PDF(Pubmed)
Abstract：
Sterilization is commonly used to remove or reduce the biotic constraints of a soil to allow recolonization by soil-dwelling organisms, with autoclaving and gamma irradiation being the most frequently used approaches. Many studies have characterized sterilization impacts on soil physicochemical properties, with gamma irradiation often described as the preferred approach, despite the lower cost and higher scalability of autoclaving. However, few studies have compared how sterilization techniques impact soil recolonization by microorganisms. Here, we compared how two sterilization approaches (autoclaving; gamma irradiation) and soil washing impacted microbial recolonization of soil from a diverse soil inoculum. Sterilization method had little impact on microbial alpha diversity across recolonized soils. For sterile soil regrowth microcosms, species richness and diversity were significantly reduced by autoclaving relative to gamma irradiation, particularly for fungi. There was no impact of sterilization method on bacterial composition in recolonized soils and minimal impact on fungal composition (P = 0.05). Washing soils had a greater impact on microbial composition than sterilization method, and sterile soil regrowth had negligible impacts on microbial recolonization. These data suggest that sterilization method has no clear impact on microbial recolonization, at least across the soils tested, indicating that soil autoclaving is an appropriate and economical approach for biotically clearing soils.IMPORTANCESterilized soils represent soil-like environments that act as a medium to study microbial colonization dynamics in more \"natural\" settings relative to artificial culturing environments. Soil sterilization is often carried out by gamma irradiation or autoclaving, which both alter soil properties, but gamma irradiation is thought to be the gentler technique. Gamma irradiation can be cost prohibitive and does not scale well for larger experiments. We sought to examine how soil sterilization technique can impact microbial colonization, and additionally looked at the impact of soil washing which is believed to remove soil toxins that inhibit soil recolonization. We found that both gamma-irradiated and autoclaved soils showed similar colonization patterns when reintroducing microorganisms. Soil washing, relative to sterilization technique, had a greater impact on which microorganisms were able to recolonize the soil. When allowing sterilized soils to regrow (i.e., persisting microorganisms), gamma irradiation performed worse, suggesting that gamma irradiation does not biotically clear soils as well as autoclaving. These data suggest that both sterilization techniques are comparable, and that autoclaving may be more effective at biotically clearing soil.
摘要：
灭菌通常用于去除或减少土壤的生物约束，以允许土壤生物重新定殖，高压灭菌和γ辐照是最常用的方法。许多研究已经描述了灭菌对土壤理化性质的影响，伽马射线通常被描述为首选方法，尽管更低的成本和更高的可扩展性的高压灭菌。然而,很少有研究比较灭菌技术如何影响微生物对土壤的重新定殖。这里,我们比较了两种灭菌方法（高压灭菌；γ辐照）和土壤洗涤如何影响微生物从不同土壤接种物中重新定殖土壤。灭菌方法对重新定殖土壤中的微生物α多样性影响很小。对于无菌土壤再生缩影，相对于γ辐射，高压灭菌显著降低了物种的丰富度和多样性，特别是真菌。灭菌方法对重新定殖土壤中的细菌组成没有影响，对真菌组成的影响最小（P=0.05）。洗涤土壤对微生物组成的影响大于灭菌方法，无菌土壤再生对微生物重新定殖的影响可忽略不计。这些数据表明，灭菌方法对微生物重新定殖没有明显影响，至少在测试的土壤中，表明土壤高压灭菌是生物清除土壤的适当和经济的方法。重要的灭菌土壤代表类似土壤的环境，相对于人工培养环境，在更“自然”的环境中充当研究微生物定植动力学的媒介。土壤灭菌通常通过γ辐照或高压灭菌进行，两者都改变了土壤特性，但是伽马射线被认为是更温和的技术。伽玛辐照可能是成本高昂的，并且对于较大的实验不能很好地扩展。我们试图研究土壤灭菌技术如何影响微生物定植，并另外研究了土壤洗涤的影响，这种洗涤被认为可以去除抑制土壤重新定殖的土壤毒素。我们发现，重新引入微生物时，γ辐照和高压灭菌的土壤均显示出相似的定植模式。土壤洗涤,相对于灭菌技术，对哪些微生物能够重新定殖土壤有更大的影响。当允许无菌土壤再生时(即，持续存在的微生物)，伽马辐照表现更差，这表明γ辐照不能像高压灭菌那样生物清除土壤。这些数据表明两种灭菌技术具有可比性，高压灭菌在生物清除土壤方面可能更有效。
