Three novel strains, SCSIO 12582T, SCSIO 12638 and SCSIO 12817, were isolated from tissue of the coral Pocillopora damicornis collected from Hainan province, PR China. The results of phylogenetic analysis based on 16S rRNA genes revealed that these three isolates showed nearly identical 16S rRNA gene sequences (99.86 %-99.93 %), forming a separate monophyletic cluster within the genus Alkalimarinus and closely related to Alkalimarinus sediminis FA028T. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) relatedness values among the three strains were 99.94 %-99.96 % and 100 %, respectively, indicating that these three isolates were affiliated with the same species. Analysis of the 16S rRNA gene sequence revealed that SCSIO 12582T (representative of the novel isolates) exhibited 98.49 % sequence similarity to A. sediminis FA028T. The ANI and dDDH values between SCSIO 12582T and A. sediminis FA028T were 74.81 % and 18.90 % respectively. These three isolates were facultatively anaerobic, Gram-stain-negative, rod shaped and catalase- and oxidase-positive. The DNA G+C content of SCSIO 12582T was 45.82 %. The major respiratory quinone was Q-9. The main cellular fatty acids were C16 : 0, summed feature 3 (C16 : 1ω7c/C16 : 1ω6c) and C16 : 1ω9c. The polar lipids present were phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. On the basis of the results of the phylogenetic, chemotaxonomic, phenotypic and genomic analysis, it was evident that isolates SCSIO 12582T, SCSIO 12638 and SCSIO 12817 represent a novel species of the genus Alkalimarinus, for which the name Alkalimarinus coralli sp. nov. is proposed. The type strain is SCSIO 12582T (=JCM35228T=GDMCC1.3061T).
Keywords: Alkalimarinus corallisp. nov; coral tissue; polyphasic taxonomy.