Resistance of an Antarctic cryptoendolithic black fungus to radiation gives new insights of astrobiological relevance

Selbmann, Laura; Pacelli, Claudia; Zucconi, Laura; Dadachova, Ekaterina; Moeller, Ralf; Vera, Jean Pierre Paul de; Onofri, Silvano

doi:10.1016/j.funbio.2017.10.012

Cited by 40 publications

(30 citation statements)

References 65 publications

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“…The RIF + BY encompass phylogenetically diverse fungi belonging to two main classes of the fungal kingdom Dothideomycetes and Eurotiomycetes. They show a notable stress-tolerance to chemical and physical injuries, such as extreme pH values, high and low temperatures, desiccation, UV and ionizing radiation, and even alpha particles [ 59 , 60 , 61 , 62 , 63 , 64 , 65 ]. Being specialized in the extremes [ 66 ], they normally occur in extreme habitats, from hot and cold deserts, rock surfaces and glaciers, saltpans, and acidic or polluted environments [ 8 , 61 , 67 , 68 , 69 ].…”

Section: Discussionmentioning

confidence: 99%

Sun Exposure Shapes Functional Grouping of Fungi in Cryptoendolithic Antarctic Communities

Coleine

Zucconi

Onofri

et al. 2018

Life

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Antarctic cryptoendolithic microbial communities dominate ice-free areas of continental Antarctica, among the harshest environments on Earth. The endolithic lifestyle is a remarkable adaptation to the exceptional environmental extremes of this area, which is considered the closest terrestrial example to conditions on Mars. Recent efforts have attempted to elucidate composition of these extremely adapted communities, but the functionality of these microbes have remained unexplored. We have tested for interactions between measured environmental characteristics, fungal community membership, and inferred functional classification of the fungi present and found altitude and sun exposure were primary factors. Sandstone rocks were collected in Victoria Land, Antarctica along an altitudinal gradient from 834 to 3100 m a.s.l.; differently sun-exposed rocks were selected to test the influence of this parameter on endolithic settlement. Metabarcoding targeting the fungal internal transcribed spacer region 1 (ITS1) was used to catalogue the species found in these communities. Functional profile of guilds found in the samples was associated to species using FUNGuild and variation in functional groups compared across sunlight exposure and altitude. Results revealed clear dominance of lichenized and stress-tolerant fungi in endolithic communities. The main variations in composition and abundance of functional groups among sites correlated to sun exposure, but not to altitude.

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Section: Discussionmentioning

confidence: 99%

Sun Exposure Shapes Functional Grouping of Fungi in Cryptoendolithic Antarctic Communities

Coleine

Zucconi

Onofri

et al. 2018

Life

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“…Adaptations of microbial systems to severe conditions in natural Earth environments are of astrobiological significance. They can act as models for searching for life beyond Earth, or to investigate the possibility of life transfer between planets [ 1 , 2 ]. In view of space exploration missions focused on identifying evidence for extant or extinct life in the Solar System and beyond, several experiments, ground-based on Earth or in space, have been performed in the last decades [ 3 , 4 , 5 , 6 ].…”

Section: Introductionmentioning

confidence: 99%

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

Onofri

Selbmann

Pacelli

et al. 2018

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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.

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“…Black fungi, indeed, are well known to be particularly adapted to highly diverse stressing environments such as saltpans, hydrocarbon-contaminated sites, exposed bare rocks and monuments, icy habitats, deserts and solar panels and building roofs [36][37][38][39][40][41]. Their extraordinary abilities to resurrect from dry conditions, e.g., [42] and to tolerate almost chemical and physical stresses including extreme pH, high and low temperature, desiccation, UV and ionizing radiation and alpha particles [43][44][45][46][47][48][49], allow these extremo-tolerant organisms to succeed when conditions are incompatible for the most [50].…”

Section: Discussionmentioning

confidence: 99%

Endolithic Fungal Species Markers for Harshest Conditions in the McMurdo Dry Valleys, Antarctica

Coleine

Pombubpa

Zucconi

et al. 2020

Life

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The microbial communities that inhabit lithic niches inside sandstone in the Antarctic McMurdo Dry Valleys of life’s limits on Earth. The cryptoendolithic communities survive in these ice-free areas that have the lowest temperatures on Earth coupled with strong thermal fluctuations, extreme aridity, oligotrophy and high levels of solar and UV radiation. In this study, based on DNA metabarcoding, targeting the fungal Internal Transcribed Spacer region 1 (ITS1) and multivariate statistical analyses, we supply the first comprehensive overview onto the fungal diversity and composition of these communities sampled over a broad geographic area of the Antarctic hyper-arid cold desert. Six locations with surfaces that experience variable sun exposure were sampled to compare communities from a common area across a gradient of environmental pressure. The Operational Taxonomic Units (OTUs) identified were primarily members of the Ascomycota phylum, comprised mostly of the Lecanoromycetes and Dothideomycetes classes. The fungal species Friedmanniomyces endolithicus, endemic to Antarctica, was found to be a marker species to the harshest conditions occurring in the shady, south exposed rock surfaces. Analysis of community composition showed that sun exposure was an environmental property that explained community diversity and structured endolithic colonization.

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Resistance of an Antarctic cryptoendolithic black fungus to radiation gives new insights of astrobiological relevance

Cited by 40 publications

References 65 publications

Sun Exposure Shapes Functional Grouping of Fungi in Cryptoendolithic Antarctic Communities

Sun Exposure Shapes Functional Grouping of Fungi in Cryptoendolithic Antarctic Communities

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

Endolithic Fungal Species Markers for Harshest Conditions in the McMurdo Dry Valleys, Antarctica

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