A series of comparative physiological and morphological analyses are described for eighteen Dendryphiella isolates. Conidial characteristics of ten isolates showed relatively little variation as a result of different incubation conditions. Isolates were markedly tolerant to NaCl and KCl, although some variation between isolates was noted. A variety of nitrogen compounds could be utilized by most isolates although some grew poorly with certain nitrogen sources. Most isolates showed a wide pH growth range, particularly at alkaline values, and broad temperature growth profiles. The relevance of these physiological characteristics to the survival and fitness of Dendryphiella species in the marine environment is discussed.

To determine the feasibility of using internal transcribed spacers (ITS1 and ITS2) and 5.8S ribosomal DNA sequences as genetic markers in molecular systematic and phylogenetic studies of Ophiostoma, the presence of multiple types of ITS in the two sibling sapstain fungi, Ophiostoma piceae and O. quercus were examined in 22 isolates from diverse geographic regions. PCR and sequence analysis revealed that two different versions of ITS sequences were present in the PCR-products amplified with the ITS primers, ITS1-ITS4 or ITS5-ITS4 or ITS1-F-ITS4, in every isolate of the two Ophiostoma species tested. Surprisingly, the two ITS sequences were shared by both species. One ITS sequence which was major in O. piceae was designated as the OPC type, and the other ITS sequence which was minor in O. piceae was designated as the OPH type. In O. quercus the OPH type was major and the OPC type was minor. The major ITS comprised more than 99% of the amplicons in both species. The results suggest that common ITS gene pools have been maintained at different levels within these sibling species.

Nine isolates of a Colletotrichum sp. collected in North America on yellow water-lily (Nuphar luteum subsp. polysepalum) at five locations in the Pacific Northwest (PNW) and one isolate from Nymphaea odorata in Rhode Island were compared to three isolates of C. nymphaeae occurring on Nymphaea alba and Nuphar luteum in Europe. The appressoria of all North American isolates were significantly wider than those of C. nymphaeae. Conidia of the nine PNW isolates were significantly wider than those of both the Rhode Island isolate and C. nymphaeae isolates. All isolates were compared using random amplified polymorphic DNA (RAPD) and restriction fragment length polymorphism of the ITS region (RFLP-ITS). Two distinct clusters were differentiated in the dendrogram based on the RAPD analysis. The ten North American isolates formed one cluster and the European isolates of C. nymphaeae formed a second cluster. The separation of the North American isolates from the European isolates was supported by distinct restriction digest phenotypes of the ITS region. Based on morphological and molecular characterization the North American fungus is proposed as a new species, C. nupharicola.

Six species of the genus Polyporus s. str. from which monosporic cultures were obtained, were studied to investigate their sexual compatibility. All species tested have an heterothallic multifactorial tetrapolar system. Results of intraspecific matings indicated a certain reproductive isolation of the Argentine and Brazilian collections of P. tenuiculus. Interspecific matings confirmed the separation of the species P. ciliatus and P. tucumanensis, as well as P. dictyopus and P. melanopus. Di-mon matings allowed the separation of P. tenuiculus from P. philippinensis.

Basidiomes of Amanita alboverrucosa, A. ochrophylla, and A. pyramidifera were collected from native mixed sclerophyll forest sites and of A. conicoverrucosa and A. punctata from planted stands of Eucalyptus maculata in New South Wales, Australia. DNA was extracted from stipe tissue and subjected to inter-simple sequence repeat (ISSR) PCR analysis conducted using the primers (GTG)5 and (GACA)4 in order to determine genotype distribution at each site. Two to nine genotypes of one of the species were identified at each field site. Genotypes of A. ochrophylla, A. conicoverrucosa and A. punctata were spread over areas of ca 10–60 m diam, suggesting vegetative spread via large below-ground mycelial genets. In contrast, genotypes of A. alboverrucosa were more spatially restricted, suggesting recent establishment via basidiospores and more limited below-ground vegetative spread. Two groups of A. pyramidifera basidiomes that were separated by ca 600 m were found to be of the same genotype. While this might reflect long distance spread of below-ground mycelium in this taxon, the proximity of the basidiomes to a roadway makes movement of vegetative basidiome tissue via vehicular activity and subsequent establishment equally plausible.

Cerato-ulmin (CU) presence was monitored on cell surface and quantitatively determined in mycelial extracts of the elm pathogens Ophiostoma novo-ulmi (races EAN and NAN) and O. ulmi and of the non-pathogenic O. piceae. CU was detected on the surfaces of Ophiostoma novo-ulmi (races EAN and NAN) and, for the first time, of the weak Dutch elm disease pathogen O. ulmi and the non-pathogen O. piceae. Quantitative determination of CU content in the mycelial extracts of the three species showed that high CU cellular content is associated with high CU content in culture filtrates. The content of CU in biomasses and in culture filtrates was influenced by temperature, growth phase and fungal species or race. CU synthesis occurred during the stationary phase and in the late logarithmic phase when fungi were grown at 23° and 32°C, respectively. High temperatures of growth (32°) did not have a negative effect on the cellular CU content but severely hampered CU secretion in high CU-producers O. novo-ulmi isolates.

The geographical distribution and ecological habitats of the Pleurotus eryngii complex in Israel are described from a study of 60 genotypes from 10 populations. Both MEA and PDA media were suitable for growth of all genotypes at all temperatures tested (4–37 °C). There was a high correlation between a coefficient of growth and the mean colony diameter growth rate. All genotypes reached the maximum growth at 27°. Growth rate at 30° was greater than at 19°. We found highly significant (P < 0.0001) variability among growth rates of Israeli genotypes, indicating ecogeographical differences among populations. The growth rate of 12 European genotypes from the Ukraine and Slovakia was higher than most of the Israeli genotypes when grown at 27° (non-stress conditions), but Israeli genotypes tolerated 37° (stress conditions) better, and recovered faster than European populations when returned to 27°. We conclude that Israeli genotypes are better adapted to hot and dry climates than European genotypes. Based on multiple regression analyses, strong correlations were found between relative humidity and rainfall parameters, but not temperature, of the locations from which Israeli isolates were collected, and their growth rates. This indicates that, paradoxically, relative humidity and rainfall have a stronger effect than temperature on the adaptability of this complex to different environments.

Phylogenetic analyses of nucleotide data from the ITS and 5.8S rDNA gene region were performed on 37 strains of Onygenales representing all the accepted species of Auxarthron (9 strains), several species of Amauroascus (16 strains), and morphologically similar genera (3 strains of Amaurascopsis, 1 of Apinisia, 1 of Shanorella, 1 of Mallochia, 2 of Nannizziopsis, 1 of Pectinotrichum, and 3 of Uncinocarpus). The inferred phylogeny provided strong support for the monophyly of Auxarthron. We propose the new combinations Auxarthron kuehnii and A. pseudoreticulatum combs nov. and provide a key to the accepted species of Auxarthron. Although this study demonstrated that Amauroascus is polyphyletic, relationships among the members of that genus could not be resolved in phylogenies inferred from the analyses of ITS sequences; the new combination A. queenslandicus comb. nov. is also proposed. Molecular data suggested that Amaurascopsis reticulatus, characterised by the absence of discrete ascomata and prominently echinulate ascospores, can be accomodated in Mallochia.

We determined the occurrence of birth rust fungus (Melampsoridium betulinum) within mature mountain birch (Betula pubescens var. czerepanovii) trees and compared the airborne urediniospore concentrations with overall rust infection levels over five successive years. Fifteen groups of three trees 3–5 m high were chosen from a homogenous mountain birch stand. Each group contained a tree with ‘low’, ‘moderate’ and ‘high’ infection covering the natural range of infection levels. The difference in rust classes remained constant throughout the study; trees in class ‘high’ consistently had always highest infection levels and trees in class ‘low’ always the lowest infection levels. Infection levels remained constant between years in ‘low’ class, while the infection levels varied significantly between years in ‘moderate’ and ‘high’ classes. The incidence of disease caused by M. betulinum varied from year to year and was correlated with the total airborne urediniospore counts. The data indicate that trees differ in resistance to birch rust and that infection levels of susceptible compared to resistant trees are more dependent on environmental conditions.

Two new aeroaquatic fungi, Ramicephala sphaerospora gen. sp. nov. and Beverwykella clathrata sp. nov., are described and illustrated from tropical and subtropical latitudes. B. clathrata, a species similar to B. cerebriformis, deviates from the latter in having a clathrate outermost cell layer instead of tightly appressed cells, a feature unique in Beverwykella. The second species, Ramicephala sphaerospora gen. sp. nov., has a unique combination of features concerning conidial ontogeny and morphology, and is therefore placed in a new genus. The genus most similar to Ramicephala is Beverwykella, from which it differs in having: (1) globose, non-flattened conidia; (2) a large central globose cell giving rise to centrifugally branching, tightly packed chains of cells; and (3) a compact peripheral cell layer, the cells of which are tightly interlocked in a zipper-like form. Similarities of R. sphaerospora to species of Pseudaegerita, Candelabrum and Cristulariella are discussed. Illustrations of and a key to all described species of Ramicephala and Beverwykella are provided.

The Cainiaceae is revived to accommodate Atrotorquata, Arecophila, Cainia, Ceriophora and Reticulosphaeria, all of which are described and illustrated. Ommatomyces is also included in the family and discussed. The essential characteristics of the family are ascomata which are usually immersed under a clypeus, unitunicate asci with a complex, J+, apical apparatus comprising a series of rings, and brown ascospores which may have longitudinal germ slits, striations, reticulate ornamentations and/or germ pores.

The adhesion of conidia of Pestalotiopsis neglecta occurs in four stages in a specific manner which allows the first cell most likely to germinate to become firmly attached its substrate while leaving the other two fertile cells free to be dispersed further, thereby increasing the chance of further successful infections. The first stage of adhesion involves the mucilaginous coating acquired from the conidial matrix and appears weak. The second stage of adhesion is also relatively weak and occurs at the bases of the pedicel. The third stage occurs with the release of a fibrillar adhesive substance from along the length of the pedicel to the top of the basal cell and at times a lesser amount of fibrillar material is released from the apical appendages. The fourth stage involves the release of fibrillar material at the point of germtube emergence. The third and fourth stages provide strong attachment.

Soil samples from six sites in Provence, France, were flooded with water and baited with cellophane, specifically to obtain Rhizophlyctis rosea; all proved positive. By standardizing the cellophane addition and counting the R. rosea thalli that grew on it, derivations of thallus recovery g−1 of soil (TRG) were possible. Where aliquot soil samples for assay were small, sterilized soil leachate was used to chemically reinforce the flood water. Mean TRG was 395 for a grassland soil and 1293 following drying and removal of small stones from it. Separated leaf humus from the same dried soil had a mean TRG of 1105. Thought was given to what these figures might represent, in terms of sporangia of R. rosea present in the soil at the time of its collection. These are the first quantitative results in soil ecology for the Chytridiales.

The two forms of acid phosphatase secreted by Botrytis cinerea were purified, characterized and found to possess fundamentally different properties. The phosphate-repressible acid phosphatase was a monomer of clearly defined molecular weight (55–56 kDa), with a polypeptide component of 43 kDa. The enzyme was secreted through the hyphal apex and accumulated in the culture fluid. Its high affinity for a wide range of substrates rendered it suitable for a putative role as an extracellular phosphate-scavenging enzyme. Secretion of a constitutive acid phosphatase occurred at low levels in phosphate-enriched culture; at phosphate starvation, the activity of this enzyme was enhanced ten-fold in the culture fluid and two-fold in the cell wall. The constitutive enzyme had strikingly different properties from those of the repressible form. It consisted of a 93 kDa polypeptide which was heavily glycosylated such that the secreted protein displayed size heterogeneity of 140–200 kDa by SDS–polyacrylamide gel electrophoresis and 320–450 kDa by native Sephacryl S-300 chromatography. Irrespective of the phosphate status, most of the secreted constitutive enzyme activity was retained by the cell wall. These results were consistent with ultrastructural histochemical observations which suggested that this enzyme form was secreted by a novel pathway via the fusion of vacuoles with the plasma membrane in mature hyphal segments.

Thirty-one isolates of the form genera Acremonium and Cephalosoporium were screened for their ability to excrete enzymes capable of degrading β-glucans. Most produced both (1 → 3)- and (1 → 6)-β-glucanases together, although the yields varied with carbon source used. Surprisingly, higher yields of (1 → 3)-β-glucanases were often seen from isolates grown on pustulan, a (1 → 6)-β-glucan which is not hydrolysed by these enzymes. Lower enzyme yields were generally obtained with glucose than with either laminarin, a (1 → 3)-β-glucan or pustulan as carbon sources, suggesting regulation of synthesis by either catabolite repression and/or induction. However, a few isolates, most notably Cephalosporium sp. OXF C13 and Acremonium strictum appeared to have some constitutive-β-glucanase activity. Most of the isolates screened were only very weakly cellulolytic against carboxymethyl cellulose or filter paper as substrates.

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.

Pseudocercospora mori produced three kinds of hyphae – primary infection hyphae, internal hyphae and secondary infection hyphae. The primary infection hyphae were developed from conidia and they penetrated the leaf through stomata directly or by lateral penetration branches – the stomatopodia. Inside the stomatal chambers the stomatopodia swelled to become vesicle-like structures. The internal hyphae produced compact stromata in the sub-stomatal chambers. Each stromata carried 1–5 conidia at a time on short unbranched conidiophores. The secondary infection hyphae were developed from internal hyphae directly or from stromata. The secondary infection hyphae emerged through stomata, branched profusely on the leaf surface and produced conidia singly on short conidiophores. The secondary infection hyphae re-entered the leaf directly or by stomatopodia. Conidia were developed also from stomatopodia and from their substomatal vesicles. The conidia developed from substomatal stromata, and those produced from the secondary infection hyphae on leaf surface were similar in their morphology and size of conidiophores. The conidia were obclavate to cylindrical, 3–17 celled and measured 4–35×1.5–2 μm. Germ tubes were often found to emerge from the conidial cell nearer to stomata. The primary infection hyphae and secondary infection hyphae produced stomatopodia above stomata.

Genetic variability was investigated in North American populations of the tree pathogenic fungi Nectria galligena and N. coccinea var. faginata. Genetic diversity was estimated by analysing RAPD and ribosomal DNA polymorphisms. The number of haplotypes was the maximum value in N. galligena (51), whereas 17 different haplotypes were detected among the 23 isolates of N. coccinea var. faginata studied. The frequency of polymorphic loci was greater in N. galligena (92%) than in N. coccinea var. faginata (35%). The estimate of genotypic diversity was a maximum in N. galligena while it represented only 59% of the maximum value for N. coccinea var. faginata. Gene diversity was also higher in the former (21%) than in the latter (6%). Moreover, four distance indexes calculated from the same genetic distance matrix gave similar results and showed that distances among isolates of N. galligena were four to nearly six times larger than distances among N. coccinea var. faginata isolates. An analysis of molecular variance based on genetic distances among haplotype frequencies confirmed that host origin (beech vs other species) was not the source of the genetic variability in N. galligena since less than 1% of the variability was attributable to the host factor. Overall, our results are consistent with the hypothesis that N. galligena is a pathogen native to North America while N. coccinea var. faginata may be a recent introduction.

Morphogenesis is not simply a matter of playing out a predefined genetic programme. Expression of developmentally important genes is epigenetic and place- and time-dependent relying on previously-formed tissue structures. Most differentiated hyphal cells require reinforcement of their differentiation ‘instructions’. This reinforcement is part of the context (chemical, electrical and structural/mechanical environment) within which they normally develop. Key words at each stage of development in fungi are: competence, induction and change. Fungal morphogenesis is compartmentalized into a collection of ‘sub-routines’ which are distinct genetically and physiologically. Flexibility in expression of developmental sub-routines illustrates that tolerance of imprecision is an important attribute of fungal morphogenesis.

Isolates of Gaeumannomyces graminis were sampled from 16 cereal crops throughout the cereal belt of southern Australia to determine the extent of genetic diversity and the scale of genetic differentiation among pathogen populations. Data from 13 isozyme and 4 RFLP loci differentiated 79 multilocus genotypes among the 320 isolates analysed. All 17 loci differed significantly in allele frequencies across all populations and significant levels of genetic differentiation were detected between most populations. Genetic differentiation among host groups was high (GST = 0.307) and groups of populations from barley, oats and wheat were significantly different. The average genetic identities among populations were low and populations formed genetically related groups based on similarities in recent cereal cropping histories and not geographical origins. Collectively, these analyses indicate restrictions to inter-population gene flow within G. graminis and imply that population differentiation results from genetic drift and host-mediated selection by different cereal species.