Kribbella caucasensis sp. nov. from the Soil of the North Caucasus Mountains

Abstract

Mycelium-forming aerobic actinomycete, strain VKM Ас-2527T, was isolated from a soil sample collected from the North Caucasus mountains. The 16S rRNA gene sequence similarities of this strain to the type strains of the known Kribbella species ranged from 95.5 to 98.5%. The dDDH (23.1–26.3%) and ANIb (78.1–81.5%) values between VKM Ас-2527T and the type strains of the phylogenetically closest Kribbella species were below the thresholds for prokaryote species delineation. The conventional chemotaxonomic characteristics of strain VKM Ас-2527T were typical of the genus Kribbella: the LL-diaminopimelic acid (LL-A2pm) in the cell wall peptidoglycan, the major menaquinone МК-9(Н4), dominant fatty acids anteiso-C15:0, iso-C16:0, and anteiso-C17:0, and the PIII-type phospholipids (with phosphatidylcholine as the key diagnostic component). The cell wall also contained branched α-mannan characteristic of the genus and the teichulosonic acid of irregular structure. The cell wall sugars included mannose, galactose, rhamnose, 3-O-methylgalactose (madurose), and 2,3-di-O-methylgalactose. The genome size was 9.5 Mb, with 68.2% G+C content. Based on the results obtained in the present study and the previously published data, a new species, Kribbella caucasensis sp. nov., is proposed, with the type strain VKM Ас-2527T.