This review summarizes existing information about mushroom lectins, with an emphasis on those from the following species which have been most extensively characterized including various Agaricus species, Amanita pantherina, Boletus satanas, Coprinus cinereus, Ganoderma lucidum, Flammulina velutipes, Grifola frondosa, Hericium erinaceum, Ischnoderma resinosum, Lactarius deterrimus, Laetiporus sulphureus, Tricholoma mongolicum and Volvariella volvacea. It is noted that the mushroom lectins exhibit a diversity of chemical characteristics. Some of them are monomeric, whereas others are dimeric, trimeric or tetrameric. Their molecular weights range from 12 to 190 kDa, and the sugar contents from 0 to 18%. Carbohydrate specificities involve mainly galactose, lactose and N-acetylgalactosamine. A small number of mushroom lectins are specific for fucose, raffinose, N-glycolyneuraminic acid and N-acetyl-d-lactosamine. Studies on immunomodulatory and antitumour/cytotoxic activities have been carried out on lectins from Agaricus bisporus, Boletus satanas, Flammulina velutipes, Ganoderma lucidum, Grifola frondosa, Tricholoma mongolicum and Volvariella volvacea.

The orientation of individual urediniospores and spore clusters of Uromyces viciae-fabae, during fall and after landing in still air, was recorded using high-speed video microscopy. Individual spores and aggregates fell in a variety of orientations. On landing spore clusters attached to the substratum without rebounding or fragmenting and typically retained their orientation during fall. Some aggregates landed and attached in orientations in which their mass was asymmetrical with respect to their point of contact. Attachment also occurred when spores fell onto spore aggregates which had previously landed on the substratum. Rate of fall was influenced by the orientation and size of cluster. When dispersed and collected on substrata under simulated field conditions, the orientation and attachment of urediniospore clusters were similar to those of aggregates deposited in still air.

Two double-stranded ribonucleic acid (dsRNA) elements were detected in an isolate of the clavicipitaceous grass endophyte Epichloë festucae obtained from an asymptomatic Festuca rubra plant. No dsRNA was detected in three other isolates of E. festucae. The size of the two dsRNA elements isolated from mycelium was of 5·2 and 3·2 kbp. Hybridization experiments with a cDNA probe complementary to the 5·2 kbp dsRNA showed that there was no sequence similarity between the dsRNA elements. Isometric virus-like particles of about 50 nm in diameter were observed by electron microscopy in sucrose-gradient purified virus preparations from the isolate containing dsRNA. The 5·2 kbp dsRNA element was present in the partially purified virus preparations, suggesting that this element is encapsidated. There was no difference with respect to growth rate or colony morphology between the dsRNA containing and dsRNA-free isolates. The presence of dsRNA and virus-like particles suggests the presence of a mycovirus in the Vit5 strain of E. festucae.

Using the mating type genes (MAT-1 and MAT-2) from Cochliobolus heterostrophus (a pathogen of maize) as probes, MAT genes from C. carbonum (also a maize pathogen) and C. victoriae (an oat pathogen) were cloned. Sequence analyses and functional tests showed that C. carbonum MAT-1 and C. victoriae MAT-2 are structurally similar to their C. heterostrophus homologues, and all three genes function comparably when expressed in C. heterostrophus. Gel blot analyses of DNAs from C. heterostrophus or C. carbonum, probed with C. heterostrophus MAT-specific fragments, revealed that field isolates from diverse geographical locations contained either MAT-1 or MAT-2, but never both. The entire currently existing collection of C. victoriae isolates, however, contained only MAT-2, and all members of the collection were found to be either female sterile or completely infertile. Thus, crosses between isolates of C. victoriae were not possible, although crosses between C. victoriae and C. carbonum (but not C. heterostrophus) were readily made, confirming previous reports that these two species are interfertile. These observations, combined with careful scrutiny of the literature, have led to the hypothesis that MAT-1 female fertile isolates of C. victoriae have never existed. All available evidence is consistent with the notion that the entire C. victoriae field population was derived from a single progenitor strain, which arose as the result of horizontal transfer of genes for pathogenicity to oats into a strain of C. carbonum that was MAT-2 and female sterile.

Hemibeltrania saikawae sp. nov., found on decaying leaves in Cuba and characterized by cylindrical to clavate, mammillate, one-celled conidia, is described and illustrated. A key to Hemibeltrania species is provided.

Universally primed PCR (UP-PCR) fingerprinting combined with UP-PCR product cross hybridization, and ITS1 ribotyping were used to study the genetic relatedness of strains of Trichoderma and Gliocladium for two purposes: (1) to evaluate the ability of the methods to discriminate closely related strains and as tools to group strains which is necessary to facilitate; (2) identification of markers for development of specific detection assays for selected strains. Included among the strains were one T. harzianum, two T. virens, and one G. roseum that had been selected previously for their antagonistic ability against soil-borne phytopathogens. Similarity among strains, found by cross dot blot hybridization using UP-PCR amplification products, was used to group them into 15 genetic entities. ITS1 ribotyping of the strains was performed by digestion of the PCR amplified rDNA spacer region and electrophoresis of the products. The differences obtained from ribotyping as well as the differences in mobility of the intact spacer region were used for grouping of the strains. The UP-PCR hybridization groups and the ITS1 based groups proved to be consistent, but the resolution of the UP-PCR based approach was superior. The results demonstrate that the combination of UP-PCR and ribotyping can aid in clarifying species distinction in Trichoderma and Gliocladium and has the potential to become a valuable tool for studies of diversity and genetic structure of populations of these fungi. Furthermore, identification of single strains by the specific UP-PCR fingerprint seems feasible.

Xylaria species are common endophytes in tropical plants. It is not known, however, whether transmission of Xylaria occurs horizontally or vertically, whether individual Xylaria strains have wide host ranges or are host-specific, or how they are dispersed. We compared frequency of Xylaria endophytes in leaves and seeds of two tree species in Puerto Rico, Casuarina equisetifolia (Australian pine) and Manilkara bidentata (ausubo). These trees were chosen because they differ markedly in morphology, habitat, distribution, and origin. In C. equisetifolia Xylaria was significantly more frequent in leaves than in seeds. Xylaria was isolated from seeds of trees in inland parks, but never from seeds of trees growing on beaches. This suggests that vertical transmission of Xylaria may be possible but is not necessary for infection. In M. bidentata, Xylaria was isolated from 97% of leaves but was never isolated from seeds, suggesting that transmission is entirely horizontal. Seedlings raised in a greenhouse far from other M. bidentata trees had a level of Xylaria infection as high as seedlings in the forest, suggesting that inocula can come from other sources and endophytic strains are not host-specific.

A dikaryotic resting spore or two monokaryotic resting spores of Plasmodiophora brassicae were inoculated onto 1-d-old seedlings of Brassica campestris. The relative DNA content of a nucleus in a dikaryotic resting spore corresponded with that of a haploid nucleus in a monokaryotic resting spore. Plasmodia and zoosporangia were observed within the galls in some root cortical cells approximately 2 mo after inoculation. Resting spores were also formed within the galls in some cortical cells, and root hair infection was observed. The frequency of resting spore formation in B. campestris seedlings inoculated with a dikaryotic resting spore or two monokaryotic resting spores was 26·2 and 3·6%, respectively. The results indicate that the life-cycle of P. brassicae was completed on plants infected with a dikaryotic resting spore or by two monokaryotic resting spores.

Various fungi interact with heavy metals (HM) differently regarding their binding ability and their tolerance. Besides the ability of the fungus to form an extensive extramatrical mycelium, its binding and transport properties are the most important factors in ameliorating the effects of HM toxicity on the mycorrhizal symbiosis. The tolerance of seven ectomycorrhizal fungi to elevated lead concentrations was tested using agar cultures and the results were compared to those from liquid culture. Critical toxic concentrations, where the growth of the mycelium was inhibited to 50%, were lower in liquid cultures (around 0·2 mm) in comparison to agar cultures (0·5–2 mm). The less tolerant fungi in agar culture were Amanita muscaria and Laccaria laccata, the most tolerant Lactarius piperatus, Pisolithus tinctorius and two strains of Suillus bovinus, DB83 from a lead polluted area and DB84 from a non-polluted area. Tolerance indices, based on the dry weight of mycelia from liquid culture, differ from the tolerance indices obtained from solid culture. L. laccata growth was limited to a lesser extent than other fungi and the growth of S. bovinus DB83 was strongly stimulated at a Pb concentration of 30 μm, which could indicate lower susceptibility of this strain to low lead concentrations. The uptake, transport and release of Pb were then studied with 210Pb tracer using Conway cells with the active tracer added to the inoculated medium in the centre compartment. The uptake of Pb by P. tinctorius (1·1% of the added activity) was much lower than the uptake by L. laccata and S. bovinus DB83 (6·2 and 5·4% of the added activity respectively). The same situation was reflected in the activity of the tracer transported in the mycelia. Further, the release of transported Pb from mycelia to the outer medium differs between L. laccata and S. bovinus DB83 mycelia, reaching 45 and 10% of the transported activity, respectively, indicating stronger binding of lead to S. bovinus DB83. The results of the tracer study are discussed with respect to various experiments with ectomycorrhizal seedlings and lead.

The effect of water activity (aw, 0·995–0·85) and temperature (15, 25°C) on the in vitro inter- and intra-specific interactions between thirteen fungi commonly isolated from maize grain were investigated. The fungi were paired and their interactions given a numerical score to obtain an Index of Dominance (ID) for each species. Aspergillus niger had the highest overall ID in most of the conditions tested, while the Aspergillus species tested were also quite dominant. Fusarium species appeared to be dominant only at high water availability (0·995 aw), while Eurotium species dominated at the lower aws (0·85–0·90). The relative growth rates of each fungus were also calculated under the same range of environmental conditions. In general, Aspergillus, Fusarium and Trichoderma species grew most rapidly under the combination of aw and temperature conditions in which they were able to grow, while Penicillium species had the slowest growth rates. There was a positive correlation between growth rate and ID for Trichoderma viride and three Fusarium spp. but not for Aspergillus and Penicillium and Eurotium spp. The different possible strategies in fungal competition for grain are discussed in relation to these in vitro findings.

A region of about 800 bp of ribosomal DNA has been sequenced in 10 isolates of Polymyxa and one isolate each of Plasmodiophora brassicae and the chytrid Olpidium brassicae. This region consists of about 330 bp at the 3′ end of the 18S gene, the 5·8S DNA and the two internal transcribed spacers. A shorter region was also sequenced from one isolate each of Spongospora subterranea and a Ligniera sp. The results supported the earlier division of P. graminis into three subgroups and the recognition of P. betae as a distinct species. In phylogenetic analyses, the Ligniera and Spongospora isolates grouped with the other plasmodiophorids and the Olpidium isolate with the Mycota. The plasmodiophorids appeared as a distinct group and were not closely related to any other eukaryotes (including a range of fungi and protozoa). The DNA sequences were used to design primers for specific amplification of either Polymyxa or P. graminis DNA.

The relative abilities of the multilayer perceptron, radial basis function, asymmetric radial basis function and learning vector quantization artificial neural networks (ANNs) and two non-neural methods to identify fungal spores were compared. ANNs were trained on morphometric data from spores of Pestalotiopsis spp. and a few species in the related Truncatella and Monochaetia. The optimized neural and statistical classifiers had similar identification success on an unseen data set – between 76·0 and 78·8% of a 16-species group and between 63·0 and 67·7% of a 19-species group. The relative merits of each classifier are discussed, as is the potential of ANNs in mycology.

Spore proteins of different species and isolates of arbuscular mycorrhizal (AM) fungi were compared by PAGE. Reproducibility of protein patterns was assessed by using cultures of the same species either grown on different host plants, or produced during successive propagation cycles and stored up to 5 years. The results consistently showed that host species, different generations and storage, did not affect protein profiles, thus validating the accuracy of the method. Comparison among different geographical isolates of the same species revealed consistent protein patterns. The stability and diversity of spore protein profiles suggested that PAGE could be used to discriminate and identify AM fungal species and isolates. By contrast, the physiological state of spores affected the quality and quantity of bands, with germinating spores showing marked profile changes, as compared to quiescent spores, both in denaturating and native analytical conditions. The disappearance of some polypeptides in germinated spores might be related to the occurrence of storage proteins in AM fungi.

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.

Concentrations of potassium nitrate, potassium phosphate, or calcium chloride were varied in stream-simulating microcosms containing leaf discs colonized by the aquatic hyphomycetes Anguillospora filiformis or Lunulospora curvula. Cumulative conidium production of the fungi determined from rates of sporulation at 2 d intervals was stimulated by increasing concentrations of both potassium nitrate and potassium phosphate but not by calcium chloride. Leaf weight loss was also stimulated by increasing concentrations of potassium nitrate and potassium phosphate. The amount of fungal biomass (determined as ATP concentrations) associated with leaf discs increased significantly only in the treatments in which A. filiformis received increasing concentrations of potassium nitrate. These results indicate that as aquatic hyphomycetes grow on leaf litter, they can obtain at least a portion of their inorganic nutrition from the water flowing over the leaves. They also suggest that sporulation is more sensitive to changes in nutrient concentrations than growth.

Growth and ochratoxin A accumulation by two isolates of Penicillium verrucosum, IBT5010 and IBT12803, were examined in co-cultures with the antagonistic yeast Pichia anomala or baker's yeast Saccharomyces cerevisiae. Each yeast was co-cultured with Penicillium verrucosum in malt extract agar supplemented with 1% yeast extract and incubated at 25°C for 14 d. Ochratoxin A was found to be stable at 25°, whether or not yeast was present. Pichia anomala and Saccharomyces cerevisiae reduced mould growth to about the same extent in vitro. Both yeasts significantly reduced the growth of Penicillium verrucosum isolates at 3×103 yeast c.f.u./plate. In all co-cultures in vitro accumulated ochratoxin A was reduced to below the detection limit (100 ng/plate) by yeast amounts as low as 3×103 c.f.u./plate. In wheat, the growth of Penicillium verrucosum IBT5010, measured as c.f.u., was not reduced in the presence of Pichia anomala, whereas the growth of Penicillium verrucosum IBT12803 was clearly inhibited by this yeast. A similar pattern was observed for ochratoxin A accumulation in wheat when the two mould strains were co-cultured with Pichia anomala. Mycotoxin production was more sensitive to the presence of yeasts than was mould growth. Co-cultivation with yeasts gave no detectable stimulation of ochratoxin A accumulation in agar or wheat.

The diversity and frequency of leaf endophytic fungi occurring in naturally regenerating and planted stands of manuka were investigated at several sites. A restricted and characteristic range of species was isolated from all sites, although marked differences were noted between natural and planted stands. In natural stands a Phyllosticta species was the single dominant endophyte. This fungus appears to be host species specific, as it was not isolated from the closely related kanuka (Kunzea ericoides) in mixed, even-aged stands of manuka and kanuka. The frequency of the Phyllosticta sp. fluctuated greatly between individual trees across single stands. No obvious environmental or other gradients were recognized which could explain this patchy distribution. The Phyllosticta sp., along with the two next most common species in natural stands, Diploceras leptospermi and an unidentified coelomycete, were absent from most of the planted stands sampled, and at very low frequencies when present. Although several of the planted stands were close to natural stands and had been established for several years, the difference between them has been maintained. The most common endophytes in planted stands were Botryosphaeria and Alternaria spp. These species, found at low levels in natural stands, are likely to be ‘opportunistic’ endophytes. They are probably also characteristic of the epiphytic mycota, invading only the living leaves of plants under stress. The difference in leaf endophyte communities between planted and natural stands of manuka may be an indication of wider differences in the microbial communities of the respective stands, and could prove significant for site restoration projects. Such projects using nursery-raised manuka plants as a pioneer species may be establishing stands lacking much of the natural diversity of manuka communities for extended periods following establishment.

The ability of Botrytis cinerea to produce cutinolytic, pectolytic and cellulolytic enzymes was re-examined in vivo and in vitro. In liquid culture, B. cinerea produced both constitutive and inductive forms of hydrolytic enzymes. The constitutive levels were 44 mU, 720 mU, 1820 mU, 12·0 U and 22·4 mU for cutin esterase, endopolygalacturonase (endoPG), exopolygalacturonase (exoPG), pectin methyl esterase (PME) and pectate lyase (PL), respectively. Unlike the other enzymes, however, carboxymethyl cellulase (CMCase) production was found to be entirely inducible. The enzymes secreted at the germination and germ-tube growth stages, and during subsequent disease development, were quantified simultaneously. Complete germination was observed within 9 h of incubation of B. cinerea on the surface of bean leaves and disease symptoms gradually increased during days 1–6 of the incubation. Significant amounts of all hydrolytic enzymes studied in the early hours and monitored during 6 d of incubation were detected, supporting the possibility of a major role for the enzymes produced by B. cinerea in the development of disease. The amount of cutinase was found to be uniform from the beginning, indicating that this enzyme may have an important role in penetrating the impervious cutin layer. The exoPG level increased from the beginning of incubation whereas that of endoPG started to rise later. PL and PME were also detected on the leaf surfaces. The patterns of in vitro production of exoPG, endoPG and PL correlated with the in vivo production of these enzymes, but there was only partial correlation in the production of PME and no correlation in the patterns of cutinase and CMCase production.