Genome-based reclassification of Kitasatospora niigatensis as a later heterotypic synonym of Kitasatospora cineracea Tajima et al. (2001).

The present study used genome-based approaches to investigate the taxonomic relationship between Kitasatospora cineracea DSM 44780 T and Kitasatospora niigatensis DSM 44781 T , two species that were previously described by Tajima et al. (Int J Syst Evol Microbiol 51:1765-1771, 2001). The digital DNA-DNA hybridization (dDDH), average amino acid identity (AAI), and average nucleotide identity (ANI) values between the genomes of the two type strains were 90.3, 98.7, and 99.1%, respectively. These values exceeded the established thresholds of 70% (dDDH) and 95-96% (ANI and AAI) for bacterial species delineation, suggesting that K. cineracea and K. niigatensis should share the same taxonomic position. Furthermore, our analysis using the 'Bacterial Pan Genome Analysis' (BPGA) pipeline and the Maximum Likelihood core-genes tree inferred using FastTree2 consistently demonstrated that K. cineracea DSM 44780 T and K. niigatensis DSM 44781 T are closely related, as indicated by the clustering of these strains in the core-genes phylogenomic tree. Based on these findings, we propose that K. niigatensis should be considered a later heterotypic synonym of K. cineracea.