Mangrovibacterium diazotrophicum gen. nov., sp. nov., a nitrogen-fixing bacterium isolated from a mangrove sediment, and proposal of Prolixibacteraceae fam. nov.

Abstract

A nitrogen-fixing bacterium, designated strain SCSIO N0430T, was isolated from a mangrove sediment sample. Analysis of the sequence of the nifH gene responsible for nitrogen fixation in this strain indicated a close relationship to an uncultured bacterium ZNZ-D11 (GenBank accession no. JF896696). 16S rRNA gene sequence analysis revealed that this isolate had less than 93 % similarity to its closest relative, Sunxiuqinia elliptica DQHS4T. A phylogenetic tree reconstructed based on 16S rRNA gene sequences revealed that strain SCSIO N0430T was a member of the phylum Bacteroidetes . Chemotaxonomic and physiological characteristics, including phospholipids and major fatty acids, readily distinguished the isolate from established members of the phylum Bacteroidetes . It is concluded that strain SCSIO N0430T represents a novel genus and species, for which the name Mangrovibacterium diazotrophicum gen. nov., sp. nov. is proposed, with the type strain of the species SCSIO N0430T ( = KCTC 32129T = DSM 27148T = JCM 19152T). Based on phylogenetic characteristics and 16S rRNA gene signature nucleotide patterns, the three genera Sunxiuqinia , Prolixibacter and Mangrovibacterium are proposed to make up a novel family, Prolixibacteraceae fam. nov., in the order Bacteroidales .