Notoacmeibacter marinus gen. nov., sp. nov., isolated from the gut of a limpet and proposal of Notoacmeibacteraceae fam. nov. in the order Rhizobiales of the class Alphaproteobacteria

A Gram-stain-negative, short rod-shaped and non-flagellated bacterium, named strain XMTR2A4T, was isolated from the gut of a marine limpet, Notoacmea schrenckii on intertidal rocks. Colonies were small, light grey and circular. Catalase- and oxidase-positive. Growth was observed at 15 to 37 °C (optimum 28-30 °C), with salinity range from 0.5 to 9 % (optimum 1-2 %), and at pH 6 to 9 (optimum pH 7). The almost full-length 16S rRNA gene of strain XMTR2A4T had the highest sequence similarity of 93.7 % with Mycoplana ramosa DSM 7292T, and of 93.5 , 93.5 and 93.4 % with Chelativorans intermedius CC-MHSW-5T, Ensifer fredii ATCC 35423T and Phyllobacterium myrsinacearum IAM 13584T, respectively. Phylogenetic analysis showed that strain XMTR2A4T formed a tight cluster with a cultured but uncharacterized strain, YP382-1-A, which was deeply separated from the species within the order Rhizobiales in the class Alphaproteobacteria. The predominant fatty acid of strain XMTR2A4T was summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c; 83.4 %). Ubiquinone-10 (Q-10) was detected as the sole respiratory quinone. The polar lipids were identified as phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, diphosphatidylglycerol, phosphatidylmonomethylethanolamine, an unidentified phospholipid and three unknown lipids. The genome size was about 3.6 Mbp and the G+C content was 61.5 mol%. Combining the results above, it was ascertained that strain XMTR2A4Trepresents a novel species of a new genus in the order Rhizobiales, for which the name Notoacmeibacter marinus gen. nov., sp. nov. is proposed. The type strain of the type species is XMTR2A4T (=MCCC 1A01882T=KCTC 52427T). A novel family in the order Rhizobiales, named Notoacmeibacteraceae fam. nov., is also proposed to accommodate the new genus.