Warming increases viral diversity and the relative abundance of virulent viruses in deep soils

Abstract

Viruses are diverse and functionally significant members of the soil community, but how they respond to climate warming remains underexplored, especially in deeper soil layers. Here, we utilized a whole-soil-profile warming experiment (∼4 °C above ambient across the top 1 m of soil) in an alpine grassland to investigate how warming influences soil viral diversity and potential activity across different soil depths. Through the integration of short- and long-read metagenomics with viromics, we discovered numerous novel viruses. Additionally, our findings revealed that after 5 years of warming, viral diversity decreased in surface soils but increased in deeper soils, mirroring but accentuating changes in host diversity. Warming increased the relative abundance of virulent viruses, possibly due to the alleviation of nutrient limitations. This study revealed the depth-dependent responses of soil viruses to climate warming, suggesting that deeper soils may become hotspots for viral diversity and activity under warming scenarios.