Somatic cells of Armillaria gallica fruit bodies have been shown to possess different genotypes for molecular-marker and mating-type loci. Here we report experiments on six quantitative traits and demonstrate that somatic cells of fruit bodies possess almost as much genetic variation for growth rate and phenotypic plasticity as do spores, the products of meiosis. Genetically distinct somatic cells therefore have the potential to grow at different rates relative to one another during primordial fruit body formation. This may confer an advantage on all cell lines within a fruit body, not just those that happen to grow better under a particular set of conditions. To our knowledge, genetic variation for fitness-related traits that make up a single genetic individual has not been reported before.

Mycorrhizal associations, including ericoid, arbuscular and ecto-mycorrhizas, are found colonising highly metal contaminated soils. How do mycorrhizal fungi achieve metal resistance, and does this metal resistance confer enhanced metal resistance to plant symbionts? These are the questions explored in this review by considering the mechanistic basis of mycorrhizal adaptation to metal cations. Recent molecular and physiological studies are discussed. The review reappraises what constitutes metal resistance in the context of mycorrhizal associations and sets out the constitutive and adaptive mechanisms available for mycorrhizas to adapt to contaminated sites.

The only direct evidence of mycorrhizal adaptation to metal cation pollutants is the exudation of organic acids to alter pollutant availability in the rhizosphere. This is not to say that other mechanism of adaptation do not exist, but conclusive evidence of adaptive mechanisms of tolerance are lacking. For constitutive mechanisms of resistance, there is much more evidence, and mycorrhizas possess the same constitutive mechanisms for dealing with metal contaminants as other organisms.

Rhizosphere chemistry is critical to understanding the interactions of mycorrhizas with polluted soils. Soil pH, mineral weathering, pollutant precipitation with plant excreted organic acids all may have a key role in constitutive and adaptive tolerance of mycorrhizal associations present on contaminated sites.

The responses of mycorrhizal fungi to toxic metal cations are diverse. This, linked to the fact that mycorrhizal diversity is normally high, even on highly contaminated sites, suggests that this diversity may have a significant role in colonisation of contaminated sites by mycorrhizas. That is, the environment selects for the fungal community that can best cope with the environment, so having diverse physiological attributes will enable colonisation of a wide range of metal contaminated micro-habitats.

In several studies of oak decline in Europe, a semi-papillate homothallic Phytophthora taxon was consistently isolated, together with other Phytophthora species, from rhizosphere soil samples. It was also found associated with necrotic fine roots and stem necroses of Fagus sylvatica and Alnus glutinosa. Due to morphological and physiological similarities, the semi-papillate isolates were previously identified as P. syringae by various authors. The morphology, physiology and pathogenicity against fine roots of Quercus robur, Q. petraea and F. sylvatica, bark of A. glutinosa, leaves of Ilex aquifolium and apple fruits of this Phytophthora species are described and compared with those of related and similar Phytophthora species, namely P. ilicis, P. psychrophila, P. quercina, P. citricola and P. syringae. The phylogenetic placement on the basis of ITS and mtDNA sequence data was also examined. Isolates of this taxon produce colonies with stellate to rosaceous growth patterns and limited aerial mycelium on various agar media. Antheridia are predominantly paragynous. In water culture catenulate hyphal swellings and semi-papillate caducous sporangia, that are usually limoniform, ellipsoid or ovoid, are formed abundandly, mostly in lax or dense sympodia. This taxon is a moderately slow growing, low temperature species with optimum and maximum temperatures around 20 and 25 °C, respectively. Tested isolates are moderately aggressive to fine roots of oaks and beech, highly aggressive to holly leaves and apple fruits, and slightly pathogenic to alder bark. Thirteen tested isolates had an identical and distinct ITS sequence which was more similar to that of P. ilicis and P. psychrophila than any other known taxa. On the basis of their unique combination of morphological characters, colony growth patterns, cardinal temperatures for growth, growth rates, pathogenicity to oaks, beech, alder, apple and holly, their host range, and ITS and mtDNA sequences the semi-papillate caducous Phytophthora isolates from oaks, beech and alder are clearly separated from related and similar Phytophthora spp., and described as a new species, P. pseudosyringae sp. nov.

Genetic variability in Crinipellis perniciosa, the causal organism of witches' broom disease in Theobroma cacao, was determined in strains originating from T. cacao and other susceptible host species Heteropterys acutifolia and Solanum lycocarpum in Brazil, in order to clarify host specificity and geographical variability. RFLP analysis of the ribosomal DNA ITS regions (rDNA ITS), and the mitochondrial DNA small subunit ribosomal DNA gene (mtDNA SSU rDNA) did not reveal any genetic variability in 120 tested strains, possibly serving only as species level markers. Genetic variability was observed in the ribosomal DNA IGS spacer region, in terms of IGS size, RFLPs and sequence data. Phylogenetic analyses (using CLUSTAL W, PHYLIP and TREEVIEW) indicated considerable differences between C. perniciosa strains from T. cacao and those from H. acutifolia (85–86%) and S. lycocarpum (95–96%). Sequence differences also indicated that C. perniciosa from T. cacao in Bahia is less variable (98%) when compared to the pathogen on T. cacao in Amazonas (97–98%), perhaps reflecting a recent introduction to T. cacao in Bahia.

The genetic structure of five Fennoscandian populations of the threatened wood-decay fungus Fomitopsis rosea (Basidiomycota) was investigated using codominant PCR–RFLP, allele specific amplification (ASA) markers, inter simple sequence repeat (ISSR) markers and mating studies. Sequence analyses of a subset of single spore isolates revealed sequence variation in four target sequences; internal transcribed spacer (ITS) and intergenic spacer (IGS1) of the nuclear ribosomal DNA, the translation elongation factor 1 alpha (efa) gene and the super oxide dismutase (sod) gene. No sequence variation was found in amplified portions of the mitochondrial large and small rRNA genes. Genotype distributions were mostly (90%) in accordance with Hardy–Weinberg expectations, and the nrDNA markers (ITS/IGS1), efa and sod were in most cases (87%) in linkage equilibrium, indicating an outcrossing reproductive mode, panmictic conditions and large population sizes of the fungus. Mating tests confirmed that F. rosea exhibits an outcrossing bipolar heterothallic mating system. Mating allele richness was high in two investigated populations. Phylogenetic analyses of ITS and IGS1 sequences from the five geographic populations revealed some geographic sub-structuring of the ITS sequences, but no sub-structuring of IGS1. The nrDNA (ITS/IGS1), efa and sod markers gave a low overall FST (0.013). The ISSR markers gave no clustering of the populations in UPGMA, and the between-population variance component was very low in AMOVA (0.4%), indicating a high level of gene flow.

The phylogenetic relationships of Tholurna dissimilis were investigated in relation to a phylogeny of twenty-three species in Caliciaceae and eighteen species from Physciaceae. ITS and LSU regions of the nuclear ribosomal DNA were used for the reconstruction of phylogenies by maximum parsimony methods. Calicium adaequatum was shown to be the closest relative of and possibly congeneric with Tholurna. Calicium is thus not monophyletic unless Tholurna is included. Calicium in the molecular phylogeny contains several distinct clades, which to some extent can be characterized morphologically. Cyphelium in a traditional sense is probably not monophyletic. Cyphelium s. str. has immersed apothecia, large smooth spores and a very thin excipulum throughout. C. inquinans and C. karelicum, which form a distinct and highly supported clade, may be accommodated in Acolium, possibly along with other Cyphelium and Calicium species. The phylogenies presented here do not support the recognition of neither Physciaceae nor Caliciaceae in a narrow sense, but they also do not exclude this. Numerous spliceosomal and unclassified insertions were found in the LSU sequences. They to some extent offered phylogenetic information both with respect to location and by their sequence similarities.

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.

Basidiomes of Amanita alboverrucosa, A. ochrophylla, and A. pyramidifera were collected from native mixed sclerophyll forest sites and of A. conicoverrucosa and A. punctata from planted stands of Eucalyptus maculata in New South Wales, Australia. DNA was extracted from stipe tissue and subjected to inter-simple sequence repeat (ISSR) PCR analysis conducted using the primers (GTG)5 and (GACA)4 in order to determine genotype distribution at each site. Two to nine genotypes of one of the species were identified at each field site. Genotypes of A. ochrophylla, A. conicoverrucosa and A. punctata were spread over areas of ca 10–60 m diam, suggesting vegetative spread via large below-ground mycelial genets. In contrast, genotypes of A. alboverrucosa were more spatially restricted, suggesting recent establishment via basidiospores and more limited below-ground vegetative spread. Two groups of A. pyramidifera basidiomes that were separated by ca 600 m were found to be of the same genotype. While this might reflect long distance spread of below-ground mycelium in this taxon, the proximity of the basidiomes to a roadway makes movement of vegetative basidiome tissue via vehicular activity and subsequent establishment equally plausible.

A data set with 1551 fungal sequences of the small subunit ribosomal RNA has been analysed phylogenetically. Four animal sequences were used to root the tree. The parsimony ratchet algorithm in combination with tree fusion was used to find most parsimonious trees and the parsimony jackknifing method was used to establish support frequencies. The full-length consensus tree, of the most parsimonious trees, is published and jackknife frequencies above 50% are plotted on the consensus tree at supported nodes. Until recently attempts to find the most parsimonious trees for large data sets were impractical, given current computational limitations. The parsimony ratchet in combination with tree fusion was found to be a very efficient method of rapid parsimony analysis of this large data set. Parsimony jackknifing is a very fast and efficient method for establishing group support. The results show that the Glomeromycota are the sister group to a monophyletic Dikaryomycota. The majority of the species in the Glomeromycota/Dikaryomycota group have a symbiotic lifestyle – a possible synapomorphy for a group ‘Symbiomycota’. This would suggest that symbiosis between fungi and green plants evolved prior to the colonization of land by plants and not as a result of the colonization process. The Basidiomycotina and the Ascomycotina are both supported as monophyletic. The Urediniomycetes is the sister group to the rest of the Basidiomycotina successively followed in a grade by Ustilaginomycetes, Tremellomycetes, Dacrymycetales, Ceratobasidiales and Homobasidiomycetes each supported as monophyletic except the Homobasidiomycetes which are left unsupported. The ascomycete node begins with a polytomy consisting of the Pneumocystidomycetes, Schizosaccharomycetes, unsupported group with the Taphrinomycetes and Neolectales, and finally an unnamed, monophyletic and supported group including the Saccharomycetes and Euascomycetes. Within the Euascomycetes the inoperculate euascomycetes (Inoperculata) are supported as monophyletic excluding the Orbiliomycetes which are included in an unsupported operculate, pezizalean sister group together with Helvellaceae, Morchellaceae, Tuberaceae and others. Geoglossum is the sister group to the rest of the inoperculate euascomycetes. The Sordariomycetes, Dothideomycetes, Chaetothyriomycetes and Eurotiomycetes are each highly supported as monophyletic. The Leotiomycetes and the Lecanoromycetes both appear in the consensus of the most parsimonious trees but neither taxon receives any jackknife support.

Many plant pathogenic foliicolous fungi recorded on Proteaceae hosts in South Africa are reminiscent of members of the Mycosphaerellaceae and their anamorphs. However, these fungi are often unusual and specific to the Proteaceae, and have proved difficult to classify in the past. To address this issue, a phylogenetic analysis of the ITS-1, 5.8S and ITS-2 DNA sequence data was performed to determine relationships between members of the Mycosphaerellaceae and some taxa apparently unique to the Proteaceae. Results from this study have confirmed Batcheloromyces to be affiliated to the Mycosphaerellaceae. Within Mycosphaerella, Batcheloromyces was also shown to be distinct from Stigmina, which clustered separately from Pseudocercospora. The separation between Mycosphaerella and Teratosphaeria (anamorph Trimmatostroma) was shown to be artificial, which was further supported by several Trimmatostroma species clustering within Mycosphaerella. From these data it is concluded that Teratosphaeria should be reduced to synonymy under Mycosphaerella, and that Trimmatostroma represents yet another additional anamorph of Mycosphaerella.

The name Marchandiobasidium aurantiacum gen. sp. nov. is introduced for the teleomorph of Marchandiomyces aurantiacus. Dolipore septa and septal pore caps of the closely related Marchandiomyces corallinus are typical of the Ceratobasidiales, and the basidiomatal characters of Marchandiobasidium aurantiacum are reminiscent of those of the monotypic genus Waitea. Morphological, ultrastructural and molecular data suggest that Marchandiobasidium should not be included in Waitea, but should be treated as a distinct genus.

Phytophthora isolates associated with Phytophthora major ITS Clade 6 were grouped into 11 phenotypic taxa. These comprised the described morphospecies P. gonapodyides, P. megaspermas. str. and P. humicola; four previously identified but so far undescribed taxa, informally designated here P. sp. O-group, P. sp. Apple-cherry, P. taxon Pgchlamydo, and P. taxon Walnut; and four previously unknown taxa, designated P. taxon Oaksoil, P. taxon Raspberry, P. taxon Forestsoil, and P. taxon Riversoil. With the exception of P.gonapodyides, each phenotypic taxon represented an unique ITS lineage. Two isolates morphologically identical to P. gonapodyides comprised a separate lineage and probably represent another taxon, designated here P. taxon Salixsoil. P. humicola, P. sp. O-group, P. sp. Apple-cherry and P. taxon Walnut grouped together as subclade I. Within subclade II, P. taxon Oaksoil, P. taxon Raspberry, P. taxon Forestsoil, P. taxon Riversoil and P. taxon Pgchlamydo formed a cluster of closely related but phenotypically distinct lineages basal to P. gonapodyides and P. megasperma, P. taxon Salixsoil being the most basal member. The taxonomy, adaptation and breeding systems of Clade 6 taxa are discussed. They show a strong association with forests and riparian ecosystems, only a limited association with agriculture and an ability to tolerate high temperatures. Also, in contrast to most other Phytophthora clades, Clade 6 taxa are predominantly sterile or inbreeding in culture. Only one taxon, P. sp. O-group, appears classically A1/A2 heterothallic.

The phylogenetic relationships of the stem rot pathogens Sclerotium rolfsii and S. delphinii were examined, based on their rDNA ITS sequences. The ITS regions were cloned and sequenced to identify three distinct ITS types: r-1, r-2, and r-3. Two different ITS types exist within S. rolfsii and S. delphinii strains. Japanese strains and one strain of S. rolfsii from the USA contain types r-1 and r-2, whereas another strain from the USA and one from Chile have only one ITS type, r-2. S. delphinii strains have types r-1 and r-3. We discuss the implications of the common presence of ITS type r-1 for the taxonomy and evolution of this species complex.

A molecular phylogenetic analysis of rDNA was performed for seven Caloplaca, seven Xanthoria, one Fulgensia and five outgroup species. Phylogenetic hypotheses are constructed based on nuclear small and large subunit rDNA, separately and in combination. Three strongly supported major monophyletic groups were revealed within the Teloschistaceae. One group represents the Xanthoria fallax-group. The second group includes three subgroups: (1) X. parietina and X. elegans; (2) basal placodioid Caloplaca species followed by speciations leading to X. polycarpa and X. candelaria; and (3) a mixture of placodioid and endolithic Caloplaca species. The third main monophyletic group represents a heterogeneous assemblage of Caloplaca and Fulgensia species with a drastically different metabolite content. We report here that the two genera Caloplaca and Xanthoria, as well as the subgenus Gasparrinia, are all polyphyletic. The taxonomic significance of thallus morphology in Teloschistaceae and the current delimitation of the genus Xanthoria is discussed in light of these results.

The distribution and behaviour of nuclei in conidia of 11 coelomycete species with tri- and tetraradiate conidia and belonging to five genera has been investigated: Cornutispora (C. ciliata, C. intermedia, C. lichenicola, C. limaciformis, and C. pittii), Eriosporella (E. calami), Furcaspora (F. abieticola, F. pinicola), Suttoniella (S. eriobotryae, S. gaubae), and Tetranacrium (T. gramineum). They have been studied by the HCl-Giemsa technique using dried, preserved material including holotypes and isotypes with ages ranging from 3 to 116 yr. Conidia of Cornutispora species showed different ploidy levels, and C. limaciformis showed a very high (>90%) frequency of stable and viable micronuclei with an unusual type of ploidy level, occurring naturally. Frequency of ploidy levels in nuclei within conidia of Cornutispora species appeared to be associated with changes in gross conidial morphology. This is the first report of micronuclei in coelomycetes. The types of appendages on arms or parts of conidia have been studied using various stains including erythrosin in ammonia and a modified Leifson's flagella staining technique. In Furcaspora species the apical and basal conidial appendages are cellular maintaining protoplasmic continuity with the arms on which they are sited. The results have been compared with those of Crucellisporium species which have tetraradiate conidia. The new species, Cornutispora intermedia, C. pittii and Furcaspora abieticola spp. nov. are described, and illustrated, and a key to all known Cornutispora species is provided.

The fungus Pochonia chlamydosporia is a biocontrol agent with commercial potential for root knot and cyst nematodes. It produces an alkaline serine protease, VCP1, during infection of nematode eggs. The gene encoding VCP1 was sequenced and the sequences of cDNAs from six isolates from different nematode hosts were compared. The gene encoding VCP1 was similar to PR1 from Metarhizium anisopliae with similar regulatory elements. Comparison of translated cDNA sequences revealed two amino acid polymorphisms at positions 65 and 99, indicating a difference between isolates from cyst and root nematodes. The positions and nature of the polymorphisms indicated that the two forms of VCP1 might have different properties and this was tested with five chromogenic polypeptide substrates. Enzyme assays revealed the two forms differed in their abilities to utilise Succ-Ala-Ala-Pro-Phe-pNa and Succ-Ala-Val-Pro-Phe-pNa, suggesting different amino acid affinities at the S3 binding region. This indicates host related genetic variation in VCP1 between isolates of P. chlamydosporia isolated from different nematode hosts, which might contribute to host preference. Such differences may be important in future exploitation of P. chlamydosporia as a nematode biocontrol agent.

In the Pacific Northwest, yellow chanterelles have long been referred to as Cantharellus cibarius, synonymous with the European yellow chanterelle. Broad scale genetic surveys of North American chanterelles with C. cibarius-like morphology have demonstrated that the nrDNA internal transcribed spacer exhibits length variability, suggesting that this common morphology masks a species complex. Recently researchers have used morphological and genetic data to identify the yellow chanterelle most frequently harvested from American Pacific Northwest forests as C. formosus, a species once thought to be rare in the region. We present three genetic data sets and one morphological data set that characterize a previously undescribed, species of yellow chanterelle from the central Cascade Mountains of Oregon. Phylogenetic analyses of the nrDNA large subunit and ITS regions show that C. cascadensis sp. nov., along with two other yellow chanterelle taxa (C. cibarius var. roseocanus and European C. cibarius), are more closely related to white chanterelles (C. subalbidus) than they are to C. formosus. Data from five microsatellite loci provide evidence that C. formosus, C. subalbidus, and C. cascadensis sp. nov. do not interbreed when they co-occur spatially and temporally in Douglas fir-western hemlock forests. This demonstrates that these three sympatric chanterelles are biological species with boundaries congruent with those delineated by nrDNA phylogenetic clades. Morphological data indicate that the colour of the pileus and shape of the stipe can be used to separate fresh collections of the two yellow species now known to co-occur in Douglas fir-western hemlock forests in Oregon.

The ketosynthase domains of putative polyketide synthase (PKS) genes from 15 species in the lichenized genus Lecanora as well as three representatives of other genera were amplified and sequenced using conserved primers. A phylogenetic analysis was carried out with the corresponding amino acid sequences, including those of non-lichenized fungi. The phylogenetic hypothesis places all PKS sequences from Lecanora and the other genera in a clade of PKSs that produce complex aromatic compounds. The PKSs from Lecanora are found in two distinct clades. One of these forms a monophyletic group with PKSs producing precursors of dihydroxy naphthalenes from non-lichenized species. This includes PKSs from the L. rupicola group and several other species which are not closely related. The other clade represents at least one functionally different protein and has no close relationships with known PKSs from other fungi. A comparison between an ITS phylogeny of the species with their DNA sequences of ketosynthase domains reveals similar PKS genes in certain closely related species. Coevolution was unapparent in other clades, suggesting the presence of paralogous genes.

Several independent molecular phylogenetic analyses have indicated that the genus Neolecta has a unique position within the Ascomycota. It is the only taxon outside the core-group of filamentous, ascoma-forming ascomycetes that also has the ability to form ascomata. Light and electron microscope studies indicate that hymenial structure and development in Neolecta spp. are unique. Ascogenous hyphae in N. vitellina branched repeatedly and successively to produce asci. Non-ascogenous hyphae were multinucleate, often with nuclei in pairs. Nuclear pairing was particularily prominent in the ascogenous hyphae. A basal septum delimited the dikaryotic ascus. Ascosporogenesis was initiated by nuclear fusion followed by a meiotic and mitotic division to form eight nuclei. The ascus apex was thin with an annular subapical thickening. Ascospores were forcibly released through a ‘split’ in the ascus apex. Woronin bodies were frequently associated with hyphal septa. Attempts to culture N. vitellina and to obtain molecular information from the type species, N. flavovirescens, were unsuccessful. However, N. flavovirescens showed several microscopic characters that indicated close relationships with the two other species in the genus, N. vitellina and N. irregularis. The position of Neolecta spp. within the Ascomycota is discussed.

Armillaria species are amongst the most important pathogens of trees and have a world-wide distribution. In recent years, the taxonomy of Northern Hemisphere Armillaria spp. has been extensively treated, but those occurring in Africa are poorly known. Previously, isolates of Armillaria from Zimbabwe have been grouped based on morphology and biochemical tests. In this study, six isolates representing the three previously characterized groups of Armillaria spp. occurring in Zimbabwe were analysed using DNA-based techniques. Three distinct clusters emerged from both PCR–RFLP and analysis of sequence data for the IGS-1 rRNA operon. The three groups corresponded to those previously identified based on morphology and biochemical tests. Differences in IGS-1 sequences strongly suggest that the Zimbabwean groups represent three distinct taxa. Isolates belonging to Group I, previously assumed to be to A. heimii, were similar to those identified as A. fuscipes from South Africa and La Reunion. Group II isolates resided in a clade apart from all other isolates and appear to represent A. heimii. The remaining isolates residing in Group III clustered with isolates from Zambia and Cameroon. These are different from A. heimii and A. fuscipes and apparently represent an undescribed taxon.