Relationships between nitrogen-specific genes and soil potentials are more complex than single linear ones

Abstract

Linkages between soil potentials and microbial functional genes are central in microbial ecology, though conflicting results have been obtained. Here, we investigated such linkages for log-transformed abundances of nitrogen (N) genes from grassland soils. The soil nitrification potential increased with rising A-amoA abundance only after it reaching 8.49 × e10 copy numbers g−1 soil, while the denitrification potential was positively correlated with narG and nirS after 8.44 × e10 and 8.12 × e10 copy numbers g−1 soil, respectively. Moreover, nitrification potential increased with rising ratio of A-amoA/B-amoA more strongly with a higher R2 after a threshold of 5.94, indicating that A-amoA controlled corresponding potential when it was abundant enough to overwhelm B-amoA. Our evaluation revealed the complexity between specific N genes and soil potentials, which were far from single linear relationships and abundant enough genes are necessary to correlate positively with corresponding functional potentials.