Obscure soil microbes and where to find them.

Many soil bacteria and fungi remain unclassified at the highest taxonomic ranks (e.g. phyla level), which hampers our ability to assess the ecology and functional capabilities of these soil organisms in terrestrial ecosystems globally. The first logical step toward the classification of these unknown soil taxa is to identify potential locations on Earth where these unclassified bacteria and fungi are feasibly most prevalent. To do this, here I used data from a global soil survey across 235 locations, including amplicon sequencing information for fungal and bacterial communities, and generated global atlases highlighting those soils where the percentages of taxa of bacteria and fungi with an unknown phyla are expected to be more prevalent. Results indicate that soil samples with the largest percentage of fungal taxa with an unknown phyla can be found in dry forests and grasslands, while those with the largest percentage of bacterial taxa with an unknown phyla are found in boreal and tropical forests. This information can be used by taxonomists and microbiologists to target these potentially new soil taxa.