We identified an alphaproteobacterium in the digestive gland of the abalone species Haliotis discus hannai. This phylotype dominated our 16S rRNA clone libraries from the digestive gland of H. discus hannai. Diversity surveys revealed that this phylotype was associated with H. discus hannai and also in another host species, H. gigantea. Whole genome phylogenies placed this bacterium as a new member affiliated with the family Rhodospirillaceae in Alphaproteobacteria. Gene annotation revealed a nearly complete glycolysis pathway but no TCA cycle, but the presence of anaerobic ribonucleoside‐triphosphate reductase and oxygen‐insensitive NAD(P)H‐dependent nitroreductase, which show the genomic potential for anaerobic metabolism. A large cluster of genes encoding ankyrin repeat proteins (ANK) of eukaryotic‐like repeat domains and a large gene set for the flagellar system were also detected. Alginate‐binding periplasmic proteins and key genes responsible for alginate assimilation were found in the genome, which could potentially contribute to the breakdown of the host's alginate‐rich macroalgal diet. These results raise the possibility that this novel alphaproteobacterium is a widespread member of the abalone microbiome that may use polysaccharides derived from its host's macroalgal diet.

中文翻译：

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从多种鲍鱼的消化腺中鉴定出的一种具有小的基因组的新型α变形杆菌。

我们在鲍鱼种类Haliotis discus hannai的消化腺中鉴定了一个α-变形细菌。这种系统型主导了我们的H. discus hannai消化腺的16S rRNA克隆库。多样性调查显示，该系统型与汉斯铁血吸虫以及另一种寄主巨型吸血鬼有关。放在这种细菌与家庭所属的新成员全基因组的系统发育红螺在α-变形菌。基因注释显示了几乎完整的糖酵解途径，但没有TCA循环，但是存在厌氧核糖核苷三磷酸还原酶和对氧不敏感的NAD（P）H依赖性硝基还原酶，显示了厌氧代谢的基因组潜力。还检测到一大簇编码真核样重复域锚蛋白重复蛋白（ANK）的基因和鞭毛系统的大基因集。在基因组中发现了藻酸盐结合的周质蛋白和负责藻酸盐同化的关键基因，这可能会导致宿主富含藻酸盐的大型藻类饮食的分解。这些结果增加了这种新颖的α-变形杆菌是鲍鱼微生物组中广泛的成员的可能性，该鲍鱼微生物组可以使用源自其宿主的巨藻饮食的多糖。