The present work reports the development of a PCR assay to detect the ascomycete Biscogniauxia mediterranea in asymptomatic tissues of Quercus cerris. To this purpose, two specific primers (MED1 and MED2) were designed by comparison of sequences comprised between ITS1 and ITS4 generic primers of 21 isolates of B. mediterranea and related species. Specificity of the primers was tested against 19 isolates of B. mediterranea and 20 isolates of related and unrelated genera, and against Quercus cerris DNA. The reliability of the results was confirmed by Southern Blot analysis. The 2 specific primers MED1 and MED2 were able to detect B. mediterranea DNA in the host tissues at picogram quantity of target DNA. This assay would greatly enhance the possibility to study the presence and localization of B. mediterranea during its latent phase in Quercus species.

The effects of different temperatures and pH on the growth and solubilization of insoluble calcium phosphate, cobalt phosphate, manganese phosphate, strontium hydrogen phosphate and zinc phosphate by Rhizoctonia solani on solidified media were assessed. Solubilization of the metal phosphates was monitored by the production of a clear zone around or underneath the fungus. R. solani efficiently solubilized all five metal phosphates except cobalt phosphate when grown on medium at pH 7. Solubilization activity by R. solani decreased with increasing pH on medium containing calcium phosphate but increased on strontium hydrogen phosphate-amended medium. The uptake of metals by the mycelia was unaffected by the pH of the medium or the growth temperature. Small quantities of crystals were produced in the agar when R. solani was grown on calcium phosphate- and strontium hydrogen phosphate-amended media and these were identified as calcium or strontium sulphates respectively: there appeared to be little or no production of insoluble oxalates although a role for oxalate in the overall solubilization process cannot be discounted. These results are discussed in relation to their physiological and environmental significance, and the important roles of fungi in effecting transformations of insoluble metal-containing compounds in the environment.

Isolates of Pisolithus and Scleroderma species from different northern temperate and tropical geographical regions were subjected to analyses of pure culture morphology, colony growth rates, isozyme (allozyme) variation and ribosomal DNA (rDNA) restriction fragment length polymorphisms (RFLPs). Cultural characteristics enabled clear species separation of isolates and together with growth rates suggested geographically-linked intraspecific variability in the Pisolithus populations. Combined or method-specific hierarchical cluster analyses of allozyme polymorphisms and RFLPs of the fungal internal transcribed spacer (ITS) and intergenic spacer (IGS) sequences confirmed the Scleroderma species groupings and considerable geographical and host-linked variation in the Pisolithus population. Isolates of Pisolithus from the Philippines were genetically very homogeneous and distinct from less related isolates from Europe, Scandinavia and North America. Based on the ITS–RFLP and isozyme polymorphism data, the isolates investigated probably represent four different ‘species groupings’ which supports similar findings from recent taxonomic and genetic studies of Australian Pisolithus species.

One hundred and thirty four dikaryotic isolates of Ganoderma, morphologically determined as G. adspersum, G. annulare, G. applanatum, G. brownii, G. lobatoideum, G. lobatum, G. lucidum, G. oerstedii, G. resinaceum, and G. tornatum, were examined by horizontal PAGE for eight enzymatic activities. A total of 94 bands were analysed. The objective was to evaluate the relatedness among the specific taxa by analysing numerically the isoenzymic patterns. To discern fungal individuals somatic incompatibility tests were used. Within each enzyme system several allozyme phenotypes could be observed. The enzymic systems analysed failed to yield diagnostic bands for each morphologically defined group, except the AKP system for G. resinaceum. Some bands were shared by all the isolates studied. On the other hand, diagnostic bands at the species complex level were encountered.

The effect of air-dry storage environment on the longevity of conidia from seven isolates of Beauveria bassiana produced at different times and locations was determined by estimating the parameters of a viability equation. Conidia were stored hermetically at six to 11 moisture contents between 2.3 and 32.0% with one (50±0.5 °C) to five constant temperatures (10, 20, 30, 40 and 50±0.5 °) for various periods up to 372 d and then tested for viability. All isolates behaved similarly (P > 0.25) in terms of the relative effect of moisture content (CW) and temperature (CH and CQ) on conidial longevity; common values were CW = 3.05 (SE = 0.07), CH = 0.0293 (SE = 0.0078), and CQ = 0.00081 (SE = 0.00011). Estimates of the low-moisture-content limit to the negative logarithmic relation between conidial moisture content and longevity were 4.6 and 5.0% at 50° and 40°, respectively, for isolate I98-1140ss, and 5.2 and 5.1% moisture content, respectively, for isolate I97-1111. Absolute longevity (KE) varied considerably (P < 0.005) among isolates, even within an isolate when conidia were produced at different locations. Among the eight samples of seven isolates, two cohorts were identified with respect to KE (P < 0.005): conidia of three isolates which were produced at Ascot had a common estimate of KE of 6.696 (SE = 0.170), whereas those produced at Nairobi or Carolina provided a lower estimate (6.203, SE = 0.029). This difference in KE means that for any given viability period in any given environment, the conidia produced in Ascot provided about three times the longevity of the other samples.

In Finland and Norway, a uninucleate Rhizoctonia sp. is causing a root dieback disease on nursery-grown Norway spruce and Scots pine seedlings. This Rhizoctonia can be fruited under laboratory conditions and the basidial characters fit well in the species concept of Ceratobasidium bicorne, a species originally described as a moss parasite under forest conditions. Further comparison using traditional methods (cultural morphology, nuclear condition, anastomosis) has not been possible as the forest population of C. bicorne has apparently never been cultured. In the present study, we isolated DNA from a herbarium sample of C. bicorne grown on the moss Polytrichastrum formosum. Sequence analysis of the PCR-amplified rDNA region containing the internal transcribed spacer (ITS) regions and the 5.8S rDNA gene was used to examine the conspecificity of the herbarium sample and the uninucleate Rhizoctonia sp. The nucleotide sequence of the 5.8S rDNA gene was identical between the herbarium sample and five sequenced uninucleate Rhizoctonia strains. Within the uninucleate Rhizoctonia sp., the sequence identity ranged from 96.1 to 100% in ITS1 and from 99.6 to 100% in ITS2. The sequence from the herbarium sample fits well within these limits, strongly suggesting that the uninucleate Rhizoctonia sp. and C. bicorne are conspecific. Interestingly, two of the uninucleate Rhizoctonia strains produced two ITS alleles: the genetic implications are also discussed.

Genetic relationships of the complex of Fusarium species associated with crown rot and head blight in cereals and some species associated with plant diseases in general were examined by distance and maximum parsimony algorithms of their internal transcribed spacer sequences. The analysis clustered the complex of Fusarium species that causes root and crown rot and head blight of cereals and three other clusters of F. sambucinum, F. venenatum and F. poae into one clade. This group of Fusarium species was also found in this study to correspond to the group defined by the presence of the tri5 gene. The tri5 gene was recently reported to co-segregate with the locus governing the type of trichothecene produced, and probably maps in the trichothecene gene cluster. The other clusters of F. avenaceum, F. tricinctum, F. torulosum, F. oxysporum, F. verticillioides and F. solani did not have the tri5 gene. Although, F. pseudograminearum was phylogenetically close with the cluster of F. graminearum, F. culmorum and F. cerealis, it could be distinctly separated from them. The distinct genetic status of F. pseudograminearum from F. graminearum corroborated with other published molecular data and isozyme findings. The molecular analysis provided a simple diagnostic tool to differentiate fungi causing crown rot from those involved in head blight.

Species delimitation within the core group of Peziza is highly controversial. The group, typified by P. vesiculosa, is morphologically coherent and in previous analyses of LSU rDNA sequences it formed a highly supported clade. Phylogenetic diversity and species limits were investigated within the group using sequences from the complete ITS region (ITS1-5.8S-ITS2). Eighty-three specimens were selected for molecular study from a larger sample of material studied morphologically to explore the intra- and interspecific variation of each putative species. The sister group taxon, P. ampelina was used as the outgroup and two specimens of P. subcitrina were additionally included. Seven independent lineages of rDNA were identified (I–VII), each representing one to several species. These lineages form two larger clades, A (II, and I or III) and B (IV–VII), supported by macromorphology: small (generally <2 cm), shallowly cup- to disc-shaped apothecia (A) and large (up to 15 cm), deeply cup-shaped to expanded apothecia (B). The overall exciple structure (a stratified or non-stratified medullary layer) and to some degree spore surface relief, likewise support the groupings. Clade A contains taxa with smooth or nearly smooth spores (except for P. lohjaënsis), while clade B contains taxa with a range of spore ornamentations, from smooth, finely warty to distinctly warty, and spiny. The position of groups I (P. vesiculosa and P. ammophila) and III (P. lohjaënsis) are uncertain, and these taxa also deviate morphologically from the other clade A members. The following species are recognized based on morphology and ITS rDNA analyses: P. ammophila and P. vesiculosa (I); P. alcis, P. ampliata, P. domiciliana, P. fimeti, P. nivalis, and a number of putative species or intraspecific entities (II); P. lohjaënsis (III); P. sp. c (IV); P. arvernensis (V); P. echinispora and P. sp. d (VI); and P. varia (VII). The nomenclature of these species is analyzed and taxa are typified as necessary. Based on ITS and morphology, we found no justification for recognizing more than one species in the ‘P. varia complex’, including 27 specimens that have been referred to under the names P. cerea, P. micropus and P. repanda, from an array of substrates and different geographical areas. Morphological characters previously used to delimit species within this complex, such as colour variation of the apothecia, presence or absence of a stipe, stratified or non-stratified medullary exciple (or thickness of the excipular layers), cell types in the outermost exciple and moniliform vs filiform paraphyses were not correlated with the subgroups supported by ITS analyses and appeared to be plastic. Therefore, P. cerea and P. micropus are placed in synonymy with P. varia. The name P. repanda is rejected. Levels of sequence divergence were low within group II, comprising 33 small apothecial specimens. Twelve fine-scale lineages were identified, but the analyses did not resolve relationships among these. P. granulosa sensu Boudier is considered a synonym of P. fimeti. These have previously been distinguished mainly by occurrence on various soil types, including burnt soil and soil mixed with sawdust or woodchips vs on dung. The substrate and habitat have been much emphasized in the taxonomy of Peziza, but the results obtained here indicate that populations on a diverse array of substrates may be closely related, or indeed, conspecific.

Epifluorescence microscopy and low temperature scanning electron microscopy were used to document the development of Uncinula necator on vine leaves and the antifungal effects of kresoxim-methyl and penconazole. Post-germinational growth and development followed a regular time course which was classified into 10 stages.

Kresoxim-methyl was applied at a range of concentrations and at different times before and after inoculation. In glasshouse trials at moderate relative humidity (60%), all pre-infectional applications completely inhibited conidial germination. Lower efficacies were observed with detached leaves at high humidity in Petri dishes. Post-infectional applications of at least 8 mg a.i. l−1 inhibited sporulation and mycelial growth and 67 mg a.i. l−1 caused a partial collapse of surface structures.

Penconazole applied at 17 mg a.i. l−1 did not inhibit germination, but prevented hyphal development and caused growth distortion with hyphal tip swelling. Pre- and post-infectional treatments had similar effects. Applications made 3 d after inoculation increased multiple appressoria and conidiophore formation.

A phylogenetic analysis based on internal transcribed spacer regions of the nuclear ribosomal RNA region (ITS) sequences has been undertaken for species in the genus Schizopora. Four known species were studied, viz. S. radula, S. paradoxa, S. flavipora, S. nothofagi, and a hitherto undescribed species from Taiwan. Allopatric differentiation was apparent in S. radula, for which several geographically representive samples were available. Among these, ITS sequence data obtained from S. radula isolates from British Columbia and Australasia were identical. All previously recognised Schizopora species were well separated from each other with respect to their ITS sequences. Mating compatibility tests also showed complete reproductive separation between species, but intercompatibility between cultures from the same species, irrespective of geographical origin. Overall, the morphology of basidiomes of S. radula from New Zealand differs only in minor respects from those of European and Argentinean origin, but shows a higher degree of variability than described for European specimens.

The phylogenetic position of the marine ascomycete genus Spathulospora was investigated using partial SSU and LSU DNA sequences obtained from dried herbarium specimens. Spathulospora was represented by the two species S. adelpha and S. antarctica. Phylogenetic analyses using Bayesian, parsimony, and neighbour-joining algorithms on SSU and LSU data sets agreed with the placement of Spathulospora. Both Spathulospora species are each others closest relatives, and group within the Lulworthiales (Sordariomycetes, Ascomycota) with support in all analyses. Members of the morphologically similar insect parasites in the Laboulbeniomycetes are not closely related to Spathulospora. Despite several striking morphological differences between Spathulospora and Lulworthiales, an important shared morphological character was found that until now had not been recognized. Ascospores of Spathulospora and some members of the Lulworthiales have apical chambers containing mucus believed to be involved in ascospore attachment. A closest relative to Spathulospora could not be determined.

Zoospores of the nematode-parasitic Catenaria anguillulae (Chytridiomycota) were studied by videomicroscopy in sealed films of water on microscope slides in the presence or absence of freeze-inactivated nematodes (Panagrellus redivivus). Zoospores swam for more than 1 h at a mean velocity of 104 μm s−1, interspersed with repeated phases (1–2 min) of amoeboid crawling on glass or nematode surfaces. They were attracted to and encysted near the mouth, excretory pore, and anus of nematodes, or eventually encysted at random on glass and nematode surfaces. The single posterior flagellum was immobile during amoeboid crawling but resumed rapid beating when the last pseudopodium was being retracted. Zoospores encysted by adhesion of the anterior of an amoeboid cell to a surface; then the cell posterior was raised above the anterior so that the flagellum projected perpendicular to the surface, and the flagellum was retracted by rotation of the cell contents. Cysts germinated within 20–60 min by a narrow germ-tube at the site of adhesion. The germ-tube grew a short distance, then formed an intercalary vesicle into which the cyst contents emptied by expansion of a cyst vacuole. In several cases the germ-tube penetrated a nematode and formed the vesicle inside the host. Rhizoids or assimilative hyphae developed from the vesicle or by growth of the germ-tube tip. An increasing proportion of zoospores that remained motile after 1 h in water films had a globose body in contrast to the normal elongated form. This seemed to be caused by damage during repeated transitions between the amoeboid and swimming phases, because pseudopodia sometimes remained firmly attached to a glass surface.

C. anguillulae showed consistent orientation (polarity) of zoospore encystment and cyst germination. This parallels the behaviour of other zoosporic fungi or fungus-like organisms (Plasmodiophora brassicae, Rozella allomycis, Pythium, Phytophthora and Saprolegnia spp.) suggesting that it is a common feature of zoosporic parasites. Surface-recognition for encystment by C. anguillulae was mediated by the zoospore soma, not the flagellum. In addition, we redefine the early development of C. anguillulae, including flagellar retraction by rotation of cell contents, non-specific adhesion of zoospores and cysts to surfaces, and evacuation of cyst contents into a vesicle from which further growth occurs.

During investigations of microfungi occurring on submerged plant material in tropical streams, seven species of Sporoschisma and one species of Sporoschismopsis were recorded. Three are newly described: Sporoschisma parcicuneatum, S. phaeocentri and Sporoschismopsis australiensis. Each of these species is described and illustrated in detail and a synopsis of remaining species of Sporoschismopsis is provided. Generic concepts and connections to teleomorphs are discussed and a key is provided to accepted species in both genera.

The basidiomycete genus Armillaria causes root rot and death to woody plants in boreal, temperate and tropical regions of the world. Armillaria root rot has been described from various parts of Africa on many different hosts. However, very little is known regarding the evolutionary relationships among Armillaria species in Africa. The aim of this study was to determine the phylogenetic relationships between isolates originating from different regions in Africa using nDNA sequences from two non-coding gene regions. The ITS and the IGS-1 regions of the ribosomal DNA operon were sequenced and analysed using different phylogenetic tree searching methods. Phylogenetic trees grouped the African taxa in two strongly supported clades. One of these represented A. fuscipes and the other an undescribed but distinct species.

The performance of isolates of the ectomycorrhizal fungi Coltricia perennis, Laccaria bicolor, Lactarius hepaticus and Paxillus involutus originating from Scots pine stands was studied on solid media with different concentrations of ammonium, glycine and glucose as inorganic nitrogen, organic nitrogen and carbon source. Laccaria bicolor was able to grow on both ammonium- and glycine-containing media. Biomass and growth rate of L. hepaticus and P. involutus on media with ammonium were generally higher than on media with glycine as nitrogen source. Coltricia perennis did not clearly show preference for either ammonium or glycine. Fractal dimensions, calculated from the biomass and radii of the fungi, were in the range 1–3. Fractal dimensions provided extra information about the foraging strategy of mycelia not obtained from growth rate and biomass production measurements, but cannot replace those because the use of fractal dimensions alone may lead to misinterpretation.

Production of lignin-modifying enzymes by 10 white-rot fungi, as measured by decolorization of Poly R 478 dye, varied in response to different carbon and nitrogen regimes. Fastest decolorization rates were achieved with wood polysaccharide monomers (glucose, xylose) as carbon source, although cellulose was the only carbon source to facilitate decolorization by all test fungi. Enzyme production by most isolates was strongly dependant on nitrogen levels, with high nitrogen conditions generally suppressing enzyme production. One unidentified isolate (HKUCC 4062) displayed apparent nitrogen deregulation of enzyme production. A cellulose-low nitrogen growth medium is recommended for agar-based screening procedures of lignin-modifying enzyme production by white-rot fungi.

The phylogeny of Nephroma was studied by nucleotide sequences of the mitochondrial ribosomal small subunit (mtSSU rDNA) and the internal transcribed spacers of the nuclear ribosomal repeat (ITS), together with chemical characters. The biological material included both bipartite and tripartite species and all Nephroma species native to northern Europe. Phylogenetic analyses demonstrated that all Nephroma species form a monophyletic group and that Peltigera constitutes the sister group to Nephroma. The two gene regions revealed qualitatively similar relationships within Nephroma and chemical characters had a minor impact on tree topologies. The results demonstrated that tripartite Nephroma species do not form a monophyletic group within the genus, this being in agreement with previous findings from bi- and tripartite Peltigera species. The results also indicated that N. resupinatum does not form a monophyletic group with all other bipartite Nephroma species but form a sister group to the studied Nephroma taxa. Furthermore, N. helveticums. lat. is highly variable and seems to represent aggregates of closely related taxa. Also N. laevigatum and N. resupinatum are genetically variable. All European Nephroma species can be rapidly and accurately identified on the basis of their fungal ITS sequences. This will prove useful in ecological and environmental studies.

On water agar, hyphae of many fungi are attracted to viable pollen grains of Pinus nigra. Hyphae of 41 of 157 species tested could penetrate the pollen grains, ramify within the interior and consume the contents. It is proposed that pollen serves as a supplementary seasonal source of nutrients, particularly nitrogen, for litter- and wood-decaying members of the Basidiomycota.

An in vitro conifer ectomycorrhizal model system was developed to study changes in gene expression during the establishment of symbiotic relationship. Using the model system and the mRNA differential display technique, we have identified cDNA clones from Laccaria bicolor that appear to be involved in establishing and maintaining the symbiotic relationship between L. bicolor and red pine. These differentially expressed cDNA clones were obtained from mRNA extracted from the fungus 6–24 h after initiation of interaction. BLAST analysis showed that sequences of these clones did not match with any of the previously characterized genes. The cDNAs had regions with varying degrees of similarity to genes involved in signal transduction and transcriptional activation.

A set of 23 non-sporulating, unidentifiable endophytic fungi associated with wild Vaccinium macrocarpon were examined for their polyketide metabolite producing potential. Using two degenerate polymerase chain reaction primers (FPKSKSU-2 and FPKSKSD-1), we cloned and sequenced 12 ketosynthase domains from 11 of the 23 cranberry endophytic fungi. Phylogenetic analyses segregated the 12 ketosynthase domains into three groups. One group of four sequences was clustered with polyketide synthase genes involved in melanin formation. The second group of two ketosynthase sequences clustered with aflatoxin encoding fungal polyketide synthases. The remaining six ketosynthase domains were not clustered with any of the known fungal polyketide synthase groups. Of the 12 ketosynthase fragments, five contained one or more introns in the ∼800 bp DNA region. In order to locate the phylogenetic origin of the polyketide synthase genes, phylogenetic relationships of the strains were inferred from small subunit ribosomal DNA sequences. Analyses of small subunit ribosomal DNA sequences showed that all but one of the strains grouped among the major clades of the ascomycetes. The exceptional strain, CR70, was probably an oomycete. Thirteen of the 22 ascomycetous fungi appeared within a clade that included Oidiodendron tenuissimum of the Myxotrichaceae.