The 29 spore-ball-forming smut fungus genera (of the total 58 recognized genera) are analysed, grouped, briefly characterized and illustrated. Problems within the genera, similarities, possible relationships and differences between genera are discussed. The following groups and genera are treated: genera with spores in pairs (Schizonella, Mycosyrinx, Geminago), genera with permanent spore balls composed of colourless spores and sterile cells and/or modified mycelia (Burrillia, Doassansia, Doassansiopsis, Heterodoassansia, Nannfeldtiomyces, Narasimhania, Pseudodoassansia, Tracya), genera with permanent spore balls composed of pigmented spores and sterile cells (Urocystis, Moesziomyces, Dermatosorus, Testicularia), and genera with spore balls containing only spores and lacking sterile cells between the spore balls. Within the latter group, the two sub-groups were distinguished: one with light, brownish spores (Sorosporium, Thecaphora, Glomosporium, Fulvisporium), and another one with dark, blackish spores (Tolyposporium, Tolyposporella, Clintamra, Orphanomyces). Heterotolyposporium has small, hyaline spores between the pigmented spore balls. Sporisorium and Macalpinomyces have sterile cells between the true or pseudo spore balls. Odd genera are: Ustacystis, Mundkurella and Uleiella. A key to the spore-ball-forming genera of smut fungi is given. The value of the spore balls in the taxonomy of the Ustilaginales is discussed. The arrangement of the genera in groups is based on the most important characters of the spore balls. It has a practical, didactic purpose and in many cases the groups do not reflect natural relationships.

Mycosphaerella tasmaniensis is newly described from Mycosphaerella leaf blotch symptoms occurring on Eucalyptus nitens in Tasmania, Australia. Single ascospore cultures produced a Mycovellosiella anamorph, described here as M. tasmaniensis. Both states occurred together, as well as separately on leaf spots. Phaeophleospora epicoccoides (=Kirramyces epicoccoides) is commonly associated with leaf spots of Eucalyptus spp. in Australia. The teleomorph, Mycosphaerella suttoniae, previously known only from Indonesia, was also collected on E. grandis leaves from Australia. A Cylindrocladium leaf blight disease of young E. grandis trees in Indonesia was found to be associated with a new species of Calonectria. Calonectria multiseptata and its anamorph Cylindrocladium multiseptatum is newly described and distinguished from other species based on their larger, multi-septate ascospores and conidia.

Variation within the internal transcribed spacer (ITS) and the intergenic spacer (IGS) of the ribosomal RNA gene of isolates representing seven European species of Armillaria was examined by PCR, coupled with RFLP analysis and partial sequencing of the ITS region.

The amplified-ITS region was about 840 bp long and uniform in length among the European isolates, while the amplified-IGS region showed four different lengths which corresponded to A. mellea, A. tabescens, A. ectypa and a group including the four other species. A. borealis, A. ostoyae, A. cepistipes and A. gallica.

Restriction digestions of the ITS and IGS regions by Alu I and Rsa I, respectively, gave rise to the same four polymorphic groups. However, A. borealis and A. ostoyae were easily separated from A. cepistipes and A. gallica by digestion of the two rDNA spacers with Hinf I and Taq I. Nde II digests of the amplified ITS could distinguish A. borealis from A. ostoyae and each of the seven species were separated by Alu I digestion of the IGS region. A North American A. mellea isolate, partly examined in this work, was found to be different from the European A. mellea isolates, while there was a close similarity between the European A. ostoyae and an isolate of the same species isolated from the U.S.A.

Cluster analysis based on the presence or absence of comigrating restriction fragments indicated more than 80% similarity between A. borealis and A. ostoyae and between A. cepistipes and A. gallica, while A. mellea, A. tabescens and A. ectypa were found in separate clusters exhibiting, respectively, about 40, 38 and 32% average similarity with the other species.

Although little intraspecific variation was observed in many species, A. gallica and A. cepistipes were found to be heterogeneous. In view of recent results suggesting several groups in A. borealis and A. cepistipes, the Alu I restriction patterns obtained in this work would identify the former species as type B, characterized by an Alu I pattern different from that of A. ostoyae, and the latter species as composed of one isolate (C4) of type B and three isolates (C1, C2 and C3) of type A.

Nucleotide sequences of the rDNA internally transcribed spacer 1 (ITS1) of one isolate of each species showed that A. mellea and A. ectypa differed from the other species by several insertions and point mutations giving rise to a level of similarity ranging from 66 to 79%. This DNA region was highly conserved within the other species which revealed a similarity of 97 to 100%.

These results demonstrate that analysis of rDNA spacers provides appropriate data to circumscribe taxonomic entities within the Armillaria complex and that the phylogenic relationships among species deduced from the present study are consistent with previous analyses based on pairing tests as well as morphological and physiological characters.

The internal transcribed spacers, ITS1 and ITS2, and 5.8S region of ribosomal DNA (rDNA) from 20 species of Ascosphaera were amplified by PCR, and their sequences determined and compared. No variation was detected in the sequences from 23 widely distributed isolates of A. apis, in sequences from 11 widely distributed A. atra isolates, in four A. aggregata isolates, or in sequences from two isolates each of A. acerosa, A. duoformis, A. flava, A. larvis, A. pollenicola and A. proliperda. However, the ribosomal sequences from each of these nine species, and from another 11 species of which only a single isolate was examined, differed from one another by 0·18–30·9%. Thus these sequences provide a rapid method for identifying species, and searches using them showed that the sequence of A. apis rDNA recorded in the international databases is, in fact, that of A. atra.

The rDNA sequences also provided data for assessing the relationships of these fungi. Of the rDNA sequences in current international databases, that of Eremascus albus was very close to, but distinct from, those of the Ascosphaera species. Comparisons of the Ascosphaera sequences showed that most formed consistent clusters irrespective of the method of comparison used (distance matrix and parsimony), or whether the ITS1 or ITS2 portions were used; A. acerosa with A. asterophora, A. atra with A. duoformis, A. colubrina closely with A. flava, A. larvis, A. major, A. variegata and more distantly with A. apis and A. celerrima, and, also, A. aggregata with A. subcuticulata, A. proliperda and more distantly with A. solina. The apparent relationships of these clusters were inconsistent, depended on the alignment of several regions of ‘indels’, and could not be resolved. The A. fusiformis, A. naganensis and A. osmophila sequences showed inconsistent relationships with the others, especially that of A. osmophila, which had an A. solina-like ITS2 region, but an atypical ITS1 sequence with a large unique repetitive insertion. The clusters based on gene sequence comparisons clearly correlated with groupings based on ascospore morphology and other characters.

Two new taxa from rain forest in Cuba are described and illustrated. They are Endophragmiella sphaeroproliferata anam. sp. nov., characterized by cymbiform, 3-septate, pale brown, smooth conidia, and Sporidesmiella intermedia anam. sp. nov., distinguished by obovoid, 2–5 distoseptate, pale brown to subhyaline conidia. A comparative tabulation of the described species of Sporidesmiella is provided.

Fungal cultures isolated from oil-polluted sea water near Mumbai, India have been studied for their capability to degrade crude oil. A yeast isolate identified as Yarrowia lipolytica was further investigated with respect to its dimorphic behaviour and alkane degradation. Y. lipolytica NCIM 3589 in the yeast form degraded the aliphatic fraction of crude oil and also pure alkanes (20–60% within 48 h) under aerobic conditions. Unlike most Y. lipolytica strains, our isolate required partial anaerobiosis for mycelium formation. Studies with two isolates suggested that mycelium to yeast transition may be the prerequisite for effective alkane degradation.

Conserved primers were used in a polymerase chain reaction to amplify the ITS region of the rDNA of 100 Microdochium nivale isolates collected from different turfgrasses in southern Ontario. The profile of the restriction digestion of the amplified ITS region revealed that all the M. nivale isolates analysed belonged to var. nivale. RAPD profiling and RFLP analyses of the IGS regions of rDNA revealed extensive genetic diversity within var. nivale. With RAPD markers, the average similarity coefficient was 66% and the estimate of genotypic diversity was 0·179. Population subdivision analysis showed that 92·2% of the total genetic diversity was found among individuals within populations compared to 7·8% among populations. In dendrograms derived from genetic distances using RAPD and IGS-RFLP markers, there was some evidence for host specialization. Most RAPD markers were shared by individuals from different turfgrasses, and the populations were not highly differentiated. The high level of genotypic diversity detected within populations and the low level of genetic differentiation among populations show that recombination and migration are likely playing important roles in the population biology of M. nivale var. nivale.

A thermostable extracellular glucoamylase from Thermomyces lanuginosus in static culture was purified to SDS–PAGE homogeneity by fractional ammonium sulphate precipitation, ion-exchange chromatography on DEAE–Toyopearl, Butyl–Toyopearl hydrophobic interaction chromatography, gel filtration on Sephacryl S-300 and ion-exchange chromatography on FPLC MonoQ. The molecular weight of the enzyme, consisting of a single polypeptide, was estimated to be 72000 by SDS–PAGE. The glucoamylase exhibited maximal activities at pH 5·0. The optimum temperature for the activity was 70°C. The enzyme was thermostable at 60° with half-lives at 70° of 20 min and 80° of about 6 min. The glucoamylase was a glycoprotein with 11·4% carbohydrate content. The enzyme hydrolysed soluble starch, amylose, amylopectin, dextrin, glycogen, maltotroise and maltose. Starch was the best substrate.

At a high arctic, polar semi-desert site (79°N) in Svalbard, nitrogen, phosphorus and potassium fertilizers were added to the soil for 5 yr to simulate increases in decomposition and nutrient mineralization which may occur as a result of increases in soil temperature and soil moisture caused by environmental change. Abundance of decomposer fungal species, isolated from standing-dead leaves of Dryas octopetala, varied between fertilized and unfertilized plots. Fungal biodiversity, as indicated by the Brillouin index, was lower in dead Dryas leaves from the fertilized plots, although more colonies were isolated from leaves of plants which had been fertilized. The fungi were cosmopolitan and not restricted to tundra areas. The dead leaves from the fertilized plots contained more nitrogen and phosphorus than those of the unfertilized plants. Leaves in the fertilized plots appeared to have been killed by winter injury resulting from an extended growing season in an atypically mild and wet autumn, which was followed quickly by extreme subzero temperatures.

Hirsutella petchabunensis is described from a single specimen collected on a Lepidoptera larva in tropical forest in Thailand. This is linked, both in the field and through cultural studies, with a distinctive helicosporous synanamorph that is assigned to Helicoma.

We conducted a series of experiments to determine if extraradical hyphae of VAM fungi acclimate to low temperatures. Blocks of field soil containing VAM fungi were either slowly cooled or held at room temperature prior to freezing. Infectivity of VAM fungi was greater in soil that was slowly cooled. We hypothesized that greater infectivity following freezing resulted from cold acclimation of extraradical hyphae. This hypothesis was tested using in vitro mycorrhizas cultured in two-compartment Petri plates, in which hyphae grew into a separate compartment. Metabolic activity of these hyphae following freezing was assessed using a vital stain. The majority of cultures that were slowly cooled prior to freezing contained active hyphae, whereas hyphal activity was almost completely eliminated by freezing in non-precooled cultures. Freezing temperature influenced survival and activity of hyphae. To our knowledge this is the first report of acclimation to cold temperatures by VAM fungi.

Aquaphila albicans gen. and sp. nov. from submerged wood in the tropics is described and illustrated. It produces hyaline, multiseptate, fusoid or falcate conidia resembling the macroconidia of Fusarium species, but differs by its conidiogenesis and the aquatic habitat. The conidiophores of A. albicans are septate, hyaline, sympodially proliferating with conidiogenous denticles. Conidial development in A. albicans has been studied in culture and results are presented. The genus is compared with similar genera.

Heterothallism was confirmed in Mortierella umbellata from Japan. Anisogamic zygospore formation is described and illustrated with time-lapse light micrographs. The anisogamic behaviour of the species is discussed with reference to previous studies on anisogamic zygospore and azygospore formation in Zygomycetes.

Barley plants experimentally infected with Erysiphe graminis f. sp. hordei were subjected to a curative treatment with tetraconazole (TC), to find out if the thickenings induced by the treatment in the fungal and host cell walls might be related to an increased production of chitosan. The presence of chitosan was assessed by colorimetric method, histological staining and ultrastructural localization with chitosanase bound to colloidal gold. The results showed that after TC treatment the amount of chitosan increase in the cell walls of hyphae and haustoria, and also in the haustorial encasements.

To identify Stagonospora avenae genetically, 53 isolates from Europe and North America were assessed by RFLP analysis and internal transcribed spacer (ITS) sequence polymorphisms in comparison with isolates of S. nodorum, S. arenaria and Septoria tritici. Our results also provided insight on possible phylogenetic divergence within the species currently identified by characteristic conidial morphology as S. avenae. Isolates from Europe, Canada, Minnesota and North Dakota showed little genetic variation. In RFLP and ITS sequence analyses, S. avenae isolates from New York and ATCC 12277 (origin unknown) had a closer relationship with barley-biotype S. nodorum, and S. avenae f. sp. triticea isolates of ATCC 26370 and ATCC 26377 from Minnesota were closely associated with wheat-biotype S. nodorum. Enzyme restrictions of ITS PCR-amplified products could facilitate the identification of Stagonospora on cereals.

Investigation of Phaeocollybia in British Columbia, Washington, Oregon and California has led to a better understanding of the characters and biology of the genus as a whole. Generically significant characters – pseudorhizas, pellicular veil, tibiiform diverticula, and sarcodimitic tissues – are examined in depth with four variations of branched and unbranched pseudorhizal patterns outlined. Basidiome development is traced from subterranean initiation to fully mature emergent basidiomes. Hypotheses on the ontogeny of Phaeocollybia basidiomes and biological associations are developed based on extensive observations of primordia and numerous field excavations. Comparisons between rhizomorphs and the thread-like pseudorhizal extensions of certain species are made and the term ‘rhizomorphic pseudorhiza’ is introduced. Possible biological strategies are explored and evidence for consideration of Phaeocollybia as a mycorrhizal genus is presented.

A morphological and molecular analysis was performed on 25 individuals of Phaeoacremonium isolated from diseased European and Californian grapevines (Esca disease). An unexpectedly high intra-generic molecular divergence was evidenced by partial rDNA sequencing between P. chlamydosporum isolates on one hand and an aggregate including P. angustius and P. aleophilum isolates and some undescribed ones on the other. These two groups show 26% nucleotide differences within the 26S rDNA fragment sequenced and were unalignable within the ITS2, suggesting distant phylogenetic relationships. Moreover, P. chlamydosporum appeared more closely related to Phialophora verrucosa (supposed to be an anamorph of the Herpotrichiellacae), than to the type species of the genus, P. parasiticum (more related to Magnaporthaceae).

The antifungal activity of five substituted flavones and their mixtures with unsubstituted flavone or a flavanone was tested on malt extract agar against five Fusarium spp. 4′-Methylflavone and 2′,6′-dichloroflavone showed the highest activity while 4′-benzyloxyflavone caused the lowest inhibition of all test substances. A significant increase in the antifungal effect of the substituted flavones could be observed if mixtures in combination with the unsubstituted flavone or flavanone were used. Some aspects of structure–activity relationships are discussed.