Isolation and characterization of Novosphingobium oxfordensis sp. nov. and Novosphingobium mississippiensis sp. nov. from soil

Members of the genus Novosphingobium are well known for the biosynthesis of glycosphingolipids. Here, two novel bacterial strains, designated BL-8A and BL-8H, were isolated from a potted tomato plant grown in Oxford, MS, USA, and characterized. The 16S rRNA gene-based and whole genome-based phylogenetic analysis revealed that both the strains belonged to the genus Novosphingobium. BL-8A has a 7.2 Mb genome, while strain BL-8H has a 6.1 Mb genome, both assembled as 4 contigs. In each case the assembly appeared to have two chromosomes with two plasmids, an unusual genomic architecture, but one that has been observed before in this genus. The analyses of dDDH values and ANIs between the two strains and their relatives further demonstrated that the two strains represented two different novel species. Comparative genomic analysis of the two isolates and four reference strains of the genus Novosphingobium showed that the most important central metabolic pathways of these strains appeared to be similar. We dubbed these species Novosphingobium oxfordensis BL-8A and Novosphingobium mississippiensis BL-8H.