Taxonomic studies on new or critical fungi of non-pathogenic Onygenales 4

Three noteworthy taxa of soil-borne onygenalean fungi are described and illustrated:Kraurogymnocarpa trochleospora, comb. nov.,Kuehniella aurea, comb. nov., andNannizziopsis albicans. In addition,Aphanoascus boninensis, which was previously described as a new species, is considered to be a synonym ofUncinocarpus orissi.     

中国半实衣属和灰线衣属（文字衣科）的初步研究

对中国半实衣属和灰线衣属地衣进行了分类学研究,共鉴定出7个种,其中半实衣属4种,灰线衣属3种。报道了采自海南的一新种——双砖孢半实衣Hemithecium duomurisporum和一中国新记录种——交织半实衣H. implicatum。给出了这些种的检索表和全部种的地衣体特征照片。     

Materials for the fungus flora of Japan (55)

From recent isolates of microfungi on soil materials collected at several localities in Japan, three onygenalean species are described and photographed as new to Japan:Aphanoascus durus, Kuehniella racovitzae, andShanorella spirotricha. (54) Yokoyama, T. and Nasu, H., Mycoscience41: 91–93, 2000.     

中国的肉座菌科Ⅲ.肉座菌属的菌生种

对肉座菌属的系统分类史进行了回顾,并对3个菌生种进行了报道;其中硫磺肉座菌(新拟)Hypocrea sulphurea(Schwein.)Sacc.为中国新记录种,拟层孔肉座菌H.fomitopsisP.G.Liuet     

Molecular and physiological diversity among Verticillium fungicola var. fungicola

The genetic and physiological variability of Verticillium fungicola var. aleophilum responsible for Agaricus bisporus dry bubble disease in North America is well documented but little is known about the var. fungicola affecting European crops. Variability was assessed within this variety and compared with that reported for the var. aleophilum. Eighteen isolates of V. fungicola var. fungicola and four var. aleophilum isolates were analysed for DNA polymorphism, mycelial growth, response to biochemicals produced by A. bisporus, fungicide resistance, and pathogenicity assessed by direct inoculation on sporophore or casing contamination. RAPD and AFLP markers delineated three French isolates from a homogeneous group containing the other var. fungicola isolates, but no correlation could be drawn between DNA polymorphism and the various traits studied. The var. fungicola isolates were more susceptible than the var. aleophilum isolates to the antibiosis effect of A. bisporus. Only mycelial growth rate at 23 °C could explain the variability in aggressiveness among the European isolates. The putative effect of the post-incubation temperature on contamination during mushroom cultivation was discussed. This work emphasized that, like the American var. aleophilum, the var. fungicola in Europe is genetically homogeneous, but physiological diversity exists, especially in France where it could be related to less standardized cultural practices.     

Taxonomic studies on new or critical fungi of non-pathogenic Onygenales 2

Six new taxa of soil-borne onygenalean fungi are described and illustrated:Amauroascus javanicus, Myxotrichum emodense, M. retardatum, Nannizziopsis patagonica, Spiromastix princeps andS. sphaerospora.     

Seasonal trends in usnic acid concentrations of Arctic, alpine and Patagonian populations of the lichen Flavocetraria nivalis

The widespread secondary metabolite usnic acid, a dibenzofuran derivative, is the principal acetone-soluble compound in the lichen Flavocetraria nivalis. Seasonal variation in concentrations were studied in four populations of this lichen, three from Arctic-alpine habitats in the Northern Hemisphere, and one from Patagonian heathland in the Southern Hemisphere. Usnic acid is produced in large amounts, making up between 4% and 8% of thallus dry weight. Large seasonal variation is seen, with a trend towards peak levels in late spring and early summer, and generally low levels during autumn and winter. However, at an Arctic steppe in Central West Greenland, remarkably high levels were also detected during late autumn and early winter. Comparisons with environmental data using model selection procedures show that usnic acid levels of three of the populations are positively correlated with time of season, as measured by the proximity in time to nearest summer solstice, solar radiation levels, and temperature conditions. All these three variables are intercorrelated, thus indicating the same overall trend. For the three driest sites, precipitation rates are included in the models that best explain the variation in usnic acid. However, the explanatory powers of the models are generally low, partly due to high variation between thalli growing together and sampled at the same time. This is the first attempt to compare statistically seasonal variation in usnic acid concentrations and environmental variables, and thus also the first time it is shown that the concentration in various populations of the same lichen species shows different types of correlation with seasonal climatic changes.     

Sub-families of alpha/beta barrel enzymes: a new adenine deaminase family

No gene coding for an adenine deaminase has been described in eukaryotes. However, physiological and genetical evidence indicates that adenine deaminases are present in the ascomycetes. We have cloned and characterised the genes coding for the adenine deaminases of Aspergillus nidulans, Saccharomyces cerevisiae and Schizosaccharomyces pombe. The A.nidulans gene was expressed in Escherichia coli and the purified enzyme shows adenine but not adenosine deaminase activity. The open reading frames coded by the three genes are very similar and obviously related to the bacterial and eukaryotic adenosine deaminases rather than to the bacterial adenine deaminases. The latter are related to allantoinases, ureases and dihydroorotases. The fungal adenine deaminases and the homologous adenosine deaminases differ in a number of residues, some of these being clearly involved in substrate specificity. Other prokaryotic enzymes in the database, while clearly related to the above, do not fit into either sub-class, and may even have a different specificity. These results imply that adenine deaminases have appeared twice in the course of evolution, from different ancestral enzymes constructed both around the alpha/beta barrel scaffold.     

<Emphasis Type="Italic">Lasiosphaeriopsis pilophori</Emphasis> sp. nov. (Sordariales) and other lichenicolous fungi on <Emphasis Type="Italic">Pilophorus</Emphasis>

Seven representatives of the Arthoniales, Dothideales, Lecanorales and Sordariales are known to occur on the lichen genus Pilophorus. Lasiosphaeriopsis pilophori sp. nov. is described from the north of the Holarctic. Cercidospora cephalodiorum is reported as new to North America. Cercidospora punctillata and Dactylospora deminuta are reported on Pilophorus for the first time. The host specificity, niche specialization and distribution of the taxa are discussed. A key to the lichenicolous fungi on Pilophorus is provided.     

Ascospore morphology of bryophilous Pezizales is closely associated with the place of infection and host ecology

Fungal spores are morphologically highly diverse and are therefore frequently used as diagnostic characters in taxonomy. However, the connection between spore morphology and fungal ecology remains poorly understood. Using phylogenetic comparative analyses, we investigated the putative relationships between four ascospore traits and the dominant place of infection, host ecology, and host taxonomic placement in 123 species of biotrophic parasites of bryophytes. Ascospore shape, ornamentation height and relative lipid content are significantly correlated in bryophilous Pezizales. Species attached by their hyphae to bryophyte rhizoids have more globose ascospores with higher ornamentation and relative lipid content than species attached to aboveground organs. Furthermore, some ascospore traits are significantly associated with host lifespan, habitat preferences, and taxonomic placement of their host bryophytes. Our results suggest that the ascospore morphology in this fungal group is closely linked to its ecology and several of the detected relationships point to the existence of distinct dispersal strategies.