Isolation of Two Novel Marine Bacteria belonging to the 4-Org1-14 and OCS116 Clades of Alphaproteobacteria and Their Genomic Characterization

초록

In this study, we have isolated and characterized two marine bacterial strains affiliated with the 4-Org1-14 and OCS116 clades, two abundant marine alphaproteobacterial groups, for which culture-dependent studies have been performed rarely. Strain IMCC3096 was non-motile, ivorycolored, and rod-shaped aerobic bacterium. Cellular growth occurred at 20?30°C, pH 6.0?7.0, and with 0.5?4.0% (w/v) NaCl. Phylogenetic analysis indicated that IMCC3096 belonged to the 4-Org1-14 clade, with <92% similarities to type strains of closely related phylogenetic groups. Strain IMCC20636 was non-motile, gray-colored, rod-shaped, and aerobic bacterium. Optimal growth was observed at 15?30°C, pH 7.0?7.5, and with 1.0?3.0% (w/v) NaCl. Phylogenetic analysis indicated that the strain belonged to the OCS116 clade of the order Rhizobiales, with <94% similarities to type strains of closely related families. The complete genomes of strains IMCC3096 and IMCC20636, determined by PacBio sequencing, were 4.29 Mb and 4.79 Mb in size with G+C contents of 64.6% and 53.9%, respectively. Since the genome sequences of the two strains are regarded as the sole genomic resource available currently for the 4-Org1-14 and OCS116 clades, further genomic and physiological analysis will contribute to understanding taxonomic and functional diversity of marine Alphaproteobacteria. [This study was supported by a grant from the Marine Biotechnology Program (PJT200620), funded by the MOF, Korea.]