Amplified fragment length polymorphism (AFLP) was used to examine genetic variation in two forms of Melampsora rust on Salix viminalis, the ‘stem-infecting form’ (SIF) and the f. sp. larici-epitea typica (LET) of M. epitea. A simple two-tube method was used to obtain genomic DNA suitable for AFLP. Eleven SIF and 26 LET isolates from the UK were tested using two primer combinations. Of the 215 AFLP markers scored, 93% were polymorphic. AFLP profiles were distinct between SIF and LET (Nei & Li's similarity coefficients between SIF and LET isolates = 22–35%). Within SIF, AFLP patterns were very similar (similarity > 98–9%), indicating that SIF is an asexual population and may have a clonal lineage. Within LET, similarities were > 69%. LET isolates collected from a site at Long Ashton in 1991–1993 were closely related and, therefore, may have come from the same local source. Similarity data from AFLP were in good agreement (Spearman's rank correlation = 0.85) with that of RAPD when both SIF and LET isolates were included, but the correlation was less obvious (= 0.49) when only LET isolates were included. Identical banding patterns were obtained when AFLP was performed using either a Perkin–Elmer 480 or a Perkin–Elmer 9700 Thermocyclers, each programmed with a different PCR profile.

Ectomycorrhizal and saprobic macrofungi growing in the wild were collected from non-auriferous and unpolluted areas and analyzed for gold. Gold was determined using long-term instrumental neutron activation analysis (INAA). In total, 154 samples, including 67 species of ectomycorrhizal fungi and 22 species of terrestrial saprobes, were examined. Gold contents of the both groups were mostly less than 20 ng g−1 of D.W. The highest concentrations (expressed in D.W.) were found in the ectomycorrhizal species Amanita strobiliformis (136 ng g−1), Russula claroflava (148 ng g−1), Cantharellus lutescens (156 and 210 ng g−1), and Boletus edulis (235 ng g−1). Among the saprobic fungi, the highest values were found in Langermannia gigantea (160 ng g−1) and Morchella esculenta (189 ng g−1). Species of Agaricus commonly had relatively high gold values, 10s of ng g−1. The gold content of macrofungal fruit bodies was considerably higher than that of vascular plants, and parallels concentrations found in plants growing in auriferous areas.

Savoryella is reported from wood submerged in rivers and streams in Australia, Brunei, Hong Kong, Malaysia, Mauritius, the Philippines and South Africa. Six species are reported:– Savoryella aquatica, S. curvispora sp. nov., S. fusiformis sp. nov., S. grandispora, S. lignicola and S. verrucosa. A key to Savoryella species is provided and descriptions and illustrations of selected freshwater Savoryella species are given.

The monotype species of the genus Verticillium, Verticillium tenerum, is a synonym of the older name Sporotrichum luteo-album. Its purported teleomorph connection with ‘Nectria’ inventa is refuted and the preserved specimens of that species are considered as probably identical with Stephanonectria keithii (Bionectriaceae). V. luteo-album takes a unique position in the Glomerella clade of ascomycetes, as sister of the Verticillium–Plectosphaerella clade, which comprises plant-pathogenic species. V. luteo-album is not closely related to V. dahliae and its relatives, which are also situated in this clade. Conservation of the name Verticillium with V. dahliae as conserved type will be necessary to retain this generic name for the plant-pathogenic Verticillium species. In anticipation of this conservation, the new combination Acrostalagmus luteo-albus (syn. Sporotrichum luteo-album) is made.

The oxidizing enzyme laccase produced by many fungi is generally considered to be active in the biodegradation of lignin, a major plant cell wall component highly resistant to microbial attack. The enzyme is secreted at high levels by the P-type of the highly aggressive pathogen Heterobasidion annosum, but at much lower levels by the S-type which correlated with their varying wood decay capability. To investigate the evolutionary relationship between laccase genes of the different H. annosum types from several geographical regions we have compared the nucleotide sequence of the laccase gene from 32 different isolates of the fungus together with two other Asian isolates (H. araucariae, H. insulare). In addition to nucleotide sequence assessment, we have also cloned, characterized and analysed the partial sequences of the laccase gene from the homokaryotic (FSE-7: S-type; Sä16-4: P-type) and heterokaryotic (Faf-8: F-type) strains of H. annosum. Using degenerate primers, two distinct laccase gene fragments of 1.64 and 2 kb were amplified from the genomic DNA of this fungus. DNA sequence analyses showed that the 1.64 kb laccase fragment in all three H. annosum types shared significant homology (86–96%). But comparative analyses of the 1.64 and 2 kb laccase gene fragment revealed only 48% nucleotide sequence similarity. Using the cDNA sequence information, exon regions were predicted and this revealed that about nine small introns interrupted the genomic DNA. Southern hybridization analysis indicated a single copy of the gene in the homokaryotic S-type (FSE-7) examined but presence of double bands in the homokaryotic and heterokaryotic P-type strains of the fungus suggest the existence of two laccase genes. Northern analyses revealed that the gene is constitutively expressed but appear to be enhanced several fold with the addition of ferulic acid or oxalic acid. Alignments of the nucleotide sequences and phylogenetic analyses are presented allowing estimations of evolutionary relationships to be made. These comparisons indicate that laccase gene of P-type is distinct from other Heterobasidion sequences, including the outgroups H. araucariae and H. insulare, while the relationship between the S- and F-groups could not be resolved. Comparative phylogenetic analyses using predicted amino acid sequence also showed strong similarity to the laccases from other basidiomycetes (Pleurotus ostreatus, Phlebia radiata and Trametes versicolor) but least similar to laccases from ascomycete fungi. In addition, the results of McDonald-Kreitman test for possible evidence of selection based on analyses of two exon regions of the H. annosum laccase gene are presented and discussed.

Bark beetles (Coleoptera: Scolytidae) are common vectors of Ophiostoma species. These fungi include primary tree pathogens and important sapstain agents. In Mexico, Ips calligraphus and Dendroctonus mexicanus occur on many species of pine. Pinus maximinoi and P. pseudostrobus are the hosts of both species of insects. Little research has been done on ophiostomatoid fungi associated with pine bark beetles in Mexico. We recently obtained specimens of these bark beetles and their galleries from Mexico. The aim of the study was to isolate and identify Ophiostoma species associated with the two beetle species. In total, six ophiostomatoid species were found to be associated with them. These included Ceratocystiopsis minuta, Ophiostoma pluriannulatum, an O. galeiformis-like species, two unidentified Sporothrix spp., as well as a new species similar to O. adjuncti, O. ips, and O. montium, that we name as O. pulvinisporum sp. nov.

A field study was carried out in a remote broadleaved Fagus longipetiolata forest in Shaanxi province, China to study the natural local distribution of Lentinula edodes. Following spatial mapping, 24 fruit bodies were collected for tissue isolation into axenic culture. 24 genets distributed on fallen tree trunks within a distance of 120 m were identified and clustered into 7 groups using the unweighted pair-group method algorithm using data based on colony morphologies, abilities to degrade aromatic poly-R478 dye, somatic incompatibility reaction patterns and DNA fingerprints. Among the parameters used, the somatic incompatibility reaction, a polygenic phenotype, was the most differentiating, identifying 22 incompatible classes. Two sets of fruit bodies of different genets were so close together that they would otherwise have been described as aggregate fruits of presumed identical origin. Eighteen genets found on the same 5.6 m long tree trunk divided roughly into two clusters, matching their spatial distribution, and a nearby branch bore another distinct cluster. More heterogeneity was encountered between isolates the greater the distance separating them on the original site. Genets on the same tree trunk showed more compatible somatic reactions among themselves, and their DNA fingerprints showed higher similarity. Nevertheless, considering the totality of phenotypic characters, each fruit body is a genet in L. edodes. Such features are concluded to result from a reproductive strategy which depends on basidiospore dispersal. Within each cluster of isolates from the collection site genets seemed to have arisen from multiple sib-mating events. Thus, a cluster may represent a lineage of L. edodes. Individualism in L. edodes is based on a strong somatic incompatibility system. Strong competition from contaminating individuals arriving as air-borne basidiospores could explain decreased and fluctuating crop yields which are now frequently observed in later flushes from the outdoor wood log cultivation system. Further, it would also explain why multispore spawn is not favoured in artificial cultivation of this economically important edible mushroom.

Four new species of Inocybe (Agaricales) with pleurocystidia and nodulose spores are recorded from a remote region of rain forest in Guyana, in northeastern South America. All four species of Inocybe occur in association with the arborescent legume genus, Dicymbe (Caesalpiniaceae, tribe Amherstieae). This constitutes the first report of a legume host genus with Inocybe in the neotropics. The new species are I. ayangannae, I. epidendron, I. lilacinosquamosa and I. pulchella. A dichotomous key, morphological descriptions, illustrations, taxonomic commentary, and a discussion of Inocybe in the tropics, are provided.

Relationships between Serpula lacrymans and S. himantioides isolates of ‘wild’ Himalayan woodland and building (European and Australian) origin were examined using RAPD–PCR and ITS rDNA sequence comparison. GelCompar analysis of the genetic fingerprints of eighteen isolates using four RAPD-primer combinations clearly distinguished S. lacrymans and S. himantioides. Little intraspecific variation was observed in S. lacrymans (including isolates of Himalayan woodland origin), relative to S. himantioides. Despite previously reported differences in growth rates and decay capabilities of ‘wild’ Himalayan woodland S. lacrymans isolates and those from buildings, RAPD fingerprints and ITS sequences indicated they were genetically similar. Interspecific ITS sequence polymorphisms were consistent with other studies and clearly demonstrated S. himantioides and S. lacrymans were distinct taxa. Evolutionary questions regarding the origins of S. lacrymans are discussed.

Appressorium formation in vitro by Phytophthora palmivora started after about 1 h of incubation of zoospores in an aqueous solution and was influenced by topographical signals, substrate hydrophobicity and available nutrients. Free floating, non-adhering germlings did not form appressoria. On smooth substrates, no appressoria were formed under high nutrient conditions (20% pea broth) independent of the hydrophobicity of the contact surface, while under low nutrient conditions (5% pea broth) appressoria formed on smooth substrates with hydrophobic, but not on smooth substrates with hydrophilic, surfaces. If the same substrates were scratched, appressoria formed over these scratches independent of levels of exogenous nutrients and substrate hydrophobicity. These findings are summarized in a model of signalling for appressorium induction.

Multivariate analyses (cluster and correspondence) were used to assess the taxonomic structure of 34 isolates of Penicillium miczynskii scored for 95 binary characters. Six isolates of P. raistrickii and P. rolfsii were added solely for the purpose of comparison. The characters used were 38 micromorphological, 15 cultural and 42 secondary metabolite characters. With just one exception, allocation of isolates to clusters was equal in the separate analyses using morphological and secondary metabolite data. The combined data set, using 95 characters, resulted in clearly-defined clusters interpretable as species on the basis of the distribution of ex-type cultures. Four species were accepted: P. miczynskii, P. manginii, P. soppii and P. atrosanguineum. Two additional species, P. syriacum and P. chrzaszczii, represented only by ex-type cultures, were interpreted as a nomen ambiguum and a form of uncertain taxonomic status, respectively.

Brief descriptions, illustrations and a synoptic key are included to aid identification of the accepted species.

The RAPD technique was used to distinguish two forms of Melampsora rust on Salix viminalis. Fifteen isolates of the stem-infecting form and 19 of the leaf-infecting form collected from the U.K. were tested with 10 arbitrary primers. All the primers generated polymorphic bands and 46 putative loci were examined. Seven primers gave a total of eight bands specific for the stem-infecting form and four primers produced five bands characteristic of the leaf-infecting form. Cluster analysis using Unweighted Pair-Group Method with Averaging (UPGMA) revealed 62% disagreement between the two forms. The RAPD band patterns of the stem-infecting form isolates were almost identical, while those of the leaf-infecting isolates showed up to 29% variation.

The diversity of Tricholoma matsutake basidiomata and their distribution across Japan was investigated, for the first time, by using PCR-RFLP and sequencing. Eight distinct IGS1 rDNA types were identified by using the restriction endonuclease Cfr13I. Four (A, B, G, H) were characterized by one IGS1 dominant sequence, which could then be recorded by direct sequencing of the PCR products. In contrast, the four other types (C, D, E, F) were characterized by up to more than four codominant IGS1 copies that needed to be cloned before sequencing. Among the copies, one was always exhibiting the RFLP pattern of type A basidiomata. Pairwise nucleotide variation among IGS1 spacer copies, recorded in RFLP types A, B, C, D, F, and H, was very low and never exceeded 1·9%. In contrast, type G emerged and its IGS1 spacer sequence exhibited at least 10·6% nucleotide variation compared with all other types. While the data recorded suggests a higher genetic diversity in the southern than in the northern part of Japan, no host/matsutake ribotype specificity could be evidenced. In Japan, the T. matsutake basidiomata belonging to RFLP type A were by far the most frequent. They were found at most sites and were usually the most abundant at each site. Furthermore, this predominance persisted over time during ca 50 years. The dominant RFLP type A may represent the original Japanese population while the other genotypes may have been more recently introduced.

The thiophene 5-(4-hydroxy-1-butinyl)2,2′-bithienyl (BBTOH) strongly inhibited in vitro eight different dermatophytes. Epidermophyton floccosum proved most sensitive to all doses of BBTOH when applied in conjunction with uv-A irradiation. BBTOH also proved quite active against Nannizia cajetani, the only dermatophyte which was also strongly inhibited when treated (50 μg ml−1) and kept in the dark. For this reason, N. cajetani was chosen as the test organism for TEM and SEM aimed at determining what treatment-induced ultrastructural and morphological modifications had occurred. TEM revealed that the photoactive mechanism of BBTOH was similar to that of 2,2′[ratio ]5′,2″-terthienyl (α-T). SEM, on the other hand, showed that early culture aging resulted from treatment.

The basic hydrolysis parameters, i.e. molecular weight of substrate, reaction time, pH, temperature, and enzyme and substrate concentration, were standardized to maximize sugar yield from dextran. Thus, a 74% conversion of 4% dextran to sugar syrup was reached in 12 h using 6 dextranase units g−1 hydrolysed substrate. The high concentrations of sucrose in the reaction medium did not affect the hydrolysis efficiency nor the activity of Penicillium notatum dextranase. Action patterns of dextranase from P. notatum on dextran were investigated. Analysis of the dextran hydrolysis end products indicated that P. notatum dextranase was a typical endo-enzyme, and isomaltose and isomaltotriose were identified as the primary final products of dextran hydrolysis.

The foraging behaviour of Armillaria rhizomorph systems is poorly understood owing to their cryptic position within the soil. We investigated foraging in a homogeneous environment (i.e. agar), finding that rhizomorph systems of the more parasitic species, A. mellea, A. ostoyae, and A. tabescens, lacked melanin and the approximately cylindrical cord-like form observed in the field. In contrast, rhizomorph systems of the more saprotrophic species, A. calvescens, A. gallica, and A. sinapina, developed radially resembling those in the field. For the three saprotrophic Armillaria species, the number of rhizomorph tips, total rhizomorph length and total rhizomorph surface area were significantly positively correlated with increasing rhizomorph system diameter and elapsed time in two developmental tests. However, the fractal dimension (D), used as a measure of foraging intensity, was temporally invariable, suggesting that one component of foraging behaviour is innate. In a heterogeneous environment (i.e. sand) and in the absence of a potential nutrient source, we observed that rhizomorph systems of A. gallica most often developed asymmetrically. While rhizomorph foraging was unresponsive to the lateral placement of an uncolonised stem segment, we were able to demonstrate directional growth toward an uncolonised Quercus velutina stem segment placed above or below the colonised source stem segment. When neighboring rhizomorph systems were conspecific genets of A. gallica, we observed that the growth of one rhizomorph system was directed toward zones unoccupied by its neighbour. However, the foraging intensity of the neighbouring genets, as measured by fractal dimension (D), was unaffected by the proximity of a neighbour. When neighbouring rhizomorph systems represented different species (A. gallica and A. mellea), A. gallica rhizomorph systems produced more total length and more foraging tips but concentrated their rhizomorph production away from the neighbouring A. mellea genet. In contrast, A. mellea rhizomorph systems produced significantly more foraging tips per unit length, both overall and in the zone of confrontation with the neighbouring A. gallica genet. Our observations are consistent with field observations of territoriality among Armillaria genets, and provide evidence that rhizomorph systems of more parasitic Armillaria spp. are able to compete effectively with the larger rhizomorph systems of more saprotrophic Armillaria species.

Fifty-three isolates of Pisolithus were obtained from various locations in central and eastern Australia. These, along with two isolates from south-east Asia and one from USA, were compared using ITS–RFLP and ITS sequencing analyses. Results of the RFLP analysis initially grouped the isolates into eight RFLP types. ITS sequences were obtained for at least one representative isolate from each RFLP type and compared by a neighbour-joining analysis with Pisolithus ITS sequences available in databases. The majority of isolates clustered into four groups within two major clades, each clade comprising isolates of similar basidiospore characteristics. Most Australian isolates corresponded with recent provisional descriptions of P. albus or P. marmoratus. One isolate (LJ30) had low sequence identity (61·6–78%) to the other isolates and probably represents a separate undescribed Australian species. Significant intraspecific variation was observed in ITS–RFLP profiles for the putative P. albus isolates, suggesting that the sole use of RFLP analysis in diversity assessment may overestimate Pisolithus species richness.

Datronia caperata, a basidiomycete fungus, is one of the dominant polypore species found in neotropical mangrove forest fragments, where it is locally specialized on Laguncularia racemosa. We examined the genetic structure of D. caperata populations from four Panamanian mangrove forests using AFLP markers. Using five primer pair combinations, 145 loci were detected, 98.6% of which were polymorphic. Each of the populations showed a high degree of genetic diversity (Nei's h ranging from 0.146 to 0.223). Results from minimum spanning trees and Mantel tests showed little evidence for small-scale spatial structure within sites. A significant amount of total genetic variation was partitioned among populations (ΦST=0.21) separated by 10s to 100s of km, a considerably greater amount than has been detected in other mushroom and wood-decaying fungi sampled at equal or greater geographic distances. These results suggest that despite production of copious basidiospores capable of long distance dispersal, some homobasidiomycete fungi may be susceptible to genetic isolation due to habitat fragmentation.

The 5′ end of the large subunit (LSU) region and the entire internal transcribed spacer (ITS) region of ribosomal DNA were sequenced from 11 species or special forms of Melampsora on Salix, and three species on Populus. For all the species, except for M. larici-epitea and M. coleosporioides, the sequences in both the examined regions were identical within a species. Within M. larici-epitea, f. sp. larici-epitea typica and f. sp. larici-retusae shared the same sequences which slightly differed from that of f. sp. larici-daphnoides. In the LSU region, M. larici-epitea, M. capraearum and the stem-infecting form on S. viminalis shared the same sequence and the Far-Eastern species M. epiphylla differed from them only slightly (p distance 0.006), indicating that they may share a common ancestral lineage. M. amygdalinae and M. coleosporioides formed a distict group (bootstrap value 100% for combined ITS and LSU data). M. larici-epitea and M. ribesii-purpurea, both belonging to the M. epitea complex, appeared to be distinct. The molecular data also suggest that the differences in certain characteristics, such as the thickness of teliospore walls and host specificity, may have evolved relatively recently.

Hebeloma strains of arctic and temperature origin, grown at 22° or 6°, were assayed for wall-bound and extracellular acid phosphomonoesterase (pNPPase) across a temperature range 2–37°. Only when grown at 6° was a cold active extracellular pNPPase induced in all the arctic strains and most of the temperature strains tested. Such enzymes are suggested to be an adaptation to low soil temperatures, and are discussed in the context of ectomycorrhizal access to soil PO4− monoesters at low temperature.