Proposal of Actinoplanes capillaceus Matsumoto et al. 2000 as a later heterotypic synonym of Actinoplanes campanulatus (Couch 1963) Stackebrandt and Kroppenstedt 1987 and an emended description of Actinoplanes campanulatus

In this study, we re-evaluated the taxonomic relationship of Actinoplanes capillaceus and Actinoplanes campanulatus by using whole-genome comparative analysis. The 16S rRNA gene sequence analysis indicated that A. campanulatus IFO 12511 T showed high 16S rRNA gene sequence similarities to A. capillaceus K95-5561 T (99.86%), A. lobatus IFO 12513 T (99.30%), A. auranticolor IFO 12245 T (99.14%), A. sichuanensis 03-723 T (98.73%), A. subglobosus A-T 5400 T (98.67%) and ˂98.60% to others. The phylogenetic tree based on 16S rRNA gene sequences revealed that A. campanulatus IFO 12511 T clustered with A. capillaceus K95-5561 T . The phylogenetic analysis based on whole-genome sequences further confirmed this result and indicated that A. campanulatus IFO 12511 T was closely related to A. capillaceus K95-5561 T . However, the average nucleotide identity and digital DNA–DNA hybridization values between them were 96.14%/96.75% and 70.90%, respectively. These values are higher than 95–96% and 70% for the delineation of prokaryotic genomic species, confirming that A. capillaceus and A. campanulatus should belong to the same species. In addition, phenotypic and genome properties between A. campanulatus NBRC 12511 T and A. capillaceus NBRC 16408 T were very similar. Therefore, based on phenotypic, chemotaxonomic and molecular data, we propose A. capillaceus [] as a later heterotypic synonym of A. campanulatus [].