Arctic and temperate strains of Hebeloma spp. were grown in axenic culture on glutamic acid, alanine, lysine and NH4+ as sole sources of nitrogen (N), with excess carbon (C) or deficient C (supplied as glucose). Their ability to utilize seed protein as a natural N source was also assessed. All strains tested had the capacity to assimilate amino acids and generally utilized alanine and glutamic acid more readily than NH4+. Some strains were able to utilize amino C when starved of glucose C, and could mineralize amino-N to NH3-N. Arctic strains, in particular, appeared to be pre-adapted to the utilization of seed protein N and glutamic acid N, which is often liberated in high concentrations after soil freezing. The results are discussed in relation to their possible ecological importance.

Anthracnose caused by Colletotrichum is a severe foliar disease in rhododendron plantations in Sweden and Latvia. Isolates of this pathogen were collected and characterised based on morphological and molecular criteria. Out of 37 isolates examined, two with falcate spores were identified as C. dematium. The remainder of the isolates had straight cylindrical conidia, which were too variable to be reliably assigned to C. gloeosporioides (syn. C. azaleae) the reported causal agent of anthracnose of Rhododendron spp. These isolates were compared with the reference strains of C. gloeosporioides, with holo- and paratypes and with reference isolates of C. acutatum. The light and scanning electron microscopy examinations revealed that conidial shape was not a reliable criterion for separation of these two taxa and for the identification of our isolates. The two internal transcribed spacers (ITS1 and ITS2) and the 5·8S rRNA gene were PCR amplified and sequenced from all the rhododendron isolates and the reference strains, including the holo- and paratype materials. In addition, a segment of mitochondrial small subunit ribosomal DNA (mtSSU rDNA) and a fragment of a β-tubulin gene from several representatives of isolates of rhododendron as well as the reference strains were amplified and sequenced. The sizes of the amplified fragments among the isolates studied were heterogeneous only for mtSSU rDNA, which allowed separation of C. acutatum from C. gloeosporioides. Parsimony analysis of the individual and combined nucleotide sequence data sets were concordant and indicated that all isolates originating from rhododendrons belonged to C. acutatum. The grouping of the isolates was further supported by bootstrap analysis. Thus, C. acutatum was identified as the causal agent of anthracnose of Rhododendron in Sweden and Latvia. To our knowledge, this is the first report of C. acutatum and C. dematium on Rhododendron. This study is also the first to determine the genetic status of the holotype of C. acutatum and also one of the paratypes on the basis of ITS sequences in comparison with world-wide living isolates of this taxon.

A method is described for identifying strains of Metarhizium suitable for use in field experiments. It involves the restriction endonuclease digestion of a PCR product derived from the Pr1 protease gene and the analysis of the fragments by electrophoresis. Using this technique, 40 Metarhizium strains produced 15 different profile types and were clustered into four groups. Correlation between the profile of restriction fragments and geographic origin was observed for certain groups of strains. This PCR strategy allowed the identification of fungal strains, using as samples spores scraped from the surface of single insects killed by the fungus or single whole dead insects with external mycelium. The sequence of the Pr1 PCR product from two strains revealed that Pr1 gene has at least three introns.

Mycelium grew from a spore-mycelial inoculum of Aspergillus oryzae added to ultra-pure water (upw) containing silicon compounds, but did not grow in upw alone. Growth of other fungi also occurred in upw only when silicon compounds were added. Increased growth of A. oryzae, and other fungi, also followed the addition of silicic acid and other silicon compounds to Czapek Dox. Aspergillus oryzae solubilized silicon compounds in both upw and nutrient-rich media. Although interactions between microorganisms and silicon have been generally neglected, the results show that silicon compounds can increase fungal growth under both oligotrophic and nutrient-rich conditions.

Penicillium brevicompactum and other isolates with the compact, complex conidiogenous apparatus typical of the species were sequenced in one ribosomal and two protein coding regions. The aligned DNA sequences were analyzed by maximum parsimony and the data from different loci were tested for compatibility using the partition homogeneity test. Analysis of each of the three loci revealed three clades corresponding to P. brevicompactum, P. olsonii and P. biourgeianum. Using the phylogenetic species concept and the genetic isolation of the clades, P. hagemi, P. patrismei, P. stoloniferum, and P. griseobrunneum are all synonyms of P. brevicompactum. P. volgaense is a synonym of Penicillium olsonii, while P. biourgeianum is a distinct species closely related to P. brevicompactum and P. olsonii. Phenotypic distinctions between the species are mostly based on colony characteristics such as colour. P. bialowiezenze, often treated as a synonym of P. brevicompactum, is most closely related to P. polonicum.

Sowerby described Agaricus cossus in 1799. The fungus possessed a smell, resembling that of a wounded larva of Cossus cossus (Lepidoptera). The species belongs in Hygrophorus, and since more than one white Hygrophorus species has this distinctive smell the epithet cossus has been variously interpreted. The complete internal transcribed spacer (ITS) region of the original type collection made in 1794, preserved in the Royal Botanic Gardens Kew herbarium, was successfully sequenced. Comparison with the ITS sequences from four other white aromatic-acidulous smelling Hygrophorus species, including the type specimen of H. quercetorum, showed that H. cossus is a species associated with Quercus and an older name for H. quercetorum. The differences in basidiome colouration developing with age and host-tree association appear to be the most useful characters to discriminate between the four species with a Cossus cossus smell. A table of morphological and ecological characters is provided.

A molecular and morphological investigation of 35 collections of Daldinia from 11 plant species revealed five taxonomic entities of Daldinia in northern Europe. These include Daldinia concentrica, D. cf. fissa, D. grandis, D. loculata and D. cf. petriniae. D. cf. fissa, D. grandis and D. loculata were found exclusively on burnt wood, but they do not form a monophyletic unit in a phylogenetic tree derived from analysis of the ITS sequence of the ribosomal DNA.

Methanol extracts from 24 Trichoderma isolates, selected as biocontrol agents and representating different species and genotypes from three of the four taxonomic sections of this genus (T. sect. Trichoderma, T. sect. Pachybasium and T. sect. Longibrachiatum) were screened for antibacterial, anti-yeast and antifungal activities against a panel of seven bacteria, seven yeasts and six filamentous fungi previously used in similar studies. Two different growth media were tested (potato dextrose broth and CYS80), and all isolates included in the antimicrobial tests showed at least one inhibitory activity against one of the target microorganisms in one of the two culture media. No statistically significant differences were detected in the number of active strains between the two culture media, but the highest number of inhibitory strains against bacteria and fungi were found in strains from Trichoderma sect. Pachybasium, whereas strains from T. sect. Longibrachiatum showed the highest anti-yeast values. In all cases, a correlation was found between the strains that were active against yeasts and fungi. However, some degree of variability was detected for strains within the same taxonomic section. In general terms, strains from T. asperellum (mainly in CYS80 medium), and T. longibrachiatum gave the best non-enzymatic antimicrobial profiles.

Mating type and RG57 fingerprints were determined for 141 isolates of Phytophthora infestans from 63 fields in all the important potato growing areas in Norway and Finland. Seventy-six multilocus genotypes were identified, of which 53 were detected only once. Norwegian and Finnish isolates were similar in terms of genotypic diversity and the genetic distances between the genotypes. The large number of genotypes and the high genetic distances between the genotypes indicate that sexual reproduction is contributing significantly to the genetic variation of P. infestans in Norway and Finland.

All hypocrealean species of the genus Geosmithia are anamorphic fungi with connections to bark beetles. G. fassatiae, G. langdonii and G. obscura are described as new sympatric species associated with Scolytus carpini, S. intricatus and S. rugulosus in Central Europe. The species represent a complex of three sister taxa with affinities to G. flava that may be distinguished by differences in morphology, unique RAPD patterns and by sequences of ITS region rDNA. Intraspecific variability and habitat specificity of new species is described and discussed. The high morphological, genetic and ecological uniformity suggest that these Geosmithia spp. are recently derived. A key to all accepted hypocrealean species of the genus is provided.

Eutypa lata, the causal agent of Eutypa dieback of grapevines, is difficult to identify on the basis of colony morphology and is often out-competed by other fungi when isolated from wood. To facilitate diagnosis of the pathogen, we designed SCAR primers capable of amplifying DNA of E. lata and constructed a genomic DNA library from which DNA sequences specific to E. lata were identified and sequenced. SCAR primers were used to identify E. lata directly from culture without the requirement for DNA extraction or prolonged incubation periods and could also detect the pathogen in DNA isolated from grapevine wood. RFLP probes were used in slot-blot assays to detect the pathogen in DNA isolated from 1 yr old cane as well as from mature grapevine trunks. The markers developed in this study have the potential to be used as a research tool to gather information on the epidemiology of the disease and to assess the efficacy of potential control agents against E. lata.

The mycoparasite Trichoderma harzianum, a biocontrol agent, forms coils and other mycoparasitic structures upon contact with host fungi. A biomimetic system consisting of nylon fibres was used to test the involvement of signal transduction pathways in the induction of coils. Two activators of G protein-mediated signal transduction induced coiling of hyphae around nylon fibres. The peptide toxin mastoparan increased coiling more than two-fold in comparison with controls. The activator fluoroaluminate (A1F4−) had a similar effect, whereas aluminium ions alone were ineffective. cAMP increased coiling about three-fold. Although the two G protein activators, mastoparan and fluoroaluminate, have very different modes of action, they share the Gα subunit as a target. We also found that two T. harzianum isolates differ in their extent of coiling around nylon fibres in the absence of effectors. The results reported here demonstrate that the biomimetic system can be used to study the biochemistry of coil induction, and will be a valuable assay to aid in the genetic manipulation of this pathway. It is proposed that a signal for mycoparasitic behaviour from the host cell surface is transduced by heterotrimeric G protein(s) and mediated by cAMP.

The saprotrophic wood-degrading abilities of strains from the intersterility groups S and P of the necrotrophic root and white rot fungus Heterobasidium annosum were tested using a conventional soil jar method and small wood blocks of Pinus sylvestris, Picea abies and Betula verrucosa. Weight loss in dry matter of wood blocks was compared with the ability of the same strains to secrete the phenol oxidase laccase under liquid and solid-state culture conditions. Results showed the much greater ability of H. annosum P strains to degrade wood, with weight losses comparable to those reported for other white rot fungi cultivated under similar conditions. In contrast, the S isolates except Br228 and Fr154 degraded the wood blocks poorly with a maximum weight loss of ca 12% recorded after 5 mo incubation. Light and scanning electron microscopy showed hyphal colonization and decay to be typical for white rot, with both simultaneous attack by cell wall thinning and preferential lignin degradation recorded for P strains. Results for wood block degradation correlated well with the ability of the intersterility groups to produce laccase in liquid culture and solid-state culture conditions, with P strains producing ca 5–6 times more laccase than S strains. Results indicate that great differences exist between H. annosum intersterility P and S groups ability to cause wood decay, but that P strains have a significantly greater competitive saprotrophic wood-degrading ability than previously realized.

Filamentous hyphal growth is inherently suited to kinetic analysis, and in many respects the fungal mycelium can be viewed as a very mechanical biological system, which lends itself to mathematical modelling. The mathematics of hyphal tip extension growth are well-established. However, even though a hyphal growth equation can be written with confidence, and we have a good understanding of the effects of tropisms on growth, it is not easy to form a mental picture of the behaviour of large populations of hyphal tips. What is required, and what we believe we have produced, is a mathematical model that is sufficiently sophisticated to produce a realistic visualization of fungal hyphal growth. This provides us with a cyberfungus that can be used for experimentation on the theoretical rules that might govern hyphal patterning, hyphal interactions, and tissue formation and organ development by actually visualizing the virtual hyphal growth patterns that result from different regulatory scenarios. From a series of model experiments the most significant observation is that complex fungal fruit body shapes can be simulated by applying the same regulatory functions to all of the growth points active in a structure at any specific time. No global control of fruit body geometry is necessary. No localized regulation is necessary. The shape of the fruit body emerges from the concerted response of the entire population of hyphal tips, in the same way, to the same signals.

105 isolates of Verticillium fungicola from Spanish mushroom crops collected between 1992 and 1999 were tested in vitro for their sensitivities to prochloraz-manganese. Dose response relationships for inhibition of mycelial growth by the fungicide were assessed in radial growth experiments on fungicide-amended malt extract agar. The ED50 values recorded for all 105 isolates studied ranged between 0.8 ppm in 1992 and 8.8 in 1998, with an average of 2.9. 86% of the isolates tested were more sensitive to prochloraz-manganese and had ED50 values below 5 ppm, while the other 14% were slightly tolerant with ED50 values equal or above 5 ppm. Of those tested from 1999, 60% (21 isolates) grew with 50 ppm and 40% (14) also at 100 ppm, although mycelial growth was inhibited at least by 82 and 87%, respectively. The resistance factor calculated ranged from low fungicide resistance (RF=3.0) in 1992 to moderate resistance (RF=12.6) in 1998. These data confirm that the sensitivity of V. fungicola to the prochloraz-manganese gradually diminishes.

Considerable taxonomic confusion exists regarding many species of Cantharellus. Several taxa have been classified in either Cantharellus or Craterellus depending on which morphological characters were emphasised. Recent phylogenetic studies based on sequence analyses suggest that some species now classified in Cantharellus should be in Craterellus. We extracted DNA from dried herbarium specimens and amplified, sequenced and cladistically analysed approximately 650 bp of the 5′ end of the nuclear large subunit ribosomal DNA gene. Our data confirm earlier results and provide molecular evidence for the classification of additional Cantharellus species (Ca. ignicolor and Ca. lutescens) within Craterellus. Furthermore, the data enable us to predict that all Leptocantharellus-like species currently classified within Cantharellus are more accurately classified within Craterellus. The species complexes of Cr. tubaeformis and Cr. cornucopioides were also investigated. These analyses did not support the monophyly of Ca. tubaeformis but the hypothesis that colour varieties of Cr. cornucopioides represent separate species was rejected.

The tef1 gene coding for translation elongation factor EF1α was identified by a PCR-based approach using degenerate oligonucleotides derived from conserved regions seen in alignments of other EF1αs. The deduced amino acid sequence was compared to other EF1αs. In Southern blot analyses no evidence for a second gene encoding EF1α in Schizophyllum commune was detected. Abundant transcript levels were detected in Northern blot analyses. The open reading frame is interrupted by seven small introns ; however, the positions of these introns are not conserved between the homobasidiomycete Schizophyllum commune and the heterobasidiomycete Puccinia graminis genes.

During growth of Agaricus bisporus fruit bodies the amount of active tyrosinase increased. The amount of active tyrosinase can be related to the degree of browning, as opposed to the fully activated tyrosinase level. Isoelectric focusing revealed that active and latent tyrosinase isoforms having different isoelectric points could be distinguished. The isoform composition was dependent on the tissue and developmental stage. In the later developmental stages new active isoforms appeared.

The current distribution and host range of the Sclerotiniaceae indicate that the family originated in the Northern Hemisphere. The ancestors were possibly present on earth during the Tertiary period when, in most northern areas, environmental conditions were wet, warm and uniform until the approach of the Pleistocene epoch. It seems from present-day host–pathogen relationships that some ancient groups of plants and a variety of angiosperms were hosts. The teleomorph of early genera was well adapted to wet conditions, with ascospores the only dispersive spore and microconidia probably serving a spermatial function. Macroconidia were probably later evolutionary developments associated with colonization of habitats drier than the original one. The onset of the Pleistocene Ice Age would have exerted considerable environmental pressures on early genera resulting in selection of adaptations which enabled survival of the gradually changing conditions, particularly sub-zero temperatures and unavailability of hosts during the harsh winter months. The major adaptations in the Sclerotiniaceae have been a range of multihyphal, reserve-rich resting structures which survive harsh environmental conditions and provide nutrients and protection for the teleomorphs, which are highly sensitive to cold and desiccation. The resting structures are useful indicators of phylogenetic relations within the family. Information on stromata and sclerotia of the Sclerotiniaceae is reviewed and then used to discuss evolution of these structures. The first type of resting structure to evolve was probably an indeterminate stroma which developed by branching and interweaving of infection hyphae within host tissues. Several, better differentiated forms were produced with their morphology related to type of host and tissue infected and to characteristics of the pathogens. The different stromata could have evolved along a common pathway or independently. The general anatomical similarity of the various structures could be accounted for because of the limited structural forms that can be produced by interweaving of filamentous hyphae. It seems that sclerotia may have developed from hyphal tissue which had the ability to produce sclerotia when the climate was cold and wet, and macroconidia when conditions were warmer and drier. Two main types of sclerotia are distinguished, tuberoid sclerotia and plano-convex sclerotia. The literature relating to the morphology and ontogeny of macroconidia is reviewed and used for speculation on the effects of environmental conditions on evolution of macroconidia, the origin of macroconidial anamorphs and stages in the evolution of botrytoid spores. It is concluded that in the Sclerotiniaceae there are at least two main pathways along which resting structures have evolved, one leading to a variety of stromata and the other to two types of sclerotia. Sclerotia predated macroconidia and both anamorphs could have originated from common generative tissue.

Analysis of 44 isolates of Phytophthora cactorum, isolated from strawberry and other hosts, by AFLP showed that the crown rot pathotype is different from leather rot isolates and from P. cactorum isolated from other hosts. 16 of 23 crown rot isolates, including isolates from Europe, Japan, Australia, and New Zealand, were identical in an analysis based on 96 polymorphic bands from seven primer combinations. Leather rot isolates of strawberry could not be distinguished from isolates from other hosts. The pathogenicity test of all 44 isolates on strawberry plants mostly gave unambiguous results, except for three American isolates, which seemed to have reduced aggressiveness compared to the crown rot isolates. These isolates also differed in the AFLP analysis. Comparing information on the origin of the isolates with results from the pathogenicity test, showed that isolates from strawberry fruits or petioles could be either leather rot or crown rot pathotypes. None of the isolates from hosts other than strawberry caused crown rot symptoms in strawberry.