Proposal for transfer of Defluviimonas alba to the genus Frigidibacter as Frigidibacter mobilis nom. nov.

A polyphasic taxonomic study was undertaken to clarify the exact position of the type strain cai42 ^T of the species Defluviimonas alba Pan et al . 2015. The results of the 16S rRNA gene sequence analysis indicated that the two sequences from cai42 ^T shared 99.6 and 99.7 % similarity to that of the type strain SP32 ^T of the species Frigidibacter albus and formed a coherent clade in the phylogenetic tree. Whole genomic comparison between cai42 ^T and SP32 ^T yielded a digital DNA-DNA hybridization estimate of 36.3 %, an average nucleotide identity of 88.8 % and an average amino acid identity of 89.8 %, clearly indicating that the two strains should belong to two genospecies of the same genus. The close relationship between the two strains was underpinned by the results of genome-based phylogenetic analysis. Although cai42 ^T and SP32 ^T shared similar physiological and biochemical properties, some striking differences, such as mobility, the temperature range for growth and the polar lipid components, could distinguish them as separate species. Therefore, the comparative phenotypic and genotypic analyses supported the incorporation of Defluviimonas alba into the genus Frigidibacter as Frigidibacter mobilis nom. nov. with the type strain cai42 ^T (=CGMCC 1.12518 ^T =LMG 27406 ^T ).