Germination of primary and secondary conidia of 33 strains (12 spp.) of co-occurring Conidiobolus and Basidiobolus from three closely adjacent managed habitats was studied in relation to general nutrient level, water activity of substratrum, light and temperature. A further 26 strains (16 spp.) derived from culture collections, and including insect pathogens and saprotrophs, were also compared. Nutrient levels triggering germ-tube formation differed widely amongst strains ; capilliconidial strains and/or presumptive pathogens usually had a low threshold. Successive generations of globose replicative conidia formed alternative conidial forms in increasing proportions. Water activity (aw) strong influenced development of non-globose conidial forms (microconidia, capilliconidia and actively discharged elongate conidia). Profiles of response to nutrients, aw, temperature and light differed between strains (and species) and the comparison represents a first stage in determining niche differentiation, including the putative interactions of these common fungi with litter invertebrates.

The elemental composition of vacuolar granules in different ectomycorrhizal fungi, Suillus bovinus, Paxillus involutus, Pisolithus tinctorius and Laccaria laccata was analysed by energy dispersive X-ray spectroscopy (EDXS) either after chemical preparation or cryofixation, freeze-drying and pressure infiltration. Vacuolar inclusions were present in living hyphae and were not an artifact of specimen preparation, and they can be referred to as polyphosphate granules. These granules were localized in fungal vacuoles and the main counter-ions were K and Mg. The postulated association of these granules with the divalent cation Ca has to be interpreted as an artifact of the specimen preparation and was caused by the chemical preparation of former EDXS studies. The incorporation of cations, such as K, Na and Zn, depended on the external supply and emphasized the importance of these granules for the intracellular homeostasis of fungal cells. EDXS studies of polyphosphate granules in ectomycorrhizal associations of Pinus sylvestris showed that the elemental composition of granules differed between the sheath and the Hartig net. In polyphosphate granules of the Hartig net a higher content of K was detectable, whereas the incorporation of Mg was reduced. These results indicated a possible role of K in the transfer of short chained, mobile polyphosphates through the hyphae to the Hartig net. The concentration of potassium and phosphate in the fungal vacuole and the cytoplasm was closely correlated, which can be explained by a possible linkage between the phosphate and K uptake, which would maintain the charge balance and the pH of the fungal cell. The estimation of different phosphate pools in axenic cultures and mycorrhizal roots revealed that the fungal metabolism was changed by the association with an ectomycorrhizal host plant. In a mycorrhizal association higher proportions of absorbed phosphate were translocated into the metabolically inactive polyphosphate pool, which demonstrates the importance of this pool for the nutrition of the ectomycorrhizal host plant.

One characteristic feature of eukaryotic cells is the organization of special functions into membranous organelles such as vesicles, mitochondria, the Golgi apparatus or nuclei. The distribution and exact positioning is an active process and is crucial for the establishment of cell polarity. For molecular analysis of the processes, filamentous fungi are ideal model organisms because hyphae are extremely polarized cells which continuously extend at their tips. In this study a novel approach was used to isolate mutants in nuclear migration and hyphal morphology. Conidia of A. nidulans, in which nuclei were stained with the green fluorescent protein (GFP) were germinated and visually analysed in a fluorescence microscope. Strains with an abnormal nuclear distribution pattern or defects in polarized growth were isolated with a micro-manipulator and transferred to agar plates to form colonies. Approximately 70 mutants with a corresponding mutant phenotype were recovered, some of which are presented in this report.

Strains of Trichoderma harzianum possess biocontrol capabilities. As background for identification of strain-specific markers for monitoring strains of interest, the relationship of strains designated as T. harzianum, including representatives of three biological forms Th1, Th2 and Th3, were analysed by Universally Primed PCR, UP-PCR, using UP and random primers. Cross dot blot hybridization of UP-PCR products generated with either of two different UP primers or a random primer showed unequivocal differences among strains. Using this approach, T. harzianum strains were distributed into two different genotypic groups. One of the T. harzianum groups included forms Th1 and Th2 while the other group accounted for the Th3 form. The relatedness of strains of each group was estimated by UPGMA analysis based on markers revealed with three primers. It was found that both genotypic groups are heterogeneous, and Th2 form strains definitely cluster together with those of Th1. Division of the three biological forms of T. harzianum into two groups was also supported by rDNA-ITS1 analysis, where Sau3A digestion of the amplified ITS1 region gave a restriction fragment profile specific for each genotypic group. Two strains with known biocontrol capabilities were found to relate to the genotypic group containing Th1 and Th2 forms and, based on variation within this group, to belong to a homogeneous group of form Th1 strains. The robustness and reliability of UP-PCR fingerprinting were demonstrated by obtaining identical banding profiles using different conditions for PCR in different laboratories.

Dichomitus is re-examined in Africa and six species are accepted. Dichomitus citricremeus and D. kirkii are described as new species. Megasporoporia is reduced to synonymy with Dichomitus, and the new combinations D. carvernulosus, D. delicatulus and D. setulosus, are proposed. An emended description of Dichomitus is provided, to accommodate species with hyphae with a dextrinoid reaction. A key to all accepted species in Dichomitus is given.

The effect of carbon source on the production of a single extracellular β-glucosidase by Acremonium persicinum was investigated using fast protein liquid chromatography. The enzyme was detected in the medium during growth of the fungus on a wide range of β-glucans, particularly those containing a high proportion of (1→6)-β-linkages. While growth of A. persicinum on gentibiose, cellobiose and laminari-oligosaccharides moderately increased β-glucosidase production, growth on sophorose provoked 10-fold greater levels of this enzyme in the culture medium. Levels of the β-glucosidase were minimal in the presence of even low concentrations of glucose, sucrose, fructose or galactose. The results are consistent with the extracellular A. persicinum β-glucosidase being an inducible enzyme, subject to carbon source control by readily metabolizable sugars, with sophorose possibly directly inducing its synthesis.

Similar small-statured, frequently excentrically stipitate species of Gymnopilus and Galerina occurring in the same habitat in Australia appear to form a continuum morphologically. As a result of detailed examination of field and microscopic characters, and an analysis of their styrylpyrone pigment content by thin layer chromatography, a satisfactory distinction can be made between similar species of the two genera. Three new species of Gymnopilus subgenus Gymnopilus, G. corticophilus, G. tomentulosus and G. tasmanicus are described and compared with G. eucalyptorum, G. tyallus and G. moabus. These six species are also compared and contrasted with three excentrically stipitate Galerina species, Ga. eucalyptorum and two new species Ga. incrustata and an unusual pink Ga. bulliformis.

Annulatascus species are common freshwater ascomycetes in the tropics. In this paper, the type species, Annulatascus velatisporus, and a new species, A. triseptatus, are described and illustrated at light and electron microscope levels. Annulatascus triseptatus differs from A. velatisporus in having three-septate ascospores surrounded by a thin sheath. The asci of both species have bilamellate ascus walls and a bipartite apical ring. The upper part of the apical ring differentiates from the inner ascus wall layer and the lower part elongates downwards during maturation. The mesosporium is the first formed ascospore wall layer followed by the episporium, which is covered with verruculose ornamentations. The mucilaginous sheath of the ascospores is fibrillar or amorphous depending on the fixation methods employed, and appears to be derived from the episporial verruculose ornamentations.

Cannonia gen. nov. is introduced to accommodate three collections of an unusual taxon, originally described as Ceratostoma australe. Cannonia is thought to be xylariaceous, due to its globose immersed ascomata with the stroma reduced to a clypeus, well-developed paraphyses, unitunicate asci lacking an apical apparatus, and dark brown, aseptate ascospores with a germ slit. Cannonia is compared with other possibly related genera and illustrated with interference contrast micrographs.

Mycelial interactions were studied between 28 isolates of Amylostereum areolatum and 15 of A. chailletii from wounded spruce in 10 sample plots in Sweden and Lithuania. Based on somatic incompatibility, nine vegetative compatibility groups (VCGs) of A. areolatum were detected. Five of these VCGs were isolated from two or more trees and included 24 (86%) of all isolates. In A. chailletii, 12 VCGs were found and three contained two isolates each. Grouping of isolates into VCGs was more pronounced in A. areolatum. Two of the A. areolatum VCGs had wide geographical distribution. VCG A2 was isolated from 14 different trees in two Swedish and four Lithuanian sample plots. VCG A1 was found in one plot in Sweden and in two in Lithuania. VCGs of A. chailletii had a local distribution and were confined to a single sample plot or to a forest stand. In A. areolatum occurrence of compatible pairings between isolates was uniform in all spatial scales of investigation: within a plot, within each country and among both countries. The proportion of somatically compatible A. chailletii isolates was significantly lower and decreased with geographic distance.

The thn (thin) mutant strain of Schizophyllum commune, which normally lacks aerial mycelium, produced excessive aerial hyphae when surrounded by multiple wild-type (wt) colonies. When thn and wt mycelia were grown together, the radial growth rate of the thn strain was increased, whereas the wt strain was clearly expressed in its growth, resulting in complete overgrowth of wt by thn hyphae. Overgrowing even occurred when mixtures of fragmented hyphae of both strains with a hundred times excess of wt hyphae over thn hyphae were grown from a single inoculum. Growth stimulation was also observed when thn and wt colonies were separated by dialysis membrane (cut-off 6–8 kDa) suggesting that low molecular weight molecules may be involved. The observed phenomena may explain the apparently very high frequency of occurrence of the recessive thn mutation in S. commune.

Protoplasts of Choanephora cucurbitarum were obtained by treatment of germlings with commercial enzymes. Colonies originated from regenerated protoplasts showed the same mating type and colony type as their respective parent. Colonies from fused protoplasts of two (+) isolates were of the (+) type, while those from two (−) isolates were of the (−) type. Colonies derived from fused protoplasts of (+) and (−) isolates were self-fertile and produced azygospores and zygospores subsequently. This result supports the hypothesis that azygospores of C. cucurbitarum are single-suspensor zygospores. Mating type heterokaryons resulting from fused protoplasts of (+) and (−) isolates with different colony types segregated into component isolates indicating that karyogamy and meiosis did not occur.

Fusarium equiseti and F. pallidoroseum are frequently reported as secondary colonizers of plant tissues. In this study they were isolated from the embryos of weathered cottonseed. Most isolates tested produced equisetin, an antibiotic, when grown on potato dextrose agar, rice, surface-sterilized cottonseed, or autoclaved cottonseed. This is the first report of equisetin from F. pallidoroseum. Equisetin was extracted from cultures of F. equiseti and F. pallidoroseum with acetone and dichloromethane, and partially purified by TLC. Two epimers of equisetin, designated as EQ and epi-EQ, were separated by HPLC. EQ or epi-EQ at 2·5–10 μg ml−1 suppressed germination or inhibited growth of various monocotyledonous and dicotyledonous seed, when the seed were incubated at 30°C under aqueous shake conditions. The two epimers also inhibited the growth of young seedlings and caused necrotic lesions on the roots, cotyledons, and coleoptiles of tested plant seedlings. The results suggest that equisetin may be a pathogenic factor of F. equiseti and F. pallidoroseum on seed and seedling health of cotton and other plants.

An EcoRI 1428 bp A+T-rich, DNA element (MYCDIRE: MYCorrhizal fungus DIspersed Repetitive Element) has been identified in the genome of Scutellospora castanea, an arbuscular mycorrhizal fungus. After sequencing, primers were designed and used in PCR reactions to amplify portions of this element in five species of arbuscular mycorrhizal fungi belonging to four genera of Glomales. Southern hybridizations and partial analysis of the main PCR products confirmed that this element was highly conserved in all the species. Southern blot analysis of single and double digested DNA from two of the glomalean fungi gave smears suggesting that MYCDIRE is scattered throughout the fungal genome. Sequence analyses revealed three copies of a previously reported autonomously replicating sequence (ARS) from Saccharomyces cerevisiae and comparisons indicated similarities of MYCDIRE with the autonomously replicating, A+T-rich element (ACARS) from Acremonium chrysogenum.

Close relationship between the Sphaerophoraceae and Austropeltum and Neophyllis, is established by phylogenetic analysis of nuclear SSU rDNA sequences, including newly produced sequences of Austropeltum glareosum, Neophyllis melacarpa and Sphaerophorus globosus. Anatomical, chemical, and ontogenetical characters, and support for this relationship, are discussed, as is the suitability of the nuclear SSU rRNA gene for phylogenetic analyses at this taxonomic level. The analysis gives no support for regarding Austropeltum (presently classified in the Stereocaulaceae) and Neophyllis (presently in the Cladoniaceae) to be closely related to either Stereocaulon ramulosum and Pilophorus acicularis (Stereocaulaceae), or Cladonia bellidiflora (Cladoniaceae), and it is pointed out that the delimitation of all three families needs further investigation. The homology of podetial and pseudopodetial structures is discussed.

Turturconchata reticulata gen. et sp. nov., isolated from the decaying stem of an herbaceous dicotyledon, is described and illustrated. It is characterized by dorsiventrally flattened olive brown conidia composed of 19–58 cells. The conidia are borne horizontally on a cuneiform basal cell originating from flexuous, curved to spiral, septate, simple or branched, indeterminate conidiogenous cells. The differences between T. reticulata and the morphologically or ontogenically somewhat related Canalisporium, Hermatomyces, Mycoenterolobium and Oncopodium are briefly discussed.

The ITS region of the rRNA genes was amplified using DNA extracted from Terfezia pfeilii fruit-bodies. Two types of restriction fragment profiles were revealed among 11 fruit-bodies by the Hinf I restriction enzyme. An additional four truffles collected from the same field one year later were found to have a mixed profile combining both types. Germinated spores from one of these mixed-profile individuals had a single profile belonging to one or the other of the two types. Roots collected around and underneath one Terfezia fruit-body were traced to different plants. Roots of a watermelon plant (Citrullus vulgaris) showed a non-vesicular-arbuscular endomycorrhizal association. Restricted ITS amplification fragments of mycorrhized roots from C. vulgaris were shown to match T. pfeilii fruit-body ITS-RFLP fragments. The significance of this finding with regard to T. pfeilii potential host range is discussed.

An in vitro conifer ectomycorrhizal model system was developed to study changes in gene expression during the establishment of symbiotic relationship. Using the model system and the mRNA differential display technique, we have identified cDNA clones from Laccaria bicolor that appear to be involved in establishing and maintaining the symbiotic relationship between L. bicolor and red pine. These differentially expressed cDNA clones were obtained from mRNA extracted from the fungus 6–24 h after initiation of interaction. BLAST analysis showed that sequences of these clones did not match with any of the previously characterized genes. The cDNAs had regions with varying degrees of similarity to genes involved in signal transduction and transcriptional activation.

Coniochaeta rhopalochaeta sp. nov. was isolated from decorticated wood of Bulnesia retama in Argentina. It is distinguished principally by the ascomata with mace-like capitate setae. C. scatigena is first recorded for Argentina. A key to the seven known Argentine species of Coniochaeta is provided. Asci of these species were studied with fluorescence microscopy; size of the fluorescent apical ring could be a useful taxonomic character.

A study of the holotype and several collections of Cercospora zeyrae on leaves of Zeyheria digitalis from the Brazilian cerrado showed that it is actually a Pseudocercospora species with amphigenous fruit structures, here designated as P. zeyheriae (Henn.) comb. nov.