Antrihabitans Stalactiti Gen. Nov., Sp. Nov., A New Member Of The Family Nocardiaceae Isolated From A Cave

Two Gram-stain-positive, strictly aerobic, non-spore-forming actinobacterial strains, designated YC2-7(T) and YC5-17, were isolated from the Yongcheondonggul (larva cave) in Jeju, Republic of Korea and their taxonomic ranks were examined by a polyphasic approach. The 16S rRNA gene tree showed that the novel isolates occupied an independent position separated from recognized genera of the family Nocardiaceae. In the 92 core gene-based phylogenomic analysis, strain YC2-7(T) was loosely associated with the type strain of Aldersonia kummingensis with 66.2% average amino acid identity. The 16S rRNA gene sequence simairity between the isolate and members of the family Nocardiaceae was below 96.7%. The cell-wall peptidoglycan was meso-diaminopimelic acid as a diagnostic diamino acid. Whole-cell sugars consisted of arabinose, galactose and glucose. The predominant menaquinone was MK-8(H-4, omega-cycl). The major polar lipids consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and phosphatidylinositol mannoside. The cellular fatty acids consisted mainly of saturated and unsaturated components with small amounts of tuberculostearic acid. Mycolic acids of 52-58 carbon atoms were present. The DNA G+C content of the genome was 63.8mol%. On the basis of combination of morphological and chemotaxonomic differences, in addition to phylogenetic distinctness, the novel isolates are considered to constitute members of a novel species of a new genus in the family Nocardiaceae, for which the name Antrihabitans stalactiti gen. nov., sp. nov. is proposed. The type strain is YC2-7(T) (=KACC 19965(T)=DSM 108733(T)).