Genetic variation within Gremmeniella abietina var. abietina was studied using the Random Amplified Microsatellite-technique (RAMS). Ninety-three isolates were investigated, originating mostly from Finland, but also from Canada, U.S.A., Japan, Norway, Italy, Iceland and Sweden. Four banding pattern types were observed corresponding to the present division of this species in Asian, North American and two types of European races. Furthermore, an additional banding pattern was also observed. Intraracial variation was observed within all races, the North American one being the most polymorphic. Isolates of the large tree type (LTT) Gremmeniella from North America, Italy and Iceland contained RAMS alleles not observed in Finland, Sweden or Norway. Therefore, the isolates of LTT Gremmeniella should not be transported even within the area of its natural occurrence.

Investigations of corticolous fungi in Patagonia have revealed the existence of a new species of Hysterium. H. andinense sp. nov. is described and compared to the related species. H. andicola is synonymized with H. insidens.

Three species of fungi endoparasitic in nematodes were obtained in pure culture for the first time. The fungi belong to Harposporium and Verticillium. Morphology of the fungi on corn meal agar was studied and infectivity proving Koch's postulates was achieved for each species. The infection method for Harposporium cycloides was shown to be by spore ingestion. Whilst all species were found to produce infection conidia in pure culture, both species of Harposporium produced accessory conidia and, in H. lilliputanum, arthroconidia were also formed.

Fusarium subglutinans has been associated with many hosts. Some isolates of the fungus are responsible for pitch canker disease of pines. A South African population of F. subglutinans from pine seedlings was characterized by comparing it to isolates from various hosts, pine and non-pine. A total of 26 isolates representing six different hosts were selected for the study. Cultural and morphological characteristics were studied. Virulence of isolates was tested on 1-yr-old Pinus patula seedlings. Sexual compatibility of isolates of F. subglutinans with B- and E-tester strains, and crossings of pine isolates in all possible combinations, were performed. Pine isolates were also compared with pitch canker and non-pine isolates using random amplified polymorphic DNAs (RAPDs). All isolates were morphologically characteristic of F. subglutinans, but differed somewhat in cultural features. Only isolates from pine were pathogenic to P. patula seedlings. Virtually no isolates were sexually compatible with the fertile tester strains. An exception was isolate MRC 115 from maize. Some pine isolates (MRC 6211 and MRC 6217) were, however, sexually compatible with South African (MRC 6213) and pitch canker (MRC 6229) isolates. Cluster patterns constructed from RAPD profiles revealed that isolates clustered according to host. South African isolates from pine were related to the pitch canker isolates from other areas, and were similar to non-pine isolates only in morphology. Virulence, genetic analyses and composite RAPD data suggest that pine isolates originate from the same gene pool, and probably represent a distinct new biological species.

In Fusarium section Liseola, the teleomorph is used to identify mating populations that represent different biological species when distinguishing morphological characters are absent in the anamorph. The Gibberella fujikuroi mating populations to which strains of Fusarium section Liseola belong were determined for isolates from sorghum grown at Ifakara, Ilonga and Kachiri, Tanzania. Representatives of all of the mating populations (A–F) were recovered at Ilonga, but C and E were absent at Ifakara and C was absent from Kachiri. The frequency of the different mating populations was similar at all three sites with A (21%) and F (49%) being the most frequent and C and E the least frequent, if they were recovered at all. The relative proportions of mating populations A and F in the population were significantly different from each other at Ilonga, but were not significantly different at Ifakara or Kachiri. Female fertile strains were more common within mating population A than within mating population F. The inbreeding effective population sizes for the A and F mating populations, respectively, were 69 and 91% of count based on mating type, and 88 and 53% of count based on male/hermaphrodite ratios.

Analysis of Phytophthora cactorum using Random Amplified Microsatellites (RAMS) revealed considerable variation among isolates, most of which correlated with the original host plants. The lack of variation among isolates originating from strawberry suggests that crown rot of strawberry is caused by a single clone within the geographical area studied. It was also shown that P. cactorum isolates form a unique group different from other Phytophthora spp. from Group I.

P. cactorum isolates from necrotic stem lesions on Betula pendula seedlings or Fragaria × ananassa plants suffering from crown rot were highly pathogenic to their original host plants. P. cactorum isolates from strawberry inoculated via wounds also caused necrotic lesions on B. pendula. On the other hand isolates from B. pendula did not cause disease symptoms on strawberry plants. On Alnus glutinosa the percentage of successful inoculations with a birch isolate was 40.

Conidial germination in Neurospora crassa was inhibited by the anticalmodulin (CaM) agents calmidazolium (CaMZ) and trifluoperazine (TFP), indicating the importance of CaM-dependent events during vegetative growth. An increase in intracellular CaM concentration, observed during conidial germination, was associated with enhanced incorporation of [3H]phenylalanine into CaM and increased CaM-dependent protein kinase activity. Phosphorylation of two proteins (71 and 25 kDa) during conidial germination, and of four proteins (71, 47, 38 and 32 kDa) during hyphal elongation was noted to be CaM-dependent since these phosphorylations were inhibited in vitro by CaMZ. The possible regulatory functions of CaM during conidial germination are discussed in relation to phosphorylation of specific proteins during vegetative growth in N. crassa.

Forty-seven isolates of Verticillium albo-atrum, 35 from hop (Humulus lupulus), seven from lucerne (alfalfa, Medicago sativa) and five from four other hosts, were analysed for DNA polymorphisms. Restriction fragment length polymorphisms (RFLPs) were detected in ribosomal RNA genes (rDNA) using Southern hybridization. Polymorphisms in mitochondrial DNA (mtDNA) were detected in ethidium bromide stained gels after digestion of total genomic DNA with restriction enzymes which recognize four bases containing only G and C. Amplified polymorphic DNA (APD) was analysed using primers based on rDNA sequences from the intergenic spacer (IGS) and 25S regions. These data were used to construct phenograms using either squared Euclidean dissimilarity coefficients (SEDC) and cluster analysis, or unweighted pair grouping with arithmetic averaging (UPGMA). rDNA RFLPs revealed one group with 44 isolates, a second group with two atypical hop isolates, and a third group containing a single avirulent lucerne isolate. mtDNA RFLPs separated rDNA group one into two subgroups, one group containing 38 isolates from different hosts and the other containing all six virulent lucerne isolates. APD analysis divided the isolates into 16 phenotypes, 12 of which contained most of the hop isolates, but there was no correlation with origin, hop cultivar, pathogenicity or year of isolation. One APD phenotype contained all six virulent lucerne isolates, indicating the genetic differentiation between hop and lucerne isolates. Two further APD phenotypes coincided with the second atypical group containing two hop isolates and a distinct avirulent lucerne isolate, respectively. The three methods revealed that three isolates differed markedly from those of the main group.

Taiwanascus tetrasporus gen. et sp. nov., a lignicolous, superficial, cleistothecial and appendaged ascomycete with unitunicate, 4-spored, deliquescent asci and hyaline, aseptate to 1-septate, filiform ascospores is described and illustrated. It is assigned to a new family, Taiwanascaceae in the unitunicate ascomycetes.

Preussia aquilirostrata is newly described from submerged plant debris in Iraq. A key to the identification of Preussia species with hairy ascomata is provided. Since Sporormiella is regarded as a synonym of Preussia, the new combinations Preussia lasiocarpa, P. pilosa, P. pilosella and P. chaetomioides are proposed.

Melanospora collipora sp. nov. is described from soil. The most noteworthy feature is the presence of a hyaline rim around the germ pores. Relationships of the new species to other members of Ceratostomataceae and Chaetomiaceae are discussed.

Communities of Aspergillus section Flavi resident in soils planted with cotton were compared among several areas in the southern United States. Incidence of A. flavus and A. tamarii differed among areas. A. flavus incidence increased with temperature and decreased with latitude. Less than 1% of isolates were A. nomius or A. parasiticus. A. flavus isolates were assigned to either the S or L strains on the basis of sclerotial morphology. S strain isolates produced numerous small (<400 μm) sclerotia; L strain isolates produced fewer, larger sclerotia. The S strain of A. flavus was found in all areas. Aflatoxin-producing potential of A. flavus differed among areas and was correlated with S strain incidence. L strain isolates produced only 33% as much aflatoxin B1 as S strain isolates. No S strain isolate produced both aflatoxin B1 and aflatoxin G1. Correlations indicated that L strain toxigenicity but not S strain toxigenicity varied geographically. While toxigenicities of most isolates were stable through single conidial transfer, 28% of isolates expressed altered levels of toxigenicity after transfer. The observed differences among communities may reflect geographic isolation and/or adaptation, and may cause different vulnerabilities to aflatoxin contamination among crops planted in diverse locations.

‘Casa Lis’ is the most characteristic building in Salamanca, Spain, belonging to the modernist trend. It was built with Villamayor sandstone from nearby Salamanca, which has high porosity providing an easy medium for water absorption and capillarity. During a restoration process on the southern wall, near an underground water flow, two well defined, naturally developed layers were observed on the sandstone surface: an outer, hard crust with greyish shades and whitish salt patches resulting from rising damp, and an inner, green layer with organic material linking the sandstone to the inorganic crust. The microbiological study of this biofilm showed an ecologically obligate, stable mutualism between a dematiaceous mitosporic fungus (Septonema tormes sp. nov.), a coccoid cyanobacterium (Cyanothece-group) and a green alga (Gloeocystis rupestris), with the accumulation of different metabolites excreted by these microorganisms. The case reported here is one of the few studies where a microbial mat, in association with the external crust, avoids a further weathering of the stone because of an unforeseen biopreservation effect due to the maintenance of humidity at constant levels under the crust avoids changes in clay swelling and subsequent surface arenization of the sandstone. The lichenized complex of a mitosporic mycobiont and two photobionts, in this case, has not been reported before as a stable association on this kind of substrate.

Dictyoporthe cinnamomi sp. nov., Pseudomassaria cyclobalanopsidis sp. nov. and Splanchnonema verruculospora sp. nov. are described and illustrated from Taiwan and compared with closely related species. A key to species of Dictyoporthe is also provided.

A method to effect rapid, near-synchronous colonization of tomato root systems by a vesicular arbuscular mycorrhizal fungus was developed. This procedure was used to compare the time course of colonization in roots of tomato that were grown under varying phosphate conditions. It was found that the primary symbiotic interaction developed through a series of regularly timed stages. Furthermore, the formation of intercellular hyphae, arbuscules and vesicles was significantly reduced in plants grown with high soil phosphate. These results show that this method is ideal for the production of material for molecular biological studies of VAM symbiosis, including investigation of the regulatory role of phosphate in the symbiosis and the processes that control the fungal life cycle.

Erynia neoaphidis is the most widespread aphid pathogen in temperate regions. A few authors have identified this species as infecting some non-aphid hosts. It exhibits high variability with respect to morphology and cultural characteristics that underlines the need for assessment of the genetic variability within this species. We used size of PCR-amplified ribosomal DNA internal transcribed spacer (ITS) coupled with RAPD-PCR pattern in order to investigate genetic variability within a sample of 30 isolates identified as E. neoaphidis and one isolate of E. kondoiensis from diverse countries and hosts. Isolates fell into four discrete ITS size groups: 575 base pairs (bp) in isolates from non-aphid hosts, 1000 (including the E. kondoiensis isolate), 1100, or 1450 bp in those from Aphididae. The 1100-type seems to be the one of most widespread, since two-thirds of the isolates from diverse locations belong to this type. ITS types can be correlated with morphological and physiological characteristics. A great deal of genetic variability exists within ITS types, as shown by RAPD-PCR. RAPD groupings could be related with geographical origin in some cases. There was no apparent relationship between host and ITS type or RAPD pattern among isolates from Aphididae. PCR-based technologies provide evidence that could be used to clarify the taxonomy of E. neoaphidis and closely related species, and will help identify markers related to epidemiological characteristics.

An examination of microscopic and macroscopic vegetative reactions between paired isolated of Rhizoctonia solani AG-8 revealed that pairs of isolates that give a C2 anastomosis reaction at the microscopic level always gives a ’tuft’ reaction at the macroscopic level. Similarly, any pair that gives a C3 anastomosis reaction at the microscopic level always gives a ’merge’ reaction at the macroscopic level. Thus, macroscopic vegetative (’tuft type’) reactions can be used to predict the microscopic (anastomosis) reaction (and vice versa) between paired isolate of AG-8. This pattern also seems to apply to paired isolates of AG-3, AG-7 and AG-10 but not the other AGs of R. solani. The C2 anastomosis reaction is always observed when two isolates from different zymogram groups of R. solani AG-8 are paired. When isolates from within any of the five zymogram groups comprising AG-8 are paired, either a C2 or a C3 anastomosis reaction will result. Many field isolates of AG-8, when paired, give a C3 anastomosis reaction. We propose that a group of field isolates of R. solani that give a C3 anastomosis reaction be designated a ’vegetatively compatible population’ (VCP).

The composition and concentration of airborne fungal propagules are probably determined by many interrelated environmental factors, such as temperature, relative humidity, atmospheric pressure, wind speed, rainfall and gas pollutants. The importance of these variables was assessed in an outdoor sampling survey conducted at regular intervals for 12 months at a single site in Turin. Samples were collected with a single-stage volumetric sieve sampler on potato dextrose agar supplemented with 15 mg l−1 streptomycin and 50 mg l−1 chloramphenicol.

Canonical Correspondence Analysis showed that the four ordination axes accounted for 93·5% of the variance in relationships between fungal entities present in more than 20% of samples and the environmental variables. The Monte Carlo permutation test demonstrated that the ordination was highly significant (P=0·01). The community's qualitative and quantitative composition mainly depended on the factors that have the greatest influence on Turin's climate, i.e., in descending order, temperature, relative humidity and rainfall. The relative importance of these environmental variables on different groups of fungi was assessed. Wind speed positively correlated with the fungi producing conidia of larger sizes.

Pseudorobillarda magna sp. nov. from bark of Geoffroea decorticans, a native tree of Argentina, is described and illustrated. It is compared with the known species in the genus. This is the first report of a species of Pseudorobillarda from South America.

In order to investigate the barotolerance of marine fungi and to elucidate their ecological role in the deep sea, high-pressure equipment was built and tested. Cultures of the marine yeasts Debaryomyces hansenii, Rhodotorula rubra and Rhodosporidium sphaerocarpum were inoculated into gas-permeable plastic foil bags and incubated in pressure vessels filled with hydraulic fluid that serves also as an oxygen reservoir. The equipment was used at temperatures from 7° to 34°C and pressures from 0·1 to 80·0 MPa. Comparison of five types of plastic foil showed effects on total cell number in batch culture. An exchange of the hydraulic fluid increased yield by replenishing oxygen, the growth-limiting factor. There were no detectable growth differences between buffered (TRIS, HEPES, imidazole, MES) and unbuffered media and thus unbuffered medium was used. Yeasts were best cultivated in an unbuffered sea-water medium (glucose–peptone–yeast extract) sealed in bags made from polyethylene foil. The fluorocarbon liquid FC-77 provided the best oxygen reservoir owing to its high oxygen and carbon dioxide solubility. An exchange of the hydraulic fluid is not necessary if sensitive growth determination methods are used. All marine yeasts cultivated under simulated deep sea conditions were able to grow at least up to a pressure of 20 MPa, with Rhodotorula rubra and Rhodosporidium sphaerocarpum growing at 40 MPa, corresponding to 4000 m depth. Thus, marine yeasts are able to grow under simulated deep sea conditions and may participate in the degradation of organic matter in the deep sea.