Prolonged grazing reduces the diversity and weakens virus-host links of metagenome-assembled viral community in acidic karst soil.

backgroundSoil viruses are fundamental yet often overlooked components of terrestrial ecosystems, where they profoundly influence microbial diversity, community assembly, and biogeochemical cycling through predator-prey dynamics and the carriage of auxiliary metabolic genes (AMGs). However, the impact of human-driven land use change on viral communities and their functional potential remains poorly understood.

resultsIn this study, we analyzed viral diversity, virus-host linkage, and functional profiles of AMGs across different land management regimes in acidic karst soil after reclamation. The results showed that both bacterial and viral communities significantly differ across the four land management regimes, which are unused land, grazing pastureland, abandoned pastureland, and fertilized grazing pastureland. Grazing led to a lower viral diversity, a decrease in lysogenic viral abundance, and fewer virus-host linkages. The diversity and function of AMGs were also significantly affected by land management regimes, with grazing leading to a reduction in both AMGs diversity and relative abundance. Furthermore, both the bacterial community and soil physiochemical properties were essential factors that shaped viral diversity and lifestyle.

conclusionsOverall, our findings indicate that inappropriate land use (long-term grazing) disrupts the virus-host balance, thereby altering the functional profiles of the soil viral community.