Department de Biologia Animal and Institut de Recerca de la Biodiversitat (IRBio), Universitat de Barcelona (UB), Barcelona, Spain.
FEMS Microbiol Ecol. 2013 Nov;86(2):268-76. doi: 10.1111/1574-6941.12159. Epub 2013 Jul 9.
Dispersal limitation and environmental selection are the main processes shaping free-living microbial communities, but host-related factors may also play a major role in structuring symbiotic communities. Here, we aimed to determine the effects of isolation-by-distance and host species on the spatial structure of sponge-associated bacterial communities using as a model the abundant demosponge genus Ircinia. We targeted three co-occurring Ircinia species and used terminal restriction fragment length polymorphism (T-RFLP) analysis of 16S rRNA gene sequences to explore the differentiation of their bacterial communities across a scale of hundreds of kilometres in the Western Mediterranean Sea. Multivariate analysis and nonmetric multidimensional scaling plots of T-RFLP profiles showed that bacterial communities in Ircinia sponges were structured by host species and remained stable across sampling locations, despite geographic distances (80-800 km) and diverse local conditions. While significant differences among some locations were observed in Ircinia variabilis-derived communities, no correlation between geographic distance and community similarity was consistently detected for symbiotic bacteria in any host sponge species. Our results indicate that bacterial communities are mostly shaped by host species-specific factors and suggest that evolutionary processes acting on long-term symbiotic relationships have favored spatial stability of sponge-associated bacterial communities.
扩散限制和环境选择是塑造自由生活微生物群落的主要过程，但宿主相关因素也可能在共生群落的结构中起主要作用。在这里，我们旨在使用丰富的寻常海绵属 Ircinia 作为模型，确定隔离距离和宿主物种对海绵相关细菌群落空间结构的影响。我们针对三种共存的 Ircinia 物种，使用 16S rRNA 基因序列的末端限制性片段长度多态性（T-RFLP）分析来探索它们的细菌群落在西地中海数百公里范围内的分化。T-RFLP 图谱的多元分析和非度量多维尺度图显示，海绵 Ircinia 中的细菌群落由宿主物种结构，并在采样地点之间保持稳定，尽管存在地理距离（80-800 公里）和多样的局部条件。虽然在一些 Ircinia variabilis 衍生的群落中观察到了显著的差异，但在任何宿主海绵物种的共生细菌中，都没有一致检测到地理距离与群落相似性之间的相关性。我们的结果表明，细菌群落主要由宿主物种特异性因素塑造，并表明长期共生关系中作用的进化过程有利于海绵相关细菌群落的空间稳定性。
