Soil extracellular DNA fragments show variable degradation rates among sequences and environmental conditions

Soil extracellular DNA (eDNA) fragments exhibit diverse degradation rates across various sequences and environmental conditions. A team of researchers developed a method using primer-labeled DNA and microcosm incubation to measure the overall and sequence-specific degradation rates of eDNA amplicon fragments in China. The study revealed substantial differences in degradation rate constants, ranging from 0.05 to 0.16 day⁻¹, among different study sites.

These rate constants showed significant correlations with factors such as soil moisture content, prokaryotic abundance, community profiles, and mean annual precipitation. A follow-up moisture gradient microcosm experiment confirmed the impact of moisture content on overall degradation rates. Additionally, sequence-specific degradation rate constants were found to correlate with pH, nitrogen content, and mean annual temperature.

The exclusion of eDNA signals using propidium monoazide altered soil prokaryotic abundance, richness, and community profiles, with the sizes of sequence-specific extracellular 16S rRNA gene amplicon fragments directly linked to their respective degradation rates. This research introduces a new approach for determining the overall and sequence-specific degradation rates of eDNA amplicon fragments, emphasizing the significant influence of eDNA on soil microbial research and suggesting improvements for environmental DNA technologies.