Thirty-nine ectomycorrhizal isolates of Paxillus involutus, Pisolithus tinctorius, Suillus bovinus, S. luteus and S. variegatus were tested on cadmium, copper, nickel and zinc amended media to determine their in vitro tolerance, measured as inhibition of biomass production. Twenty-one isolates were from heavy metal polluted sites, whereas the others were from non-contaminated soils. There was a strong interspecific variation in metal tolerance. S. luteus, S. variegatus and P. tinctorius were more tolerant of Cu, Cd and Zn when compared with P. involutus, whereas the reverse was true for Ni. A high intraspecific heterogeneity in metal tolerance was also found. EC50 values for isolates originating from polluted sites were not statistically different from EC50 values for isolates originating from non-contaminated sites. The findings are discussed in relation to the potential benefits of ectomycorrhizal fungi in protecting their host plants from metal contamination.

Arbuscular mycorrhizal (AM) fungi, classified in the order Glomales, cannot easily be identified by hyphal morphology. PCR can be used successfully to identify the fungi within the host or soil. Some of the primers that have been used are based on a few sequences of a variable region in the SSU rRNA gene. To verify the specificity of primers of this type which have been used in earlier publications, and to provide data for future primer design, we analysed 51 partial Glomales SSU rRNA gene sequences from 33 glomalean isolates.

To distinguish contaminants from the AM fungi (AMF) all sequences were verified by phylogenetic analyses. Together with sequences from the EMBL database a set of 88 sequences from 58 isolates was analysed, comprising 39 species. The phylogenetic trees reveal at least three distinct well supported Glomus clades and other interesting relationships within the Glomales. Sequence data show that most of the primers published in earlier studies are not useful at the proposed taxonomic level. For example, the VANS1 primer site is not specific for the Glomales, and is homologous to fewer than half of the AMF sequences investigated. Primer regions that have been considered to be family-specific within the Glomales do not show strict specificity. Because clades in the phylogenetic trees fit well to several sequence patterns, priming sites for AMF are discussed and sequence data for future analyses provided.

Mycotoxins are secondary metabolites produced by many phytopathogenic and food spoilage fungi including Penicillium, Fusarium and Aspergillus. The toxicity and carcinogenicity of many of these mycotoxins, and their potential to contaminate foods and animal feedstuffs is a cause of serious concern globally, both from a food safety and food trade standpoint. Thus the rapid identification of mycotoxigenic fungi would be desirable, such that early intervention steps could be applied to help limit the amounts of contaminated materials, particularly cereals and cereal-based products, gaining access to the human food chain. With this in mind a number of PCR-based methodologies have been developed for the identification of mycotoxin biosynthetic genes in different fungal genera, together with assays developed using other genes or random amplification of polymorphic DNA (RAPD) methodologies for the identification of specific toxigenic fungi. In addition, reverse transcription (RT)-PCR, competitive PCR and Real Time quantitative PCR methodologies have also been developed for this purpose. The development of each of these techniques, their usefulness, limitations and adaptability will be discussed together with descriptions of specific examples where these techniques have been utilised in different experimental settings.

The study of mould spores is of major importance as many fungi can cause considerable economic losses worldwide acting as plant pathogens or triggering respiratory diseases and allergenic processes in humans. Knowledge of spore production relationships to different altitudes or weather patterns can be applied in a more efficient and reliable use of pesticides or improving diagnosis and treatment of respiratory allergic diseases. In this way monitoring of Cladosporium cladosporioides, C. herbarum and Alternaria spp. airborne spores during 2002 was carried out by means of three LANZONI VPPS 2000 pollen traps located in areas of north-west Spain at various altitudes and with various weather patterns.

High spore counts were recorded in the late summer and early autumn, with a fairly similar hourly spore-count pattern, increasing the concentrations in the late evening (7–10 p.m.). High spore concentrations were detected in inland rural areas in front of coastal ones. As the continentality index increased, C. cladosporioides spore concentrations rose and Alternaria declined. C. herbarum concentrations increased with increasing height above sea level. The weather factor displaying the strongest positive correlation with mean daily spore counts was temperature. The optimal conditions for high airborne spore concentrations were recorded at temperatures ranging from 23–29 °C and RH values of around 80%, followed rapidly by rainfall in Vigo and Ourense and preceded by heavy rain two days prior to recording peak values in Trives.

Aseptic root exudates were collected from the liquid culture of roots of two host (Daucus carota and Lycopersicum esculentum) and one non-host plant (Beta vulgaris) of arbuscular mycorrhizal (AM) fungi. Exudate was also collected from maize (Zea mays FRB6) seedlings which were grown hydroponically under aseptic conditions. Exudate fractions of host roots stimulated hyphal branching behind any actively growing hyphal tip of three AM fungi tested (Gigaspora gigantea, G. rosea, and Glomus intraradices). Fractionation patterns obtained from C18 Sepak cartridges loaded with carrot root exudates isolated from roots grown under various phosphorus regimes, TLC analyses, and solubility properties of fractionated components, indicated a range of hydrophilic to hydrophobic hyphal branching stimulators. The 50/70% methanol fraction from a C18 cartridge induced hyphal branching patterns of G. gigantea that were dose dependent and were identical to those observed when germinated G. gigantea spores were grown with host roots in dual culture. Exudate fractions from B. vulgaris inhibited hyphal tip growth, but inhibited hyphal tips formed recovery branches which would allow continued fungal growth. These recovery hyphae were also formed when germinated G. gigantea spores were grown in dual culture with sugar beet roots. The recovery branches induced by non-host roots and the prolific branching induced by host roots have ecological implications.

In order to investigate phylogenetic relationships of selected members of Peronosporaceae to the genera Pythium, Halophytophthora, Phytophthora, and Peronophythora, Bayesian analysis of partial sequences of the ITS1-5.8S-ITS2 region was performed. In addition, sequences of the complete ITS1-5.8S-ITS2 region were analysed for 101 collections belonging to the genera Peronospora, Hyaloperonospora, Perofascia, Pseudoperonospora, Phytophthora and Peronophythora, using Bayesian inference of phylogeny and maximum parsimony. The results confirm a close relationship of these genera. The strongly supported Peronosporaceae clade is located within the paraphyletic genus Phytophthora (including Peronophythora). Monophyly of the genera Pseudoperonospora and Hyaloperonospora are strongly supported, but monophyly of Peronospora s. str. can neither be confirmed nor rejected. Within Peronospora s. str., basic relationships often remain unclear; however, some groups form highly supported monophyletic clades. Peronospora species parasitising the same host families or orders are only partly resolved as monophyletic, indicating frequent host-jumping also between distantly related host families. All species inhabiting flowers of different host families form a strongly supported monophyletic group.

In order to integrate ustilaginomycetous anamorphs into the general phylogenetic system of Ustilaginomycetes, partial nuclear large subunit ribosomal DNA sequences of 56 teleomorphic and 19 anamorphic species of the Ustilaginomycetes were analysed. Maximum parsimony and neighbour joining confirm the new suprageneric system of Ustilaginomycetes and indicate that (i) the species of Pseudozyma represent anamorphs of Ustilaginales parasitizing grasses, (ii) Pseudozyma prolifica, the type of Pseudozyma, is very closely related to Ustilago maydis, (iii) Pseudozyma tsukubaënsis is probably synonymous with Ustilago spermophora, (iv) the species of Malassezia represent a group of its own within the Exobasidiomycetidae, (v) Tilletiopsis cremea, T. lilacina and T. washingtonensis belong to the Entylomatales and (vi) T. flava, T. fulvescens and T. minor are members of the Georgefischeriales. Like all Tilletiopsis species tested, T. albescens and T. pallescens are members of the Exobasidiomycetidae, but they cannot be ascribed to any of the known orders of this subclass. The description of the Malasseziales is emended.

Seven dominant mangrove species of an estuarine mangrove forest in south India were studied for the presence of foliar endophytes. Mitosporic fungi, ascomycetes and sterile mycelia were isolated from the leaves of the mangrove hosts studied. Although many endophytes were common to more than one host, the endophyte assemblage of each mangrove species was dominated by different endophyte species.

A world-wide study of the Oidium species causing economic damage on tomato has identified two taxa using classical morphological, scanning electron microscope (SEM) and molecular phylogenetic analyses. The material consisted of a total of 25 tomato powdery mildew isolates and 29 herbarium specimens coming from all continents where tomatoes are grown. A taxon with non-catenate conidia widespread in Europe, Africa, North and South America and Asia was identified as an O. subgen. Pseudoidium species (teleomorph: Erysiphe sect. Erysiphe). Formerly mistaken for O. lycopersicum (or O. lycopersici), it is now recognised as a distinct species, O. neolycopersici sp. nov. A phylogenetic analysis of the internal transcribed spacer (ITS) sequences of the ribosomal DNA (rDNA) indicated that O. neolycopersici is closely related to Erysiphe macleayae, E. aquilegiae and other Pseudoidium species. Only a taxon with catenate conidia was found on Australian specimens. This was identified as a species of O. subgen. Reticuloidium (teleomorph: Golovinomyces sp.). Phylogenetic analysis of the rDNA ITS sequences showed that this species is closely related to O. longipes infecting eggplant. Because it is most likely to be the same species as the original O. lycopersicum, which was actually first described in Australia, this is here neotypified as O. lycopersici.

Correct morphological identification of Alternaria is important and demands a combination of modern standardised methods and up-to-date literature. The production of secondary metabolites has previously been used as a means of identification and classification. In this study, 153 fungal isolates belonging to the genus Alternaria were examined. They were grown under standardised conditions and subjected to morphological and chemical examination. All isolates were grouped according to their three-dimensional sporulation pattern on potato carrot agar and their colony colour on dichloran rose bengal yeast extract sucrose agar (DRYES). After extraction, all isolates were analysed by a high performance liquid chromatograph equipped with a diode array detector and the resulting metabolite profiles were subjected to multivariate statistic analyses. The analyses of metabolite profiles showed that the isolates could be divided into three major species-groups that were morphologically identifiable as the A. infectoria species-group, the A. arborescens species-group and the A. tenuissima species-group. The A. infectoria species-group is chemically very different from both the A. arborescens and the A. tenuissima species-groups with only a few metabolites in common. None of the 35 A. infectoria species-group isolates produced any known metabolites and all had white or greyish white colonies on DRYES. The A. arborescens species-group and the A. tenuissima species-group, shared most of the known metabolites and had colonies of various shades of green on DRYES. One cluster of isolates belonging to the A. tenuissima species-group was able to produce tentoxin, which has not been reported previously from any A. tenuissima isolate. The results suggest that each species-group contains several taxa and these taxa need to be formally described before species specific metabolite profiles can be established.

The occurrence of fungi and slime moulds on 70 decaying beech logs was surveyed based on the presence/absence of sporocarps. In total 277 species of fungi and 25 of slime moulds were recorded and summarised in a log/species datamatrix. The structure of the datamatrix was analysed using detrended correspondance analysis (DCA). The ecological nature of the gradients expressed by the first three DCA-axes was then investigated by environmental and log related variables. The first and strongest gradient corresponded to changes in the community development during the decay process. The second gradient was complex and corresponded to both decay rate and microclimatic stress. The third, rather weak, gradient was influenced by soil conditions. The gradients are discussed in a context of fungal ecological strategy theories. A model generalised from the community development on the studied logs is proposed.

Schizochytrium limacinum sp. nov, a thraustochytrid, is described from sea water from a mangrove area of the Yap Islands in the west Pacific Ocean. It is closest to S. aggregatum, and differs from other Schizochytrium spp. in its limaciform amoeboid cells, the size of zoospores, released without an amoeboid stage, and the assimilation profile of carbon sources.

Five fungal strains that are able to grow on toluene were isolated from enrichment cultures. Three different techniques were used: solid state-like batches, air biofilters and liquid cultures. Fungal growth in the latter systems was favoured by combining low pH and low water activity. Soil and groundwater samples from gasoline-polluted environments were used as inocula. The isolates were identified as deuteromycetes belonging to the genera Cladophialophora, Exophiala and Leptodontium and the ascomycete Pseudeurotium zonatum. The previously isolated toluene-degrading fungus Cladosporium sphaerospermum was included in the present study. Results showed that fungi grew on toluene with doubling times of about 2 to 3 days. Some of the strains also grew on ethylbenzene and styrene. The apparent half-saturation constant (Km) for toluene oxidation ranged from 5 to 22 μM. Degradation activity was inhibited by 50% at toluene concentrations ranging from 2.4 to 4.7 mM. These kinetic parameters are comparable to analogous data reported for toluene-degrading bacteria. The ability of fungi to grow at low water activities and low pH suggest that they may be used for the purification of gas streams containing aromatic hydrocarbons in air biofilters.

Sphaeropsis sapinea is an opportunistic pathogen causing serious damage to conifers, pre-disposed by adverse environmental conditions or mechanical damage. Three different morphological forms of the fungus have been described and are commonly referred to as the A, B and C morphotypes. Isolates of the different morphotypes have also been separated based on differences in pathogenicity and molecular characteristics. These differences, however, overlap and have not been considered sufficiently robust to justify the description of separate taxa. The aim of this study was to consider relationships between isolates representing different S. sapinea morphotypes, using multiple gene genealogies inferred from partial sequences of six protein-coding genes and six microsatellite loci. Genealogies generated for the protein-coding genes and microsatellite loci were not congruent but both consistently grouped isolates representing the A and C morphotypes in separate but closely related clades. In contrast, isolates of the B morphotype grouped together in a clade that was equally different to the A and C morphotypes as it was to the clade encompassing isolates of Botryosphaeria obtusa. These results provide strong evidence to show that the B morphotype isolates are distantly related to S. sapinea and represent a discrete taxon, which we describe here as Diplodia scrobiculata sp. nov.

Extraradical hyphae of Glomus intraradices or G. claroideum were extracted from root free sand of two-compartment pot cultures and used to determine fungal phosphatase activity [p-nitrophenyl phosphate (p-NPP) hydrolysis]. Enzyme activity was assayed with respect to pH, temperature and different fractions of the hyphae (external soluble, wall-bound and internal phosphatases). The results showed an overall maximum enzyme activity at pH 5·2–5·6 for both fungi, with a possible secondary maximum at pH [ges ]8·8 for G. claroideum. Of the two fungi tested, G. intraradices had the highest external phosphatase activity in two experiments and the same activity in one experiment, reaching 184 μmol p-NPP hydrolysed mg−1D.W. h−1. Phosphatase activity at pH 5·2 decreased sharply with temperature, with 4·5 and 10·5% of the enzyme activity remaining at 5 °C relative to that at 37° for G. intraradices and G. claroideum, respectively. Separation of the phosphatase activity into external soluble, wall-bound and internal fractions revealed that up to 70% of the measured activity was associated with the hyphal wall, and the rest with internal structures. Exuded phosphatases were not found in measurable amounts. The implications of these results on possible hyphal utilization of organic P in soil are discussed.

We have investigated the wheat infection process of Mycosphaerella graminicola (teleomorph of Septoria tritici) through the combined application of differential interference contrast light, confocal laser scanning, and cryo-scanning electron microscopies. Several aspects of fungal development have been documented, including the presence of extracellular cirrus and germling matrices, as well as nutrient-sensitive morphogenesis. The use of confocal laser scanning microscopy was invaluable in documenting the time course of pathogen invasion and symptom development. These data were used to generate summary diagrams of the asexual infection cycle of M. graminicola, to benchmark the efficacy of various crop protection strategies.

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.

Sterile mycelia isolated from Pinus tabulaeformis were grouped into white morphotype strains based on cultural characteristics. Eighteen of the isolates were randomly selected and identified to various taxonomic levels based on nuclear ribosomal DNA (nrDNA) sequence analysis. The 5.8S gene and flanking internal transcribed spacer (ITS1 and ITS2) regions of nrDNA were amplified and sequenced. Phylogenetic analysis of the 5.8S gene sequences indicated that the white morphotype strains were Ascomycota. Further identification was achieved by means of sequence similarity comparison and phylogenetic analysis of the ITS regions. Results showed that strains WMS9 and WMS10 were Lophodermium species (Rhytismataceae), while strains WMS11, WMS13 and WMS18 were species of Rhytismataceae. Strains WMS2, WMS3, WMS4, WMS5 and WMS6 were identified to Rosellinia, strain WMS1 to Entoleuca, and strain WMS14 to Nemania (Xylariaceae). Strains WMS7, WMS8, WMS12, WMS15, WMS16 and WMS17 were xylariaceous species. The potential of using DNA sequence analysis in the identification of endophytic fungi is discussed.

The effects of temperature and water availability on growth and interactions between fumonisin-producing isolates of Fusarium moniliforme and F. proliferatum and seven other fungi from maize grain were determined in vitro. The type of interaction and index of dominance (ID) between species were markedly influenced by temperature and aw. Generally, F. moniliforme and F. proliferatum were very competitive and dominant against the Penicillium spp. and A. flavus. They were in turn dominated by A. niger, but mutually antagonistic when paired with F. graminearum and A. ochraceus. Under slightly drier conditions (<0·98 aw) A. ochraceus became more competitive and dominant over the fumonisin-producing species. A. flavus was dominant only at 30°C and <0·96 aw. F. moniliforme and F. proliferatum demonstrated dominance against all species over a range of temperatures and 0·994 to 0·96 aw. At lower aw levels they were less competitive. The growth rate of the two fumonisin-producing species was significantly reduced by F. graminearum, regardless of aw. F. moniliforme and F. proliferatum reduced growth of Penicillium and Aspergillus spp., especially at >0·96 aw. At <0·96 aw, growth of these species was unaffected. Using Biolog plates the effect of aw and temperature on utilization patterns of carbon sources in maize were evaluated for the first time. The niche overlap indices relative to F. moniliforme and F. proliferatum were determined and compared with that of each interacting species. NOIs for F. moniliforme and F. proliferatum were >0·90 at >0·96 aw and 25 and 30°, indicative of co-existence with other species. Most of species had NOIs >0·90, except in some cases when paired with F. moniliforme, where NOIs <0·80 suggested the occupation of different niches. Although there was no significant correlation between the ID and NOI methods both suggested that the niche overlap between species was in a state of flux and significantly influenced by both temperature and water availability. This suggests that interpretation of ID, or NOIs carried out under one set of environmental conditions may be misleading when considering interactions between species and also where screening for biocontrol potential is being considered.