Bacterium from Pomegranate Rhizosphere from

Abstract—In the field of agricultural microbiology attempts are being made to find novel microbes for use as efficient biofertilizers including phosphate solubilizing microbes (PSM). Particularly, research on use of microbes for improving availability of phosphorus continues to be a major area of focus. Here we report isolation of Ralstonia pickettii- a novel phosphate solubilizing bacterium from a unique source- rhizosphere soil of pomegranate as well as some other relatively less explored sources from different parts of Western India. 23/134 cultures were found to be potential phosphate solubilizing bacteria. Further, 8/23 isolates were tested for an array of plant growth promoting attributes viz. solubilization of inorganic phosphate, production of phosphatase enzymes, indole acetic acid, siderophores, etc. The three cultures that showed best phosphate solubilization under shake flask conditions were culture no. GN/PSB/PC2, identified as Ralstonia (574 ppm), culture no. GN/PSB/KC5- Burkholderia tropica (400 ppm) and GN/PSB/CC2- Burkholderia cepacia (~375 ppm). Some of the cultures were found to produce appreciable amounts of plant growth promoters like indole acetic acid and siderophores. Index Terms—Ralstonia pickettii, Burkholderia spp., pomegranate, phosphate solubilizing bacteria, phosphatase