Abundance and phylogenetic distribution of eight key enzymes of the phosphorus biogeochemical cycle in grassland soils.

Grasslands are one of the most diverse and widely distributed biomes on the Earth's surface. Nutrient cycling is one of the main ecosystem services provided by grasslands. The organic fraction of phosphorus (P) represents over half of the total P in soil and is a valuable reservoir. Soil microorganisms, involved in the P cycle, mediate organic P release through three enzyme families: alkaline phosphatases, nonspecific acid phosphatases, and phytases (P-enzymes). This study aimed, through a metagenomic approach, to assess the abundance and phylogenetic distribution of prokaryotic P-enzymes in a wide distribution of grass biomes across the globe and how they are related with environmental variables. To generate a functional perspective of phosphorus cycling, 43 soil metagenomes from 17 sites/projects representing different environmental conditions were examined for eight key P-enzymes. Multivariate analyses showed that Tmax, pH and evapotranspiration were highly associated with P-enzymes abundance and diversity. In addition, they tend to respond in a correlated manner to these variables suggesting an intricate relationship of abundance and diversity between them. On the other hand, their association with the general functional profiles was more idiosyncratic.