Genomic Insight Into the Streptomyces Aurantiacus Clade: Reclassification of Streptomyces Ederensis as a Later Heterotypic Synonym of Streptomyces Umbrinus and Streptomyces Glomeroaurantiacus as a Later Heterotypic Synonym of Streptomyces Aurantiacus

Abstract

The taxonomic relationships and genome features of the type strains in the Streptomyces aurantiacus clade, including Streptomyces aurantiacus, Streptomyces ederensis, Streptomyces glomeroaurantiacus, Streptomyces umbrinus, Streptomyces phaeochromogenes, Streptomyces dioscori and Streptomyces tauricus, were investigated. Type strains of these species shared high 16S rRNA gene sequence similarity to each other. Multilocus sequence analysis (MLSA) based on atpD, gyrB, recA, rpoB and trpB genes revealed that S. ederensis and S. umbrinus belong to the same species. Also, S. aurantiacus and S. glomeroaurantiacus belong to the same species, but the remaining species are not closely related to each other. MLSA results were verified by the results average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) analyses; while the ANI and dDDH values between S. ederensis and S. umbrinus are 98.1 and 85.4 %, respectively, these values between S. aurantiacus and S. glomeroaurantiacus are 98.9 and 90.7 %, respectively. The presence of almost the same set of biosynthetic gene clusters and highly consistent phenotypic test results also supported the synonymy between S. ederensis and S. umbrinus, as well as between S. aurantiacus and S. glomeroaurantiacus. Therefore, S. ederensis should be reclassified as a later heterotypic synonym of S. umbrinus and S. glomeroaurantiacus should be reclassified as a later heterotypic synonym of S. aurantiacus.