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.

Extracellular enzymes play an important role in the pathogenicity and virulence of phytopathogenic fungi. Several isolates of Colletotrichum coccodes, causal agent of anthracnose on tomato, were screened to determine the relationship between protease activity and virulence. A direct relationship was observed between extracellular protease activity and the induction of disease symptoms of fruit and mortality in plants. Isolate Cc155 exhibited the highest protease activity after five days of growth in protease induction medium and produced an extracellular serine protease (sp78) that was 78 kDa, auto-degradative, glucose repressible, and non-glycosylated. To determine the role of sp78 in pathogenicity, a UV-induced extracellular protease deficient mutant (np155) was generated from the wildtype isolate Cc155. Np155 maintained growth rates comparable to Cc155 and produced wildtype levels of extracellular cellulase but did not produce extracellular protease. Unlike Cc155, np155 caused no disease symptoms on tomato fruit and 0% mortality on tomato seedlings. These results suggest that extracellular protease activity is required for pathogenicity and virulence of C. coccodes, and that the elimination of protease activity transforms a virulent pathogen to a non-pathogenic endophyte.

Fluorescent stains offer an effective means of visualising bacteria and fungi in soil or litter samples. Fluorescent brightener (FB) 28 (also known as Calcofluor White M2R) is commonly used to stain such microorganisms. However, during production of soil thin-sections we observed erratic crystallisation of this stain, particularly in soils colonised by Rhizoctonia solani. We report on the evaluation of alternative stains to FB 28 for their propensity to crystallize in interaction with fungi, staining efficiency, and suitability for application in soil thin-section production. All of the additional candidate stains namely Fluorescent Brightener Agent (FBA) 15/25, FBA 71 and SCRI Renaissance 2200 (SR 2200) were highly effective in staining agar-cultured hyphae, but differed in the degree to which they stained hyphae cultured in soil. All stains tested, except SR 2200, stained hyphae of R. solani insufficiently when growing on or through soil. These stains also showed extensive crystallisation in solutions that had been in contact with R. solani colonised soil. However, SR 2200 stained hyphae of R solani growing over soil as effectively as hyphae growing on agar and showed no evidence of crystallisation; the intensity of staining exceeded that of the ‘benchmark’ FB 28 for hyphae grown in two soil types. These excellent fluorescent properties of FBA 220 persisted in soil thin-sections, resulting in bright hyphae that could be readily visualised in situ in undisturbed soils.

The wood of one Picea abies stump, including its roots (1·3 m in length), was sliced into 2 cm thick discs. The stump originated from a thinning conducted 7 yr prior to the investigation in a 30 yr old spruce stand planted on previous farmland that became heavily infected by Heterobasidion annosum. After incubation of the wood discs, interaction zones were observed on the surfaces and H. annosum was isolated from the areas between the zones and from the zone lines, resulting in 296 isolates. The isolates were tested with somatic incompatibility to detect 35 different genets. Of the 27 genets colonising the upper part of the stump (excluding the roots), 12 had proceeded into the roots. Seven genets found in the roots were not found in the upper part of the stump and one genet isolated from an interaction zone on the top of the stump was not found elsewhere in the stump or in the roots. Two of the genets had grown into root contact with other trees.

A piece of Baltic amber (Tertiary, Eocene) contains a sporocarp of a slime mould which is assigned to the recent genus Arcyria and described as A. sulcata sp. nov. Apart from a fossil stemonitoid myxomycete, there are no further unambiguous fossil records of slime moulds and therefore the fossil gives new insights into the evolutionary history of the Myxomycetes.

Larix kaempferi seedlings, in the process of becoming established during the revegetation process following a volcanic eruption, were assessed for the types, occurrence patterns and diversity of their ectomycorrhizas along an elevation gradient. On the basis of macro- and microscopic characteristics, 12 types of ectomycorrhizas were classified. In general, ectomycorrhizal types differed more by site than by seedling age. The majority of root systems of seedlings with an age ranging from 1 to 5 years were colonized by 1 or 2 types of mycorrhizal fungi at low and intermediate elevations, 2 or 3 types at a higher elevation. Under the more stressed environments of high and intermediate elevations, the mean d.w. of 1 yr old seedlings, 40% of which were colonized by 3 or 4 mycorrhizal fungi, was double the weight of the same aged seedlings at lower elevation sites, only 10% of which were colonized by 3 or 4 mycorrhizal fungi. The correspondence between the type and frequency of mycorrhizas, the elevation gradient and litter accumulation suggests that change in litter accumulation along gradient may influence not only mycorrhizal types and their occurrence, but also the diversity of mycorrhizas on one seedling. Diversity of mycorrhizas on the same seedling is assumed to be critical for the establishment of seedlings from the very beginning on stressed sites, and may also be influenced by the availability of nutrients. The more intensive competition between mycorrhizas that occurs due to a reduction in the food source (tip roots) shared by the mycorrhizal fungi with similar resource requirements, results in frequent co-occurrence of mycorrhizas in the same root system or even the same root tip. As a result, the diversity of mycorrhizal types seems to become simplified as the seedlings age.

Interrelations of fungal mycelium with other soil biota are of paramount importance in forestry and soil ecology. Here we present the results of statistical analysis of a comprehensive data set collected in the first (and the only) British fungus sanctuary over a period of four months. The variables studied included a number of soil properties, bacteria, protozoan flagellates, ciliates and amoebae, microbial and plant feeding nematodes, various microarthropods, and two fungal biomarkers – glomalin and ergosterol. One way ANOVA showed that the dynamics of the microbiota studied was influenced by seasonal changes. Superimposed on these changes, however, was variability due to biological interactions and habitat characteristics. Two fungal biomarkers, ergosterol and glomalin, were differently influenced by other biota and abiotic variables. The results indicate that the dynamics of soil fungi is influenced not only by soil microarthropods, but also by those found in forest litter. The overall outcome, therefore, is likely to be very complex and will depend upon specific conditions of any particular ecosystem.

Fungal communities on decaying fronds of Livistona australis, Oraniopsis appendiculata (Australia), Arenga engleri, Livistona chinensis (Hong Kong), Arenga undulatifolia, Salacca affinis, and Oncosperma horridum (Brunei) were examined for fungi. In all, 288 different taxa were identified. The fungal communities on different frond parts (i.e. leaves, rachis-tips, mid-rachides and rachis-bases), on different hosts, at different sampling sites, at different stages of decay, and in different seasons were compared.

Fungal species compositions were distinct on different hosts and at different sites. Three-dimensional correspondence analysis resulted in: (a) three clusters corresponding to distinct communities on samples in Australia, Brunei and Hong Kong; (b) fungi on palms of the same genera (Arenga undulatifolia and A. engleri; Livistona australis and L. chinensis) at different sites, being more coherent than on palms of different genera at different sites; (c) fungi on palms of different genera at the same site being more coherent than on palms of the same genera at different sites. Fungal taxa on the same palm genus or species in different sampling sites were significantly different. Evidence for host specificity and fungal recurrence on different hosts and frond parts were found. No evidence of seasonal patterns of fungal communities was found on the palm hosts. Only 10% of the fungi were common to all three palm species studied in Brunei and 17% were common to the two palm species at Victoria Peak, Hong Kong.

Significant differences were found in the fungal communities colonising each of the different frond parts (leaves, rachis-tips, mid-rachides and rachis-bases). The greatest differences in most palms were found between the leaves and rachides.

When investigating fungal diversity it is recommended to examine a combination of naturally occurring fronds and frond baits throughout the decomposition process. Since a large number of forests, plant species and even types of plant tissues have yet to be explored by mycologists, we predict that there are an incredibly large number of fungi on these unexplored substrata.

This study has confirmed that fungi on palms are very diverse and suggests some reasons for this. The data has important implications towards future biodiversity studies and estimates of global fungal numbers. Future studies and estimations must reflect and incorporate these results.

The patterns of conidial discharge of Erynia neoaphidis were measured from three species of aphids: nettle aphid (Microlophium carnosum), grain aphid (Sitobion avenae) and pea aphid (Acyrthosiphon pisum). The effects of release height, morph of aphid and temperature on the horizontal and vertical discharge of conidia were studied. Numbers of conidia deposited in the dorsal and lateral directions were distributed with distance in truncated bell shaped patterns. Discharge distances ranged from 2 to 11 mm and half the conidia caught travelled further than 5 mm. There was little difference in the horizontal dispersal patterns of conidia when ejected from cadavers of different morphs of the same species, or from different species. The weight of infected aphids showed little correlation with discharge patterns. Values of maximum discharge distance, Dm, were generally between 6 and 9 mm. Temperature had a significant effect on conidia discharged from the dorsal surface of apterous A. pisum cadavers. Dm was greater at 18 °C than at 10 or 25 °. Vertical discharge distances for conidia released from A. pisum cadavers ranged between about 2 and 8 mm. The maximum height to which conidia were projected vertically was not affected by temperature. However, the average height tended to be greater at 18 °. Half of the conidia reached heights of about 3.5 mm while the maximum heights reached were about 8 mm. The initial speeds of conidia were estimated from measured discharge distances. The results suggest that conidia of E. neoaphidis may be ejected at speeds of about 8 ms−1.

Aquaphila albicans gen. and sp. nov. from submerged wood in the tropics is described and illustrated. It produces hyaline, multiseptate, fusoid or falcate conidia resembling the macroconidia of Fusarium species, but differs by its conidiogenesis and the aquatic habitat. The conidiophores of A. albicans are septate, hyaline, sympodially proliferating with conidiogenous denticles. Conidial development in A. albicans has been studied in culture and results are presented. The genus is compared with similar genera.

Apple fruits and grapevine leaves were inoculated with four wild-type strains of Botrytis cinerea. Two types of symptoms were observed on apple, firm or soft rot. Extracts from infected tissues were analysed for polygalacturonase (PG) and pectin methylesterase (PME) isozyme profiles. They showed that different specific PG isozymes occur in grapevine leaves and in soft rot on apple fruit. PG and PME profiles were also studied in genetic transformants altered in their colonization ability and/or the type of rot that they caused on apple fruit. No PG activity was found in apples infected by firm-rotting wild-type strains or transformants, whereas two neutral PG isozymes (pIs 7.3 and 7.6) were expressed in soft-rotting strains. No association was found between the production of these PG isozymes and the colonization level. The PME patterns were not correlated with the rotting type nor the colonization level. In vitro, firm-rotting strains and transformants showed no PG activity in glucose medium whereas soft-rotting ones produced several PG isozymes. In polygalacturonic acid cultures, all strains and transformants produced a single, common acidic isozyme. Unlike PG, no variation in the PME isozyme patterns in vitro could be correlated with the culture substrate on apple or the rotting type. The variation in pectinase profiles between in vitro and in planta contexts and the role of PGs in B. cinerea pathogenicity on apple fruit is discussed. We suggest that neutral PG isozymes are involved in the soft-rotting type on apple fruit.

A thermostable extracellular glucoamylase from Thermomyces lanuginosus in static culture was purified to SDS–PAGE homogeneity by fractional ammonium sulphate precipitation, ion-exchange chromatography on DEAE–Toyopearl, Butyl–Toyopearl hydrophobic interaction chromatography, gel filtration on Sephacryl S-300 and ion-exchange chromatography on FPLC MonoQ. The molecular weight of the enzyme, consisting of a single polypeptide, was estimated to be 72000 by SDS–PAGE. The glucoamylase exhibited maximal activities at pH 5·0. The optimum temperature for the activity was 70°C. The enzyme was thermostable at 60° with half-lives at 70° of 20 min and 80° of about 6 min. The glucoamylase was a glycoprotein with 11·4% carbohydrate content. The enzyme hydrolysed soluble starch, amylose, amylopectin, dextrin, glycogen, maltotroise and maltose. Starch was the best substrate.

Rust fungi in the genus Phragmidium are frequent pathogens of both wild and cultivated roses. We investigated the occurrence and relationships of rusts on dog roses, Rosa sect. Caninae (Rosa canina, R. corymbifera and R. rubiginosa) in Germany. Two Phragmidium species, P. mucronatum and P. tuberculatum, were able to infect each of the three dog rose species examined. However, the overall infection of R. rubiginosa was significantly lower, which could be important for rose breeding. Despite overlapping host ranges, the evolutionary background of P. tuberculatum and P. mucronatum is quite distinct. Phylogenetic analyses of the D1/D2 region of the LSU rDNA suggest that P. mucronatum shares a common ancestor with other rose rusts, whereas P. tuberculatum evolved from a Rubus-Sanguisorba rust clade and must have undergone a host shift to Rosa spp.

‘Casa Lis’ is the most characteristic building in Salamanca, Spain, belonging to the modernist trend. It was built with Villamayor sandstone from nearby Salamanca, which has high porosity providing an easy medium for water absorption and capillarity. During a restoration process on the southern wall, near an underground water flow, two well defined, naturally developed layers were observed on the sandstone surface: an outer, hard crust with greyish shades and whitish salt patches resulting from rising damp, and an inner, green layer with organic material linking the sandstone to the inorganic crust. The microbiological study of this biofilm showed an ecologically obligate, stable mutualism between a dematiaceous mitosporic fungus (Septonema tormes sp. nov.), a coccoid cyanobacterium (Cyanothece-group) and a green alga (Gloeocystis rupestris), with the accumulation of different metabolites excreted by these microorganisms. The case reported here is one of the few studies where a microbial mat, in association with the external crust, avoids a further weathering of the stone because of an unforeseen biopreservation effect due to the maintenance of humidity at constant levels under the crust avoids changes in clay swelling and subsequent surface arenization of the sandstone. The lichenized complex of a mitosporic mycobiont and two photobionts, in this case, has not been reported before as a stable association on this kind of substrate.

Whole genome sequencing of several filamentous ascomycetes is complete or in progress; these species, such as Aspergillus nidulans, are relatives of Saccharomyces cerevisiae. However, their genomes are much larger and their gene structure more complex, with genes often containing multiple introns. Automated annotation programs can quickly identify open reading frames for hypothetical genes, many of which will be conserved across large evolutionary distances, but further information is required to confirm functional assignments. We describe a comparative and functional genomics approach using sequence alignments and gene expression data to predict the function of Aspergillus nidulans genes. By highlighting examples of discrepancies between the automated genome annotation and cDNA or EST sequencing, we demonstrate that the greater complexity of gene structure in filamentous fungi demands independent data on gene expression and the gene sequence be used to make confident functional assignments.

The Claviceps purpurea population colonising British Spartina salt marsh stands is characterised by unusually long cylindrical conidia (average 9·5–12 μm) and sclerotia floating on the water surface. RAPD, AFLP and rDNA comparison defined these isolates as the third genetically distinct homogenous population (G3) of C. purpurea. The same morphological and genetical markers were found also in S. alterniflora isolates from Spartina from the USA. All G3 isolates belonged to a chemotype producing ergocristine and ergocryptine. In phylogenetic trees based on rDNA and AFLP, a G1 population from fields and meadows appeared as the sister clade to the one formed by G3 (Spartina) and G2 (wet and shady habitats), both with floating sclerotia and elongated conidia. British stands of S. anglica were probably colonised by isolates introduced from America, rather than by isolates from species of neighbouring biotopes.

On water agarose conidial germination of Ampelomyces quisqualis was greatly enhanced in the presence of powdery mildew conidia. All seven species of powdery mildews tested, representing five genera, were effective in increasing germination of the mycoparasite. Aqueous extract of conidia of Oidium euonymi-japonicae was also stimulatory to the mycoparasite. Germination of conidia of A. quisqualis on water agarose decreased as conidial concentration increased. Germination of the mycoparasite's conidia at a low concentration on water agarose was greatly decreased when they were separated by a polycarbonate membrane from conidia of the same species at a high concentration and incubated. After being incubated with conidia of the mycoparasite at a high concentration, water agarose became inhibitory to germination of conidia of the same species at a low concentration, suggesting the presence of a diffusible self-inhibitor. Water agarose is essentially free from nutrients which may support growth of contaminants that interfere with the effect of stimulators or inhibitors.

Cellulose-acetate electrophoresis (CAE) was used to investigate isozyme polymorphisms of 34 Group 1 and Group 2 isolates of Fusarium graminearum. Of the 26 enzyme systems screened, alkaline phosphatase, NADP-dependent glutamate dehydrogenase, peptidase D and phosphoglucomutase were found to be suitable for distinguishing members of Group 1 from members of Group 2. A great deal of similarity in the isozyme patterns among the isolates of a same group, independently of geographic origin, indicated that isolates within a given group are descendant from a same ancestral population. Significant differences in the isozyme patterns between the isolates of Group 1 and Group 2 indicated, however, that the two groups were of different ancestry. Group 1 isolates have since been named F. pseudograminearum. Due to the short run time, minimal need of equipment, small sample volume and staining requirements, CAE generally provides a rapid and accurate method for isozyme analysis of Fusarium species.

A molecular study of the mycorrhizal symbiosis between barley and Glomus intraradices used differential display PCR and a synchronous colonization method to identify genes that are differentially expressed in symbiosis. Several PCR products were consistently differentially amplified. PCR amplification of genomic DNA from either G. intraradices or barley as templates showed that three such products were encoded by G. intraradices. Sequence analysis of the deduced amino acid sequences of the fungal fragments, following extension by 3′-RACE, revealed similarities to proteins from higher eukaryotes. One (GINMYC1) shows similarity to TRIP15, a human protein that interacts in a hormone-dependent manner with the thyroid receptor. A second (GINMYC2) is similar to O-linked N-acetylglucosamine transferases from vertebrates, and the third (GINHB1) contains a putative leucine zipper and a homeodomain which indicates that it binds DNA and may act as a transcriptional regulator. Fragments of the expected sizes were amplified by RT–PCR from mRNA of mycorrhizal barley roots for all three fungal cDNAs, which indicates that the corresponding genes are expressed during intraradical growth of G. intraradices. The results provide a promising insight to fungal gene expression early in formation of this compatible and mutualistic symbiosis.

Coniothyrium canker, caused by Coniothyrium zuluense, is a serious stem canker disease of Eucalyptus in subtropical parts of South Africa. A Coniothyrium associated with similar symptoms to those in South Africa was observed on E. camaldulensis in 1996 in Thailand. It was previously thought that C. zuluense was restricted to South Africa. This study compares South African isolates of C. zuluense with isolates of the Coniothyrium from Thailand. Results of morphological comparisons indicate that the South African and Thailand isolates are the same. This was further confirmed when all Coniothyrium isolates associated with stem cankers on Eucalyptus spp. grouped together in a single major clade for both rDNA sequence data and AFLP analysis. This clade was distant from isolates of other Coniothyrium spp. included for comparative purposes. Although the Coniothyrium isolates from South Africa and Thailand resided in two separate clades, these were closely related and, we believe that the isolates from Thailand represent C. zuluense. This is the first record of the important Eucalyptus stem canker pathogen outside South Africa.