Marinobacterium rhizophilum sp nov isolated from the rhizosphere of the coastal tidal-flat plant Suaeda japonica

A Gram-negative, strictly aerobic, marine bacterium, designated strain CL-YJ9(T), was isolated from sediment closely associated with the roots of a plant (Suaeda japonica) inhabiting a coastal tidal flat. Cells of the novel strain were straight and rod-shaped and were motile by means of monopolar flagella. A phylogenetic analysis based on 16S rRNA gene sequences revealed that strain CL-YJ9(T) belongs to the genus Marinobacterium and was most closely related to Marinobacterium halophilum mano11(T) (94.1 % sequence similarity) and to other members of the genus Marinobacterium (92.5-93.7 % sequence similarity). The strain grew with 1-5 % NaCl (optimum, 3%) and at 5-30 degrees C (optimum, approx. 25 degrees C) and pH 6.0-9.0 (optimum, pH 7.0). The predominant cellular fatty acids were summed feature 3 (C-16:1 omega 7c and/or iso-C-15:0 2-OH, 40.3 %), C-18:1 omega 7c (26.6 %), C-16,C-: 0 (116.6 %) and C-10: 0 3-OH (7.1 %). The major isoprenoid quinone was Q-8. The G + C content of the genomic DNA was 61 mol%. On the basis of the data from this polyphasic study, strain CL-YJ9(T) belongs to the genus Marinobacterium but is distinguishable from the recognized species. Strain CL-YJ9(T) therefore represents a novel species, for which the name Marinobacterium rhizophilum sp. nov. is proposed. The type strain is CL-YJ9T (=KCCM 42386(T)=DSM 18822(T)).