This issue of Mycological Research News features: CBS centenary: collect, study and preserve; In this issue; The origins of Saccharomyces cerevisiae; and Diversity of fungal laccase gene sequences in salt marshes.

A review of aspects of fungal genetic resource collections and their role in the genomic age precedes papers on relationships within Pythium and the Coronophorales using molecular phylogenetic approaches. Diplodia pinea and D. scrobiculata on pines in North America are reassessed. The polygalacturonase encoding gene of Rhizopus oryzae is characterized, the kinetics of selenite uptake in Saccharomyces cerevisae are described, viability tests for Rhinosporidium seeberi endospores are assessed, and aspects of the detection of the isoepoxydon dehydrogenase gene involved in patulin biosynthesis are explored. Other papers consider fire and the availability of hypogeous fungi as animal food in Australia, interactions between scarce tooth fungi and others, Termitomyces species consumed in China, red-capped species of Russula sect. Xerampelina, and rapid detection of Mycosphaerella species on Eucalyptus.

The following new scientific names are introduced: Chaetosphaerellaceae and Scortechniaceae fams. nov.; Bertia tropicalis, Lasiobertia portoricensis, Nitschkia meniscoidea, and Termitomyces bulborhizus spp. nov.; and B. multiseptata (syn. B. moriformis var. multiseptata) comb. nov.

Fungal research and education has for many years been supported by public service genetic resource centres, whose roles have been to maintain, preserve and supply living cultures to the research community. In the genomic era, genetic resource centres are perhaps more important than ever before. The cultures held, many of which are described and validated by expert biosystematists, are valuable resources for the future. There is a need to supply genomic and proteomic research programmes with fully characterised organisms, as usage of organisms from unreliable sources can prove disastrous, not least in economical terms. However, mycologists often require more than just the organisms, for example, their associated information is vital for bioinformatic applications and some researchers may only require genomic DNA from the organism rather than the organism per se. Genetic resource centres are continually adapting to meet the needs of their users and the wider mycological research community, this associated with OECD international initiatives should ensure they exist to support research for many years to come. This review considers the impact of such initiatives, the current roles of fungal genetic resource centres, the mechanisms used to preserve organisms in a stable manner and the range of resources that are offered for genomic research.

The phylogeny of 116 species and varieties of Pythium was studied using parsimony and phenetic analysis of the ITS region of the nuclear ribosomal DNA. The D1, D2 and D3 regions of the adjacent large subunit nuclear ribosomal DNA of half the Pythium strains were also sequenced and gave a phylogeny congruent with the ITS data. All the 40 presently available ex-type strains were included in this study, as well as 20 sequences of recently described species from GenBank. Species for which no ex-type strains were available were represented by either authentic strains (6), strains used in the 1981 monograph of the genus by van der Plaats-Niterink (33), or strains selected on morphological criteria (17). Parsimony analysis generated two major clades representing the Pythium species with filamentous or globose sporangia. A small clade of species with contiguous sporangia was found in between the two main clades. A total number of 11 smaller clades was recognized, which often correlated with host-type or substrate and in several cases with a subset of morphological characters. Many characters used in species descriptions, such as antheridium position, did not correlate with phylogeny. A comparison of the ex-type and representative strains with all ITS sequences of Pythium in GenBank revealed limited infraspecific variation with the exception of P. rostratum, P. irregulare, P. heterothallicum, and P. ultimum. The total number of species examined was 116 (including 60 ex-type strains). Twenty-six species had ITS sequences identical or nearly identical to formerly described species, suggesting possible conspecificity. The importance of comparing ITS sequences of putative new species to the now available ITS database in order to avoid unwarranted new species names being introduced.

The Nitschkiaceae has been placed in the Coronophorales or the Sordariales in recent years. Most recently it was accepted in the Coronophorales and placed in the Hypocreomycetidae based on sequence data from large subunit nrDNA. To confirm and corroborate the taxonomic placement and monophyly of the Coronophorales, additional taxa representing the diversity of the group were targeted for phylogenetic analysis using partial sequences of the large subunit nrDNA (LSU). Based on molecular data, the Coronophorales is found to be monophyletic and its placement in the Hypocreomycetidae is maintained. The order is a coherent group with morphologies that include superficial, often turbinate, often collabent ascomata that may or may not contain a quellkorper and asci that are often stipitate and at times polysporous. Three species with accepted Nitschkia names, together with Fracchiaea broomeiana and Acanthonitschkea argentinensis, comprise the paraphyletic nitschkiaceous complex. Two new families, Chaetosphaerellaceae and Scortechiniaceae fams nov., are described for the clades containing Chaetosphaerella and Crassochaeta and the taxa having a quellkorper (Euacanthe, Neofracchiaea and Scortechinia) respectively. The Bertiaceae is accepted for the clade containing Bertia species. Three new species are described: Bertia tropicalis, Lasiobertia portoricensis, and Nitschkia meniscoidea spp. nov.

Diplodia pinea (syn. Sphaeropsis sapinea) is a well-known latent pathogen of Pinus spp. with a worldwide distribution. As such, this fungus is native where pines are endemic in the northern hemisphere and it has been introduced into all countries of the Southern Hemisphere where pines are exotic. The newly described D. scrobiculata (formerly known as the B morphotype of D. pinea) is thought to have a much more limited distribution. D. scrobiculata was first reported as an endophyte and weak pathogen of P. banksiana, where it was found to coexist with D. pinea. Diplodia scrobiculata is now known to have a much broader distribution in Northern America and Europe. In this study, seven Simple Sequence Repeat (SSR) markers were used to evaluate genetic diversity and gene flow between populations of D. scrobiculata. Results indicate a strong geographic isolation between populations of D. scrobiculata from different regions in North America, with unique alleles fixed in the different populations. The data fits the isolation by distance model indicating limited dispersal. Geographic isolation in combination with isolation by distance suggests prolonged reproductive isolation. Intensive collections of endophytes from native P. radiata in California have yielded only D. scrobiculata and not the significantly more pathogenic D. pinea. SSR analysis of three populations of D. scrobiculata from native P. radiata identified many shared alleles among the populations and moderate to high gene flow between them. The three Californian populations are distant and distinct from populations of D. scrobiculata from elsewhere. Under stress conditions, P. radiata is known to be very susceptible to D. pinea in plantations in the Southern Hemisphere. Native P. radiata is currently experiencing severe stress due to pitch canker caused by Fusarium circinatum. Such stress would provide ideal conditions for an associated outbreak of D. pinea. Thus, it is critical to prevent the movement of D. pinea into the last remaining native stands of P. radiata.

The polygalacturonase (PG)-encoding gene (rpg1) of Rhizopus oryzae, the causal pathogen of rhizopus rot of mulberry, was cloned and sequenced. PGs were partially purified from incubation mixture of 2% pectin medium and their N-terminal amino acid sequences were determined by a gas-phase protein sequencer. RT-PCR was performed using degenerate primers designed from the amino acid sequences, which resulted in part of a PG-encoding gene being obtained. By 3′-RACE and TAIL-PCR analyses, the entire region of the PG-encoding gene was cloned and sequenced. The structural gene comprised 1199 bp coding for 383 amino acids with a putative signal peptide of 26 amino acids, and the open reading frame was interrupted by single intron of 47 bp. Phylogenetic analysis using the deduced amino acid sequence revealed that R. oryzae RPG1 belonged to a clade consisting of exo-PGs of ascomycete fungi.

Uptake of 75[Se]-selenite by Saccharomyces cerevisiae has been characterized. At a 0.5 mM selenite, ~0.14 nmol Se (106 cells)−1 was rapidly accumulated by the cells at a rate of ~56 pmol.min−1 (106 cells)−1 which was independent of temperature and glucose. This rapid phase was followed by a slower uptake phase which was sensitive to glucose, temperature and metabolic inhibitors [2,4-dinitrophenol (DNP), carbonyl cyanide m-chlorophenyl hydrazone (CCCP), potassium cyanide (KCN) and sodium azide (NaN3)] and therefore presumed to be metabolism-dependent. Two transport systems appeared to be involved in selenite uptake. At the low range of selenite concentrations used (0.025–0.1 mM), a high affinity transport system occurred with apparent Km and Vmax values of 54.0 μM and 3.14 pmol.min−1 (106 cells)−1 respectively. A low affinity system was present at higher concentrations (0.1–1.0 mM) with apparent kinetic parameters of Km=435 μM and Vmax=11.6 pmol.min−1 (106 cells)−1. Elevated sulphate concentrations (up to 2.5 mM) did not affect the accumulation of selenite. However, the transport rate from 0.5 mM selenite was stimulated by sulphite, with the maximum effect occurring at 0.5 mM sulphite. Methionine had a detectable inhibitory action on selenite uptake whereas cystine and cysteine completely inhibited active transport of selenite. Transmission electron microscopy of 5 mM selenite-grown cells revealed the presence of abundant small cytoplasmic vesicles containing electron-dense granules which could represent an intracellular selenium-detoxification mechanism.

This report describes tests with Evan's Blue and MTT (3-[4, 5-dimethyl-2-thiazolyl]-2, 5-diphenyl-2H-tetrazolium bromide) for the assessment of the viability of rhinosporidial endospores. MTT stained a proportion of the spherical bodies that we regard as the Electron Dense Bodies (EDBs), and the cytoplasm of freshly prepared endospores or ones that were stored at 4 °. Slow-freezing at −20 °C, exposure to 10% formalin, or 0.1% sodium azide of the endospores abolished MTT-staining in both sites. Evan's Blue stained the EDBs and cytoplasm of fresh endospores or those stored at 4 °, and of sodium azide-treated or frozen (−20 °)-thawed endospores. TMRE (tetramethyl-rhodamine ethyl ester) specifically labelled the spherical bodies, supporting the conclusion that these spherical bodies have a mitochondrial-like structure. TMRE-staining was however retained in endospores after their treatment with formalin, sodium azide and slow-freezing while MTT-staining was abolished in all these treated endospores.

These results indicate that EvB and TMRE were capable of revealing the morphological integrity of endospores but failed to identify the metabolic inactivation of the endospores after treatment with formalin, sodium azide or slow-freezing. Only MTT was capable of identifying metabolically active endospores and hence their viability and could prove to be of value in standardizing models of infection.

The European Union (EU) has introduced statutory limits for patulin in fruit products. Species definitions need to be unambiguous for this capability, especially to determine ‘weak spots’ in food, drink and feed production. Fungi were analysed for the isoepoxydon dehydrogenase (IDH) gene of the patulin metabolic pathway to indicate potential patulin production. In several cases inhibition of PCR product formation was indicated. Dilution as a means of overcoming PCR inhibition and to determine optimal concentrations was assessed and the ramifications for nucleic acid analysis in general are highlighted. The inhibitors may be secondary metabolites. However, inhibition was not involved obviously for Penicillium brevicompactum. The gene was detected frequently from Aspergillus section Clavati and Penicillium subgenus Penicillium species. Some strains within certain species were negative for the gene. Detection of the gene product in Byssochlamys is reported.

Changes in pre- and post-fire biomass of hypogeous fungal sporocarps remaining at locations where an endangered mycophagous marsupial, the northern bettong (Bettongia tropica), had foraged, were assessed in fire-prone sclerophyll forest in northeastern Australia. Low to medium intensity experimental fires were set during the late dry season in 1995 and 1996 and post-foraging biomass of sporocarps (expressed as biomass of sporocarps remaining at recent B. tropica diggings) was measured at unburnt and burnt sites at approximately six-week intervals for a period of 14 months. Post-foraging biomass was significantly higher at burnt sites immediately following fire compared with control sites, solely due to increased biomass of hypogeous species belonging to the family Mesophelliaceae. Several months after fire, post-foraging biomass was significantly higher on unburnt sites compared with very low biomass on burnt sites. Twelve months after fire, the biomass on burnt and unburnt sites was not significantly different, having returned to biomass observed pre-fire. All evidence points toward mesophellioid fungi being greatly more available to bettongs on recently burnt ground, but fire may make several other sporocarp taxa considerably less available several months following fire.

Creolophus cirrhatus, Hericium erinaceus and H. coralloides were paired against over 20 other wood decay fungi from beech (Fagus sylvatica) covering a range of ecological strategies, on 2% malt agar (MA), 0.5% MA, 0.5% MA adjusted to −1.25 MPa by addition of KCl, 0.5% MA adjusted to pH 4 with KOH/H3PO4 and 0.5% MA under 5% O2/30% CO2 all at 20 °C. Creolophus cirrhatus and H. coralloides were also paired against 17 other species in wood, incubated at 20 ° for 36–38 wk. They were average to good combatants, deadlocking with or replacing over half of the antagonists, H. erinaceus being slightly more combative than the other two species. Outcomes in wood were representative of those in agar. Abiotic conditions altered the outcomes slightly, reduced water potential favouring C. cirrhatus and H. erinaceus. Overall extension rate of C. cirrhatus and H. erinaceus often increased in the presence of antagonists. There was prolific production of fruit bodies in controls and interactions, though notably not under altered gaseous regime. Results are discused in an ecological context.

The new species, Termitomyces bulborhizus, is described from south-west China. The stipe of the basidiome is swollen into a prominent bulbous base at ground level, and this, together with the floccules on the stipe surface, distinguishes this species within the genus. T. bulborhizus is compared with closely related species, including three originally described from China, and a key to T. bulborhizus and related species is provided.

The microscopic structure of herbarium material of alpine and arctic species of Russula sect. Xerampelinae from Europe and Greenland was studied. Based on our observations two taxa with prevailingly red pilei are accepted from the area: R. subrubens and R. pascua. Other related species occurring in arctic areas are R. cicatricata with a coppery coloured pileus and R. clavipes with a prevailingly greenish olivaceous pileus. As a consequence of the study of type material, R. chamiteae var. chamiteae and R. chamiteae var. microsperma are synonymized with R. subrubens. No European collections could be referred to R. oreina, and accordingly we suggest that this species is absent from Europe.

It is difficult to accurately identify Mycosphaerella species associated with leaf diseases of Eucalyptus based on morphological characters, as there is considerable overlap between very similar species and subspecies, and isolation from the host is not easy. Thus, a PCR and RFLP assay based on the ITS region of nr DNA was developed for the rapid detection and differentiation of M. nubilosa, M. cryptica and two non-sporing unidentified Mycosphaerella species isolated from the foliage of trees in resistant and susceptible families of E. globulus in a seed orchard at Kinglake West, Victoria, Australia. The M. nubilosa primer pair MNF/MNR was highly specific. A PCR-RFLP system based on the primer pair MCF/MCR, coupled with two restriction enzymes (DdeI and Tru1I), differentiated M. cryptica, M. nubilosa, M. tasmaniensis and M. aff. vespa. One of the unidentified field-isolated Mycosphaerella species was identified as M. grandis on the basis of ITS sequence data while the other species remains unidentified. A PCR-RFLP system based on the primer pair U1F/U1R, coupled with the restriction enzyme StyI, differentiated between the two unidentified species. Unexpectedly, unlike isolation and culture studies, these assays detected M. nubilosa, M. cryptica and M. grandis in all single lesions examined on both juvenile and adult leaves, and on both highly resistant and highly susceptible E. globulus trees at this site.