Aestuariirhabdus litorea gen. nov., sp. nov., isolated from a sea tidal flat and proposal of Aestuariirhabdaceae fam. nov.

A Gram-negative, moderately halophilic and facultatively aerobic bacterium, designated strain GTF13 T , was isolated from a sea tidal flat. Cells were curved rods and motile by a single polar flagellum showing catalase and oxidase activities. Growth was observed at 20–37 °C, pH 5.0–8.5 and 1.0–6.0 % (w/v) NaCl. Strain GTF13 T contained C 16:0, summed feature 3 (comprising C 16 : 1   ω6 c /C 16 : 1   ω7 c ), summed feature 8 (comprising C 18 : 1   ω6c/C 18 : 1   ω7 c ) and C 12 : 0 3-OH as major fatty acids and ubiquinone-9 and ubiquinone-8 as major quinones. Phosphatidylethanolamine and two unidentified phospholipids were detected as major polar lipids. The G+C content of the genomic DNA was 59.8 mol%. Strain GTF13 T was most closely related to Simiduia agarivorans SA1 T , Endozoicomonas montiporae CL-33 T and Pseudomonas segetis FR1439 T , belonging to different families or orders of the class Gammaproteobacteria , with less than 92.0 % 16S rRNA gene sequence similarities. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain GTF13 T formed a phylogenetic lineage with the family Litoricolaceae , but the genome-based phylogenomic tree showed that strain GTF13 T formed a distinct phylogenetic lineage within the order Oceanospirillales . The very low 16S rRNA gene sequence similarities and distinct phylogenetic relationships, together with distinct phenotypic and chemotaxonomic properties, served to differentiate strain GTF13 T from phylogenetically closely related families. Here, strain GTF13 T is proposed as a novel genus and species, for which the name Aestuariirhabdus litorea gen. nov., sp. nov. is proposed, within a new family Aestuariirhabdaceae fam. nov. of the order Oceanospirillales . The type strain is GTF13 T (=KACC 19788 T =JCM 32043 T ).