Draft Genome Sequence of the Yeast Rhodotorula sp. Strain CCFEE 5036, Isolated from McMurdo Dry Valleys, Antarctica.

A draft genome sequence was assembled and annotated of the basidiomycetous yeast Rhodotorula sp. strain CCFEE 5036, isolated from Antarctic soil communities. The genome assembly is 19.07 megabases and encodes 6,434 protein-coding genes. The sequence will contribute to understanding the diversity of fungi inhabiting polar regions

Sun exposure drives Antarctic cryptoendolithic community structure and composition

AbstractThe harsh environmental conditions of the ice-free regions of Continental Antarctica are considered one of the closest Martian analogues on Earth. There, rocks play a pivotal role as substratum for life and endolithism represents a primary habitat for microorganisms when external environmental conditions become incompatible with active life on rock surfaces. Due to the thermal inertia of rock, the internal airspace of lithic substratum is where microbiota find a protected and buffered microenvironment, allowing life to spread throughout these regions with extreme temperatures and low water availability. The high degree of adaptation and specialization of the endolithic communities makes them highly resistant but scarsely resilient to any external perturbation and thus, any shifts in microbial community composition may serve as early-alarm systems of environmental perturbation, including climate change.Previous research concluded that altitude and distance from sea do not play as driving factors in shaping microbial abundance and diversity, while sun exposure was hypothesized as significant parameter influencing endolithic settlement and development. This study aims to explore our hypothesis that changes in sun exposure translate to shifts in community composition and abundances of main biological compartments (fungi, algae and bacteria) in the Antarctic cryptoendolithic communities. We performed a preliminary molecular survey, based on DGGE and qPCR tecniques, of 48 rocks with varying sun exposure, collected in Victoria Land along an altitudinal transect from 834 to 3100 m a.s.l.Our findings demonstrate that differences in sun radiation between north and south exposure influence temperature of rocks surface, availability of water and metabolic activity and also have significant impact on community composition and microbial abundance

A comparative study of the seed germination capabilities of Anacamptis palustris (Orchidaceae), a threatened terrestrial orchid, and other more common Anacamptis species, by asymbiotic culture in vitro

The increasing emphasis on terrestrial orchid conservation has led to conservation actions for a wide range of threatened Mediterranean species. Many terrestrial orchids are currently at great risk for extinction as a result of a multiplicity of threatening processes. We focus on orchid seed germination capabilities in vitro, specifically germination capability of a threatened species, Anacamptis palustris, compared to three other more common species (A. laxiflora, A. morio, and A. papilionacea), and also discuss its potential impact on orchid distribution and conservation. Asymbiotic germination tests were performed with mature seeds using BM-1 medium. In vitro seed germination and protocorm developmental stages were evaluated up to 20 weeks after sowing. Significant differences in seedling development were detected among the species, and a correlation was evident between the rarity of the species and their germinability. Thus, the presence of intrinsic, biological factors that affect and limit the distribution of A. palustris may exist

Metagenomes in the Borderline Ecosystems of the Antarctic Cryptoendolithic Communities.

Antarctic cryptoendolithic communities are microbial ecosystems dwelling inside rocks of the Antarctic desert. We present the first 18 shotgun metagenomes from these communities to further characterize their composition, biodiversity, functionality, and adaptation. Future studies will integrate taxonomic and functional annotations to examine the pathways necessary for life to evolve in the extremes

Outline analysis for identifying Limodorum species from seeds

Limodorum trabutianum Batt. is an orchid species of the Italian flora, with a central-western stenomediterranean distribution, that is sporadic in the western part of the distribution area of the more common L. abortivum (L.) Sw., an eurimediterranean species. It occurs in Italy only with a few populations in Tuscany, Latium, Umbria, Sicily and Sardinia [1], often with L. abortivum [2], [3], [4] from which it is easily recognizable only during anthesis for the denser inflorescence spike, the ribbon-like lip without differentiation in epychile and hypochile, and for the spur that is very short or absent [5]. On the contrary, the identification of these two taxa during the fruiting phase is rather difficult or even impossible. The aim of this study is to verify the taxonomic value of Limodorum seeds, particularly of their shape, as highlighted from recent studies for other orchids [6], [7], in order to establish its usefulness for recognizing the two species. We have identified 5 Italian populations of the two taxa: 2 populations of L. trabutianum, one within the Marturanum Regional Park (Barbarano Romano, Viterbo), the other near Cortona (Arezzo), and 3 populations of L. abortivum, near S. Martino al Cimino (Viterbo), in the M. Casoli Reserve (Bomarzo, Viterbo), and in the same site of L. trabutianum within the Marturanum Park. The phenology of these populations was monitored to collect mature seeds from naturally dehiscing capsules. The intra- and interspecific variability of seed shapes was analyzed with the methodology of Elliptic Fourier descriptors [8], which allows to describe in terms of harmonics each two-dimensional shape with a closed outline. For this outline analysis we used the software package SHAPE 1.3 [9]. An average of 100 seeds from each species and from each site was photographed with a NIKON Coolpix 5000 camera mounted on a LEITZ-ARISTOPLAN microscope, obtaining 500 digital images with a resolution of 300 dpi and a size of 800 x 1000 pixels. All images were prepared using Adobe Photoshop 7.0: as a first step, every foreign element was eliminated from the picture, thereby isolating the single seed, then its contrast with the background was maximized, and finally all images were saved in .bps format (24bit). The color images were converted to binary with Chain Coder before tracing the outlines in Chain-code, a coding system that describes the geometrical information of the shapes. Then the Chain-code file was transformed into a Normalized Elliptic Fourier file using Chc2Nef using 20 harmonics. The matrix of the harmonic coefficients underwent a process of data normalization based on the first harmonic, to transform the data into shape variables. Subsequently, a PCA was performed on the variancecovariance matrix of normalized coefficients using PrinComp, which gives a graphical output of the principal components (average shape ± standard deviations). The first results of the outline analysis confirm a low intraspecific variability of seed shape, but show a very high interspecific variability: L. abortivum seeds are very elongated, from fusiform to filiform, while L. trabutianum seeds are much wider and have a very lower length/ width ratio. These results allow to distinguish between these two species even during the fruiting phase, simply using seed shape as a diagnostic character, avoiding the use of traditional morphometric analysis which need microscopic measurements

A comparative study of the seed germination capabilities of Anacamptis palustris (Orchidaceae), a threatened terrestrial orchid, and other more common Anacamptis species, by asymbiotic culture in vitro

The increasing emphasis on terrestrial orchid conservation has led to conservation actions for a wide range of threatened Mediterranean species. Many terrestrial orchids are currently at great risk for extinction as a result of a multiplicity of threatening processes. We focus on orchid seed germination capabilities in vitro, specifically germination capability of a threatened species, Anacamptis palustris, compared to three other more common species (A. laxiflora, A. morio, and A. papilionacea), and also discuss its potential impact on orchid distribution and conservation. Asymbiotic germination tests were performed with mature seeds using BM-1 medium. In vitro seed germination and protocorm developmental stages were evaluated up to 20 weeks after sowing. Significant differences in seedling development were detected among the species, and a correlation was evident between the rarity of the species and their germinability. Thus, the presence of intrinsic, biological factors that affect and limit the distribution of A. palustris may exist

Integrity of the DNA and Cellular Ultrastructure of Cryptoendolithic Fungi in Space or Mars Conditions: A 1.5-Year Study at the International Space Station

The black fungi Cryomyces antarcticus and Cryomyces minteri are highly melanized and are resilient to cold, ultra-violet, ionizing radiation and other extreme conditions. These microorganisms were isolated from cryptoendolithic microbial communities in the McMurdo Dry Valleys (Antarctica) and studied in Low Earth Orbit (LEO), using the EXPOSE-E facility on the International Space Station (ISS). Previously, it was demonstrated that C. antarcticus and C. minteri survive the hostile conditions of space (vacuum, temperature fluctuations, and the full spectrum of extraterrestrial solar electromagnetic radiation), as well as Mars conditions that were simulated in space for a 1.5-year period. Here, we qualitatively and quantitatively characterize damage to DNA and cellular ultrastructure in desiccated cells of these two species, within the frame of the same experiment. The DNA and cells of C. antarcticus exhibited a higher resistance than those of C. minteri. This is presumably attributable to the thicker (melanized) cell wall of the former. Generally, DNA was readily detected (by PCR) regardless of exposure conditions or fungal species, but the C. minteri DNA had been more-extensively mutated. We discuss the implications for using DNA, when properly shielded, as a biosignature of recently extinct or extant life

Pre-Cambrian roots of novel Antarctic cryptoendolithic bacterial lineages

8openInternationalBothBackground Cryptoendolithic communities are microbial ecosystems dwelling inside porous rocks that are able to persist at the edge of the biological potential for life in the ice-free areas of the Antarctic desert. These regions include the McMurdo Dry Valleys, often accounted as the closest terrestrial counterpart of the Martian environment and thought to be devoid of life until the discovery of these cryptic life-forms. Despite their interest as a model for the early colonization by living organisms of terrestrial ecosystems and for adaptation to extreme conditions of stress, little is known about the evolution, diversity, and genetic makeup of bacterial species that reside in these environments. Using the Illumina Novaseq platform, we generated the first metagenomes from rocks collected in Continental Antarctica over a distance of about 350 km along an altitudinal transect from 834 up to 3100 m above sea level (a.s.l.). Results A total of 497 draft bacterial genome sequences were assembled and clustered into 269 candidate species that lack a representative genome in public databases. Actinobacteria represent the most abundant phylum, followed by Chloroflexi and Proteobacteria. The “Candidatus Jiangella antarctica” has been recorded across all samples, suggesting a high adaptation and specialization of this species to the harshest Antarctic desert environment. The majority of these new species belong to monophyletic bacterial clades that diverged from related taxa in a range from 1.2 billion to 410 Ma and are functionally distinct from known related taxa. Conclusions Our findings significantly increase the repertoire of genomic data for several taxa and, to date, represent the first example of bacterial genomes recovered from endolithic communities. Their ancient origin seems to not be related to the geological history of the continent, rather they may represent evolutionary remnants of pristine clades that evolved across the Tonian glaciation. These unique genomic resources will underpin future studies on the structure, evolution, and function of these ecosystems at the edge of life.openAlbanese, Davide; Coleine, Claudia; Rota-Stabelli, Omar; Onofri, Silvano; Tringe, Susannah G; Stajich, Jason E; Selbmann, Laura; Donati, ClaudioAlbanese, D.; Coleine, C.; Rota-Stabelli, O.; Onofri, S.; Tringe, S.G.; Stajich, J.E.; Selbmann, L.; Donati, C

Life beyond Earth: the antarctic black fungus in planetary simulations

The cryptoendolithic black fungus Cryomyces antarcticus inhabits the ice-free area of the Antarctic McMurdo Dry Valleys, one of the best terrestrial analogue environment for Mars. There, conditions on rock surface are often incompatible with life; hence, microbes develop within porous rocks as last chance for survival. The almost complete isolation over a timescale of evolutionary significance led to the evolution of unique, extremely adapted and resistant, genotypes. C. antarcticus is particularly skilled in stress tolerance being able to tolerate injuries well beyond the harsh conditions of its natural environment. Because of its uncommon resistance, the fungus has been chosen as eukaryotic model for astrobiological studies to test the endurance of eukaryotic cells to space conditions. In the experiment here reported, the fungus C. antarcticus was exposed, in the frame of the STARLIFE irradiation campaign, to different types and qualities of ionizing radiation with different linear energy transfer values (0.2 to 200 keV/µm). Irradiation with up to 1 kGy of accelerated He, Ar and Fe ions, and 55.57 kGy of gamma rays (60Cobalt). Single gene PCR, RAPD fingerprinting, qPCR and PMA coupled with qPCR analyses reveal minimal damage to DNA or plasma membranes induced by the treatments. This experiments further confirm the stunning stress tolerance of the fungus and its high relevance in astrobiological investigations, including the search for life on Mars, the reliability of the Lithopanspermia theory, and the estimation of planetary contamination risk