Polyphasic evidence for the transfer of Promicromonospora yunnanensis to Cellulosimicrobium cellulans

Polyphasic taxonomic investigations of Promicromonospora yunnanensis AS4.1333 deposited in the China General Microbiological Culture Collection Center (CGMCC) indicated that strain AS4.1333 was closely related to Cellulosimicrobium cellulans DSM43879(T), the two organisms shared a 16S rRNA gene similarity of 99.6% which correspond to 5 nt differences at 1423 positions. Corresponding DNA-DNA reassociation value was 89.3%, significantly higher than 70% cut-off point recommended for the delineation of genomic species by Wayne et al. (1987). Results of chemotaxonomic analyses of cell wall (Whole-organism hydrolysates were rich in rhamnose, fucose and galactose; peptidoglycan type A4a), mycolic acids (One dimensional TLC of whole-organism acid methanolysates revealed the absence of a lower spot (Rf value around 0.47) that corresponded to mycolic acids), principal menaquinones (MK-9 (H4)), phospholipid type (PV) and the G + C content of the DNA (73.8 mol%) supported the conclusions of the genotypic analyses. The very similar morphological and physiological characteristics agreed with the high degree of relatedness. On the basis of phylogenetic analyses based on the almost complete 16S rRNA gene sequence, DNA-DNA reassociation values, chemotaxonomic properties, morphological and physiological characteristics, it is concluded that strain AS4.1333 should be removed from the genus Promicromonospora, and strain AS4.1333 and Cellulosimicrobium cellulans should be considered to be a single species. Promicromonospora yunnanensis AS4.1333 was proposed to transfer into Cellulosimicrobium cellulans. The type strain remains DSM43879T.