Genome analysis and description of Tunturibacter gen. nov. expands the diversity of Terriglobia in tundra soils.

Increased temperatures in Arctic tundra ecosystems are leading to higher microbial respiration rates of soil organic matter, resulting in the release of carbon dioxide and methane. To understand the effects of this microbial activity, it is important to better characterize the diverse microbial communities in Arctic soil. Our goal is to refine our understanding of the phylogenetic diversity of Terriglobia, a common but elusive group within the Acidobacteriota phylum. This will help us link this diversity to variations in carbon and nitrogen usage patterns. We used long-read Oxford Nanopore MinION sequences in combination with metagenomic short-read sequences to assemble complete Acidobacteriota genomes. This allowed us to build multi-locus phylogenies and annotate pangenome markers to distinguish Acidobacteriota strains from several tundra soil isolates. We identified a phylogenetic cluster containing four new species previously associated with Edaphobacter lichenicola. We conclude that this cluster represents a new genus, which we have named Tunturibacter. We describe four new species: Tunturibacter lichenicola comb. nov., Tunturibacter empetritectus sp. nov., Tunturibacter gelidoferens sp. nov., and Tunturibacter psychrotolerans sp. nov. By uncovering new species and strains within the Terriglobia and improving the accuracy of their phylogenetic placements, we hope to enhance our understanding of this complex phylum and shed light on the mechanisms that shape microbial communities in polar soils.