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

Abstract

Two novel filamentous bacteria, designated as IB182353T and IB182357, were isolated from stony coral of the South China Sea. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strains IB182353T and IB182357 were closely related to Hazenella coriacea DSM 45707T (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 IB182353T 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 IB182353T was distinguishable from its related type strains by the contents of two fatty acids, iso-C15 : 0 and iso-C17 : 1  ω10c. Based on polyphasic taxonomic characterization, we propose that strains IB182353T 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 IB182353T (=MCCC 1K04631T=JCM 34206T).