Viral lifestyles link revegetation to microbial function in rare earth tailings

Vegetation restoration is a primary strategy for rehabilitating degraded mine tailings, a process critically driven by soil microorganisms. However, the role of soil viruses in regulating these microbial communities remains largely unexplored during ecosystem restoration. We compared restored and adjacent unrestored rare earth tailings sampled in 2014 and 2020 using soil physicochemical and enzyme measurements, 16S rRNA gene sequencing, metagenomics with viral genome reconstruction, and path analysis. Results showed that revegetation markedly improved soil quality, with the soil quality index increasing from 0.42 to 0.77 in restored tailings, whereas no significant change was observed in unrestored tailings. Metagenomic analyses recovered 1727 viral genomes and showed that revegetation increased viral richness by 89%, significantly reshaped viral community composition, and increased the proportion of lytic viruses from 27% in unrestored tailings to 48% in restored tailings. These viral shifts were accompanied by bacterial community reassembly, higher abundance of genes involved in cellulose, hemicellulose, peptidoglycan and chitin degradation, and enhanced activities of carbon- and phosphorus-acquiring enzymes. Virus-host analyses further identified lineage-specific infection regimes, with Acidobacteriota-associated viruses showing the highest lytic proportion. Path modeling indicated that shifts in viral lifestyles influenced bacterial community reassembly and extracellular enzyme activity, ultimately contributing to soil quality improvement during the revegetation of rare earth tailings. These findings indicate that viral life-strategy shifts represent an important feature of microbial functional recovery in revegetated rare earth tailings and may constitute a key pathway through which revegetation improves soil quality.