Nocardiopsis suaedae sp. nov. and Nocardiopsis endophytica sp. nov., two novel halophilic actinobacteria isolated from halophytes.

A polyphasic approach was used to describe two halophilic actinobacterial strains, designated LSu2-4 and RSe5-2, which were isolated from halophytes [ (L.) Dum. and (L.) L.] collected from Prachuap Khiri Khan province, Thailand. Comparative analysis of 16S rRNA gene sequences showed that strains LSu2-4 and RSe5-2 were assigned to the genus , with YIM 90109(99.2 and 99.2 % similarities, respectively) and DSM 44494(99.0 and 98.8 % similarities, respectively) being their closely related strains. Whereas the 16S rRNA gene sequence similarity between LSu2-4 and RSe5-2 was 99.4 %. Phylogenetic and phylogenomic analyses based on 16S rRNA gene and whole-genome sequences revealed that both strains clustered with YIM 90109 and DSM 44494. The average nucleotide identity (ANI) based on blast, ANI based on MUMmer and digital DNA-DNA hybridization (dDDH) relatedness values between the two strains and their closest type strains were below the threshold values for identifying a novel species. Morphological characteristics and chemotaxonomic features of both strains were typical for the genus by formed well-developed substrate mycelia and aerial mycelia which fragmented into rod-shaped spores. Whole-cell hydrolysates contained -diaminopimelic acid as the diagnostic diamino acid. The predominant menaquinones were variously hydrogenated with 10 isoprene units and contained phosphatidylcholine in their polar lipid profiles. Major fatty acids were iso-C and 10-methyl C. analysis predicted that the genomes of LSu2-4 and RSe5-2 contained genes associated with stress responses and biosynthetic gene clusters encoding diverse bioactive metabolites. Characterization based on chemotaxonomic, phenotypic, genotypic and phylogenetic evidence demonstrated that strains LSu2-4 and RSe5-2 represents two novel species of the genus , for which the names sp. nov. (type strain LSu2-4=TBRC 16415=NBRC 115855) and sp. nov. (type strain RSe5-2=TBRC 16416=NBRC 115856) are proposed.