The common reed (Phragmites australis), a cosmopolitan aquatic macrophyte, plays an important role in the structure and function of aquatic ecosystems. We compared bacterial community compositions (BCCs) and their assembly processes in the root-associated compartments (i.e., rhizosphere and endosphere) of reed and bulk sediment between summer and winter. The BCCs were analyzed using high-throughput sequencing of the bacterial 16S rRNA gene; meanwhile, null-model analysis was employed to characterize their assembly mechanisms. The sources of the endosphere BCCs were quantitatively examined using SourceTracker from bulk sediment, rhizosphere, and seed. We observed the highest α-diversity and the lowest β-diversity of BCCs in the rhizosphere in both seasons. We also found a significant increase in α- and β-diversity in summer compared to that in winter among the three compartments. It was demonstrated that rhizosphere sediments were the main source (∼70%) of root endosphere bacteria during both seasons. Null-model tests indicated that stochastic processes primarily affected endosphere BCCs, whereas both deterministic and stochastic processes dictated bacterial assemblages of the rhizosphere, with the relative importance of stochastic versus deterministic processes depending on the season. This study suggests that multiple mechanisms of bacterial selection and community assembly exist both inside and outside P. australis roots in different seasons.

中文翻译：

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不同季节芦苇根相关细菌群落多样性和群落组装的相反模式。

常见的芦苇（芦苇）），一种世界性水生植物，在水生生态系统的结构和功能中起着重要作用。我们比较了夏季和冬季之间芦苇和大量沉积物与根相关的区室（即根际和内层区）中的细菌群落组成（BCC）及其组装过程。使用细菌16S rRNA基因的高通量测序分析了BCC；同时，采用空模型分析来表征其组装机理。使用SourceTracker对散装沉积物，根际和种子中的内圈BCC来源进行了定量检查。我们观察到在两个季节中，根际中BCC的α多样性最高，β多样性最低。我们还发现，与三个冬季相比，夏季的α和β多样性显着增加。结果表明，在两个季节中，根际内细菌的根源都是根际沉积物（约占70％）。零模型测试表明，随机过程主要影响内层球囊BCC，而确定性过程和随机过程都决定了根际细菌的组合，随机性与确定性过程的相对重要性取决于季节。这项研究表明内部和外部都存在多种细菌选择和群落聚集的机制 随机性和确定性过程的相对重要性取决于季节。这项研究表明内部和外部都存在多种细菌选择和群落聚集的机制 随机性和确定性过程的相对重要性取决于季节。这项研究表明内部和外部都存在多种细菌选择和群落聚集的机制南极体育根源不同的季节。