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Viruses are distributed across the globe, but the soil virome remained relatively understudied compared to the aquatic ecosystems. Land use changes are profoundly affecting the diversity of soil microbes that are vital for soil health, but the response of soil viral communities has not been systematically explored. Here we investigated the ecological patterns of soil viral communities across various land use types encompassing forest, agricultural, and urban soil. We recovered 59,626 viral populations (VPs) via size-fractioned viromic approach with additional mitomycin treatment to induce virus release from bacterial fraction. Significantly different profiles of viral communities were observed among land use types rather than geographic locations. Soil pH was one of the major determinants of viral community structures, and was strongly associated with the changes of in-silico predicted host ranges of soil VPs. Habitat disturbance and variation of soil moisture potentially contributed to the dynamics of lysogenic VPs. Microdiversity analysis implied diverse origins of the ubiquitous VPs across land use types, while, selection act on soil VPs, resulting in strong speciation of soil viral communities upon land use types. These findings provide mechanistic understandings of the ecology and evolution of soil viral communities and their associated ecosystem services in changing environments.

Denitrification is a vital link in the global bio-nitrogen cycle. Here, we isolated a strain (M9-3-2T) that is a novel benzo[a]pyrene (BaP)-tolerant, anaerobic and aerobic denitrifying bacterium from a continuous BaP-enrichment cultured mangrove sediment. In silico comparative genomics and taxonomic analysis clearly revealed that strain M9-3-2T (=MCCC 1K03313T=JCM 32045T) represents a novel species of a novel genus named as Nitrogeniibacter mangrovi gen. nov., sp. nov., belonging to family Zoogloeaceae , order Rhodocyclales . In addition, the species Azoarcus pumilus is transferred into genus Aromatoleum and named Aromatoleum pumilum comb. nov. The predominant respiratory quinone of strain M9-3-2T was ubiquinone-8 and the major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, three unidentified phospholipids and three unidentified aminophospholipids. In this study, the capacity of strain M9-3-2T to eliminate nitrate was detected under anaerobic and aerobic conditions, and the removal rates of nitrate were 6.1×10−6 µg N/l/h/cell and 3×10−7 µg N/l/h/cell, respectively. Our results suggested that strain M9-3-2T could play an important role in the nitrogen removal regardless of the presence of oxygen in natural or/and man-made ecosystems.