16S rRNA Gene Diversity in Ancient Gray and Pink Salt from San Simón Salt Mines in Tarija, Bolivia

Global soil metagenomics reveals distribution and predominance of Deltaproteobacteria in nitrogen-fixing microbiome

BACKGROUND

Biological nitrogen fixation is a fundamental process sustaining all life on earth. While distribution and diversity of N2-fixing soil microbes have been investigated by numerous PCR amplicon sequencing of nitrogenase genes, their comprehensive understanding has been hindered by lack of de facto standard protocols for amplicon surveys and possible PCR biases. Here, by fully leveraging the planetary collections of soil shotgun metagenomes along with recently expanded culture collections, we evaluated the global distribution and diversity of terrestrial diazotrophic microbiome.

RESULTS

After the extensive analysis of 1,451 soil metagenomic samples, we revealed that the Anaeromyxobacteraceae and Geobacteraceae within Deltaproteobacteria are ubiquitous groups of diazotrophic microbiome in the soils with different geographic origins and land usage types, with particular predominance in anaerobic soils (paddy soils and sediments).

CONCLUSION

Our results indicate that Deltaproteobacteria is a core bacterial taxon in the potential soil nitrogen fixation population, especially in anaerobic environments, which encourages a careful consideration on deltaproteobacterial diazotrophs in understanding terrestrial nitrogen cycling. Video Abstract.

Genome Sequence and Methylation Pattern of Haloterrigena salifodinae BOL5-1, an Extremely Halophilic Archaeon from a Bolivian Salt Mine

The halophilic archaeon Haloterrigena salifodinae BOL5-1 was isolated from a Bolivian salt mine and sequenced using single-molecule real-time sequencing. The GC-rich genome was 5.1 Mbp, with a 4.2-Mbp chromosome and 5 plasmids ranging from 96 to 281 kbp. The genome annotation was incorporated into HaloWeb (https://halo.umbc.edu) and the methylation patterns into REBASE (http://rebase.neb.com).

Halophilic microbes capable of surviving extreme conditions are of interest for biotechnology and astrobiology (1–12). Our recent focus has been on high elevation and subsurface hypersaline environments, which yield polyextremophilic varieties. In this announcement, isolation of an extremely halophilic archaeon, Haloterrigena salifodinae BOL5-1, is reported, together with the first complete genome sequence for this species.

The halophilic archaeon Haloterrigena salifodinae BOL5-1 was isolated from a Bolivian salt mine and sequenced using single-molecule real-time sequencing. The GC-rich genome was 5.1 Mbp, with a 4.2-Mbp chromosome and 5 plasmids ranging from 96 to 281 kbp. The genome annotation was incorporated into HaloWeb (https://halo.umbc.edu), and the methylation patterns were incorporated into REBASE (http://tools.neb.com/genomes/view.php?seq_id=99167&list=1).