Viruses are expected to be pivotal members of soil ecosystems, and recent advances in viral size fraction metagenomic (viromic) approaches have improved our ability to interrogate soil viral ecology. However, viromics relies on extraction buffers to effectively desorb viral particles from the soil matrix for downstream analysis, and viral extraction efficiency could be affected by the interplay between viral particles, soils, and extraction buffer chemistry. Here, we investigated whether extraction buffer chemistry affected extractable viral community composition measured by viromics from different soil types, for both biological (samples collected 1 m apart) and technical (subsamples from the same soil homogenate) replicates. We investigated pH manipulation of protein-supplemented phosphate-buffered saline buffer (PPBS, pHs 4.5, 5.5, 6.5, and 7.5) on forest, grassland and wetland soils that exhibited different soil edaphic properties, and we tested different buffer chemistries (PPBS, Carbonated Buffer, Glycine, and Saline Magnesium) on just the wetland soil. Spatial distance (i.e., biological replicate) was the primary driver of extractable viral community composition across all buffers and soils tested. Differences in viral community composition according to extraction buffer properties were only observed in the grassland technical replicates at PPBS buffer pH 4.5, and in both the wetland technical and biological replicates treated with different buffer chemistries, but the effects of buffer chemistry were secondary to spatial distance in the biological replicates. The lack of buffering capacity in the grassland soil technical replicates likely increased sorption of viral particles at pH 4.5, but neither protein composition nor isoelectric point explained this phenomenon. Given that most soil viral ecological studies to date include sample collection over distances much farther apart than the 1-m distances considered here, results suggest that extraction buffer chemistry is likely of much lower importance than ecological considerations, such as spatial distance, in the design of future soil viral ecological investigations.

中文翻译：

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探索病毒颗粒、土壤和提取缓冲液的理化特性及其对可提取病毒群落的影响

病毒预计将成为土壤生态系统的关键成员，病毒大小分数宏基因组（病毒组）方法的最新进展提高了我们研究土壤病毒生态学的能力。然而，病毒组学依赖于提取缓冲液来有效地从土壤基质中解吸病毒颗粒以进行下游分析，并且病毒提取效率可能会受到病毒颗粒、土壤和提取缓冲液化学之间的相互作用的影响。在这里，我们研究了提取缓冲液化学成分是否影响通过病毒组学从不同土壤类型测量的可提取病毒群落组成，对于生物（相距 1 m 采集的样品）和技术（来自同一土壤匀浆的子样品）重复。我们研究了对森林、草原和湿地土壤表现出不同土壤特性的蛋白质补充磷酸盐缓冲盐水缓冲液（PPBS，pH 4.5、5.5、6.5 和 7.5）的 pH 操作，并测试了不同的缓冲液化学成分（PPBS、碳酸化缓冲液）。缓冲液、甘氨酸和盐水镁）仅适用于湿地土壤。空间距离（即生物复制）是所有测试的缓冲液和土壤中可提取病毒群落组成的主要驱动因素。仅在 PPBS 缓冲液 pH 4.5 的草原技术重复中以及在用不同缓冲液化学物质处理的湿地技术和生物重复中观察到根据提取缓冲液特性的病毒群落组成的差异，但缓冲液化学的影响次要于空间距离在生物复制中。草原土壤缺乏缓冲能力，技术上复制了 pH 4.5 时病毒颗粒吸附的增加，但蛋白质组成和等电点都无法解释这种现象。鉴于迄今为止大多数土壤病毒生态研究都包括比此处考虑的 1 米距离更远的样本收集，结果表明，在设计中，提取缓冲液化学物质的重要性可能远低于生态考虑因素（例如空间距离）未来土壤病毒生态调查。