Sphingobacterium pakistanensis sp. nov., a novel plant growth promoting rhizobacteria isolated from rhizosphere of Vigna mungo

Abstract

The taxonomic status of a bacterium, strain NCCP-246T, isolated from rhizosphere of Vigna mungo, was determined using a polyphasic taxonomic approach. The strain NCCP-246T can grow at 16–37 °C (optimum 32 °C), at pH ranges of 6–8 (optimum growth occurs at pH 7) and in 0–4 % (w/v) NaCl. Phylogenetic analysis based upon on 16S rRNA gene sequence comparison revealed that strain NCCP-246T belonged to genus Sphingobacterium. Strain NCCP-246T showed highest similarity to the type strain of Sphingobacterium canadense CR11T (97.67 %) and less than 97 % with other species of the genus. The DNA–DNA relatedness value of strain NCCP-246T with S. canadense CR11T and Sphingobacterium thalpophilum JCM 21153T was 55 and 44.4 %, respectively. The chemotaxonomic data revealed the major menaquinone as MK-7 and dominant cellular fatty acids were summed feature 3 [C16:1 ω7c/C16:1 ω6c] (37.07 %), iso-C15:0 (28.03 %), C16:0 (11.85 %), C17:0 cyclo (8.84 %) and C14:0 (2.42 %). The G+C content of the strain was 39.2 mol%. On the basis of DNA–DNA hybridization, phylogenetic analyses, physiological and, biochemical data, strain NCCP-246T can be differentiated from the validly named members of genus Sphingobacterium and thus represents as a new species, for which the name, Sphingobacterium pakistanensis sp. nov. is proposed with the type strain NCCP-246T (= JCM18974 T = KCTC 23914T).