Soil CPR Bacteria and Nanoarchaea Rare-Biosphere Community

A rare-biosphere community of Candidate Phyla Radiation (CPR) bacteria and DPANN archaea recovered from grassland soil by concentrating particles smaller than 0.2 micrometers prior to metagenomic sequencing. CPR and DPANN sequences were enriched 100- to 1,000-fold compared to bulk soil (estimated at roughly 1 to 100 cells per gram of soil for each lineage) and include Doudnabacteria (SM2F11) and Pacearchaeota - organisms rarely reported in soil - alongside Saccharibacteria, Parcubacteria, and Microgenomates as well as Diapherotrites, Parvarchaeota, Aenigmarchaeota, Nanoarchaeota, and Nanohaloarchaeota. Most members likely live symbiotic anaerobic lifestyles, but some Saccharibacteria, Parcubacteria, and Doudnabacteria encode components of aerobic metabolism that may be particularly relevant in oxic soil habitats.