Sustained soil-to-soil contact as a new approach to experimental microbiome transfer

The reproducible transfer of microbiomes between soils would greatly facilitate controlled investigations of soil microbial ecology, microbiome impacts on soil function and health, and plant-microbiome interactions. Although a variety of approaches to soil microbiome transfer are described in the literature, a common method involves directly diluting the source soil into a sterile recipient soil at various concentrations. In addition to transferring microorganisms, this approach also transfers soils particles and compounds from the source soil, proportional to the amount of soil transferred, which can make it difficult to determine the impact of soil characteristics on the resulting microbiome structure or plant-microbiome interactions. Transferring a low percentage of source soil also results in low microbial diversity in the recipient soil. In this study, we used 16s rRNA amplicon sequencing to explore the use of prolonged contact between source and recipient soils across membrane filters as an approach to microbiome transfer, and contrast this with the direct transfer of soil at two concentrations from three different source soils.

实现土壤间微生物组（microbiome）的可重复转移，将极大推动土壤微生物生态学、微生物组对土壤功能与健康的调控效应，以及植物-微生物组互作等领域的可控性研究。尽管现有文献已报道多种土壤微生物组转移策略，但主流方法是将源土壤以不同浓度直接稀释至无菌受体土壤中。该方法在转移微生物的同时，还会按转移比例同步带入源土壤的颗粒与有机组分，这会使得研究者难以厘清土壤特性对最终微生物组结构或植物-微生物组互作的真实影响。此外，低比例源土壤转移还会导致受体土壤的微生物多样性水平显著偏低。本研究采用16S rRNA扩增子测序（16s rRNA amplicon sequencing）技术，探究通过滤膜实现源土壤与受体土壤长时间接触的微生物组转移方案，并将其与从三种不同源土壤中以两种浓度直接进行土壤转移的效果开展对比分析。