Silver and silver nanoparticles (AgNPs) are extensively used as antimicrobial agents in various products and consequently enter the soil ecosystem, in which they accumulate and can have adverse effects on above and belowground organisms. Since the composition of the soil microbiome could have a significant impact on soil fertility, we focused, in this study, on the effect of AgNPs on soil microbial communities. We evaluated the biomass, plant growth-promoting activities, and microbial genetic (taxonomical) and functional diversity in the soil and the “soil-plant” system using chemical, microbiological, and molecular biological methods, especially qPCR, RFLP, and REP-PCR. By compiling the results of the applied assays, we were able to correlate the changes in genetic diversity with the changes in functional diversity and their impact on the composition of soil organic matter. The effect of AgNPs was predominantly dose-dependent, whereas the concentration 100 mg kg_dw⁻¹ had the highest effect on all followed parameters. From the taxonomical point of view, AgNPs had the most significant impact on the relative abundance of Bacteroidetes, which increased in a dose-dependent manner, and Firmicutes, which decreased in a dose-dependent manner, and they caused the predominance of Ascomycota among Fungi. These changes in taxonomic diversity result in a significant decrease in the functional diversity of the microbial communities. Especially for the concentration 100 mg kg_dw⁻¹, we detected a significant decrease in the ability of the microbial community to utilize simple carbon substrates, determined by Biolog EcoPlates. We detected also a significant alteration in enzyme activity. The activity of enzymes responsible for depolymerization of complex organic matter was in a dose-dependent manner increased, whereas the highest activity reach samples amended with AgNPs at 100 mg kg_dw⁻¹. All these changes result in the accumulation of simple organic matter, which could increase osmotic pressure and have severe consequences on soil fertility. In amended soils, we detected alterations of activity of plant growth-promoting bacteria, specifically in the production of indole-3-acetic acid, 1-aminocyclopropane-1-carboxylic acid deaminase, and siderophores. All these activities are related to mitigating abiotic stress. The presence of plants in experimental soil had both a mitigating and deepening effect on the toxicity of AgNPs. Both effects probably relate to the influence of AgNPs on the selection of different microbial communities in the soil and the “soil-plant” system.

银和银纳米粒子 (AgNPs) 被广泛用作各种产品中的抗菌剂，因此会进入土壤生态系统，在其中积累并对地上和地下生物产生不利影响。由于土壤微生物组的组成可能对土壤肥力产生显着影响，因此我们在本研究中重点关注 AgNPs 对土壤微生物群落的影响。我们使用化学、微生物学和分子生物学方法，特别是 qPCR、RFLP 和 REP-PCR，评估了土壤和“土壤-植物”系统中的生物量、植物生长促进活性以及微生物遗传（分类）和功能多样性. 通过汇编应用分析的结果，我们能够将遗传多样性的变化与功能多样性的变化及其对土壤有机质组成的影响联系起来。AgNPs 的作用主要是剂量依赖性的，而浓度为 100 mg kg_dw ^-1对所有跟随参数的影响最大。从分类学的角度来看，AgNPs 对拟杆菌的相对丰度影响最显着，呈剂量依赖性增加，厚壁菌门的相对丰度呈剂量依赖性减少，它们导致子囊菌在真菌中占优势。 . 分类多样性的这些变化导致微生物群落功能多样性的显着下降。特别是对于浓度为 100 mg kg _dw ^-1，我们检测到微生物群落利用简单碳底物的能力显着降低，由 Biolog EcoPlates 确定。我们还检测到酶活性的显着变化。负责复杂有机物解聚的酶的活性以剂量依赖性方式增加，而最高活性达到用 100 mg kg _dw ^{-1 的}AgNPs 修正的样品. 所有这些变化都会导致简单有机物质的积累，这可能会增加渗透压并对土壤肥力产生严重影响。在改良的土壤中，我们检测到植物生长促进细菌的活性发生了变化，特别是在吲哚-3-乙酸、1-氨基环丙烷-1-羧酸脱氨酶和铁载体的产生中。所有这些活动都与减轻非生物胁迫有关。实验土壤中植物的存在对 AgNPs 的毒性具有缓解和深化作用。这两种影响可能都与 AgNPs 对土壤和“土壤-植物”系统中不同微生物群落选择的影响有关。