This month Mycological Research News features recent work on generic concepts in cantharelloid fungi, and ectomycorrhizal fungi raiding saprotrophic ones for nutrients. Amongst topics covered by the 18 research papers in this issue are molecular systematics of Craterellus, variation at the molecular level in Chondrostereum purpureum and Monascus, genetic exchange between Metarhizium strains, β-1,3-glucanase regulation in Trichoderma harzianum, specific isozymes in Botrytis cinerea, lipid and fat composition of arbuscular mycorrhizal fungi, PCR detection of Verticillium chlamydosporium, the storage of Erynia, destruxin production by Metarhizium strains, ultrastructure of Entomosporium mespili, utilization of various substrates by Aspergillus fumigatus, Tuber melanosporum inoculation and molecular detection, and studies on freshwater ascomycetes from Thailand and Crepidotus species in Mexico. New scientific names introduced are: Botryobasidium musaisporum, Deltosperma oblongum, Melanochaeta garethjonesii, Ophiostoma setosum, Unguiculariopsis changbaiensis, and C. damingshanica spp. nov.; and Craterellus ignicolor (syn. Cantharellus ignicolor) comb. nov.

Considerable taxonomic confusion exists regarding many species of Cantharellus. Several taxa have been classified in either Cantharellus or Craterellus depending on which morphological characters were emphasised. Recent phylogenetic studies based on sequence analyses suggest that some species now classified in Cantharellus should be in Craterellus. We extracted DNA from dried herbarium specimens and amplified, sequenced and cladistically analysed approximately 650 bp of the 5′ end of the nuclear large subunit ribosomal DNA gene. Our data confirm earlier results and provide molecular evidence for the classification of additional Cantharellus species (Ca. ignicolor and Ca. lutescens) within Craterellus. Furthermore, the data enable us to predict that all Leptocantharellus-like species currently classified within Cantharellus are more accurately classified within Craterellus. The species complexes of Cr. tubaeformis and Cr. cornucopioides were also investigated. These analyses did not support the monophyly of Ca. tubaeformis but the hypothesis that colour varieties of Cr. cornucopioides represent separate species was rejected.

Isolates of Chondrostereum purpureum were characterised on malt agar by rapid growth of white, flat, velvety to cottony mycelium and formation of yellow fruitbody crusts with apiculate basidiospores. The presence of cystidia was diagnostic, but not a reliable taxonomic character. Above 33 °C isolates exhibited a differential growth response and only three failed to grow following 20 d incubation at 36°. Tolerance of high temperature was not correlated with RAPD banding patterns nor geographic origin. All isolates were pathogenic to willow, poplar and apple regardless of their original host, locality or RAPD profiles. No zones of demarcation were observed following infection of wounds by multiple isolates. RAPD banding patterns exhibited considerable diversity, enabling discrimination of isolates with single primers, and this was indicative of the extensive genetic diversity within the NZ population. No RAPD banding combinations specific to host species or locality were observed. An explanation is given for the wide dissemination of C. purpureum isolates throughout NZ.

Genetic variation within a collection of 25 isolates of Monascus from red rice and sofu was assessed with RAPD markers using genetic distances (1-Jaccard's coefficient) calculated for all combinations of isolates. Cluster analysis based on genetic distance was performed using the Ward's minimum variance method. Five distinct clusters were revealed based on genetic distances between and among clusters. The robustness (reproducibility) of the cluster assignments was tested by resampling (bootstrap) analysis. Cluster distribution was visualized as a three-dimensional graph based on multiple correspondence analysis. A dendrogram, based on the clusters, was constructed to examine the relationships. Three clusters accounted for 21 isolates; the fourth cluster consisted of three isolates which were quite distinct from each other and all other isolates. The fifth cluster, a single isolate from Japan, was very different from all others in RAPD patterns and was used as an outgroup. Resampling analysis indicated that the 25 isolates represented four genetic lineages of red rice fungi, suggesting that a relatively narrow genetic source of Monascus isolates is used in food products in Asia.

Recombination between two strains of Metarhizium anisopliae, subcultured on artificial medium and passed through an insect host was investigated. When grown on agar culture, or passed through a host, strains did not show detectable genetic changes. When passed through an insect in the presence of the other strain, genotypic changes in the isolates, as detected by esterase electrophoresis, restriction digestion of total genomic DNA and RAPD-PCR, were apparent. The instability of molecular markers suggests recombination between strains.

The β-1,3-glucanase system of the mycoparasitic T. harzianum, isolate T-Y, was found to be composed of at least five different enzymes. Their migration distance in acrylamide gels corresponded to peptides with molecular masses of 30–200 kDa, and they were named accordingly. The largest enzyme – Gβ-1,3–200, was the most abundant when T-Y was grown with no carbon source. Its secretion was almost eliminated when T-Y was grown on media containing a high concentration of carbon sources such as N- acetylglucosamine (GlcNAc) or malic acid. Several isolates of T. harzianum were found to have a β-1,3-glucanase secretion system, controlled by catabolite repression. Each isolate exhibited a different β-1,3-glucanase profile. Gβ-1,3–200 was isolated and purified: its molecular mass was approximately 75 kDa, and its activity was of the exo-type, specific to β-1,3-glucan linkages. Four short peptides resulting from proteolysis of this enzyme were sequenced, and their sequences were most homologous to LAM1.3, a previously isolated β-1,3-glucanase.

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.

The lipid and fatty acid compositions of Glomus intraradices and G. claroideum mycelia, extracted from quartz sand in a compartmentalized growth system, were analysed. The fungi were grown in association with Cucumis sativus and Trifolium subterraneum, respectively. For both fungi, the fatty acids 16[ratio ]1ω5 and 16[ratio ]0 dominated in the neutral lipid fraction, and 18[ratio ]1ω7 made up a significant part of the phospholipids. The fatty acids were used as estimators of the amount of neutral lipids and phospholipids of AM fungi as well as to calculate the biomass of different parts of their mycelium. The phospholipid content was higher in hyphae than in spores, whereas the opposite was observed for neutral lipids. In 3-mo-old G. intraradices mycelium, spores accounted for 90% of the external biomass, and calculations indicated that about 20% of the spore biomass consisted of neutral lipids. In both fungi the fatty acid compositions of hyphae and spores were similar regardless of the age of the mycelium.

Using the signature fatty acid 16[ratio ]1ω5 to calculate the distribution of AM biomass for a 2-mo-old mycelium of G. claroideum, we found that the fungal biomass was equally distributed between the external mycelium and the internal mycelium in the host root.

PCR-based methods to detect Verticillium chlamydosporium on infected plant roots were developed. Arbitrary ERIC primers and those based on rRNA genes, to identify fungi grown in pure culture, were unsuitable for DNA extracted from nematode-infested roots, because of interference by plant and nematode DNA. A novel method utilizing specific primers designed from an amplified and cloned fragment of the V. chlamydosporium β-tubulin gene was developed. Although it could not discriminate between different isolates of V. chlamydosporium, one primer set could identify the fungus on tomato roots infested with root-knot nematodes. The V. chlamydosporium β-tubulin sequence data showed close homology to sequences from plant endophytic Acremonium and Epichloë species and the saprotrophic Trichoderma viride.

Mycelial preparations of Erynia neoaphidis were tested under different drying and storage conditions. For unformulated mycelial discs and formulated alginate granules, sporulation was best maintained if drying at 20–22 °C was performed at 60 or 90% r.h. rather than an ambient humidity of 30%. Storage experiments were performed on preparations dried at 90% r.h. for 72 h. Estimates for a 50% decline in sporulation with storage time (ST50) were computed if there were statistically significant fits using exponential or non-parametric linear regression. For mycelial discs, values of ST50 were between 36–39 d when maintained at 10° with silica gel or 20% r.h., and 14–26 d when kept at 10° and 35% r.h. or with silica gel and 15 or 20°. For alginate granules, ST50 values of 6–9 d were obtained at 10° and 20–55% r.h. A 5- to 9-fold increase in sporulation was produced with granules containing 2% w/v sucrose and 5% w/v starch compared to granules without additives. Elevated humidities are recommended for drying E. neoaphidis mycelia and viability of dried preparations is best maintained if they are stored at 10° compared with 15 or 20°.

Inter- and intra-specific variation in destruxin production was detected in Metarhizium and may be important in determining virulence and/or specificity against insects. Strains of M. anisopliae var. anisopliae produced different amounts of destruxins A, B and E, but strain V220 did not produce any destruxins. M. anisopliae var. majus, M. flavoviride and M. album which are reported to be specific towards Coleoptera, Orthoptera and Hemiptera, respectively, had different destruxin profiles with destruxin A predominant. In time course studies on M. anisopliae var. anisopliae V245, destruxin E levels declined with time while destruxin A levels increased. The most virulent strains, Ma23 and V245, produced large quantities of destruxins but some low toxin producers were also virulent, suggesting that destruxins are not the only pathogenicity determinants. Some weakly to moderately pathogenic strains were highly pathogenic when injected into Galleria mellonella larvae, demonstrating the importance of the cuticle as a barrier to fungal infection. Only trace amounts of destruxin A or a combination of A and B could be detected in Galleria larvae infected with M. anisopoliae var. anisopliae or M. anisopliae var. majus. No destruxins were detected in larvae infected with M. flavoviride. Destruxin production may be influenced by the nutrients in insects or culture media.

Acervuli of E. mespili developed subcuticularly on both surfaces of infected Photinia leaves. Acervuli developed as single or aggregated, confluent structures. Conidium initials arose from hyphae which developed between the cuticle and epidermis. As conidia developed the cuticle was displaced and eventually ruptured. Development of the first conidium from a conidiogenous cell was holoblastic. Subsequent conidia developed in an enteroblastic, annellidic fashion. Three to four conidia arose from a single conidiogenous cell. A mature conidium consisted of four to six cells including an apical cell and a basal cell which developed first. These were separated by a septum with a plugged pore. A similar septum separated the basal cell from the conidiogenous cell. A long, slender, enucleate appendage then arose from the tip of the apical cell. During this time the basal cell gave rise to two to four small lateral cells, separated by septa from the basal cell. An appendage then developed from each lateral cell. Each cell of a mature conidium contained a single nucleus and a complement of cytoplasmic organelles and inclusions, many of which were more prominent in freeze substituted conidia than in chemically fixed conidia. The conidium wall labelled for chitin using wheat germ agglutin-gold conjugate. Its outer surface was coated with fibrillar material.

Aspergillus fumigatus is saprotrophic with an unusual ability to colonize the respiratory tract. The mechanisms that permit pathogenicity may have evolved to adapt the fungus to life as a saprobe. To define the nature of these adaptations and identify common themes in fungal pathogenesis to vertebrates, insects and plants, we compared A. fumigatus with a plant pathogen (Haematonectria haematococca) and an insect pathogen (Metarhizium anisopliae) in their abilities to degrade and utilize host-derived macromolecules (horse lung polymers, porcine mucin, hyaluronic acid, alfalfa cell walls and cockroach cuticle). Each fungus produced a similar range of proteases on mucin and lung polymers, and high levels of several glycosidic enzymes on mucin and plant cell walls, which contain inductive carbohydrate substrates. Following 18 h of growth by A. fumigatus at pH 4 or pH 8, the degradation of mucin carbohydrates and mucin protein were approximately 40% and 75% respectively, suggesting that the aspartyl proteases (produced at pH 4) and the subtilisin proteases (produced at pH 8) are more important than carbohydrases for degrading mucin. The highly glycosylated mucin residue remaining after 18 h growth resisted further degradation, in part due to bound sialic acid as A. fumigatus secretes a sulphatase but not sialidase. Hyaluronidase activity (an important virulence factor in bacteria) was not produced by A. fumigatus, M. anisopliae or H. haematococca, but each fungus secreted a range of other enzymes (phospholipase A2, phospholipase C, acid phosphatase, alkali phosphatase, phosphodiesterase and esterase) that are common toxic components of bacteria as well as reptilia and invertebrate venoms. Thus thermotolerant opportunists such as A. fumigatus may sustain themselves and cause disease in human hosts using depolymerases that are widely distributed in fungi and that provide them with the versatility to exploit many environments.

Five local oak species, Quercus boissieri, Q. calliprinus, Q. cerris, Q. ithaburensis and Q. libani were identified as hosts of Tuber melanosporum, the black truffle of Perigord, following inoculation of roots. Q. cerris and Q. libani developed abundant mycorrhizal roots, similar to the amount found in roots of Q. pubescens, the traditional host of this mycorrhizal fungus. Roots of Q. ilex, Q. hartwissiana and Q. pedunculiflora, introduced species in Israel, were also heavily colonized by the mycorrhizal fungus. Mycorrhized hazel (Corylus avellana) roots, were also obtained by the same inoculation procedure. Recovery of T. melanosporum from roots of inoculated oak was improved when chloramphenicol was added to the isolation medium. Recovery varied between 14 and 54% for C. avellana and Q. calliprinus, respectively. Recovery was highest for the two local species, Q. calliprinus (54%) and Q. boissieri (50%), followed by Q. pubescens (44%) and Q. ilex (41%). Identification of the isolated fungi was conducted using arbitrarily-primed PCR. Identical band patterns were observed among AP-PCR-amplified DNA extracted from an authentic culture of the fungus, ascocarps (truffles) and cultures isolated from roots. In addition, AP-PCR was reliable for differentiating between representative isolates of T. melanosporum, T. magnatum, T. borchii, T. maculatum, T. dryophilum, T. macrosporum and T. uncinatum.

Two species of Melanochaeta and three species of Sporoschisma are reported from Thailand. Two connections of Sporoschisma and Melanochaeta are confirmed. Melanochaeta hemipsila has Sporoschisma saccardoi as its anamorph with a Chalara synanamorph in culture. Melanochaeta garethjonesii is described as a new species and linked with S. uniseptatum. S. nigroseptatum was recorded but no evidence of a Melanochaeta teleomorph state could be found.

Ophiostoma setosum is described as a new species commonly associated with exposed sapwood of Tsuga heterophylla in western North America. It is characterized by the production of a typical ophiostomatoid teleomorph, a Pesotum anamorph with conspicuous, dark seta-like hyphae on the synnema stipes and apices, and a Sporothrix mycelial anamorph with solitary or short-catenate conidia. Mating experiments demonstrate that the species has two mating types controlled by two alleles at a single locus and is reproductively isolated from similar biological species of the O. piceae complex. Phylogenetic analysis of DNA sequences from the ITS2 and 5′ end of the large nuclear subunit (26S) of the ribosomal DNA supports the close relationship of O. setosum and O. piceae.

A morphological study of Mexican collections of Crepidotus cinnabarinus, C. croceitinctus, C. palmarum and C. quitensis is provided. The relationships of these species with close allies are examined and discussed. Microscopical observations on the type collections of C. carpaticus, C. cinnabarinus, C. croceitinctus, C. luridus vars luridus, minor and oaxacae, C. macedonicus, C. palmarumm, C. quitensis, C. subcroceitinctus and C. unicus are included. Illustrations of the microscopic features of all taxa are presented.

Two new species of Unguiculariopsis are described from tropical Guangxi and the Changbai Mountains in northeastern China. Unguiculariopsis changbaiensis and its anamorph Deltosperma oblongum occurs on a pyrenomycete and U. damingshanica is lichenicolous.

The morphology of Botryobasidium musaisporum sp. nov., a species with bananiform basidiospores collected in Taiwan, is illustrated, described, and discussed. Only one other Botryobasidium with bananiform basidiospores is known, B. bananisporum described from Africa. A key to 13 Taiwanese Botryobasidium species is provided.