PCR-DGGE and sequence analysis revealed intragenomic SSU nrDNA polymorphisms in four out of six Scutellospora species tested, and demonstrated that SSU nrDNA intragenomic polymorphism could be used as a marker to differentiate several closely related Scutellospora species.

SSU rRNA gene sequences of Anamylopsora pulcherrima (Anamylopsoraceae), Placopsis gelida, Trapelia involuta and T. placodioides (Agyriaceae) were determined and aligned with the corresponding sequences of 39 other ascomycetes. Phylogenetic analysis (maximum parsimony, spectral analysis) of these sequences placed the Agyriineae outside the Lecanorales and suggested a sister group relationship to Ostropales/Pertusariales. The resurrection of the order Agyriales is proposed based on molecular and morphological data, such as faintly amyloid asci opening by dehiscence. The sequence data support the two families Agyriaceae and Anamylopsoraceae to be accommodated within the order Agyriales. The Agyriales, Ostropales and Pertusariales can be placed in the class Lecanoromycetes.

The interactions between Pythium oligandrum hyphae and two types of sclerotia, i.e. the plano-convexoid sclerotium of Botrytis cinerea and the tuberoid sclerotium of Sclerotinia minor, were investigated by ultrastructural and cytochemical experiments. In the mycoparasitism of P. oligandrum, some differences in relation to sclerotium anatomy and the role of the rind layer in preventing invasion are documented. Both types of sclerotia showed neither alterations of the heavily melanised rind walls, nor direct rind wall penetration by P. oligandrum. This oomycete successfully entered B. cinerea sclerotia only through breaches at the junction of rind cells and corresponding to gaps in melanin deposits. On the other hand, none of these breaches was observed in the small sclerotia of S. minor, and P. oligandrum ingress in the sclerotia stopped at the inner rind layer. After the penetration of B. cinerea sclerotia by the mycoparasite, it extensively colonised the cortical and medulla areas by intercellular growth. The invaded tissues displayed pronounced alterations as well as some disorganisation of tissue in places. Colonisation was associated with severe chitin degradations of all host walls, which occurred even at some distance from P. oligandrum hyphae. The observation of wall thickenings in some P. oligandrum–hyphae suggests that the sclerotial cells constitute a harsh environment unsuitable for survival of the mycoparasite. These wall thickenings could be interpreted as P. oligandrum defence-like reactions.

Restrictions patterns of the ITS rDNA and a partial fragment of the β-tubulin gene were shown to help identify Phaeoacremonium species associated with diseased grapevines. PCR-RFLP markers revealed a high frequency of P. parasiticum, together with P. aleophilum, in fungi isolated from stems and trunks of mature diseased vines showing ‘hoja de malvón’ disease, and from young declining plants in Argentina. This distribution is different from that in vineyards in other parts of the world, where P. aleophilum is dominant. Indeed, this is the first report associating P. parasiticum with diseased vines.

Downy mildew of oilseed poppy (Papaver somniferum) has become a serious disease issue for the Tasmanian poppy industry since its first record in 1996. Previous reports have reported the pathogen as Peronospora arborescens, which is differentiated from the related species P. cristata, also known to infect Papaver spp., by conidium dimensions alone. This study investigated the taxonomic status of the downy mildew pathogen, using both morphological characters and molecular analysis of the internal transcribed spacer (ITS) region of the ribosomal DNA (rDNA). The inherent variability of conidium dimensions made differentiation of species difficult. Sequence homology and phylogenetic analyses of the ITS region showed the pathogen to be more closely related to P. cristata than P. arborescens. It is therefore proposed that downy mildew of oilseed poppy in Tasmania be reattributed to the pathogen P. cristata. In addition to this work, PCR primers have been developed for the specific detection of the downy mildew pathogen in Tasmania.

Isozymes of five Australian Ganoderma species were studied using cellulose acetate gel electrophoresis (CAGE) and PAGE. Phenetic analysis supported the distinction between the five species, which were separated by unbiased genetic distances of between 0.532 and 3.330. Estimates of heterozygosity and polymorphisms identified considerable genetic variability within populations and species. The putative saprotrophic G. australe, G. incrassatum and G. cupreum had the lowest genetic variability while the pathogen Ganoderma sp. Group 6.3, morphologically similar to G. lucidum, had the highest, followed by G. weberianum. Isolates of G. adspersum, G. applanatum from Europe and G. australe from Australia differed at most loci, thus the commonly accepted synonymy between G. australe and G. adspersum was not supported. Pectic isozymes alone were sufficient to distinguish three laccate (possessing a cutis surface consisting of a palisade of inflated hyphal ends) Australian species, G. weberianum, Ganoderma sp. Group 6.3 and G. cupreum, but they did not distinguish between the non-laccate G. australe and G. incrassatum. The laccate group contains species of greatest economic importance. Australian species were resolved by a single isozyme (glucose-6-phosphate dehydrogenase) using CAGE, demonstrating the potential for this method as a rapid diagnostic tool for identifying species of Ganoderma. This is the first reported population genetics based study of Ganoderma using isozymes.

Sequences of the internal transcribed spacer (ITS) region of the nuclear ribosomal DNA of ectomycorrhizal fungi were analysed and a specific PCR primer pair for Tricholoma matsutake was designed. Using the primer pair, part of the ITS region of T. matsutake (400 bp) was amplified, but no amplified fragment was detected for other ectomycorrhizal fungi. PCR was performed on DNA extracted from mycorrhizas of T. matsutake and Shiro soil (extramatrical mycelium of T. matsutake and soil complexes) and the 400 bp fragments were also specifically amplified. This indicates that presence of T. matsutake at any of its life stages can be easily confirmed by PCR typing.

Botryosphaeria spp. from seeds of the native afromontane forest tree species, Podocarpus falcatus and Prunus africana, in Ethiopia have been identified. This is achieved by combining anamorph morphological characters and ITS sequence data. From a relatively small sample, four Botryosphaeria spp. were encountered. Two of the species from P. falcatus and the one from P. africana have not been previously described. The two species from P. falcatus were represented by only one isolate each and are not named here. The morphology of their Diplodia and Dothiorella anamorphs is, however, characterised. The anamorph of the other Botryosphaeria sp. from P. africana is described here as Diplodia rosulata sp. nov. Furthermore, B. parva is identified from P. falcatus based on ITS phylogeny. This species is also an important pathogen of various commercially important tree species in Ethiopia and elsewhere. This study highlights the ability of Botryosphaeria spp. to infect seeds and the possibility that they might be distributed in this way. The study also contributes to recent attempts to stabilize the taxonomy of Botryosphaeria anamorphs, especially regarding Diplodia, which is currently in taxonomic disarray.

Ericoid mycorrhizal fungi increase the ability of their host plants to colonise soils polluted with heavy metal ions, although the mechanisms are not clearly understood. Two mycorrhizal mycelia of Oidiodendron maius isolated from contaminated soil were previously shown to tolerate high concentrations of heavy metal ions in the growth medium. The influence of zinc ions on the secretion and activity of polygalacturonase (PG), an extracellular enzyme that hydrolyses the pectin component of the plant cell walls, was investigated because of their significance during saprotrophic growth. Two major PG isoforms expressed both in the absence and in the presence of increasing concentrations of zinc ions were identified. The PG isoforms were purified from the tolerant Oidiodendron strains as well as from ericoid fungal isolates from non-polluted soils. Addition of increasing concentrations of Zn and Cd ions to the purified enzymes resulted in an increase of PG activity of both tolerant and non tolerant O. maius isolates at doses below 1 mM. By contrast, at the same metal ion concentrations PG activity of a sterile isolate from non-polluted soil was unaffected or slightly inhibited. We speculate that the response of PG to heavy metal ions may have been a pre-adaptive factor for the colonisation of polluted soils by O. maius.

Intraspecific variation of 25 Metarhizium anisopliae var. anisopliae isolates from various insect hosts and geographical origins was studied using RFLP analysis of the rDNA gene complex and the mtDNA. Heterologous and homologous mitochondrial and ribosomal probes were used to produce RFLP profiles of the isolates. The rDNA analysis allowed the differentiation of only seven isolates but provided evidence for the possible presence of introns in different sites of the nuclear rRNA-gene-complex. PCR amplification of the ITS1-5.8S-ITS2 rDNA region and the mtDNA regions corresponding to the SrRNA and the LrRNA, followed by restriction analysis of the PCR products underlined the conserved nature of these regions. By contrast, digestion with any one of endonucleases Hae III, Cfo I, Hpa II and subsequent RFLP analysis of the mtDNA, allowed the classification of the 25 isolates in 10 distinct groups. Double digestions using the restriction endonucleases Kpn I and Sac I led to maximum isolate differentiation, producing unique patterns for 16 isolates and subdividing the remainder into four groups of two or three isolates. This indicates the potential of mtDNA RFLP analysis as an excellent tool for fingerprinting M. anisopliae isolates and for studying genetic polymorphism.

Xylomyces is re-examined, the type specimen X. chlamydosporis redescribed and illustrated, and new distribution records are provided. Four new species, X. elegans sp. nov., X. giganteus sp. nov., X. punctatus sp. nov. and X. pusillus sp. nov. are described from wood submerged in freshwater collected in various countries. The chlamydospores of these species are drawn at the same scale as a composite diagram for comparison and each is illustrated with light micrographs. Xylomyces foliicola is regarded as atypical in the genus. A key to the accepted species in Xylomyces is provided.

The diversity of ectomycorrhizal mycobionts of Pisonia grandis (Nyctaginaceae) from coral cays in the Capricorn-Bunker group, Great Barrier Reef, Australia, was examined. Only two ectomycorrhiza morphotypes (brown and black) were identified in soil from seven cays and DNA from both morphotypes was subjected to ITS-RFLP and sequence analysis. The brown morphotype was present in soil from all cays but the black morphotype was only observed in soil from three cays. ITS-RFLP analysis showed that the brown and black morphotypes were formed by different fungal taxa, with the RFLP pattern for the black morphotype being consistent with that of the culture previously obtained from black ectomycorrhizal roots on Heron Island. Comparison with the GenBank database revealed that closest matches to both morphotypes were sequences for various Thelephoraceae (Basidiomycota), but the brown and black morphotypes had only 80% sequence similarity to each other. Neighbour-joining analysis of these sequences with sequences for other Thelephoraceae grouped the brown and black morphotypes in a well-supported clade with several Tomentella species, suggesting that both belong to this genus. The data are discussed in relation to ectomycorrhizal fungal diversity and the coral cay habitat.

The phylogenetic relationship of 52 specimens representing 30 species of Anthracoidea (Ustilaginales) was investigated by molecular analyses using sequence data from the large subunit (LSU) of nuclear rDNA. Phylogenetic trees were inferred with neighbour-joining (NJ), maximum parsimony (MP), and Bayesian Markov chain Monte Carlo (MCMC) methods. The results are discussed with respect to the species concept and the subdivision of the genus into subgenera and sections. Collections from different hosts and localities were compared. Our analyses can neither support nor significantly reject the hypothesis of the bipartition of the genus Anthracoidea. Thus, the representatives of the subgenus Proceres appeared in the NJ analysis as a moderately supported monophylum, whereas MCMC analysis revealed a polyphyletic topology for this group. Paraphyly of the subgenus Anthracoidea was supported by all methods used. Sections Echinosporae and Leiosporae were each represented by two species in our analyses which grouped together with high support. Section Anthracoidea should be restricted to a highly supported group with extremely irregular to angular teliospore shape. However, these three sections do not cover the whole diversity of the subgenus Anthracoidea. Molecular data largely supported the traditional circumscription of species, and species delimitations are discussed.

Four new taxa are described, each having multiseptate ascospores with hyaline end cells; Savoryella limnetica, Ascotaiwania wulai, A. hsilio and A. sawada. Savoryella and Ascotaiwania are evaluated and separated by the following characters: Savoryella has broad, up to 8 μm paraphyses (sparse) that are septate and rounded at their ends, and smaller asci with an apical thickening containing a plugged pore and 3-septate ascospores; Ascotaiwania has narrow, filiform, septate paraphyses up to 2 μm wide, but these deliquesce early and are rarely observed in mature ascomata. Ascotaiwania also has asci with a well-developed apical ring and plugged pore and ascospores generally with more than 3 septa. Ultrastructural studies of A. lignicola showed that the ascopores are covered by a thin mucilaginous sheath and unitunicate asci with the wall comprising an outer, 30–40 nm electron-dense layer and an inner, 420–450 nm, thick, electron-transparent layer. Asci have a well-developed apical apparatus consisting of an electron-dense apical ring with a plug. The plug deliquesces prior to ascospore release. The ascospore wall comprises an electron-dense episporium and a less electron-dense mesosporium. External to the episporium is a fibro-granular sheath.

A synopsis of the subgenus of lichenicolous fungi Lichenogramma is presented. It comprises eight species of Lichenostigma with oval to elongate ascomata connected to superficial strands of vegetative hyphae. Five of them are described here as new: Lichenostigma diploiciae (on Diploicia subcanescens); L. epipolina (on Diplotomma epipolium); L. gracilis (on Acarospora fuscata); L. rouxii (on Squamarina spp.); and L. subradians (on Acarospora spp., mainly subgen. Acarospora). The concept of the genus Lichenostigma is enlarged to accommodate also species with submuriform ascospores. A key to all the species of the subgenus is provided.

Several fungi associated with leaf spots and stem cankers of Proteaceae are reported. The new species Kabatiella proteae, Phloeosporella protearum, Septoria grandicipis, Stilbospora proteae and Trimmatostroma elginensis are described. Several new teleomorph-anamorph connections are reported, including Mycosphaerella stromatosa and Pseudocercospora stromatosa, Teratosphaeria microsporum and Trimmatostroma microsporum, and Lembosia proteae and Clasterosporium proteae. Additional species described are Lophiostoma fuckelii and Verrucisporota proteacearum which are also newly recorded associated with leaf spots of Proteaceae in South Africa.

Selected isolates of Phytophthora infestans from around England and Wales were fingerprinted using both RG57, a multi-locus RFLP probe, and Amplified Fragment Length Polymorphisms (AFLPs). The larger number of polymorphisms detectable with the AFLP method allowed resolution of several similar AFLP genotypes among isolates with identical RG57 fingerprints. However, some isolates with the same RG57 genotype had remarkably dissimilar AFLP genotypes, suggesting that there has been convergent evolution of some RG57 fingerprints. Also, some isolates with dissimilar RG57 fingerprints had similar or identical AFLP fingerprints. Both techniques distinguished isolates of mitochondrial DNA haplotype Ia from those of haplotype IIa. However, with AFLPs only, most of the isolates of A2 mating type were very similar and were distinguished from those of A1 mating type, suggesting that gene flow between A1 and A2 genotypes is limited and that sexual recombination is rare.