Calcium Exerts a Strong Influence upon Phosphohydrolase Gene Abundance and Phylogenetic Diversity in Soil

The mechanisms by which microbial communities maintain functions within the context of changing environments are key to a wide variety of environmental processes. In soil, these mechanisms support fertility. Genes associated with hydrolysis of organic phosphoesters represent an interesting set of genes with which to study maintainance of function in microbiomes, since they participate in the same process and so in many respects are interchangeable. Here, we shown that the richness of ecotypes for each gene varies considerably in response to organic manuring and various inorganic fertilizer combinations . We show, at unprecedented phylogenetic resolution, that phylogenetic diversity of phosphohydrolase genes are more responsive to soil management and edaphic factors than the taxonomic biomarker 16S rRNA gene. Available phosphorus exerted no significant influence on gene distribution: instead we observed gene niche separation according to soil pH and exchangeable calcium. We infer a degree of competition between genes, ensuring that a gene most optimally adapted to the prevailing edaphic factors spreads through the population, thus maintaining microbiome function.