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

Grassland biomes provide valuable ecosystem services, including nutrient cycling. Organic phosphorus (Po) represents more than half of the total P in soils. Soil microorganisms release organic P through enzymatic processes, with alkaline phosphatases, acid phosphatases and phytases being the key P enzymes involved in the cycling of organic P. This study analysed 74 soil metagenomes from 17 different grassland biomes worldwide to evaluate the distribution and abundance of eight key P enzymes (PhoD, PhoX, PhoA, Nsap-A, Nsap-B, Nsap-C, BPP and CPhy) and their relationship with environmental factors. Our analyses showed that alkaline phosphatase phoD was the dataset's most abundant P-enzyme encoding genes, with a wide phylogenetic distribution. Followed by the acid phosphatases Nsap-A and Nsap-C showed similar abundance but a different distribution in their respective phylogenetic trees. Multivariate analyses revealed that pH, T-max, SOC and soil moisture were associated with the abundance and diversity of all genes studied. PhoD and phoX genes strongly correlated with SOC and clay, and the phoX gene was more common in soils with low to medium SOC and neutral pH. In particular, P-enzyme genes tended to respond in a positively correlated manner among them, suggesting a complex relationship of abundance and diversity among them.

Automated summary

Grassland biomes provide important ecosystem services through nutrient cycling, with organic phosphorus (Po) being a significant component of soil phosphorus. This study analyzed soil metagenomes from different grassland biomes worldwide to investigate the distribution and abundance of key P enzymes and their relationship with environmental factors. The results showed that alkaline phosphatase phoD was the most abundant P enzyme gene, followed by acid phosphatases Nsap-A and Nsap-C. pH, T-max, SOC, and soil moisture were found to be associated with the abundance and diversity of all studied genes, and the presence of certain genes correlated with specific soil properties.