Pre-Cambrian roots of novel Antarctic cryptoendolithic bacterial lineages

Microbiome

Silvano Onofri¹  Claudia Coleine¹  Laura Selbmann²  Susannah G. Tringe³  Jason E. Stajich⁴  Davide Albanese⁵  Claudio Donati⁵  Omar Rota-Stabelli⁵ 

[1] Department of Ecological and Biological Sciences, University of Tuscia, Largo dell’Università, 01100, Viterbo, Italy;Department of Ecological and Biological Sciences, University of Tuscia, Largo dell’Università, 01100, Viterbo, Italy;Mycological Section, Italian Antarctic National Museum (MNA), Via al Porto Antico, 16128, Genoa, Italy;Department of Energy Joint Genome Institute, One Cyclotron Road, 94720, Berkeley, CA, USA;Department of Microbiology and Plant Pathology and Institute of Integrative Genome Biology, University of California, Watkins Drive 3401, Riverside, 92507, Riverside, CA, USA;Research and Innovation Centre, Fondazione Edmund Mach, Via E. Mach 1, 38098, San Michele all’Adige, Italy;

关键词: Antarctica;    Extremophiles;    Cryptoendolithic communities;    Bacteria;    Evolution;    Adaptation;    Metagenomics;    MAG;    Functionality;   

DOI  :  10.1186/s40168-021-01021-0

来源: Springer

【 摘 要 】

BackgroundCryptoendolithic 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.).ResultsA 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.ConclusionsOur 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.Ar7T6ZUsn22t2KkUgdSXvLVideo abstract

【 授权许可】

CC BY