Nocardiopsis codii sp. nov., and Rhodococcus chondri sp. nov., two novel actinomycetal species isolated from macroalgae collected in the northern Portuguese coast

Two novel actinomycetal strains, designated CC- R113T and CC- R104T, were isolated from the tissues of two macroalgae collected on the northern Portuguese coast. Phylogenetic analyses based on the 16S rRNA gene showed that strain CT- R113T belongs to the genus Nocardiopsis, being closely related to Nocardiopsis umidischolae 66/93T and Nocardiopsis tropica VKM Ac-1457T, with 98.65 and 98.39 % sequence similarity, respectively. The clade formed between the three type strains was confirmed by phylogenomic analysis. The genome of strain CT- R113T was 7.27 Mb in size with a G+C content of 71.3 mol %, with average nucleotide identity (ANI) values of 89.59 and 90.14 % with strains 66/93T and VKM Ac- 1457T, respectively. The major cellular fatty acids were identified as C18: 1 omega 9c, iso-C16 :0 and anteiso- C17: 0. Menaquinone 10 (MK- 10) was the major respiratory quinone. Comparative analysis of 16S rRNA gene sequences showed that strain CC- R104T belongs to the genus Rhodococcus and is most closely related to Rhodococcus pyridinivorans DSM 44555T, with 98.24 % sequence similarity. However, phylogenomic analysis revealed that strain CC- R104T establishes a clade with Rhodococcus artemisae DSM 45380T, being more distant from Rhodococcus pyridinivorans DSM 44555T. The genome of strain CC- R104T was 5.34 Mb in size with a G+C content of 67.01 mol%. The ANI value between strains CC- R104T and DSM 45380T was 81.2 % and between strains CC-R104T and DSM 44555T was 81.5 %. The major cellular fatty acids were identified as C18 : 1 omega 9c, C16:0 and summed feature 3. Menaquinone 8 (MK- 8) was the only respiratory quinone. For both CC- R113T and CC- R104T, optimum growth was observed at pH 7.0, 28 degrees C and 0-5 % NaCl and whole- cell hydrolysates contained meso- diaminopimelic acid as the cell- wall diamino acid. On the basis of phenotypic, molecular and chemotaxonomic characteristics, strains CT- R113T and CC- R104T are considered to represent novel species, for which the names Nocardiopsis codii sp. nov. (type strain CT- R113T=LMG3323 4T=UCCCB172T) and Rhodococcus chondri sp. nov. (type strain CC- R104T=LMG33233T=UCCCB171T) are proposed.