Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental Sciences, China Agricultural Universitygrid.22935.3f, Beijing, China.
College of Land Science and Technology, China Agricultural Universitygrid.22935.3f, Beijing, China.
mSystems. 2022 Aug 30;7(4):e0035222. doi: 10.1128/msystems.00352-22. Epub 2022 Jul 26.
The gradual accumulation of microplastics has aroused increasing concern for the unique niche, termed "plastisphere." As research so far has focused on their characteristics in aquatic ecosystems, our understanding of the colonization and assembly of the attached bacterial communities on microplastics in soil ecosystems remains poor. Here, we aimed to characterize the plastisphere microbiomes of two types of microplastics (polylactic acid [PLA] and polyethylene [PE]) differing in their biodegradability in two different soils. After incubation for 60 days, considerably lower alpha diversity of bacterial community was observed on the microplastic surfaces, and prominent divergences occurred in the microbial community compositions between the plastisphere and the bulk soil. The temperature, rather than polymer type, significantly induced the differences between the plastisphere communities. The rRNA gene operon () copy numbers were significantly higher in the PLA plastisphere, suggesting potential degradation. The co-occurrence network analysis showed that the PE plastisphere exhibited greater network complexity and stronger stability than those in the PLA plastisphere. The stochasticity ratio indicated the remarkable importance of stochastic process on community assembly in PE and PLA plastispheres, while the null model analysis showed the nonnegligible roles of deterministic processes in shaping the plastisphere communities. Higher contributions of homogenous selection in the PLA plastisphere were observed in comparison with the PE plastisphere, which could probably be attributed to the selective pressure induced by microplastic degradation. Our findings enhance our mechanistic understanding of the diversity patterns and assembly processes of plastisphere in soil environments and have important implications for microbial ecology and microplastic risk assessment. The increasing pervasive microplastic pollution is creating a new environmental compartment, termed plastisphere. Even though there was conclusive information characterizing the plastisphere, the underlying mechanisms shaping the bacterial communities in the plastisphere in the soil remain unclear. Therefore, we incubated two types of microplastics (PE and PLA) in two different soils and explored the differences between plastisphere and bulk soil communities. Additionally, the co-occurrence network and the assembly processes of plastisphere were subjected to further analysis. Our results highlight the importance of selective recruitment of microplastics and contribute to the understanding of the diversity patterns and assembly processes of plastisphere in soil environments.
微塑料的逐渐积累引起了人们对独特小生境“塑料圈”的日益关注。由于目前的研究主要集中在水生生态系统中它们的特征上，我们对土壤生态系统中附着在微塑料上的细菌群落的定殖和组装的理解仍然很差。在这里，我们旨在描述两种类型的微塑料（聚乳酸[PLA]和聚乙烯[PE]）在两种不同土壤中的生物降解性对塑料圈微生物组的影响。经过 60 天的培养，微塑料表面的细菌群落的 alpha 多样性明显较低，微生物群落组成在塑料圈和土壤本体之间出现明显分歧。温度，而不是聚合物类型，显著诱导了塑料圈群落之间的差异。PLA 塑料圈的 rRNA 基因操纵子()拷贝数明显较高，表明可能发生了降解。共现网络分析表明，PE 塑料圈表现出比 PLA 塑料圈更大的网络复杂性和更强的稳定性。随机比表明，在 PE 和 PLA 塑料圈中，群落组装过程中随机过程的重要性显著。零模型分析表明，确定性过程在塑造塑料圈群落方面也起着不可忽视的作用。与 PE 塑料圈相比，PLA 塑料圈中同质选择的贡献更高，这可能归因于微塑料降解引起的选择压力。我们的研究结果增强了我们对土壤环境中塑料圈多样性模式和组装过程的机制理解，并对微生物生态学和微塑料风险评估具有重要意义。日益普遍的微塑料污染正在创造一个新的环境隔室，称为塑料圈。尽管已经有确凿的信息描述了塑料圈，但在土壤中塑造塑料圈内细菌群落的潜在机制仍不清楚。因此，我们将两种类型的微塑料（PE 和 PLA）在两种不同的土壤中进行了孵育，并探索了塑料圈与土壤本体群落之间的差异。此外，还对塑料圈的共现网络和组装过程进行了进一步分析。我们的研究结果强调了微塑料选择性招募的重要性，并有助于理解土壤环境中塑料圈的多样性模式和组装过程。
