This issue of Mycological Research News features: Fungal irritability and survival mechanisms; In this issue; Genetic markers in single spores of AM fungi; Rice blast fungus attacks leaves and roots differently; Why picking wild mushrooms might be bad behaviour; and life-style choices in lichen-farming and lichen-dwelling fungi.

Physiological and ecological papers in this part investigate peroxide accumulation and cell death, stress responses to peroxide and paraquat, and fungal decomposition of leaves in streams.

Molecular studies address: phylogenetic relationships of Lecanoromycetes; correlations with toxin production in Fusarium species; detection techniques for ectomycorrhizal fungi; the status of Xanthoria aureola; the identity of a sterile red endophyte of cereals; Lepista in Australia; native Alternaria brassicicola populations; and the placement of southern African truffles.

The following new scientific names are introduced: Eremiomyces and Kalaharituber gens. nov.; E. echinulatus (syn. Choirmyces echinulatus) and K. pfeilii (syn. Tuber pfeilii) combs. nov.

Podospora anserina and Coprinopsis cinerea (syn. Coprinus cinereus) are endowed with a defence system able to differentiate self vs. non-self and involving the generation of peroxide. Indeed, they produce peroxide when confronted with a filamentous fungus, only in non-self confrontations. Both species are not able to recognize yeasts and show a differential response to bacteria. The accumulation of peroxides in the ascomycete Podospora anserina requires an NADPH oxidase and a MAP kinase cascade, previously shown to be involved in fruit body formation, cell differentiation and cell degeneration. Confrontation is accompanied by the death of the contestant hyphae only in specific combinations of species. As in animals and plants, data suggest that peroxide is likely involved in signalling rather than playing a direct toxic role. Fungi display more complex behaviours than generally acknowledged, i.e. they are able to recognize potential contestants and built up defence reactions involving evolutionary conserved enzymes.

Although, oxidative stress response, which protects organisms from deleterious effects of reactive oxygen species (ROS), has been extensively studied in pro- and eukaryotes, the information about filamentous fungi is fragmentary. We investigated the effect of two ROS-generating agents (paraquat, PQ, and H2O2) on cellular growth and antioxidant enzyme induction in 12 fungal species. Our results indicate that exposure of fungal spores or mycelia to PQ and H2O2 promoted oxidative stress, as evidenced by remarkable inhibition of spore germination and biomass production; stimulation of cyanide-resistant respiration; accumulation of oxidative modified proteins. Cell responses against both superoxide and peroxide stresses include enhanced expression of superoxide dismutase (SOD) and catalase, however, the extent was different: treatment with PQ increased mainly SOD, whereas exogenous H2O2 led to enhanced catalase. We also found that G6PD has a role in the mechanism of protection against superoxide and peroxide stresses. The activation of antioxidant enzyme defence was blocked by the translation inhibitor, cycloheximide, suggesting that there was de novo enzyme synthesis.

The phylogeny of Lecanoromycetes (Ascomycota, Fungi) is investigated utilizing parsimony and Bayesian Markov Chain Monte Carlo analyses, of combined nLSU rDNA and mtSSU rDNA sequence datasets. The results suggest that Acarosporaceae, Candelariaceae, Phlyctis and Pycnora are not members of the monophyletic Lecanorales, and that Timdalia and Pleopsidium are members of a monophyletic Acarosporaceae. Pycnora, Candelariaceae and Acarosporaceae form a monophyletic group. Umbilicariaceae, Hypocenomyce scalaris, H. friesii, Ophioparmaceae, Boreoplaca, Elixia and Fuscidea form either a basal paraphyletic assemblage in Lecanoromycetes, or a monophyletic group which is the sister-group to Lecanorales and the rest of Lecanoromycetes (excluding Acarosporaceae). The Acarosporaceae forms a group with Pycnora and Candelariaceae, which may be outside the Lecanoromycetes. Chaetothyriales, Verrucariales, Eurotiales, Lichinales and Mycocaliciales form a monophyletic group, but with low support. We briefly discuss incongruence between datasets from different genetic markers, comparing the differences between the separate parsimony analyses, where the ILD test indicated a very significant incongruence. The phylogenetic significance of ascus-types that have influenced most recent Ascomycota classifications heavily is also discussed, and we finally point out risks with formalizing classifications too early.

Partial translation elongation factor 1 alpha (TEF-1α) gene and intron sequences are reported from 148 isolates of 11 species of the anamorph genus Fusarium; F. avenaceum (syn. F. arthrosporioides), F. cerealis, F. culmorum, F. equiseti, F. flocciferum, F. graminearum, F. lunulosporum, F. sambucinum, F. torulosum, F. tricinctum and F. venenatum. The sequences were aligned with TEF-1α sequences retrieved from 35 isolates of F. kyushuense, F. langsethiae, F. poae and F. sporotrichioides in a previous study, and 39 isolates of F. cerealis, F. culmorum, F. graminearum and F. pseudograminearum retrieved from sequence databases. The 222 aligned sequences were subjected to phylogenetic analyses using maximum parsimony and Bayesian Markov Chain Monte Carlo maximum likelihood statistics. Support for internal branching topologies was examined by Bremer support, bootstrap and posterior probability analyses. The resulting trees were largely congruent. The taxon groups included in the sections Discolor, Gibbosum and Sporotrichiella sensu Wollenweber & Reinking (1935) all appeared to be polyphyletic. All species were monophyletic except F. flocciferum that was paraphyletic, and one isolate classified as F. cfr langsethiae on the basis of morphology that grouped with F. sporotrichioides. Mapping of toxin profiles, host preferences and geographic origin onto the DNA based phylogenetic tree structure indicated that in particular the toxin profiles corresponded with phylogeny, i.e. phylotoxigenic relationships were inferred. A major distinction was observed between the trichothecene and non-trichothecene producers, and the trichothecene producers were grouped into one clade of strictly type A trichothecene producers, one clade of strictly type B trichothecene producers and one clade with both type A and type B trichothecene producers. Furthermore, production of the type A trichothecenes T-2/HT-2 toxins are associated with a lineage comprising F. langsethiae and F. sporotrichioides. The ability to produce zearalenone was apparently gained parallel to the ability to produce trichothecenes, and later lost in a derived sublineage. The ability to produce enniatins is a shared feature of the entire study group, with the exception of the strict trichothecene type B producers and F. equiseti. The ability to produce moniliformin seems to be an ancestral feature of members of the genus Fusarium which seems to have been lost in the clades consisting of trichothecene/zearalenone producers. The aims of the present study were to determine the phylogenetic relationships between the different species of Fusarium commonly occurring on Norwegian cereals and some of their closest relatives, as well as to reveal underlying patterns such as the ability to produce certain mycotoxins, geographic distribution and host preferences. Implications for a better classification of Fusarium are discussed and highlighted.

This study aims to clarify taxonomic relationships within the current concept of Xanthoria parietina in northern Europe. For comparison, X. calcicola was also included in the study. Morphological as well as molecular data were utilized. Morphology indicated the presence of three species, Xanthoria parietina, X. calcicola, and X. aureola, the latter of which is resurrected here from synonymy. The most important separating characters involve colour and thickness of the thallus, lobe width, morphology of laminar structures, and the texture of the upper surface. X. aureola, as recognized here, mostly occurs on seashore rocks. Part of the IGS region as well as the complete ITS were sequenced in 70 individual thalli representing ten geographical regions in Europe. In total, 19 different IGS haplotypes and 20 different ITS haplotypes were present in the data set. Owing to indications of possible recombination between the IGS and the ITS, the two data sets were analyzed separately. Haplotype networks were estimated, both of which indicate that X. parietina is distinct from X. aureola and X. calcicola. In our sample, the two latter do not share haplotypes, but are only separated by a few mutational steps.

The taxonomic position and properties of an unidentified fungus isolated from wheat roots was investigated. The Sterile Red Fungus (SRF) is characterised by its fast growing habit, red pigmentation, non-sporing nature and mycelial form resembling some Laetisaria and Limonomyces species. rDNA variation was used to study the relationship of the SRF to Laetisaria spp. and Limonomyces spp. Nucleotide sequence obtained from eight Laetisaria and three Limonomyces species representing the ITS 1 region, were analysed by PCR and direct sequencing. Plant growth promoting properties of the five taxa were also determined. The SRF had closest identity (98%) to British material of Limonomyces roseipellis. UPGMA analysis of ITS 1 DNA sequence support a close relationship between SRF and L. roseipellis. The relationship inferred by nucleotide sequence data was supported by phenotypic analysis; both L. roseipellis and the SRF were shown to promote the growth of wheat plants. Unexpectedly, Laetisaria arvalis and material named as Limonomyces roseipellis from New Zealand appeared to be closely related with 98% rDNA sequence identity, suggesting the misidentification of the New Zealand collection.

To determine the relationship of Australian members of the genus Lepista with those from other parts of the world, genetic variation of isolates representing 27 accessions was assayed by cleaved amplified polymorphic sequences (CAPS) and random amplified polymorphic DNA (RAPD). CAPS and RAPD identified eight and seven groups, respectively. CAPS Groups 1 and 2 and RAPD Group 1 consisted of French and Australian accessions classified as morphospecies L. nuda. CAPS Group 3 and RAPD Groups 2 and 2A consisted of mostly Australian isolates identified as L. sordida var. sordida or L. sordida var. umbonata. Isolates earlier identified as morphospecies L. sp. were also placed in CAPS Group 3 and RAPD Group 2A indicating that these isolates are L. sordida var. sordida. In addition, three smaller groups were distinguished. A French isolate of L. sordida var. sordida was placed in distinctly separate CAPS and RAPD groups to Australian L. sordida var. sordida Groups 4,4 respectively. A French isolate of L. sordida var. aianthina was placed in CAPS and RAPD Groups 3,3. An accession of L. saeva was placed in CAPS Group 6 and RAPD Group 5, separate from other isolates. RAPD Groups 6 and 7 consist, respectively, of Greek and American accessions of L. nuda that were only distantly related to the Australian and French accessions of this morphospecies: CAPS also separated these isolates from each other and from all other isolates.

The data suggest that the classification of morphospecies and varieties within Lepista cannot be determined on the basis of morphology alone. The Greek and American accessions of L. nuda are separated from the French and Australian accessions and may not be L. nuda. Similarly, the Australian accessions currently classified as L. sordida var. sordida together with the accessions of L. sordida var. umbonata are distinct from the French accessions of L. sordida var. sordida suggesting that Australian isolates may represent a new species or variety. Further studies using a combination of morphological and genetic characterization are required to provide a more accurate understanding of Lepista species.

An assessment of the inter- and intraspecific resolution of 5′ nrDNA ITS TRFLP was conducted by computer-simulated restriction analysis of 316 ectomycorrhizal GenBank sequences. Generally, sequences with a similarity of <90% could be distinguished with two to three independent enzyme digests, although sequences with similarity >95% were likely to remain unresolved. Choice of restriction enzyme strongly influenced resolution, especially when less than three enzymes were used. Although our results showed that 5′ nrDNA ITS TRFLP is a powerful tool for distinguishing between species of ectomycorrhizal fungi, closely related species, including species of Rhizopogon, Dermocybe, Hebeloma, and Lactarius produced indistinguishable 5′ nrDNA ITS TRFLP – profiles. 5′ nrDNA ITS TRFLP may also split a species, and the probability of this occurring reflected intraspecific sequence variation. For groups of closely related species, the use of 3′ nrDNA ITS in conjunction with 5′ nrDNA ITS produced improved resolution comparable with RFLP analyses. Overall, our results show that nrDNA ITS TRFLP is a valuable addition to the array of molecular tools available to ectomycorrhizal ecologists. However, simple assessments of ectomycorrhizal species diversity based on numbers of unique TRF created with a single restriction enzyme must be viewed with caution, as for each enzyme we examined, identical TRF common to groups of unrelated species were observed. In addition, to maximize the effectiveness of TRFLP in surveys of ectomycorrhizal fungi it will be useful to combine information from at least two independent enzyme digests in order to distinguish and track species in the field.

Substantial polymorphism was detected between isolates from five populations of Alternaria brassicicola attacking Cakile maritima along the New South Wales coast of Australia, with a maximum of two genotypes being shared between population pairs. Of ten pair-wise population comparisons, six had no pathogen genotypes in common; only one genotype occurred five times, and most (93%) were found only once. Although an UPGMA based on Nei's measure of genetic distance separated the five populations, a cluster analysis using individual isolates failed to group them according to population, indicating significant gene flow. An analysis of molecular variance indicated ca 14% of the variation occurred between populations, representing moderate population differentiation over the spatial scale of the study. Tests of the relative contribution of clonality and sexual recombination indicated low, albeit significant levels of linkage disequilibrium in all populations. The level of linkage disequilibrium, and the high genotype diversity, provides support for the contention that a hitherto unidentified sexual stage might be a significant factor in the life-cycle of A. brassicicola.

The ITS region including the 5.8S rRNA gene as well as the 5′ end of the 28S rRNA gene of hypogeous Pezizaceae and Tuberaceae were studied to clarify the generic placement of two southern African desert truffles, Terfezia pfeilii and Choiromyces echinulatus. The results show that neither species belongs in the genus to which it has been assigned on the basis of morphological characters. As expected, two Choiromyces spp. grouped close to the representative of the Tuberaceae (Tuber melanosporum). However, C. echinulatus diverged from the other Choiromyces species and emerged near members of the genus Terfezia, being even closer to that genus than T. pfeilii. Two new genera and new species combinations, Kalaharituber gen. nov. with K. pfeilii (syn. T. pfeilii) comb. nov. and Eremiomyces gen. nov. with E. echinulatus (syn. C. echinulatus) comb. nov. are therefore introduced to accomodate these taxa. Both genera are closely related to Terfezia, and thus are placed in the Pezizaceae.

Maple, linden and oak leaves were immersed in a stream for 1–21 d. Cumulative mass loss, ergosterol content, and species richness of released aquatic hyphomycete conidia increased with time. Numbers and richness of attached conidia were highest on days 1 and 2. Denaturing gradient gel electrophoresis revealed up to seven fungal phylotypes on the leaves before their immersion in the stream and after one day of stream exposure. After 5 d of immersion the contribution of these terrestrial fungi decreased and that of aquatic hyphomycetes increased. The dominant phylotypes belonged to Anguillispora filiformis, Articulospora tetracladia and Flagellospora curvula, which also dominated the community of released spores. The molecular diversity was highest on day 2 and 3 on all substrates. This may be due to a few species of terrestrial fungi, later outcompeted by aquatic hyphomycetes, and to many different conidia of aquatic hyphomycetes, some of which may germinate but are unable to establish themselves and reproduce.