Coarse woody debris is important for mycodiversity in forest ecosystems, but its availability in managed stands is reduced. Leaving dead wood during felling is suggested as an option to sustain and restore the diversity. However, little is known what fungi would colonise freshly cut wood left on managed sites, and how the colonisation process is influenced by ecological factors. During summer and autumn, 120 freshly cut Picea abies stem sections over 8 cm in diameter were placed upright in mapped locations over two discrete plots separated by 100 m in a north-temperate forest. After seven weeks the sections were collected, and isolation and identification of fungi was done from their upper surfaces. In all 943 fungal strains were isolated, representing 97 species. Species richness in the summer survey was 42.5% higher than during the autumn survey. Low species similarity characterized the different seasons (Sorensen indices: SS=0.36 and SN=0.34) and for 21 species (22%) observation frequency was significantly affected by season. As a result, community structures in summer and autumn differed notably (z-test; P<0.001). Species richness between the two plots differed by less than 10%, but there were 64 species (66%) found only in one of them, thus qualitative similarity was low (SS=0.49). Quantitative similarity was higher (SN=0.63), indicating that the dominant species colonised wood to a similar extent in both areas. Fungal community structure differed significantly among the two plots (z-test; P<0.001). Our data showed that freshly cut CWD contributed to mycodiversity in managed north-temperate forest, providing habitats for numerous individuals from over 100 species. The fungal community within a single stand differed markedly both across small distances and over the seasons. In order to sustain and enhance mycodiversity in managed stands, coarse wood should always be left during harvesting. This study also demonstrates the importance of molecular identification and ITS sequence databases for exploring fungal diversity in natural communities.

The maize endophyte Acremonium zeae is antagonistic to kernel rotting and mycotoxin producing fungi Aspergillus flavus and Fusarium verticillioides in cultural tests for antagonism, and interferes with A. flavus infection and aflatoxin contamination of preharvest maize kernels. Chemical studies of an organic extract from maize kernel fermentations of Acremonium zeae (NRRL 13540), which displayed significant antifungal activity against Aspergillus flavus and F. verticillioides, revealed that the metabolites accounting for this activity were two newly reported antibiotics pyrrocidines A and B. Pyrrocidines were detected in fermentation extracts for 12 NRRL cultures of Acremonium zeae isolated from maize kernels harvested in Illinois (4/4 cultures), North Carolina (5/5), Georgia (1/2) and unrecorded locations within the USA (2/2). Pyrrocidine B was detected by LCMSMS in whole symptomatic maize kernels removed at harvest from ears of a commercial hybrid that were wound-inoculated in the milk stage with A. zeae (NRRL 13540) or (NRRL 13541). The pyrrocidines were first reported from the fermentation broth of an unidentified filamentous fungus LL-Cyan426, isolated from a mixed Douglas Fir hardwood forest on Crane Island Preserve, Washington, in 1993. Pyrrocidine A exhibited potent activity against most Gram-positive bacteria, including drug-resistant strains, and was also active against the yeast Candida albicans. In an evaluation of cultural antagonism between 13 isolates of A. zeae in pairings with A. flavus (NRRL 6541) and F. verticillioides (NRRL 25457), A. zeae (NRRL 6415) and (NRRL 34556) produced the strongest reaction, inhibiting both organisms at a distance while continuing to grow through the resulting clear zone at an unchanged rate. Maximum colony diameters for A. zeae (NRRL 6415) and (NRRL 13540), on potato dextrose agar after 14 d, were attained within the range of 25–30 °C, with less growth recorded at 15 ° and 37.5 ° and no growth at 5 °. Potential interactions between A. zeae and other maize endophytes are considered and the significance of these interactions relative to the aflatoxin and fumonisin contamination of preharvest maize is presented. This is the first report of natural products from Acremonium zeae.

An assessment of the inter- and intraspecific resolution of 5′ nrDNA ITS TRFLP was conducted by computer-simulated restriction analysis of 316 ectomycorrhizal GenBank sequences. Generally, sequences with a similarity of <90% could be distinguished with two to three independent enzyme digests, although sequences with similarity >95% were likely to remain unresolved. Choice of restriction enzyme strongly influenced resolution, especially when less than three enzymes were used. Although our results showed that 5′ nrDNA ITS TRFLP is a powerful tool for distinguishing between species of ectomycorrhizal fungi, closely related species, including species of Rhizopogon, Dermocybe, Hebeloma, and Lactarius produced indistinguishable 5′ nrDNA ITS TRFLP – profiles. 5′ nrDNA ITS TRFLP may also split a species, and the probability of this occurring reflected intraspecific sequence variation. For groups of closely related species, the use of 3′ nrDNA ITS in conjunction with 5′ nrDNA ITS produced improved resolution comparable with RFLP analyses. Overall, our results show that nrDNA ITS TRFLP is a valuable addition to the array of molecular tools available to ectomycorrhizal ecologists. However, simple assessments of ectomycorrhizal species diversity based on numbers of unique TRF created with a single restriction enzyme must be viewed with caution, as for each enzyme we examined, identical TRF common to groups of unrelated species were observed. In addition, to maximize the effectiveness of TRFLP in surveys of ectomycorrhizal fungi it will be useful to combine information from at least two independent enzyme digests in order to distinguish and track species in the field.

Haloaleurodiscus gen. nov. (Homobasidiomycetes) is described from Japanese mangrove forests with one species H. mangrovei sp. nov. The genus is morphologically characterized by having resupinate basidioma, nodose-septate hyphae, sulphoaldehyde-positive gloeocystidia, dendrohyphidia and amyloid basidiospores with minute warts. These morphological features are similar to those of Aleurodiscuss. lat., but H. mangrovei differs from the Aleurodiscus primarily in occurring in white pocket-rot and is not closely related based on ribosomal DNA sequence analyses. Molecular data suggest that this species is phylogenetically placed in the root of the ‘Peniophorales’ clade. In addition, ecological and physiological features of the species are provided.

Penetration of Monosporascus cannonballus into and growth within cantaloupe roots was studied using light and electron microcopy. Germ tubes penetrated the epidermis, and hyphae grew, without branching, almost directly to the xylem. The hyphae traversed the endodermis into protoxylem cells, and then grew extensively within the lumen of metaxylem vessels. Eventually, the hyphae grew back out into the cortical cells. A relatively low percentage of cells within both the cortex and xylem of lesions contained hyphae. The hyphae were generally localized within the lesion and could rarely be isolated more than 2 mm away from the margin of the lesion. Regardless of tissue type, hyphae were predominately intracellular. M. cannonballus appeared to be most similar to vascular wilt pathogens in its mode of parasitism, but does not spread via the vascular system to above-ground plant tissues.

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.

Entomophaga maimaiga is a naturally occurring fungal pathogen specific to larvae of the gypsy moth, Lymantria dispar. E. maimaiga is thought to be native to Asia where its epizootics can suppress gypsy moth outbreaks. However, in the USA this beneficial fungal pathogen was not observed until 1989, although an isolate of E. maimaiga from Tokyo was released in Massachusetts to control gypsy moths as early as in 1910–1911, and another isolate from Ishikawa Prefecture in Japan was later released in 1985 and 1986 in New York and Virginia. Our objectives were to: (1) test the hypothesis that E. maimaiga populations in the USA have reduced genetic variability due to founder effects compared to the putative ancestral populations in Asia; (2) track the origin of the North American populations of this fungus; and (3) assess whether genetic differences among E. maimaiga isolates are correlated to morphological differences. We compared genetic diversity among 30 E. maimaiga isolates originating from seven states in the USA, five prefectures in Japan, one province of China and one region of far eastern Russia by AFLPs. Among 14 USA isolates, only ten polymorphic AFLP loci were found, whereas 56 polymorphic loci were found among 16 Asian isolates; 29 loci were polymorphic among 12 isolates from Japan alone. Average gene diversity (h¯) for the polymorphic loci was 0.223±0.005 for Asia (including Japan), 0.131±0.006 for Japan only, and 0.041±0.004 for the USA. Thus, native populations from Asia were more diverse than the USA populations. These results are consistent with the expectation of a population founded from a source population by a small number of individuals. Distance and parsimony analyses of AFLP data showed that the isolates from the USA formed one distinct clade that was most closely related to Japanese isolates collected outside the Tokyo area. No morphological variation of E. maimaiga from different geographical locations was detected.

Substantial polymorphism was detected between isolates from five populations of Alternaria brassicicola attacking Cakile maritima along the New South Wales coast of Australia, with a maximum of two genotypes being shared between population pairs. Of ten pair-wise population comparisons, six had no pathogen genotypes in common; only one genotype occurred five times, and most (93%) were found only once. Although an UPGMA based on Nei's measure of genetic distance separated the five populations, a cluster analysis using individual isolates failed to group them according to population, indicating significant gene flow. An analysis of molecular variance indicated ca 14% of the variation occurred between populations, representing moderate population differentiation over the spatial scale of the study. Tests of the relative contribution of clonality and sexual recombination indicated low, albeit significant levels of linkage disequilibrium in all populations. The level of linkage disequilibrium, and the high genotype diversity, provides support for the contention that a hitherto unidentified sexual stage might be a significant factor in the life-cycle of A. brassicicola.

In an effort to meet the stringent requirements towards registration of microorganisms as biopesticides, several molecular techniques were tested as part of a strategy to develop a quality control system for Pseudozyma flocculosa, the active ingredient of Sporodex, a biofungicide used for the control of powdery mildew fungi. In the first approach, multiplex PCR fingerprints generated by three sets of primers allowed differentiation of several isolates of P. flocculosa from closely related species, or genera such as Tilletiopsis. The same set of primers was used in quality control experiments and revealed fungal contamination that was otherwise not observed by standard culture and microscopy techniques. In addition, the use of random amplified microsatellites generated by (GT)n and (CCA)n primers was applied as a measure of possible genetic variation over 65 repeated subcultures of P. flocculosa. Finally, a novel technique was developed and named reverse intron PCR (RIP), based on the presence of an intron revealed by partial sequencing of mtLSU of P. flocculosa. RIP allowed not only differentiation of P. flocculosa from other species but also separated the isolates of different origins within P. flocculosa. This new technique could find useful applications in phylogenetic studies of closely related fungal species and isolates.

A Cylindrocladium-like hyphomycete collected on leaf litter of Celtis tala in Argentina had rDNA sequence data (ITS and LSU) that showed it resides in the Hypocreales, and is a member of the Nectriaceae, closely related to, but distinct from Cylindrocladium. A new genus, Dematiocladium and species, D. celtidis gen. sp. nov. is, therefore, introduced to accommodate this fungus. Based on morphology, it can be distinguished from other conidial hypocrealean genera with hyaline, penicillate conidiophores and cylindrical conidia by lacking stipe extensions and vesicles, and by the presence of brown to dark brown, thick-walled setae.

Rabbit pellets collected from the field were colonized by Podospora pleiospora at the exclusion of other coprophilous fungi, suggesting antibiosis. In liquid culture, P. pleiospora produced sordarin (1); sordarin B (2), a new compound in which sordarose is replaced by rhamnose; hydroxysordarin (3); and sordaricin (4). The major compounds 1 and 2 exhibited minimum inhibitory concentrations of 0.5–2.5 μg ml−1 against the yeasts Nematospora coryli and Sporobolomyces roseus, but showed little or no activity against bacteria or coprophilous filamentous fungi. In liquid culture, the production of 1 and 2 together amounted to 2.7 μg ml−1, whereas in rabbit dung only 1 was produced at a similar concentration (2.3 μg g−1 fresh weight). The biosynthesis of these substances was unaffected by the presence of inoculum of other fungi tested (Sporobolomyces roseus or Penicillium claviforme) in liquid culture or on dung. Sordarin-type natural products are therefore synthesized by P. pleiospora at sufficiently high concentrations to account for antibiosis against yeasts, but not against filamentous fungi.

Assessment of genetic and phenotypic diversity is necessary to confidently distinguish genotypes of Pleurotus eryngii when seeking traits of interest and to identify strains with high yield potential. We studied 154 strains from Italy for quantitative (shape, size and yield), qualitative (colour, malformations and growing behaviour), and molecular (RAPD and minisatellite) traits. This population consisted of isolates mostly belonging to P. eryngii var. eryngii, var. ferulae or var. nebrodensis, from different regions of Italy. A replicated cultivation trial, with three blocks and three replicates for each strain within the block, was used as an experimental design to calculate trait estimates. Significant differences were observed between strains for basidiome number and weight, while no significant differentiation for quantitative morphological traits was observed between geographical origins and taxonomic groups. Qualitative morphological traits were efficient in differentiating isolates of P. eryngii var. nebrodensis. On average, yield per strain (basidiome weight) was correlated more with basidiome number than with size. The most stable yield traits were basidiome number and weight per strain. An average heritability of 0.31 was estimated for yield related traits. A significant difference between var. ferulae and var. eryngii populations was detected for basidiome production measured as ‘average harvest time’. Molecular markers showed a high level of heterogeneity within populations and a low, but significant, degree of differentiation among populations defined a priori. No population-specific marker was detected and the differential pattern of variation between vars. ferulae and eryngii was due to frequency-dependent alleles. The nebrodensis type was more differentiated from var. eryngii than from var. ferulae using either molecular or qualitative morphological traits.

The entomopathogenic fungus Metarhizium anisopliae var. acridum is registered as a mycopesticide for acridid control in Africa and Australia. Traditionally, identification of M. anisopliae var. acridum infection in grasshoppers and locusts has relied upon development of fungal growth in infected cadavers. Conventional methods of detection of this entomopathogen in the environment and non-target organisms have been based on culture and bioassay. A PCR-based method for the detection of M. anisopliae var. acridum was developed. Sequence data from the distinct ITS rDNA regions facilitated the design of PCR primers that were used in PCR-based diagnostic assays for the detection of fungal DNA. The amplified sequence was 420 bp in length and specific to M. anisopliae var. acridum. Isolates of M. anisopliae var. anisopliae and M. flavoviride produced no PCR product with these primers. Other fungal entomopathogens, plant pathogens, mycopathogens, and soil saprophytes were also not detected by the pathogen-specific primers. The assay was also effective for the detection of M. anisopliae var. acridum DNA in the presence of soil DNA extracts and in infected grasshoppers.

The external morphological changes occurring during initiation and early stages of fruit body development of a Morchella sp., before the development of asci, were examined by scanning electron microscopy. Four stages of primordial development were distinguished. First, disk-shaped knots of 0.5–1.5 mm were observed on the surface of the substrate. Next, the knot inflated and a primordial stem emerged from its centre. Afterward, the stem lengthened, oriented upward, and two types of hyphal elements developed: long, straight and smooth basal hairy hyphae and short stem hyphae, some of which were inflated and projected out of a cohesive layer of tightly packed hyphal elements. Finally, when the stem was 2–3 mm long, pre-apothecia emerged in the apical end, with ridges and pits having distinguished types of paraphyses. Extracelluar mucilage covered the ridge layer and helped give the tissue its shape and rigidity.

Stipe elongation in fruit bodies of Coprinopsis cinerea (syn. Coprinus cinereus) was examined from a biomechanical perspective. Two strains were studied: the self-compatible Amut Bmut homokaryon that produces normal fruit bodies with relatively short stipes, and mutant B1918 that produces abnormally elongated stipes. Measurements of the pressure exerted by developing mushrooms were made using strain gauges, and these data were compared with measurements of the pressures exerted by vegetative hyphae of the same strains. The experiments demonstrate that AmutBmut hyphae elongating within stipe tissue push with the same pressure (approx. 0.5 atmosphere) as vegetative hyphae growing through their food sources. In purely biomechanical terms, the fruit body may therefore be viewed as a relatively uncomplicated sum of its parts. Analysis of the mutant strain B1918 demonstrated that hyperelongation of the stipe is not associated with any difference in the pressure exerted by the fruit body. The fault in the mechanism of stipe extension in B1918 may be reflected in the increased fluidity of the cell wall of vegetative hyphae of this strain, but further work is necessary to resolve this.

Combined analyses of ITS and LSU rDNA sequences were utilized to resolve the phylogenetic relationships of 98 members of the smut genera Lundquistia, Melanopsichium, Moesziomyces, Macalpinomyces, Sporisorium, and Ustilago (Basidiomycota: Ustilaginales). Minimum Evolution and Bayesian inference of phylogeny resolve three major groups of almost identical composition: Sporisorium, Ustilago, and a basal assemblage of both Ustilago and Sporisorium species. Macalpinomyces deserves generic rank regarding its type species M. eriachnes; all other Macalpinomyces species of our study clearly turn out to be part of Ustilago or Sporisorium. Lundquistia evidently belongs to Sporisorium. Moesziomyces, probably paraphyletic, stands basal to all other genera. Interestingly, Melanopsichium belongs to the Ustilago clade, being the only member of the ingroup not parasitizing on Poaceae. The patchy distribution of commonly used morphological characters along our phylograms points to their variability and dependence on the host's morphological traits instead of being valuable for resolving parasite phylogeny. The new combination: Sporisorium fascicularis comb. nov. (syn. Lundquistia fascicularis) is made.

Phylogenetic analysis of the ITS rDNA region was carried out with two economically important downy mildews, Pseudoperonospora cubensis, which infects species of Cucumis, Cucurbita, and Citrullus belonging to Cucurbitaceae, and P. humuli, which infects plants of the genus Humulus belonging to Cannabaceae. Two closely related species, P. cannabina and P. celtidis, were also included to reveal taxonomic relationships with the first two mildews. All four species formed a well-resolved clade when compared with the ITS sequences of other downy mildew genera, using Bayesian inference and maximum parsimony. The P. cubensis isolates obtained from different hosts and (or) geographical origins in Korea, exhibited no intraspecific variability in the ITS sequences. The phylogenetic analyses of P. cubensis and P. humuli showed that they share a high level of sequence homology; the morphology of the sporangiophores, sporangia, and dehiscence apparatus confirmed the similarity of the two species. We therefore reduce P. humuli to the status of a taxonomic synonym of P. cubensis.