Marinactinospora thermotolerans gen. nov., sp. nov., a marine actinomycete isolated from a sediment in the northern South China Sea.

A novel marine actinomycete, designated SCSIO 00652(T), was isolated from a marine sediment collected from the northern South China Sea at a depth of 3865 m. The strain formed branched substrate mycelia and no fragmentation was found. Abundant aerial mycelia differentiated into long spore chains and the spores had a wrinkled surface. Growth occurred on ISP medium 2 with 0-5 % (w/v) NaCl and at 10-55 degrees C. The whole-cell hydrolysate contained meso-diaminopimelic acid and glucose as the whole-cell sugar. blast search results based on an almost-complete 16S rRNA gene sequence showed the novel strain had the highest similarity (96.5 %) with Nocardiopsis trehalosi VKM Ac-942(T). The phylogenetic tree of the family Nocardiopsaceae indicated that strain SCSIO 00652(T) formed a distinct lineage at the deepest branch with a high bootstrap value. Additionally, the profiles of menaquinones, phospholipids and fatty acids showed there were marked differences between strain SCSIO 00652(T) and the recognized genera of the family Nocardiopsaceae. Based on the polyphasic data, a new genus, Marinactinospora gen. nov., is proposed within the family Nocardiopsaceae with the type species Marinactinospora thermotolerans sp. nov. The type strain of the type species is SCSIO 00652(T) (=DSM 45154(T)=CCTCC AA 208041(T)).