Microbulbifer bruguierae sp. nov., isolated from sediment of mangrove plant Bruguiera sexangula, and comparative genomic analyses of the genus Microbulbifer

A Gram-negative, non-motile, strictly aerobic, rod-shaped bacterium, designated as H12 T , was isolated from the sediments of mangrove plant Bruguiera sexangula taken from Dapeng district, Shenzhen, PR China. The pairwise 16S rRNA gene sequence analysis showed that strain H12 T shared high identity levels with species of the genus Microbulbifer , with the highest similarity level of 98.5 % to M. pacificus SPO729 T , followed by 98.1 % to M. donghaiensis CN85 T . Phylogenetic analysis using core-genome sequences showed that strain H12 T formed a cluster with type species of M. pacificus SPO729 T and M. harenosus HB161719 T . The complete genome of strain H12 T was 4 481 396 bp in size and its DNA G+C content was 56.7 mol%. The average nucleotide identity and digital DNA–DNA hybridization values among strain H12 T and type species of genus Microbulbifer were below the cut-off levels of 95–96 and 70 %, respectively. The predominant cellular fatty acids of strain H12 T were iso-C 15 : 0 (22.5 %) and C 18 : 1 ω 7 c (13.9 %). Ubiquinone-8 was detected as the major respiratory quinone. The polar lipids of strain H12 T comprised one phosphatidylglycerol, one phosphatidylethanolamine, one unidentified aminoglycophospholipid, one unidentified glycophospholipid, three unidentified glycolipids, two unidentified aminolipids, and one unidentified lipid. Based on polyphasic evidence, strain H12 T represents a novel species of the genus Microbulbifer , for which the name Microbulbifer bruguierae sp. nov. is proposed. The type strain is H12 T (=KCTC 92859 T =MCCC 1K08451 T ). Comparative genomic analyses of strain H12 T with strains of the genus Microbulbifer reveal its potential in degradation of pectin.