Dr. Saranya Devi K

Screening of oryza sativa indigenous rhizobacteria for its bio-control and plant growth promoting potential.

• Authors Details :  
• Shyama P. Nair,  
• Saranya Devi K

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Bacteria that colonize plant roots and enhance the plant growth are denoted as Plant Growth Promoting Rhizobacteria (PGPR). The objective of this study is to isolate and identify Oryza sativa indigenous rhizobacteria and test for its, bio-control and various plant growth promoting traits under in-vitro condition. Nine rhizobacterial colonies isolated from healthy rice rhizosphere soil were screened for bio-control activity against rice pathogen Helminthosporium oryzae (rice brown spot) and Rhizoctonia solani (sheath blight) by performing dual culture method. The isolate B9 showed maximum antagonism against R. solani (73.7%) followed by isolate B2 (51.2%), isolate B1 (47.5%) and isolate B5 (42.5%) with different range of mycelial inhibition. Among nine rhizobacterial isolates tested, the growth of pathogenic fungi H. oryzae was only inhibited by the isolate B9 (20.5%). The isolates B1, B2, B5 and B9 exhibited maximum bio-control activities were further screened for different PGP traits, such as Phosphate (P) solubilization, Indole-3-Acetic Acid (IAA) production, Hydrogen Cyanide production (HCN) and extracellular enzyme production under in-vitro condition. The isolate B9 revealed the maximum P solubilization efficiency (99 SE), 45 μg/ml of IAA, HCN, amylase and cellulase production in maximum amount. The isolate B9 exhibited maximum bio-control, and PGP traits were identified by morphological and biochemical characterization and it was identified as Bacillus subtilis. In pot experiment, the rice seeds treated with B. subtilis exhibited significant shoot and root biomass when compared with un-inoculated rice and fungus-infected rice. This study highlighted the beneficial properties of native PGPR’s on growth promotion of rice and it could be formulated as bio-control as well as plant growth promoting agent, to reduce the application of chemical fertilizers in agricultural lands.

Article Subject Details

• Microbiology

Article Keywords Details

• Helminthosporium oryzae
• Oryza sativa
• Rhizobacteria
• Rhizoctonia solani
• Bacillus subtilis

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