Morrow Kathleen M, Tedford Abbey Rose, Pankey M Sabrina, Lesser Michael P
Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH 03824, USA.
School of Marine Science and Ocean Engineering, University of New Hampshire, Durham, NH 03824, USA.
FEMS Microbiol Ecol. 2018 Apr 1;94(4). doi: 10.1093/femsec/fiy030.
Symbiotic associations with subcuticular bacteria (SCB) have been identified and studied in many echinoderms, including the SCB of the brooding brittle star, Amphipholis squamata. Previous studies on the SCB of A. squamata placed the isolated bacterium, designated as AS1, in the genus Vibrio (Gammaproteobacteria), but subsequent studies suggested that the SCB of echinoderms belong to the Alphaproteobacteria. This study examines the taxonomic composition of SCB associated with A. squamata from the Northwest Atlantic using the 16S rRNA gene and next generation sequencing. Results show the presence of a single dominant bacterial type, within the Roseobacter clade, family Rhodobacteraceae, which composes 70%-80% of the A. squamata microbiome. These Rhodobacteraceae sequences were identified as members of the genus Octadecabacter. Additionally, the original isolate, AS1, from the brittle star A. squamata also belongs in the genus Octadecabacter based on Sanger sequencing of cloned 16S rRNA gene sequences. By comparison, adjacent seawater and sediment porewater communities were significantly more diverse, hosting bacteria in the phyla Proteobacteria, Bacteroidetes, Cyanobacteria, Verrucomicrobia and Actinobacteria. Thus, a distinct SCB community is present in A. squamata that is dominated by a member of the genus Octadecabacter and is identical to the original isolate, AS1, from this brittle star.
在许多棘皮动物中都发现并研究了与皮下细菌（SCB）的共生关系，包括孵育型蛇尾纲动物鳞蛇尾（Amphipholis squamata）的SCB。先前对鳞蛇尾SCB的研究将分离出的细菌（命名为AS1）归为弧菌属（γ-变形菌纲），但随后的研究表明棘皮动物的SCB属于α-变形菌纲。本研究使用16S rRNA基因和下一代测序技术，研究了来自西北大西洋的鳞蛇尾相关SCB的分类组成。结果显示，在红杆菌科的红杆菌分支中存在单一优势细菌类型，占鳞蛇尾微生物群的70%-80%。这些红杆菌科序列被鉴定为十八杆菌属的成员。此外，基于克隆的16S rRNA基因序列的桑格测序，来自蛇尾纲动物鳞蛇尾的原始分离株AS1也属于十八杆菌属。相比之下，相邻海水和沉积物孔隙水群落的多样性明显更高，含有变形菌门、拟杆菌门、蓝细菌门、疣微菌门和放线菌门的细菌。因此，鳞蛇尾中存在一个独特的SCB群落，该群落以十八杆菌属的一个成员为主导，并且与来自这种蛇尾纲动物的原始分离株AS1相同。
