Biochemical characterization and PGP traits of plant growth promoting Rhizobacteria

摘要

Plant growth promoting rhizobacteria (PGPR) are known to influence plant growth by various mechanisms. In search of efficient PGPR strains with multiple activities, a total of 57 bacterial isolates belonging to Bacillus, Pseudomonas, Azotobacter and Rhizobium were isolated from different rhizospheric soil of sorghum, maize, groundnut, chilli, tomato and castor of southern telangana zone. These isolates were biochemically characterized and screened in vitro for their plant growth promoting traits likephosphate solubilization, production of indoleacetic acid (I A A), hydrogen cyanide (HCN) and siderophore. All the isolates of Azotobacter and 90.5 % of Rhizobium produced IAA. But only 25% of Pseudomonas and 20% of Bacillus produced IAA. 45% of Pseudomonas, Rhizobium and Azotobacter solubilized phosphate with highest solubilization zone of 17,13 and 14 mm respectively. Whereas 35% of Bacillus isolates solubilized phosphate with highest solubilization zone of 19 mm. Production of HCN was commonly detected in the isolates of Rhizobium (67.5%) followed by Pseudomonas (65%), Bacillus (55%) and Azotobacter (25%). Production of siderophores was detected in the isolates of Rhizobium (43%) followed by Pseudomonas (25%), Bacillus (25%). None of the Azotobacter isolates were able to produce siderophore.