This month Mycological Research News features recent work on the advance of the daisy rust Puccinia distincta in the UK, questions whether hyphae should be viewed as eusocial, draws attention to work showing that fertilization with AM-fungi may promote desirable grass species, and introduces a freely accessible index of 340 K names of fungi now available on-line. The untimely death of one of Mycological Research's editors, David A. Wood, is also reported.

Amongst topics covered by the 16 research papers in this issue are PCR-based techniques for the detection of Fusarium oxysporum and Gremmeniella abietina. Tuber dryophilum shares a specific protein with T. borchii. Toxic ephrapectins occur in Tolypocladium species; the extracellular enzymes of Trichoderma strains able to grow at 5 °C are examined; nutrients favouring oxalic acid production in Aspergillus niger have been studied; and the branching of Neurospora crassa hyphae is predictive on rapid falls in temperature. Elegant colour and ultrastructural studies on the extracellular matrix of Bipolaris sorokiniana are presented. In addition to documentation of the daisy rust spread, the life-history of Chrysomyxa woroninii is elucidated and the success of Lophodermium pinastri along an altitudinal gradient discussed.

The growth of fungal partners from different lichens is compared, and cell wall polysaccharides are shown to be of taxonomic value in Fusarium and Gibberella.

Systematic papers include ones on Pyrenopezia betulicola, and microfungi on Proteaceae. New scientific names introduced are: Kabatiella proteae, Lembosia proteae, Mycosphaerella stromatosa, Perennipora najenshana, Phloeosporella protearum, Pseudocercospora stromatosa, Septoria grandicipis, Stilbospora proteae, Teratosphaeria microsporum, Trimmatostroma microsporum, and T. elginense spp. nov.; and Diplotomma rivasmartinezii (syn. Buellia rivasmartinezii) comb. nov.

A PCR assay and a hybridisation assay were developed for identification of Fusarium oxysporum. Based on sequence data from the 28S rDNA, two primers (PFO2 and PFO3) and one 20-mer probe (HFO1) were designed. These oligonucleotides were tested with 16 strains of F. oxysporum and 80 strains of 23 other Fusarium species or of eight species from other fungal genera. A PCR procedure for specific amplification of DNA from the F. oxysporum strains using primers PFO2 and PFO3 was set up. Under the conditions defined, no PCR product was obtained with these primers from the 80 other strains. The oligonucleotide probe HFO1 was labelled using a non-radioactive method and evaluated for specificity in dot blot hybridisation experiments with rDNA amplified by PCR. Under optimised conditions, the probe hybridised exclusively with DNA from F. oxysporum strains. Both PCR and hybridisation procedures were validated with 53 additional isolates of F. oxysporum representative of the populations present in four different soils. These specific assays appear to be reliable tools for the identification of F. oxysporum and may have various applications in ecological studies.

Scleroderris canker of conifer is caused by Gremmeniella abietina var. abietina, which comprises several taxa, including races, varieties, and biotypes. The European race of G. abietina var. abietina was introduced into North America early in the century, most likely on asymptomatic infected pine seedlings, and is currently widespread in eastern North America. In order to detect latent infections and differentiate the North American and European races of the fungus, we developed oligonucleotide primers to amplify by PCR portions of the ITS of the ribosomal DNA of G. abietina var. abietina. The 417 bp amplified DNA fragment comprises two Msp I restriction sites in the NA race but only one in the EU race. DNA extractions directly from infected asymptomatic needles, or from single fruiting bodies, followed by PCR amplification and Msp I digestion allowed the detection and race identification of both races of G. abietina var. abietina from seedlings and branches of Pinus resinosa and P. banksiana. A nested PCR assay was sensitive enough to detect the equivalent of a single infected seedling in a bulk sample of 1000 healthy seedlings. Validation tests were conducted by comparing PCR and isolation assays with 104 fascicles. All samples for which the fungus was isolated yielded a positive PCR assay and there was no false negative, i.e. samples for which the fungus was isolated but not detected by PCR. Among the samples from which the fungus was not isolated, most yielded a negative PCR assay (71%), but a proportion (29%) yielded positive PCR assays. In several of those cases, aggressive contaminants had apparently overgrown the pathogen. The method described here can lead to the detection and race identification of the NA and EU races of G. abietina var. abietina directly from infected tissues without the need to culture the fungus and should find applications in nursery inspection and quarantine.

This paper reports a study aimed at gaining new information on the molecular composition of fruitbodies of Tuber spp. The presence of proteins homologous to TBF-1, which is highly specific for the fruitbody-phase of Tuber borchii, has been investigated in other white truffles. SDS-PAGE analyses revealed that only Tuber dryophilum fruitbodies possess a similar protein. This protein was purified by HPLC and partially sequenced, confirming a high degree of homology with TBF-1. Several PCR analyses of the genomic DNA, were performed to evaluate whether the absence of proteins homologous to TBF-1 in other white truffle species was a result of the absence of the coding genes. T. dryophilum gave an amplification product corresponding to the entire gene (tdf-1), but no products were obtained from the other species. Tdf-1 was sequenced and its organisation studied since it is one of the first genes isolated from a Tuber species. The deduced amino acid sequence was compared to that of TBF-1, to evaluate the presence of conserved regions, in an attempt to gain new information about their role in fruitbody formation.

This study shows for the first time that Tolypocladium species produce efrapeptins, a group of toxic peptides, in vivo but the quantities are too small to account for insect death, suggesting that these insecticidal compounds work in concert with other pathogenicity determinants. There is inter- and intraspecific variation in efrapeptin production in vitro by Tolypocladium species. T. parasiticum produced only efrapeptin E, in small quantities. Efrapeptins were detectable 48 h after inoculation and increased with biomass. The relative amounts of individual efrapeptins (C, D, E, F, G) produced by T. niveum in vitro were D > E > F > C > G but in vivo they were D > F > C > E > G. Efrapeptins were toxic to a wide range of insects when injected into the haemocoel. Mortality was dose-related. Efrapeptins also exhibited limited antifungal and antibacterial activity. Micrococcus luteus was considered an excellent indicator of efrapeptin presence in culture filtrate extracts because of its extreme sensitivity to these compounds.

Of three hundred and sixty Trichoderma strains investigated, fourteen, identified as T. aureoviride, T. harzianum and T. viride, grew well at 5 °C on both minimal and yeast extract agar media. In dual culture tests at 10°, most strains antagonized the phytopathogens Rhizoctonia solani and Fusarium oxysporum f. sp. dianthi. T. aureoviride and T. viride were more effective against Pythium debaryanum than T. harzianum. The activities of extracellular chitinases (EC 3.2.1.30), β-glucosidases (EC 3.2.1.21) and proteases (EC 3.4.21.1; EC 3.4.21.4), which are thought to be involved in the mycoparasitic process, were also examined and results showed that these enzymes were highly active at 5° in the cold-tolerant strains.

The effects of varying carbon, nitrogen, phosphate and sulphate source on solubilization of natural gypsum by Aspergillus niger were assessed. The fungus was grown on Czapek Dox agar amended with 0.5% (w/v) gypsum. Solubilization activity was monitored by measuring the clear zone formed underneath and around the growing colonies. On different concentrations of glucose, nitrate, ammonium, urea, phosphate and sulphate, linear growth rate [Rg] was not significantly correlated with gypsum solubilization rate [Rs], but the solubilization ratio [Rs/Rg] was increased by increasing the concentration of glucose, nitrate, and urea. On ammonium nitrogen, the mycelial dry weight was negatively correlated with linear growth, and gypsum solubilization activity was markedly lower than that on nitrate or urea. Gypsum solubilization was strongly correlated with both biomass dry weight and oxalic acid production. The fungus was unable to grow on carbonate, as a carbon source, but the addition of sucrose alleviated the effect of alkalinity caused by sodium carbonate. The optimum C[ratio ]N ratio for gypsum solubilization was 50[ratio ]1, and the importance of phosphate, rather than sulphate, was also shown. Implication of critic acid in the solubilization process was also suggested. This work emphasizes the importance of organic acids, particularly oxalic acid, production by fungi in gypsum solubilization and revealed the optimum nutritional conditions for the solubilization process.

The mechanisms responsible for controlling hyphal extension and branching are still poorly understood. We have investigated these processes by studying their dependence on temperature and nutrient concentration. Tip growth is highly responsive to temperature change, increasing linearly from 4 to 37 °C. Over this range of temperatures the branching pattern shows virtually no response. Likewise, varying nutrient concentration does not affect branch distribution. Colonies subjected to rapid extreme temperature downshifts (for example from 25 to 4°) display a strong and highly predictable branching response. There are three stages to this response. First there is an initial lag phase of growth without branching. After this, the growing tips display a series of tightly spaced, dichotomous branches dubbed starbursting. Following continued growth at 4°, tips enter a recovery phase, returning to normal branching frequencies with lateral branches. The strength of the response to cold is correlated with the ratio of growth rates before and after the downshift. The combined observations point to a homeostatic set point for branch distribution that compensates for temperature and nutrient concentration.

Extracellular matrix (ECM) surrounding conidia and germlings of B. sorokiniana was studied using light microscopy (LM), scanning (SEM) and transmission electron microscopy (TEM). Conidial ECM surrounding dry-inoculated, ungerminated conidia was fluid-like and observed only using a cryo-preparation technique, suggesting that the material was water soluble. ECM enveloping germlings appeared fibrillar in LM, TEM and SEM but amorphous in cryo-SEM, indicating that the structure of the ECM is dependent on the water content of the matrix. Fibrillar ECM formed thread-like structures that extended over long distances on the substrate or towards neighbouring conidia and hyphae. TEM of germlings negatively stained with uranyl acetate revealed the presence of fungal fimbriae. The strong resemblance between the extending organization of fibrillar thread-like ECM structures and fimbriae suggested that fimbriae constitute a basic structural component of the ECM and serve as the aggregation centre for the other ECM components. Histochemical labelling revealed significant differences between ECM surrounding the fungus at different morphological stages. The germ tube ECM was labelled for both proteins and polysaccharides whereas germling ECM consisted of two layers: an inner rich in proteins and an outer composed mainly of polysaccharides. Furthermore, the newly released ECM localized on germ tubes and hyphal tips showed affinity for microspheres carrying any type of surface properties while hyphal ECM had affinity only for negatively charged microspheres. This together suggests that ECM after its release is subjected to structural changes.

The recently reported epidemic of rust in Britain on wild and cultivated varieties of the daisy (Bellis perennis), caused by Puccinia distincta, was preceded by records on cultivated plants at Bristol in 1972 and Bognor Regis in 1973 and by sporadic observations of rust on cultivated daisies thereafter in the period from 1978–1996. The first verifiable report of the pathogen on wild B. perennis was from Leeds in 1988. In the spring of 1997, a rust epidemic broke out on wild as well as cultivated daisies, as indicated by numerous reports mainly from the south of Britain. The current paper charts the distribution of P. distincta in Britain from 1972 onwards and speculates about its likely origin.

The rust fungus Chrysomyxa woroninii causes perennial witches' brooms on several species of Ledum in northern and subalpine regions of Europe, North America and Asia. Spruce bud rust has been assumed to be the aecial state of C. woroninii because of the close proximity of infected Ledum plants and systemically infected buds on Picea. The lack of experimental evidence for this connection, however, and the presence of other species of Chrysomyxa on the same hosts has led to confusion about the life-cycle of C. woroninii. In this study, infections on both spruce and Ledum were studied in the field and in a greenhouse. The link between the two states was proven by inoculating spruce with basidiospores from Ledum groenlandicum. After infection of spruce in spring, probably through the needles, the fungus overwinters in the unopened buds until the next spring, when the infected shoots are distinguished by stunting and yellow or red discolouration. Microscopic examination of dormant Ledum shoots showed that C. woroninii overwinters in this host in the bracts and outer leaves of the vegetative buds, and in the pith and cortex of the stem. The telia of C. woroninii, on systemically infected Ledum leaves of the current season, are easily distinguished from the telia of other Chrysomyxa species on the same hosts. The latter produce localized telia and uredinia only on overwintered leaves, produce aecia on spruce needles in the same year as infection occurs, and are not systemic in spruce. The restricted habitat distribution of C. woroninii and the need for overwintering outdoors suggest that this rust fungus has specific environmental requirements for survival.

An investigation was conducted into whether fungal dynamics are determined by the balance between colonization and fructification, both of which are controlled by climatic factors, particularly rainfall. The distribution of Lophodermium pinastri on Pinus sylvestris needles was studied along two altitude transects over two successive years. Annual rainfall increased in a similar way along the two transects. Colonization (black zones) and the presence of fruiting bodies (ascomata and/ or conidiomata) were observed. Both increased with altitude. At low altitude, needles bore black lines only. The number of needles bearing fruiting bodies increased at altitudes above 1000 m and were present on all needles at high altitude. Empirical and dynamic mathematical models were developed and evaluated in relation to rainfall, assuming that spore production correlates with fructification, and colonization to spore dispersal.

Although several new techniques for isolating and culturing lichens have been reported in recent years, there is little information available concerning the variability in development of species from different taxonomic groups. A comparison of the early stages of the germination and growth of Xanthoria parietina (Teloschistaceae), Parmelia saxatilis (Parmeliaceae), Physconia distorta and two Diplotomma species (Physciaceae) was performed on two different media: one inorganic, and the other containing 4% glucose (LBM; Lilly-Barnett medium). Different germination and development rates, and isolation success rate (single- and multispore cultures) are reported. The new combination Diplotomma rivasmartinezii (Barreno & A. Crespo) Barreno & A. Crespo is made.

Alkali-extractable and water-soluble cell-wall polysaccharides were purified from cell walls of some species of Fusarium and Gibberella. Their structures were determined by chemical analysis and NMR. The polysaccharides consisted of a main chain of β-(1 → 6)-linked galactofuranose units almost fully branched at positions O-2 by single residues of glucopyranose or acidic chains containing glucuronic acid and mannose. Individual differences were found, concerning the proportion of neutral and acidic side chains. These polysaccharides showed major differences from those of Microdochium nivale, Plectosphaerella cucumerina, Fusarium ciliatum, F. aquaeductuum and F. cavispermum. Highly specific polyclonal antibodies were raised against this structure, which were used in immunocompetence and immunofluorescence experiments.

We isolated ascospores and conidia of fungi associated with leaf spots common in birch leaves, and prepared mycelial cultures from them. The taxonomic positions of the fungi were determined by analysing morphological characteristics with photomicroscopy. The relationship between the teleomorph and anamorph was tested using random amplified microsatellite fingerprints, in which the variation was not explained by the origin of isolates (e.g. ascospores or conidia). This suggested that the ascospores and conidia would have been produced by the same biological species. In pathogenicity tests birch leaves inoculated with mycelia derived from ascospores developed spots showing that the fungus could be the cause of the leaf spots. The anamorph was isolated from the developing spots. Based on these results and on review of the literature we concluded that the causative agent of the leaf spot disease of birch in Finland is Pyrenopeziza betulicola, the anamorph of which belongs to Cylindrosporium.

Several fungi associated with leaf spots and stem cankers of Proteaceae are reported. The new species Kabatiella proteae, Phloeosporella protearum, Septoria grandicipis, Stilbospora proteae and Trimmatostroma elginensis are described. Several new teleomorph-anamorph connections are reported, including Mycosphaerella stromatosa and Pseudocercospora stromatosa, Teratosphaeria microsporum and Trimmatostroma microsporum, and Lembosia proteae and Clasterosporium proteae. Additional species described are Lophiostoma fuckelii and Verrucisporota proteacearum which are also newly recorded associated with leaf spots of Proteaceae in South Africa.

A new basidiomycete, Perenniporia nanjenshana sp. nov., found growing saprotrophically on the basal stem of Daphniphyllum pentandrum var. oldhamii in Taiwan, is described and illustrated. It is distinguished from other species of Perenniporia by the resinous to woody basidiomes and large (9.5–14 μm long) ovoid to subglobose, non-truncate basidiospores. Cultural characteristics are described for the species. A key to the world species of Perenniporia with large (> 8 μm long) basidiospores is provided.