Isolation, Characterization and Identification of Potent Plant Growth Promoting Rhizobacteria From Asparagus Racemosus

Abstract

Present study was aimed to assess plant growth promoting activity of rhizobacteria isolated from rhizospheric soil of Asparagus racemosus. Thirty rhizobacteria were isolated and tested for Plant Growth Promoting Activity, with six of them being employed in further research. Functional plant growth promoting traits such as phosphorus solubilization, zinc and potassium solubilization, indole-3-acetic acid (IAA) production, siderophore production, and growth on Nfree media were used to characterize the isolates. Phosphate solubilization was much higher in isolates A and B (84.24 ±0.01 and 86.16 ±0.02 µg/ml respectively) and IAA production (90.11±0.1 and 253.45±0.01 respectively). Both isolates were capable of producing siderophore.Three of the six isolates were potassium solubilizers, two were zinc solubilizers, and three demonstrated exopolysaccharide production. 16S rRNA gene sequence analysis was used to identify isolates with the highest PGPR performance. Overall potent isolates were identified as Exiguobacterium acetylicum strain RGK and Enterobacter mori strain RGK1 respectively and deposited in GeneBank under accession number OL771442 and OL656822 respectively. These strains could be used as an PGPR inoculant having multiple PGP-traits for plant growth promotion. Key words: PGPR, Plant Growth Promoting Traits, Exiguobacterium acetylicum RGK , Enterobacter mori RGK1, Asparagus racemosus.