215 research outputs found
Mountain tips as reservoirs for new rock-fungal entities: Saxomyces gen. nov. and four new species from the Alps
No full textAs part of a worldwide sampling nineblack fungi were isolated from rocks collected
in four distinct sites of the Alps at high altitudes. Based on a nucSSU, nucLSU and mtSSU multilocus
phylogeny, seven of them were found to cluster into a distinct and well-supported clade in a
basal position within the Class Dothideomycetes. As in other rock fungi these new groups of
isolates were characterized by a meristematic growth and a scarcely differentiated morphology with
highly melanized and thick-walled toruloid hyphae. Nonetheless, few peculiar characters were also
observed as convoluted hyphal tips and the production of spherical propagules. The new genus and
speciesSaxomyces alpinus and S. penninicus, are here described based on morphological and
molecular data, in a yet to be defined order of the Dothideomycetes. The remaining two black fungi
clustered in Cryomyces, a genus previously exclusively found in rocks from the McMurdo Dry
Valleys in Antarctica. These two isolates were genetically distant from other Antarctic Cryomyces
Manuscript with revisions accepted
Click here to download Manuscript: Selbmann_ms_02 04 2013 reviosions accepted.docx
species based on ITS sequences, and they showed a peculiar morphology; they are here described as
the new species C. montanus and C. funiculosus. Implications of our results on the evolution,
adaptation and dispersal of rock-inhabiting fungi under extreme conditions are discussed.
Taxonomic novelties: Saxomyces Selbmann & Isola, Saxomyces alpinus Zucconi & Selbmann,
Saxomycespenninicus Zucconi & Onofri, Cryomyces funiculosus Selbmann & de Hoog, Cryomyces
montanus Isola & Zuccon
AMBIENTE LITICO E SPECIAZIONE. CARATTERIZZAZIONE SU BASE MOLECOLARE DI UN NUOVO TAXON DI FUNGHI NERI MERISTEMATICI DI PROVENIENZA ALPINA
No full textCARATTERIZZAZIONE MOLECOLARE DI FUNGHI MELANIZZATI ISOLATI DA ROCCE PROVENIENTI DA AMBIENTI ESTREMI. DATI PRELIMINARI
No full textRock-inhabiting fungi and their role in deterioration of stone monuments in the Mediterranean area
No full textMost of the cultural heritage is in the Mediterranean area. Stone was historically the most durable and widely used building material; therefore, the greatest deal of antiques is represented by stone monuments located in outdoor environments. Atmospheric agents, pollution, and various stresses are the main causes of deterioration of artistic heritage as well as many micro-organisms that often cause irreversible damages. Conservation of this invaluable patrimony, therefore, is a demanding challenge. Rock-inhabiting fungi (RIF) are very active agents causing visible alteration patterns and exfoliation of stone monuments; ecological conditions in the Mediterranean rocks are optimal for RIF development. Along with environmental conditions, fungal colonization depends also on bioreceptivity of the surfaces and survival strategies of colonizing species. This paper represents an overview of RIF biodiversity on stone monuments known at present, mechanisms of attack and colonization and outdoor conditions allowing the settlement of RIF propagules, colonization, and the following biodeterioration processe
Antarctic Epilithic Lichens as Niches for Black Meristematic Fungi
No full textSixteen epilithic lichen samples (13 species), collected from seven locations in Northern and Southern Victoria Land in Antarctica, were investigated for the presence of black fungi. Thirteen fungal strains isolated were studied by both morphological and molecular methods. Nuclear ribosomal 18S gene sequences were used together with the most similar published and unpublished sequences of fungi from other sources, to reconstruct an ML tree. Most of the studied fungi could be grouped together with described or still unnamed rock-inhabiting species in lichen dominated Antarctic cryptoendolithic communities. At the edge of life, epilithic lichens withdraw inside the airspaces of rocks to find conditions still compatible with life; this study provides evidence, for the first time, that the same microbes associated to epilithic thalli also have the same fate and chose endolithic life. These results support the concept of lichens being complex symbiotic systems, which offer attractive and sheltered habitats for other microbes
Isolation and screening of fungi as potential degradors of volatile aromatic hydrocarbons
No full textRock black fungi: excellence in the extremes. From the Antarctic to Space
No full textThis work focuses on rock-inhabiting fungi (RIF) of Antarctic rocky deserts, considered the closest to a possible Martian habitat, as the best example of adaptation to the extremes. The study of RIF ecophysiology, resistance and adaptation provides tools that shed light on the evolution of extremophily. These studies also help define the actual limits for life and provide insight for investigating its existence beyond our planet. The scientific results obtained from over 20 years of research on the biodiversity, phylogeny and evolution toward extremotolerance reviewed here demonstrate how these fascinating organisms can withstand conditions well beyond those in their natural environment. A final focus is given on results and perspectives arising from a recent proteomic approach, and from astrobiological experiments and their significance for future space exploration. These studies demonstrate that Antarctic RIF offer an excellent opportunity to investigate many basic, but also applicative areas of research on extremophily
Phylogenomic analysis resolves the evolutionary pattern of diversification of cyanobacteria and reveals the evolutionary affinity of novel Antarctic lineages
No full textEstablishing phylogenetic relationships among the major cyanobacterial lineages remains elusive. Here we report a phylogenetic analysis of a large and well curated dataset, which allowed us to resolve with maximum statistical support the general pattern of cyanobacterial diversification and to address the limited knowledge regarding the diversity of Antarctic cyanobacteria. The analysis included novel Metagenome-Assembled Genomes (MAGs) sampled from diverse lithic habitats across Antarctica at elevations up to 3.4 km. The results presented here revealed previously undetected lineages and provided a robust phylogenetic framework for a natural cyanobacterial classificatio
Phylogenetic relationships of rock-inhabiting black fungi belonging to the widespread genera Lichenothelia and Saxomyces
No full textRock-inhabiting fungi (RIF) are adapted to thrive in oligotrophic environments and to survive under conditions of abiotic stress. Under these circumstances, they form biocoenoses with other tolerant organisms, such as lichens, or with less specific phototrophic consortia of aerial algae or cyanobacteria. RIF are phylogenetically diverse, and their plastic morphological characters hamper the straightforward species delimitation of many taxa. Here, we present a phylogenetic study of two RIF genera, Lichenothelia and Saxomyces. Representatives of both genera inhabit rather similar niches on rocks, but their phylogenetic relationships are unknown so far. The cosmopolitan genus Lichenothelia is recognized by characters of fertile ascomata and includes species with different life strategies. In contrast, Saxomyces species were described exclusively by mycelial characters found in cultured isolates from rock samples collected at high alpine elevations. Here, we use an extended taxon sampling of Dothideomycetes to study the phylogenetic relationships of both Lichenothelia and Saxomyces. We consider environmental samples, type species, and cultured isolates of both genera and demonstrate their paraphyly, as well as the occurrence of teleomorphs in Saxomyces. We applied three species delimitation methods to improve species recognition based on molecular data. We show the distinctiveness of the two main lineages of Lichenothelia (Lichenotheliales s. str.) and Saxomyces and discuss differences in species delimitation depending on molecular markers or methods. We revise the taxonomy of the two genera and describe three new taxa, Lichenothelia papilliformis, L. muriformis, and Saxomyces americanus, and the teleomorph of S. penninicus
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