A novel method to monitor the biological soil crust reactivation by flow cytometry, and metagenomic analysis of its viral community

Viruses are the most abundant biological entities in all ecosystems worldwide. Their ubiquity and dominance on the planet are a measure of their role on the microbial ecology and biogeochemical cycles. In the biological soil crusts (BSC), which are the most important hotspots of microbial evolution and nutrient fluxes in drylands, their the role of viruses remained undefined until recently. Here we present an innovative method, based on flow cytometry (FCM) and biological markers, to monitor the viable cells in the reactivated BSC under controlled hydration, temperature and light/dark exposure. The BSCs reactivation is was aimed to isolate the associated virus-like particles (VLPs) through a tangential flow filtration and cesium chloride ultracentrifugation steps, followed by DNA extraction and shotgun metagenomic virome analysis. A novel biotech-approach, linking microbial community reactivation with to the virus VLPs extraction and characterization, was developed. This study addresses for the first time a complete description of the BSC-associated virome, shedding the light on the viral abundance, diversity, virus-host interactions and on the microbial genes mobilization in the complex soil matrix.