Isolation and Molecular Characterization of Plant Growth Promoting Rhizobacteria from Groundnut (Arachis Hypogaea L.) Rhizosphere

Abstract

Plant growth promoting rhizobacteria (PGPR) have been extensively employed as biofertilizers to enhance the soil nutrition for several crop plants. Rhizobacteria with beneficial effects for plants could therefore be used to reduce the dependence on synthetic chemical fertilizers in conventional agriculture. Within this study, we have explored for isolation of potential PGPR for groundnut crop from agricultural fields of Saurashtra region, Gujarat. A total of forty-two isolates from rhizospheric soil with different colony characteristics were isolated. All the strains were tested for plant growth promoting (PGP) traits to observe their properties and potential for plant growth promoting of all forty-two isolates. Plant growth promoting traits such as indole acetic acid (IAA), hydrogen cyanide (HCN), ammonia production, phosphate solubilisation and gibberellins production were performed. Thirty-four isolates produced IAA in the range of 20.7–133 µg/mL, seventeen isolates were positive for ammonia production in the range of 21.4–55.5 µg/mL, twenty-six isolates produced HCN in the range of 5.65–114.3 µg/mL,4 isolates displayed phosphate solubilisation in the range of 65.6–259.5 µg/mL, and 5 isolates were positive for gibberellins production in the range of 10.2–112.1 µg/mL. Moreover, only RGKP3 and RG12 isolates displayed positive results for all PGP traits. The potent isolate RGKP3 was further identified using 16SrRNA sequencing. The strain has close evolutionary similarities with Priestia megaterium. In future study, the potent PGPR will be studied to promote groundnut plant growth, enhanced crop production, and as a potential biofertilizer.