Similar drivers but different effects lead to distinct ecological patterns of soil bacterial and archaeal communities

Bacteria and archaea play important roles in soil biogeochemical cycles and the health of terrestrial organisms. They usually coexist in various soil habitats; however, the ecological patterns of bacteria and archaea in the same soil habitats still remain unclear. Here, we compared the community features of the two domains in bulk soils under different vegetation covers. Generally, both bacterial abundance and α-diversity were higher than those of archaea, and the differences were more noticeable in agricultural soils than in non-agricultural saline soils. Compared with bacteria, the archaeal community showed more niche limitation with less widely distributed taxa. Interestingly, similar edaphic factors were correlated with both bacteria and archaea but with opposite effects, of which salinity was the most important driving factor. With the rise of salinity, bacterial α-diversity and abundance decreased, but archaeal diversity increased. Majority of the dominant bacterial taxa showed significantly negative correlation with salinity, such as Alphaproteobacteria, Betaproteobacteria, Acidobacteria and Nitrospirae. In contrast, except Thaumarchaeota, most archaeal predominant taxa from Euryarchaeota, Woesearchaeota and Nanohaloarchaeota were positively related to salinity. Furthermore, network analyses showed that not only bacteria but also considerable archaea-related nodes, edges and potential keystone taxa existed in the networks, especially in saline soils, indicating that archaea also had important positions in microbial co-occurrence networks. These results extended our understanding on the ecological patterns of prokaryotes in terrestrial ecosystems.