Impact of soil viruses on C emissions can be enhanced by viral shuttle processes in soil

Abstract

Soil viruses can greatly influence both microbial catabolism and anabolism. Understanding such influences is crucial for unraveling the fate of soil organic carbon (C). However, previous studies on soil viruses have primarily focused on their role in soil C loss, overlooking their role in C sequestration. In this study, soil viruses and microbes were introduced into sterilized samples of crop and forest soils from typical red and brown soil regions of China to examine the effects of soil viruses on C dynamics, from the perspective of C release and retention. The results showed that the viral effects on soil C emissions varied between soil types. However, they significantly enhanced the accumulation of recalcitrant dissolved and metal-bound organic C, which in turn reinforced the viral effects on C emissions. Furthermore, the accumulation of dissolved and metal-bound organic C was always associated with the microbial utilization of dissolved organic nitrogen (N), highlighting the coupled C and N cycling during the viral shuttle process. Our research demonstrates for the first time the virus-mediated coupling of C and N cycling in soils and the dual role of viruses in soil C release and stabilization, providing a new understanding of virus-driven soil C cycling.