Two novel actinobacterium strains ZYX-F-536T and ZYX-F-553 were isolated from marine sediment in Yongxing Island, Hainan Province, China. Based on 16S rRNA gene sequence analysis, the strain ZYX-F-536T belongs to the genus Micromonospora, with high similarities to strain ZYX-F-553 (99.9%), Micromonospora alfalfae MED01T (99.0%), Micromonospora auratinigra DSM 44815T (99.0%), Micromonospora saelicesensis Lupac 09T ZYX (99.0%), Micromonospora arida LB32T (99.0%) and Micromonospora foliorum PSH25T (98.9%). The novel isolate ZYX-F-536T contained meso-diaminopimelic acid, glycine and d-alanine in the cell wall. The whole-cell sugars were rhamnose, ribose, glucose and xylose. The predominant menaquinones were MK-10(H4) (38.6%), MK-10(H6) (31.2%) and MK-10(H8) (20.1%). The characteristic phospholipids were phosphatidylethanolamine, phosphatidylinositol, diphosphatidylglycerol and two unknown phospholipids. The major fatty acids (>10%) were C15:0, C16:0, C17:0 and anteiso-C17:0. Genome sequencing showed a DNA G+C content of 71.9 mol%. The low ANI and dDDH values demonstrated that strain ZYX-F-536T could be readily distinguished from the closely related species. Based on phylogenetic, chemotaxonomic and physiological characteristics, strain ZYX-F-536T represents a novel species of the genus Micromonospora, for which the name Micromonospora yongxingensis sp. nov. is proposed. The type strain is ZYX-F-536T (=CCTCC AA 2025094T=JCM 38260T).
Keywords: 16S rRNA gene; Micromonospora yongxingensis sp. nov. polyphasic taxonomy; marine sediment.