T4-type viruses: Important impacts on shaping bacterial community along a chronosequence of 2000-year old paddy soils

There is increasing evidence to suggest that viruses may influence the succession of individual populations of microorganisms, biogeochemical cycles and, ultimately, microbial community structure. However, it is still not well understood if T4-type viruses can affect the bacterial communities of terrestrial ecosystems. Here, we report an investigation of the impact of T4-type phage and bottom-up (environmental factors) controls on bacterial community structures along a 2000-year paddy soil chronosequence. T4-type myoviral and bacterial communities were evaluated by clone sequencing and high-throughput sequencing of the gene encoding the major capsid protein (g23) and 16S ribosomal DNA, respectively. Long-term (centurial/millennial) anthropogenic managements of paddy soils resulted in an accumulation of nutrients and soil acidification. Significant shifts in soil bacterial and phage communities were detected during the development of paddy soils at millennial time scales. The Mantel test and variation partitioning analysis (VPA) suggested that the profile of bacterial community composition was strongly affected by both T4-type phage and environmental variables. Network analysis between phage and bacterial taxa indicated that six bacterial families were implicated as potential hosts of T4-type phages. These results suggest that phage lysis is important in shaping bacterial communities in the soil environment.