Reclassification of sphingomonas aeria as a later heterotypic synonym of sphingomonas carotinifaciens based on whole-genome sequence analysis

Abstract

The 16S rRNA gene sequences of Sphingomonas carotinifaciens L9-754T and Sphingomonas aeria B093034T possess 99.71% sequence similarity. Further studies were undertaken to clarify the taxonomic assignments of these species. Whole-genome comparisons showed that S. aeria B093034Tand S. carotinifaciens L9-754T shared 96.9% average nucleotide identity, 98.4% average amino acid identity and 76.1% digital DNA–DNA hybridization values. These values exceeded or approached the recommended species delineation threshold values. Furthermore, a phylogenetic tree based on 41 of the most conserved genes provided additional evidence that S. aeria B093034T and S. carotinifaciens L9-754T are very closely related. Based on this evidence we propose the reclassification of S. aeria Xue et al. 2018 as a later heterotypic synonym of S. carotinifaciens Madhaiyan et al. 2017.