The present study aims to unravel the mechanism of differential response of oxidative stress indices in response to rhizobacterial inoculation in Phaseolus vulgaris L. Oxidative burst triggered at the early events of the symbiotic interaction especially during nodulation stage which is necessary for the efficient development of healthy root nodules. To test our hypothesis, common bean seeds were inoculated with Rhizobium spp or co-inoculated with rhizobacteria and compared with uninoculated control plants. Afterward, at late flowering stage, the common bean nodules were collected, and the levels of ascorbic acid (AsA), hydrogen peroxide and lipid peroxidation activities were evaluated. There was constant increase in oxidative stress indices such as ascorbic acid, hydrogen peroxide (H2O2), and lipid peroxidation which might attributes to generation of free radicals during nodulation stage. However, ascorbic acid content in nodules was much higher than that in the root. Our results also

Phaseolus vulgaris L., oxidative stress, ascorbic acid, lipid peroxidation, H2O2.