The group Nitriliruptoria, recently classified as a separate class of phylum Actinobacteria, has five members at present, which belong to halophilic or halotolerant Actinobacteria. Here, we sequenced the genomes of Egicoccus halophilus EGI 80432^T and Egibacter rhizosphaerae EGI 80759^T, and performed a comparative genomics approach to analyze the genomic differences and salt adaptation mechanisms in Nitriliruptoria. Phylogenetic analysis suggested that Euzebya tangerina F10^T has a closer phylogenetic relationship to Euzebya rosea DSW09^T, while genomic analysis revealed highest genomic similarity with Nitriliruptor alkaliphilus ANL-iso2^T and E. halophilus EGI 80432^T. Genomic differences of Nitriliruptoria were mainly observed in genome size, gene contents, and the amounts of gene in per functional categories. Furthermore, our analysis also revealed that Nitriliruptoria possess similar synthesis systems of solutes, such as trehalose, glutamine, glutamate, and proline. On the other hand, each member of Nitriliruptoria species possesses specific mechanisms, K⁺ influx and efflux, betaine and ectoine synthesis, and compatible solutes transport to survive in various high-salt environments.

中文翻译：

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Nitriliruptoria的比较基因组学分析揭示了基因组差异和盐适应策略

Nitriliruptoria组最近被归类为放线放线菌门类，目前有五个成员，分别属于嗜盐或卤代放线放线菌。在这里，我们测序了嗜盐大肠杆菌（Egicoccus halophilus） EGI 80432 ^T和根癌土壤杆菌（Egibacter rhizosphaerae EGI 80759 ^T）的基因组，并进行了比较基因组学方法分析了硝化细菌的基因组差异和盐适应机制。系统发育分析表明，桔实蝇F10 ^T与玫瑰实生DSW09 ^T具有较近的系统发育关系。，而基因组分析则显示与嗜碱杀硝菌ANL-iso2 ^T和嗜盐大肠杆菌EGI 80432 ^T具有最高的基因组相似性。Nitriliruptoria的基因组差异主要观察到基因组大小，基因含量和每个功能类别中的基因数量。此外，我们的分析还表明，硝化尿素具有类似的溶质合成系统，例如海藻糖，谷氨酰胺，谷氨酸和脯氨酸。另一方面，硝化细菌的每个成员都有特定的机制，K ⁺ 大量涌入和流出，甜菜碱和ectoine的合成以及相容的溶质能够在各种高盐环境中生存。