Incorporating viruses into soil ecology: A new dimension to understand biogeochemical cycling

Viruses, with an estimated abundance of 10³¹ on Earth, are an important component of soil ecosystems. As obligate parasites that entirely depend on hosts for reproduction and survival, viruses have been linked to microbial community diversity and metabolic activities in soil. Emerging evidence indicates that soil viruses influence a broad-spectrum of processes that sustain soil biodiversity, biogeochemical cycling, fertility, and plant health. Research on soil viruses is in its early stages. Even observational assessments of viral ecology such as abundance, diversity, distribution, life strategies, ecological relevance, and functions, are only just beginning to be revealed. In this review, we summarize the state of knowledge concerning the potential function(s) of soil viruses and how they likely influence microbial community composition, nutrient cycles, and carbon dynamics for example. As major drivers of microbial mortality and functioning across a wide range of spatial and temporal scales, soil viruses appear to be key regulators of cellular metabolism and microbial community properties and as well as biogeochemical processes critical to ecosystem function. We conclude that soil viruses are an indispensable component of soil ecology demanding further investigation. Defining abiotic interactions of viruses within the soil environment, revealing the virus-host interaction networks, and elucidating the roles of soil viruses in carbon and nutrient cycling are but a few of the many aspects of soil viral ecology worthy of future investigation. A more complete view of viral participation in soil food webs in the face of a changing climate will lead to improved management of soil ecosystem services and environmental sustainability.