Whole genome-based reclassification of several species of the genus Microbispora

The classification of Microbispora , a bacterial genus of significant ecological, agricultural, biotechnological, and clinical importance, has traditionally been carried out based on 16S rRNA gene sequences or phenotypic characteristics, which may lead to equivocal conclusions and it is not in line with the current standards. Moreover, some of the recent species descriptions have not been made using whole genome sequences (WGS), or when used, not all the species were included in the analyses. Consequently, some of the taxonomic conclusions drawn are equivocal, and therefore some currently accepted species should be synonymized. In this study, we revised the taxonomy of the genus Microbispora using digital DNA-DNA hybridization (dDDH) and average nucleotide identity (ANI) values, and by reconstructing phylogenetic relationships using whole genome sequences. Based on the clear phylogenomic separations and on the sequence divergence values, we propose to elevate Microbispora rosea subsp. rosea and Microbispora rosea subsp. aerata to the species level, and therefore to create Microbispora aerata sp. nov. with JCM 3076 T (= DSM 43176 T = ATCC 15448 T = IFO 14624 T = NBRC 14624 T = VKM Ac-1507 T ) as the type strain. Hence, with this proposition, the correct name for Microbispora rosea subsp. rosea is M . rosea . Furthermore, we propose to reclassify M . camponoti as a subspecies within M . bryophytorum . Consequently, we propose the creation of the following two subspecies: Microbispora bryophytorum subsp. bryophytorum subsp. nov. with DSM 46710 T (= CGMCC 4.7138 T = NEAU TX2-2 T ) as the type strain, and Microbispora bryophytorum subsp. camponoti subsp. nov., comb. nov. with DSM 2C-HV3 T (= DSM 100527 T = CGMCC 4.7281 T ) as the type strain. In addition, we propose to reinstate M . amethystogenes as an independent species and not as a M . rosea synonym, and reclassify “ M . cellulosiformans ” as a subspecies within M . amethystogenes . Hence, we propose the creation of the following two subspecies: Microbispora amethystogenes subsp. amethystogenes subsp. nov. with NBRC 101907 T (= DSM 43164 T = JCM 3021 T = NRRL B-2637 T ) as the type strain, and Microbispora amethystogenes subsp. cellulosiformans subsp. nov., comb. nov. with Gxj-6 T (= DSM 109712 T = CGMCC 4.7605 T ) as the type strain. Lastly, we propose M . fusca NEAU-HEGS1-5 T and “ M . tritici ” MT50 T as later homotypic synonyms of M . triticiradicis NEAU-HRDPA2-9 T .