Contrasting Euryarchaeota communities between upland and paddy soils exhibited similar pH-impacted biogeographic patterns

Euryarchaeota, as an important and ubiquitous Archaea phylum, contributes substantially to global energy cycling. However, there is a considerable lack of knowledge regarding their biogeographic patterns in terrestrial ecosystems. Here barcoded pyrosequencing was employed to compare the relative abundance, diversity and community composition of Euryarchaeota in 92 soil samples, collected from a variety of ecosystem types. A total of 96,534 euryarchaeal sequences were classified from pyrosequencing of the archaeal 16S rRNA gene, comprising 22.5% of the total archaeal sequences detected. Paddy soils harbored contrasting Euryarchaeota communities from upland soils (including cropland, grassland, forest, and tea orchard soil), at all taxonomic resolutions from phylum to genus level. Within upland soils, the relative abundance of Euryarchaeota in Archaea, and Euryarchaeota operational taxonomic unit (OTU) richness are significantly influenced by soil pH and H2O%. Similar observations held true for the beta diversity patterns, with soil pH and H2O% best explaining the variance of the pairwise Bray-Curtis dissimilarity. By comparison, within paddy soils, the Euryarchaeota abundance in Archaea, and the alpha and beta diversity patterns, could be best predicted along the gradients of soil pH and NH4+-N. These findings were further corroborated by the evident pH-, H2O%- or NH4+-N-associated distributions of several major Euryarchaeota orders. Taken together, our results emphasized the significant importance of soil pH as the prevailing environmental factor in shaping the terrestrial Euryarchaeota.