Centre for Limnology, Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Tartu County, Estonia.
Department of Biological Oceanography, Leibniz Institute for Baltic Sea Research Warnemünde (IOW), Rostock, Germany.
Microbiologyopen. 2024 Jun;13(3):e13. doi: 10.1002/mbo3.1413.
The factors that influence the distribution of bacterial community composition are not well understood. The role of geographical patterns, which suggest limited dispersal, is still a topic of debate. Bacteria associated with hosts face unique dispersal challenges as they often rely on their hosts, which provide specific environments for their symbionts. In this study, we examined the effect of biogeographic distances on the bacterial diversity and composition of bacterial communities in the gastrointestinal tract of Ampullaceana balthica. We compared the effects on the host-associated bacterial community to those on bacterial communities in water and sediment. This comparison was made using 16S ribosomal RNA gene sequencing. We found that the bacterial communities we sampled in Estonia, Denmark, and Northern Germany varied between water, sediment, and the gastrointestinal tract. They also varied between countries within each substrate. This indicates that the type of substrate is a dominant factor in determining bacterial community composition. We separately analyzed the turnover rates of water, sediment, and gastrointestinal bacterial communities over increasing geographic distances. We observed that the turnover rate was lower for gastrointestinal bacterial communities compared to water bacterial communities. This implies that the composition of gastrointestinal bacteria remains relatively stable over distances, while water bacterial communities exhibit greater variability. However, the gastrointestinal tract had the lowest percentage of country-specific amplicon sequence variants, suggesting bacterial colonization from local bacterial communities. Since the overlap between the water and gastrointestinal tract was highest, it appears that the gastrointestinal bacterial community is colonized by the water bacterial community. Our study confirmed that biogeographical patterns in host-associated communities differ from those in water and sediment bacterial communities. These host-associated communities consist of numerous facultative symbionts derived from the water bacterial community.
影响细菌群落组成分布的因素尚不清楚。地理模式的作用——暗示有限的扩散——仍然是一个争论的话题。与宿主相关的细菌面临着独特的扩散挑战，因为它们通常依赖于宿主，而宿主为它们的共生体提供了特定的环境。在这项研究中，我们研究了生物地理距离对 Ampullaceana balthica 胃肠道细菌多样性和组成的影响。我们比较了宿主相关细菌群落与水和沉积物中细菌群落的影响。这是通过 16S 核糖体 RNA 基因测序来完成的。我们发现，我们在爱沙尼亚、丹麦和德国北部采样的细菌群落，在水、沉积物和胃肠道之间存在差异。它们在每个基质的国家之间也存在差异。这表明基质的类型是决定细菌群落组成的主要因素。我们分别分析了水、沉积物和胃肠道细菌群落随地理距离增加的周转率。我们观察到，与水细菌群落相比，胃肠道细菌群落的周转率较低。这意味着胃肠道细菌的组成在距离上相对稳定，而水细菌群落则表现出更大的可变性。然而，胃肠道的特有扩增子序列变体比例最低，这表明细菌从当地的细菌群落中定植。由于水和胃肠道之间的重叠度最高，似乎胃肠道细菌群落是由水细菌群落定植的。我们的研究证实，宿主相关群落中的生物地理模式与水和沉积物细菌群落中的模式不同。这些宿主相关的群落由来自水细菌群落的大量兼性共生体组成。
