Anaeromyxobacter oryzae sp. nov., Anaeromyxobacter diazotrophicus sp. nov. and Anaeromyxobacter paludicola sp. nov., isolated from paddy soils

Three bacterial strains (Red232(T), Red267(T) and Red630(T)) were isolated from paddy soils sampled in Japan. Cells of these strains were Gram-stain-negative, facultative anaerobic, long rod-shaped with monotrichous flagella or pilus-like structures for motility, and formed red colonies on agar plates. Phylogenetic trees based on 165 rRNA gene and multiple single-copy gene sequences showed that the three strains formed a cluster with the type strains of Anaeromyxobacter species, independent from any other strain genera. Similarity values of the 165 rRNA gene sequences and genomes among the three isolated strains and the type strain of Anaeromyxobacter, Anaeromyxobacter dehalogenans 2CP-1(T), were 95.4-97.4% for 165 rRNA gene sequence, 75.3-79.5% for average nucleotide identity, 19.6-21.7% for digital DNA-DNA hybridization and 64.1-72.6% for average amino acid identity, all of which are below the species delineation thresholds. Nitrogenase genes were observed in the genomes of the three novel strains, but not in A. dehalogenans 2CP-1(T). Moreover, multiple genomic, physiological and chemotaxonomic features supported the discrimination between these three strains. Based on the evidence in this study, the three isolates represent three novel independent species for which the following names are proposed: Anaeromyxobacter oryzae sp. nov., Anaeromyxobacter diazotrophicus sp. nov. and Anaeromyxobacter paludicola sp. nov. The type strains are Red232(T) (=NBRC 114074(T)=MCCC 1K03954(T)), Red267(T) (=NBRC 114075(T)=MCCC 1K04211(T)), and Red630(T) (=NBRC 114076(T)=MCCC 1K03957(T)), respectively.

Automated summary

Three novel bacterial strains belonging to the Anaeromyxobacter genus were isolated from paddy soils in Japan. They displayed distinct genomic, physiological, and chemotaxonomic characteristics that distinguished them from other strains within the genus.