Functional insights of novel Bathyarchaeia reveal metabolic versatility in their role in peatlands of the Peruvian Amazon

Pavia M.J.; Garber A.I.; Avalle S.; Macedo-Tafur F.; Tello-Espinoza R.; Cadillo-Quiroz H. · Microbiology Spectrum (2024) · DOI: 10.1128/spectrum.00387-24

Resumen

The decomposition of soil organic carbon within tropical peatlands is influencedby the functional composition of the microbial community. In this study, building upon our previous work, we recovered a total of 28 metagenome-assembled genomes (MAGs) classifiedas Bathyarchaeia from the tropical peatlands of the Pastaza-Marañón Foreland Basin (PMFB) in the Amazon. Using phylogenomic analyses, we identifiednine genus-level clades to have representatives from the PMFB, with four forming a putative novel family ("Candidatus Paludivitaceae") endemic to peatlands. We focus on the Ca. Paludivitaceae MAGs due to the novelty of this group and the limited understanding of their role within tropical peatlands. Functional analysis of these MAGs reveals that this putative family comprises facultative anaerobes, possessing the genetic potential for oxygen, sulfide,or nitrogen oxidation. This metabolic versatility can be coupled to the fermentation of acetoin, propanol, or proline. The other clades outside Ca. Paludivitaceae are putatively capable of acetogenesis and de novo amino acid biosynthesis and encode a high amount of Fe3+ transporters. Crucially, the Ca. Paludivitaceae are predicted to be carboxydotrophic, capable of utilizing CO for energy generation or biomass production. Through this metabolism, they could detoxify the environment from CO, a byproduct of methanogenesis, or produce methanogenic substrates like CO2 and H2. Overall, our results show the complex metabolism and various lineages of Bathyarchaeia within tropical peatlands pointing to the need to further evaluate their role in these ecosystems.

Instituciones: Universidad Nacional de la Amazonía Peruana