Sphingobium rhizovicinum sp nov., isolated from rhizosphere soil of Fortunella hindsii (Champ. ex Benth.) Swingle

The taxonomic status of a pale-yellow-coloured bacterial isolate from rhizosphere soil of Fortunella hindsii (Champ. ex Benth.) Swingle was characterized using a polyphasic taxonomic approach. Comparative analysis of the 16S rRNA gene sequence showed that the isolate constituted a distinct branch within the genus Sphingobium. The generic assignment was confirmed by chemotaxonomic data, which revealed the presence of a fatty acid profile that was characteristic for the genus Sphingobium, consisting of straight-chain saturated and unsaturated as well as 2-OH fatty acids and the lack of 3-OH fatty acids, ubiquinone with ten isoprene units (Q-10) as the predominant respiratory quinone, and a polar lipid pattern that consisted of the predominant compounds phosphatidylethanolamine, phosphatidylglycerol, phosphatidyl monomethylethanolamine, phosphatidyidimethylethanolamine, diphosphaticlylglycerol, sphingoglycolipid and an unknown glycolipid. Spermidine was the major polyamine component. The genotypic and phenotypic data (physiology and fatty acid and polar lipid profiles) showed that the isolate merits classification as representing a novel species of the genus Sphingobium, for which the name Sphingobium rhizovicinum sp. nov. is proposed. The type strain is CC-FH12-1(T) (=CCM 7941(T) =BCRC 17770(T)).