21 research outputs found
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 extreme
Metagenomics untangles potential adaptations of Antarctic endolithic bacteria at the fringe of habitability
Survival and growth strategies of Antarctic endolithic microbes residing in Earth's driest and coldest desert remain virtually unknown. From 109 endolithic microbiomes, 4539 metagenome-assembled genomes were generated, 49.3 % of which were novel candidate bacterial species. We present evidence that trace gas oxidation and atmospheric chemosynthesis may be the prevalent strategies supporting metabolic activity and persistence of these ecosystems at the fringe of life and the limits of habitabilit
Antarctolichenia onofrii gen. nov. sp. nov. from Antarctic endolithic communities untangles the evolution of rock-inhabiting and lichenized fungi in Arthoniomycetes.
Microbial endolithic communities are the main and most widespread life forms in the
coldest and hyper-arid desert of the McMurdo Dry Valleys and other ice-free areas across Victoria
Land, Antarctica. There, the lichen-dominated communities are complex and self-supporting assemblages
of phototrophic and heterotrophic microorganisms, including bacteria, chlorophytes, and
both free-living and lichen-forming fungi living at the edge of their physiological adaptability. In
particular, among the free-living fungi, microcolonial, melanized, and anamorphic species are highly
recurrent, while a few species were sometimes found to be associated with algae. One of these fungi
is of paramount importance for its peculiar traits, i.e., a yeast-like habitus, co-growing with algae
and being difficult to propagate in pure culture. In the present study, this taxon is herein described
as the new genus Antarctolichenia and its type species is A. onofrii, which represents a transitional
group between the free-living and symbiotic lifestyle in Arthoniomycetes. The phylogenetic placement
of Antarctolichenia was studied using three rDNA molecular markers and morphological characters
were described. In this study, we also reappraise the evolution and the connections linking the lichenforming
and rock-inhabiting lifestyles in the basal lineages of Arthoniomycetes (i.e., Lichenostigmatales)
and Dothideomycetes