Department of Animal Biology, University of Barcelona, Diagonal Avenue 643, 08028, Barcelona, Spain.
Microb Ecol. 2013 Aug;66(2):437-47. doi: 10.1007/s00248-013-0215-2. Epub 2013 Mar 26.
Research on sponge microbial assemblages has revealed different trends in the geographic variability and specificity of bacterial symbionts. Here, we combined replicated terminal-restriction fragment length polymorphism (T-RFLP) and clone library analyses of 16S rRNA gene sequences to investigate the biogeographic and host-specific structure of bacterial communities in two congeneric and sympatric sponges: Ircinia strobilina, two color morphs of Ircinia felix and ambient seawater. Samples were collected from five islands of the Bahamas separated by 80 to 400 km. T-RFLP profiles revealed significant differences in bacterial community structure among sponge hosts and ambient bacterioplankton. Pairwise statistical comparisons of clone libraries confirmed the specificity of the bacterial assemblages to each host species and differentiated symbiont communities between color morphs of I. felix. Overall, differences in bacterial communities within each host species and morph were unrelated to location. Our results show a high degree of symbiont fidelity to host sponge across a spatial scale of up to 400 km, suggesting that host-specific rather than biogeographic factors play a primary role in structuring and maintaining sponge-bacteria relationships in Ircinia species from the Bahamas.
海绵微生物组合的研究揭示了细菌共生体在地理变异性和特异性方面的不同趋势。在这里，我们结合了复制的末端限制性片段长度多态性（T-RFLP）和 16S rRNA 基因序列克隆文库分析，调查了两种同属和同域海绵：Ircinia strobilina、Ircinia felix 的两种颜色形态和周围海水中细菌群落的生物地理和宿主特异性结构。样本取自巴哈马群岛的五个岛屿，这些岛屿之间的距离为 80 至 400 公里。T-RFLP 图谱显示海绵宿主和周围浮游细菌之间的细菌群落结构存在显著差异。克隆文库的成对统计比较证实了细菌组合对每个宿主物种的特异性，并区分了 I. felix 的颜色形态之间的共生体群落。总体而言，每个宿主物种和形态内的细菌群落差异与位置无关。我们的研究结果表明，在高达 400 公里的空间尺度上，共生体对宿主海绵具有高度的保真度，这表明宿主特异性而非生物地理因素在巴哈马群岛的 Ircinia 物种中构建和维持海绵-细菌关系方面发挥着主要作用。
