Polycladospora coralii gen. nov., sp. nov., a novel member of the family Thermoactinomycetaceae isolated from stony coral in the South China Sea

Two novel filamentous bacteria, designated as IB182353 T and IB182357, were isolated from stony coral of the South China Sea. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strains IB182353 T and IB182357 were closely related to Hazenella coriacea DSM 45707 T (with 93.4 and 93.5% similarity, respectively). The average nucleotide identity, average amino acid identity and digital DNA–DNA hybridization results showed that the pairwise similarities between isolate IB182353 T and the other recognized Thermoactinomycetaceae species were less than 68.9, 60.5 and 21.1 %, respectively. Both strains produced aerial and substrate mycelia, grew optimally at 25–30 °C, pH 8.0–9.0 and with 2–3 % (w/v) NaCl. The cell-wall peptidoglycan type was meso -DAP and the whole-cell hydrolysates contained ribose. The polar lipids consisted of phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, one unidentified aminophospholipid and three unidentified phospholipids. The genomic DNA G+C content was 39.5 mol%. Strain IB182353 T was distinguishable from its related type strains by the contents of two fatty acids, iso-C 15 : 0 and iso-C 17 : 1 ω 10 c . Based on polyphasic taxonomic characterization, we propose that strains IB182353 T and IB182357 represent a novel genus and species within the family Thermoactinomycetaceae , for which the name Polycladospora coralii gen. nov. sp. nov. is proposed. The type strain is IB182353 T (=MCCC 1K04631 T =JCM 34206 T ).