This month Mycological Research News reports how elevated carbon dioxide levels affect soil fungi, on cryptic species of macromycetes and species concepts, punching appressoria, and fungi in the Dead Sea. Amongst the topics covered in the 17 research papers included in this issue are ones presenting a new molecular taxonomy for Metarhizium, insights into the taxonomy of small-spored Alternaria species, sequencing and expression of an enolase gene in Cunninghamella, a novel extracellular protease from Beauveria bassiana, tests of different mathematical models on the effect on a lichen's growth by neighbouring thalli, how the taenia in Trichiales capillitium is formed, histological details of the incompatibility reaction between Plasmodiophora brassicae and Arabidopsis, and a key to the known Beltraniopsis species. The following new species and varieties are described: Beltraniopsis miconiae, Chrysosporium fluviale, Leptographium piceaperdum, and Metarhizium anisopilae vars acridum, lepidotum, and majus, and M. flavoviride vars novazealandicum and pemphigum.

The taxonomy of Metarhizium has been reassessed using sequence data and RAPD patterns from 123 isolates recognised as M. anisopliae, M. flavoviride or M. album. A high level of genetic diversity was found which was best resolved at the species/variety level by sequence data from the ITS and 28S rDNA D3 regions. RAPD patterns correlated closely with the sequence data and revealed a much greater degree of diversity useful for distinguishing strains within a variety. Ten distinct clades were revealed by the cladogram based on the combined sequence data set. Several major evolutionary lines were revealed, but the taxonomic relationships at the base of the tree are poorly resolved. The data support the monopoly of the M. anisopliae group, and recognise four clades within it. Two correspond with M. anisopliae var. anisopliae and M. anisopliae var. majus. The other two are described as new varieties based on their distinctive ITS sequence data: M. anisopliae var. lepidiotum and M. anisopliae var. acridum vars nov. M. album, M. flavoviride var. flavoviride and M. flavoviride var. minus are recognised and redefined according to ITS sequence data. Three clades represent two new varieties, M. flavoviride var. novazealandicum and M. flavoviride var. pemphigum vars nov., based on their distinct ITS sequence data. The third, with two isolates, has not been named pending further data.

Accurate identification of small-spored Alternaria spp. is challenging because of morphological plasticity under non-standard conditions and the common misapplication of the name A. alternata to a variety of morphologically distinct taxa. A system used by some authors of naming phytotoxigenic alternarias as pathotypes of A. alternata has further clouded the meaning and usefulness of this specific epithet. Two hundred and sixty isolates of small-spored Alternaria, primarily from fruit substrates, were segregated into morphological groups and then subjected to RAPD-PCR analysis using total genomic DNA and three different primers. When cultured under defined conditions, the pattern of sporulation observed at 50 × magnification was predictive of genetic relatedness as determined by cluster analysis of RAPD fragment patterns. In RAPD analyses, morphological groups or species were resolved as distinct branches of the dendrogram: Alternaria gaisen (= A. kikuchiana, A. alternata Japanese pear pathotype, group 2), A. longipes (= A. alternata tobacco pathotype, group 5), the ‘tenuissima’ group (group 5), the arborescens group (group 3) and the ‘infectoria’ group (group 6). Isolates in groups for which there were only a few representatives clustered as a branch. Analysis of RAPD fragment patterns confirmed that when Alternaria isolates are cultured and observed under defined conditions, their phenotypic plasticity is minimized and valid taxonomic separations can be made upon morphological characteristics. We conclude that A. alternata, A. gaisen, A. longipes and other small-spored saprotrophic or perthotrophic taxa are recognizable as morphologically distinct taxa. We suggest that the ‘pathotype’ system of naming small-spored Alternaria taxa confers no predictive value relative to observable morphological and genetic characters, and should be abandoned.

DNA polymorphisms among Magnaporthe grisea isolates from rice and from finger millet were examined using restriction analysis of genomic DNA. The rice-infecting isolates produced 50–70 resolvable EcoRI fragments with the rice blast-derived repetitive sequence probe MGR586, while isolates infecting finger millet showed only one prominent band. Probes derived from a repetitive sequence (grasshopper) from a finger millet also distinguished the two pathogenic forms; grh pES 3–3 (35–70 EcoRI RFLPs) and grh pKE 2–2 (2–12 EcoRI RFLPs) hybridized exclusively with isolates infecting finger millet. Probes of two avirulence genes derived from rice blast genomes hybridised exclusively with rice blasts. These distinctions in Indian blast populations matched those observed elsewhere in Asia and in the Americas. No genomes were observed in the field that shared RFLPs from rice-infecting and finger millet-infecting isolates, even among isolates from a Himalayan area where the two forms have coexisted for centuries. Pathogenicity tests showed that the blast fungus from the two hosts did not cross-infect, nor did the two forms cross in the laboratory. The results confirm that the rice and millet-infecting M. grisea populations in India are distinct.

The ITS regions of 14 isolates of endophytic fungi obtained from the root systems of four Woollsia pungens plants were sequenced and compared to sequences of Hymenoscyphus ericae, Oidiodendron maius and to sequences from other fungal taxa currently available in the GenBank and EMBL nucleotide databases. Sequence data suggested that six distinct taxa were present in the root systems of the four plants and that up to four of these were present in the root system of a single plant. One of the endophytes was identified as an Oidiodendron species, while most other isolates probably belong to the Leotiales.

A polyclonal antibody was raised against microsomes prepared from Cunninghamella elegans and used to screen a C. elegans cDNA library. A cDNA clone from this screen was obtained, which corresponds to the C. elegans enolase gene. A single open reading frame (ORF) of 1311 bases was found, which encodes a protein of mol. wt 46882.9. The gene was found to start with an unusual initiation codon TCG, not a standard ATG codon. This was demonstrated first by ORF analysis of the determined sequence and was further confirmed by alignment of the protein with other published enolase sequences. The enolase gene was sub-cloned and over-expressed in Escherichia coli using the expression vector pQE30. Purified recombinant protein from this sub-clone showed the predicted molecular size in SDS–PAGE gel separations. Enolase enzyme activity was also detected that indicating the TCG initiation codon was correct. The C. elegans enolase was found to cluster with other fungal enolases in a phylogenetic analysis. Bacterial enolases and those of animals were separated in different clusters.

An extracellular protease designated BBP (Beauveria bassiana protease) was purified from a B. bassiana isolate and subsequently characterized. It was produced in the late stages of growth in a gelatin medium, and was purified using a combination of ion-exchange chromatography and preparative gel electrophoresis. Inhibition by phenylmethylsulphonyl fluoride and chymostatin indicates that BBP is a serine type with chymotrypsin activity. Substrate specificity indicates that the protease has elastase activity as well. The protease was stable at 25 °C and had an alkaline pH optimum (7.5–9.5). Another protease was purified from the same isolate that produced BBP, and was identified as Pr1 based on its isoelectric point, amino terminal sequence, substrate specificity and cuticle degrading ability. A comparison between the two showed that BBP had a lower isoelectric point (pI 7.5) than Pr1 (pI [ges ] 10) and was 0.5 kDa smaller. The proteases also exhibited differences in substrate specificity with Pr1 being most active against Suc-Ala-Ala-Pro-Phe-pNA, and BBP being most active against MeOSuc-Ala-Ala-Pro-Met-pNA. The two proteases had equal cuticle-degrading activity and both were expressed in cuticle media, although the timing of their expression differed.

Evidence that chemical changes in litter exposed to elevated CO2 might alter the composition and function of fungal communities in soil is presented. Some potential effects of elevated atmospheric CO2 on the decomposition of Fraxinus excelsior leaf litter and the interactions of the colonizing fungi, growing singly or in simple associations in microcosms, were investigated. Fungal colonization was monitored by analysis of the ergosterol content of litter and specific PCR-amplified ribosomal DNA spacer products. After < 42 d, fungal colonization was less on litter with a higher C[ratio ]N ratio when obtained from seedlings grown in elevated CO2 (600 ppm). After triple-species inoculation percentage α-cellulose and, in some combinations, nitrogen content was reduced on litter from seedlings grown in elevated CO2.

The influence of neighbours on individual performance in natural populations of the lichenized ascomycete Umbilicaria spodochroa was investigated using three different neighbourhood models; the polygon model, the fixed radius model and the nearest neighbour model. The data set consisted of the exact position of the holdfast points of the peltate lichens within 29 sample squares in crowded populations as well as the mass, diameter, and no. of apothecia of all thalli. A total of 11246 individual thalli were sampled and measured. The predictive power of all three neighbourhood models was moderate, but highly significant for the whole data as well as within most individual sample quadrats. The nearest neighbour model had the best predictive success, closely followed by the polygon model. The fixed radius model had approximately half the power of the two other models. We suggest that the difference is due to different degrees of realism in the models. Thallus mass was commonly the performance parameter best predicted, followed by thallus diameter and number of apothecia. The predictive power of the models for these natural populations was comparable to values obtained in several laboratory studies with vascular plants. The predictive success of the three different models was strongly correlated for single populations, indicating different levels of interference in different populations.

Duddingtonia flagrans was grown in shake flask culture on Sabouraud's dextrose medium with and without the addition of agar (to form a slightly more viscous medium). The addition of agar increased the number of chlamydospores produced in late stationary phase, with 8.6×105 chlamydospores ml−1 being obtained on a medium containing 5 g agar l−1. The pH optimum for growth was between 5.5–7.5 but colonies formed on plate cultures buffered at pH 10.5. When grown in shake flask culture at 25 °C and pH 7 on malt extract–yeast extract–peptone–glucose medium (MYPG), D. flagrans had a specific growth rate of 0.21 h−1 (doubling time 3.3 h) and produced 5.1±0.07 mg biomass ml−1. To increase chlamydospore production in a liquid medium, D. flagrans was also grown in a two phase culture system in which late exponential phase biomass produced in MYPG medium was transferred to Vogel's mineral salts medium containing various nitrogen (mycological peptone, casein) and carbon (sodium acetate, starch and glycerol) sources. The highest chlamydospore concentrations (6.2×105 and 5.6×105 ml−1) were observed when the biomass was transferred to Vogel's medium containing 10 g starch or glycerol l−1, respectively.

A mechanism is proposed for the creation of taenia on the capillitium of Trichiales. Polymerization of elater wall material forms spiralling fibrils, releasing water which passes by osmosis into the lumen. This extends the bulbous extremities of Trichia decipiens elaters producing the characteristically tapered tips. The edge of the elater shrinks as water is lost, and is moulded by the fibrils into a system of taenia.

Four isolates of the entomopathogenic fungus Erynia neoaphidis, from different hosts and locations in Switzerland, were distinguished by their DNA fragment banding pattern obtained by RAPD–PCR. The isolates differed in sporulation and germination rates, but not in virulence (overall mean LD50 16 conidia mm−2) against the aphid Acyrthosiphon pisum. The sporulation rate was 6 to 24 conidia mm−2 10 min−1. On nutrient agar, 24–73% of the conidia produced secondary conidia and 32–68% produced germ-tubes on polystyrene. Differentiation of primary into secondary conidia or germ-tubes is possibly dependent on the presence of free water on the contact surface; on a dry surface, conidia germinated mostly with a germ-tube, whereas on a wet surface the conidia produced a secondary conidium. Experimental support is provided for the claim that, in addition to LD50 values, features such as sporulation rate, spore germination, capacity to form secondary conidia and intraspecific variation should be considered in selecting isolates of E. neoaphidis for biocontrol agents.

The obligate biotrophic pathogen Plasmodiophora brassicae induces cataplastic galls in the roots of various species of the Brassicaceae. The ecotypes Ze-0, Tsu-0, and Ta-0 of Arabidopsis thaliana carry alleles of a dominant single gene (RPB1) for resistance against this pathogen. The pathotype-specific resistance reactions in the roots were accompanied by a hypersensitive response. Infected cells were surrounded by necrotic boundaries and thereby the pathogen growth was restricted. The pathogen could induce hyperplasia and hypertrophy to a slight extent and develop spores within mini-galls surrounded by the necrotic cells, if it was able to colonise meristematic tissue. Ecotype Ze-0 showed the highest level of resistance to P. brassicae isolate ‘e’ as indicated by the very limited number of infected cells, whereas the resistance of the ecotype Ta-0 was rated lower. The results are discussed in relation to the interaction of the pathogen with Brassica crops.

Two main taxa of Phomopsis associated with Phomopsis cane and leaf spot disease of grapevine have been recognized in Australian vineyards. The present investigation identifies Diaporthe viticola, recorded for the first time since 1867 on grapevines, as the teleomorph of Taxon 1. Perithecia of D. viticola were found on 1 and 2 year old canes of cvs Chardonnay, Shiraz, Riesling, Cabernet and Pinot Noir in many vineyards in southern Australia. The teleomorph was induced in vitro on oatmeal agar and on sterilised segments of grapevine cane inoculated with isolates of Phomopsis Taxon 1.

Sclerotinia nivalis causing lettuce drop was found in central China. It was identified on the basis of comparisons of morphological features, cultural characteristics and sclerotial proteins with those of S. sclerotiorum, S. trifoliorum, S. minor and S. nivalis. This is the first report of S. nivalis in China and lettuce is a new host for this pathogen.

Ophiostoma piceaperdum and O. europhioides are well-known, first described from conifers in Canada. They have been considered to be synonymous. After studying the type material, as well as a collection of isolates of O. piceaperdum and O. europhioides, we have concluded that they cannot be distinguished from each other, so we support the synonymy of O. europhioides and O. piceaperdum and provide a description for the Leptographium anamorph of O. piceaperdum. Ceratocystis pseudoeurophioides has previously been distinguished from O. europhioides based on differences in anamorph morphology. This species has also been reduced to synonymy with O. penicillatum, which was reported to have cucullate ascospores. Later descriptions of O. penicillatum reported it to have allantoid ascospores. We conclude that C. pseudoeurophioides cannot be distinguished from O. piceaperdum and is, therefore, reduced to synonymy with that species.

A new keratinophilic species, Chrysosporium fluviale sp. nov., isolated from river sediments in Catalonia, Spain, is characterized by having small, slender and verrucose conidia borne on slightly swollen conidiogenous cells. Morphological and molecular characters obtained by sequencing of the corresponding ITS-5.8S rDNA regions and of the RFLPs support the separation of Chrysosporium fluviale from the morphologically closest C. evolceanui, C. indicum and the Chrysosporium anamorph of Arthroderma curreyi.

Beltraniopsis miconiae sp. nov. was isolated on decaying leaves of Miconia cabussu and characterized by the constriction at the subequatorial zone of the conidium and inflated apical cell of the setiform conidiophore. It is described and illustrated and a key to the known Beltraniopsis species is provided.