bioRxiv preprint doi: https://doi.org/10.1101/2020.07.13.194282; this version posted July 13, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC 4.0 International license. Unexpected diversity of CPR bacteria and nanoarchaea in the rare biosphere of rhizosphere-associated grassland soil Alexa M. Nicolas1, Alexander L. Jaffe1, Erin E. Nuccio2, Michiko E. Taga1, Mary K. Firestone3,4, Jillian F. Banfield3,5-7* 1 Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA 2 Nuclear and Chemical Sciences Division, Lawrence Livermore National Laboratory, Livermore, CA, USA 3 Department of Environmental Science, Policy, and Management, University of California, Berkeley, Berkeley, CA 4 Earth and Environmental Sciences, Lawrence Berkeley National Laboratory, Berkeley, CA 5 Department of Earth and Planetary Science, University of California, Berkeley, Berkeley, CA 6 Chan Zuckerberg Biohub, San Francisco, CA 7 Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA * Corresponding author email:
[email protected]. Abstract Candidate Phyla Radiation (CPR) bacteria and nanoarchaea populate most ecosystems, but are rarely detected in soil. We concentrated particles less than 0.2 µm from grassland soil, enabling targeted metagenomic analysis of these organisms, which are almost totally unexplored in soil. We recovered a diversity of CPR bacteria and some nanoarchaea sequences, but no sequences from other cellular organisms. The sampled sequences include Doudnabacteria (SM2F11) and Pacearchaeota, organisms not previously reported in soil, as well as Saccharibacteria, Parcubacteria and Microgenomates.