Description of sp. nov. and sp. nov., isolated from riverside soil, reclassification of as comb. nov., and emended description of the genus .

Three Gram-positive, aerobic and rod shaped actinobacteria, designated strains MMS21-STM10, MMS21-STM12 and MMS21-STM26, were isolated from riverside soil and subjected to polyphasic taxonomic analysis. The strains grew optimally at mesophilic temperatures (25-30 °C) and neutral to slightly alkaline pH (7-8), and NaCl was not required for growth. Best growth was observed on nutrient agar or marine agar media. The strains contained diphosphatidylglycerol, phosphatidylglycerol and a series of unidentified phospholipids, glycolipids and aminolipids, and anteiso-C and iso-C as the main fatty acids in common. The genome sizes ranged between 2.65 and 2.78 Mbp, and the DNA G+C contents between 70.4 and 72.3 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain MMS21-STM10 showed highest sequence similarity of 98.3 % to CV-2, and MMS21-STM12 and MMS21-STM26 of 99.2-99.3 % to WY83, respectively. In the whole genome-based comparison using the orthologous average nucleotide identity and digital DNA-DNA hybridization, each of strains MMS21-STM10 and MMS21-STM12 could be separated from other species of . The genome analysis also indicated that both strains contained gene clusters involved in the biosynthesis of alkylresorcinol, microansamycin and carotenoids. The phenotypic characteristics again differentiated the strains from related species, and two new species of , sp. nov. (type strain, MMS21-STM10=KCTC 49773=LMG 32522) and sp. nov. (type strain, MMS21-STM12=KCTC 49750=LMG 32523) are proposed accordingly. It was also evident that KN1116 should be reclassified as a new species of , and comb. nov. (type strain, KN1116=CGMCC 1.17143=KCTC 49299) is proposed. In addition, an emended description of is proposed based on this study.