Rhodococcus spongiicola sp. nov. and Rhodococcus xishaensis sp. nov., from marine sponges

Two novel Rhodococcus strains, LHW50502 T and LHW51113 T , were isolated from marine sponges obtained on Xisha Island, Hainan Province, PR China. Rods and cocci, typical characteristics of the genus Rhodococcus , were observed. The strains contained meso -diaminopimelic acid as the diagnostic diamino acid in the cell-wall hydrolysates and galactose, arabinose, ribose and glucose as the whole-cell sugars. The major fatty acid identified was C 16 : 0 . MK-8(H 4 ) was the predominat menaquinone of both strains. Stains LHW50502 T and LHW51113 T had almost identical (99.6 %) 16S rRNA gene sequences but shared relatively low similarities with previously characterized Rhodococcus species (well below 98.7 %). The results of phylogenetic analysis supported their closest relationship; however, the average nucleotide identity and digital DNA–DNA hybridization values between these two strains indicated that they belonged to distinct species. Taken together, the results of this study indicate that strains LHW50502 T and LHW51113 T represent two novel species of the genus Rhodococcus , for which the names Rhodococcus spongiicola sp. nov. (type strain LHW50502 T =DSM 106291 T =CCTCC AA 2018033 T ) and Rhodococcus xishaensis sp. nov. (type strain LHW51113 T =DSM 106204 T =CCTCC AA 2018034 T ) are proposed.