Prauserella cavernicola sp. nov., isolated from cave rock

A novel actinomycete, designated strain ASG 168(T), was isolated from cave rock collected from Stegodon Sea Cave in Thailand. Long chains of non-motile spores that were oval or spherical in shape with a smooth surface developed on aerial mycelia. Substrate mycelia fragmented into irregular rod-shaped elements. A polyphasic taxonomic study showed that strain ASG 168(T) had typical characteristics of members of the genus Prauserella. 16S rRNA gene sequence analysis indicated that strain ASG 168(T) shared 97.5 % similarity with Prauserella marina MS498(T) and 96.7 % with Prauserella coralliicola SCSIO 11529(T). Average nucleotide identity values with P. coralliicola SCSIO 11529(T) and P. marina MS498(T) were 82.98 and 76.08 %, respectively. The cell wall peptidoglycan contained meso-diaminopimelic acid. The whole cell sugars contained ribose, arabinose and galactose. The predominant menaquinone was MK-9(H4). The predominant fatty acids were iso-C-16:0, C-16:0 and summed feature 3 (C-16:1 omega 7c/C-16:1 omega 6c). The phospholipid profile consisted of phosphatidylethanolamine, phosphatidylmethylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, phosphatidylinositol mannosides and two unknown phospholipids. The G+C content of the genomic DNA was 70.6 mol%. Differentiation of strain ASG 168(T) from closely related species was evident from digital DNA-DNA hybridization values of 29.2 and 21.3 % with P. coralliicola and P. marina, respectively. Based on comparative analysis of phenotypic, chemotaxonomic and genotypic data, the novel actinomycete strain ASG 168(T) (=TBRC 13679(T)=NBRC 114887(T)) is proposed to be the type strain of a novel species, Prauserella cavernicola sp. nov.