Enzymatic amelioration of drought stress in rice through the application of plant growth promoting rhizobacteria (PGPR)

Recently, the role of plant growth promoting rhizobacterial (PGPR) on plant growth promotion and maintenance of plant homeostasis under abiotic stress is gaining importance. In present study, plant growth promoting rhizobacterial (PGPR) strains Pseudomonas fluorescence strain P2 and P16, Pseudomonas jessenii R62, Pseudomonas synxantha R81, Bacillus cereus 5507(1B), Bacillus cereus BSB 38 (14B) were tested for their role in enhancing plant growth and induction of stress related enzymes in swarna and swarna sub1 varieties of rice (Oryza sativa L.). Two PGPRs, Pseudomonas jessenii, R62, Pseudomonas synxantha, R81 were used as consortia. Most of the PGPR inoculated plants showed enhanced growth parameter as compared to uninoculated plants under drought stress. Quantitative analyses of stress related enzymes indicated that most of the plants inoculated with PGPRs showed higher activity of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) as compared to uninoculated plants. Among all the treatments, consortia of Pseudomonas jessenii R62 and Pseudomonas synxantha R81 treated plants showed better improvements in most of the growth parameter as well as stress related enzymatic activities. The greater induction of stress related enzymes in plants may be the mechanism through which these PGPRs help plants to tolerate the consequences of drought stress and maintenance of plant homeostasis under severe drought.