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

The taxonomic status of a bacterium, strain NCCP-246(T), isolated from rhizosphere of Vigna mungo, was determined using a polyphasic taxonomic approach. The strain NCCP-246(T) 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-246(T) belonged to genus Sphingobacterium. Strain NCCP-246(T) showed highest similarity to the type strain of Sphingobacterium canadense CR11(T) (97.67 %) and less than 97 % with other species of the genus. The DNA-DNA relatedness value of strain NCCP-246(T) with S. canadense CR11(T) and Sphingobacterium thalpophilum JCM 21153(T) 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-246(T) 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-246(T) (= JCM18974 (T) = KCTC 23914(T)).

Molecular identification and characterization of phosphate solubilizing pseudomonas sp. isolated from rhizosphere of mash bean (Vigna mungo L.) for growth promotion in wheat

Bio-inoculants have potential role in plant growth promotion. The present study evaluated the potential of Pseudomonas strains as bio-inoculants in wheat on the basis of plant growth promotion and physiological characterization. The 16S rRNA gene sequencing and phylogenetic analysis revealed that four isolated strains belonged to genus Pseudomonas. These strains were positive for phosphorus solubilization and indole acetic acid production, whereas only two strains were positive candidate for their nitrogen fixing ability as determined by presence or absence of nifH gene through amplification from polymerase chain reaction. The pot experiment showed that the integrated use of Pseudomonas strains as co-inoculant and 50% applied mineral fertilizers enhanced the maximum wheat growth and development from 58 to 140% for different shoot and root growth parameters. The strain NCCP-45 and NCCP-237 were closely related to Pseudomonas beteli and Pseudomonas lini, respectively. These isolated strains can be used to increase crop productivity by using as a bio-fertilizer inoculum.