Environmental DNA is made-up of intracellular (iDNA) and extracellular (eDNA) pools. In soils, eDNA can be present up to 40% and could distort the assessment of living microorganisms. Distribution of microbial community is inconsistent among different size-aggregates, and the persistence and turnover of eDNA are thus uneven. Uneven persistence and distribution of eDNA could lead to heterogeneity in community analysis biases that arise due to eDNA sequences at micro-scale distribution. Here, we investigated the diversity and structure of eDNA and iDNA bacterial communities in bulk soil and different size-aggregates. Significant differences were observed between eDNA and iDNA bacterial diversity and composition. Changes in community composition are more important than the amount of eDNA to assess the biases caused by eDNA in community analysis. Furthermore, variations were also observed in aggregates-levels for eDNA and iDNA community which indicates that colonization pattern of iDNA community and protection of eDNA through absorbance on particle surface within soil-matrix is heterogeneous. Our work provides empirical evidence that eDNA presence could mask the detection of aggregates-level spatial dynamics in soil microbial community and have potential to qualitatively baffle observed live effects of given treatment by adequately muting the actual response dynamics of the soil microbiome.

中文翻译：

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细胞外 DNA 会阻碍土壤细菌群落的评估，但影响随微观空间分布而变化

环境 DNA 由细胞内 (iDNA) 和细胞外 (eDNA) 池组成。在土壤中，eDNA 的含量最高可达 40%，并且可能会影响对活微生物的评估。不同大小聚集体之间微生物群落的分布不一致，因此 eDNA 的持久性和周转不均匀。eDNA 的不均匀持久性和分布可能导致由于微尺度分布的 eDNA 序列而产生的群落分析偏差的异质性。在这里，我们研究了大块土壤和不同大小聚集体中 eDNA 和 iDNA 细菌群落的多样性和结构。在 eDNA 和 iDNA 细菌多样性和组成之间观察到显着差异。群落组成的变化比 eDNA 的数量更重要，以评估 eDNA 在群落分析中造成的偏差。此外，还观察到 eDNA 和 iDNA 群落的聚集体水平的变化，这表明 iDNA 群落的定植模式和通过土壤基质内颗粒表面吸收对 eDNA 的保护是异质的。我们的工作提供了经验证据，表明 eDNA 的存在可以掩盖土壤微生物群落中聚集体水平空间动态的检测，并有可能通过充分减弱土壤微生物组的实际响应动态来定性地阻碍观察到的给定处理的生活效果。