Nocardia australiensis sp. nov. and Nocardia spumae sp. nov., isolated from sea foam in Queensland, Australia

Strains USC-21046T and USC-21048T were isolated from foaming coastal marine waters on the Sunshine Coast, Queensland, Australia. Both strains displayed growth and morphological characteristics typical for members belonging to the genus Nocar-dia. The major polar lipids were diphosphatidylglycerol and phosphatidylethanolamine, and the major fatty acids were C16:0, C18: 1 omega 9c, C18: 0 and C18:0 10 -methyl. The mycolic acids of strains USC-21046T and USC-21048T consisted of chain lengths between 50-64 and 56-68, respectively. Moreover, both of those strains contained meso- diaminopimelic acid and ribose, arabinose, glucose and galactose as whole cell sugars. Based on the phylogenomic results, both strains belonged to the genus Nocardia with strain USC-21046T showing an 80.4 % genome similarity to N. vinacea NBRC 16497T and N. pseudovaccinii NBRC 100343T, whereas USC-21048T strain showed an 83.6 % genome similarity to N. aobensis NBRC 100429T. Both strains were delineated from their closely related relatives based on physiological (e.g. growth on sole carbon source) and chemotaxonomic (e.g. cel-lular fatty composition) differences. The digital DNA-DNA hybridization (dDDH) values between USC-21046T and USC-21048T and their closely related relatives were below the dDDH threshold value of <= 70 % used for the taxonomic classification of novel species status. The genome length of strains USC-21046T and USC-21048T were 6 878 863 and 7 066 978 bp, with G+C contents of 65.2 and 67.8 mol%, respectively. For the novel isolates, we propose the names Nocardia australiensis sp. nov. with the type strain USC-21046T (=DSM 111727T=NCCB 100867T) and Nocardia spumae sp. nov. with the type strain USC-21048T (=DSM 111726T=NCCB 100868T).