Bacteria associated with Symbiodinium may exert relevant roles in the Symbiodinium and the coral host. The bacterial isolate Ep20 was obtained from cell suspensions of Symbiodinium retrieved from the endemic coral Mussismilia braziliensis (Abrolhos Bank, Brazil). Here we aimed to analyze the genomic repertoire of Ep20 to gain insights into its possible roles in the coral holobiont. Ep20 enhanced the growth of Symbiodinium under controlled laboratory conditions, possibly through nitrogen fixation and vitamin production. The genome of Ep20 contains 5.5 Mbp (65% G + C content), 5397 genes, 53 tRNAs, and four rRNAs. Ep20 was identified as Mameliella alba, a member of the Roseobacter Clade Bacteria (RCB, Alphaproteobacteria). The genomic repertoire of Ep20 includes genes responsible for i. Aerobic Anoxygenic Photosynthesis (AAP), ii. Cofactors and vitamins (B₁₂), iii. Gene Transfer Agents (GTAs), iv. Dimethylsulfoniopropionate (DMSP) metabolism, v. Carbon and Nitrogen fixation, and vi. Secondary metabolites (e.g., Terpenes). The genomic attributes of Ep20 hint at a possible mutualistic interaction with Symbiodinium, both in the free-living and in the coral holobiont lifestyles.

中文翻译：

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巴西地方性珊瑚Mussismilia巴西的Mameliella alba Ep20与共生菌相关的基因组库

与共生素相关的细菌可能在共生素和珊瑚宿主中发挥相关作用。细菌分离物Ep20是从巴西特有的Mussismilia braziliensis（巴西阿布鲁洛斯银行）回收的共生菌的细胞悬液中获得的。在这里，我们旨在分析Ep20的基因组库，以深入了解其在珊瑚全核生物中的可能作用。Ep20可以通过控制固氮和生产维生素来增强Symbiodinium在受控实验室条件下的生长。Ep20的基因组包含5.5 Mbp（65％的G + C含量），5397个基因，53个tRNA和四个rRNA。Ep20被确定为Mameliella alba，是Roseobacter进化枝细菌（RCB，丙酸杆菌）。Ep20的基因组库包括负责i的基因。有氧产氧光合作用（AAP），ii。辅助因子和维生素（B ₁₂），iii。基因转移代理（GTA），iv。丙二酸二甲酯（DMSP）代谢，碳和氮固定，vi。次生代谢产物（例如萜烯）。Ep20的基因组特性暗示了在自由生活和珊瑚礁生活中生活方式可能与Symbiodinium相互影响。