Alleviation of drought stress by ACC (1-amino cyclopropane -1carboxylate) deaminase producing plant growth promoting rhizobacteria isolates in Capsicum annum. L

Plant growth promoting rhizobacteria (PGPR) with multiple PGP traits and ACC deaminase activity have additional advantage to mitigate drought stress. Strains with these characters and resistant to drought conditions could be hypothesized to be efficient isolates to overcome drought stress. The present study shows the ability of two such isolates IS-7 (Bacillus halotolerans) and IS-74 (Enterobacter hormaechei) to help the capsicum plants sustain even severe drought conditions (12.5% WHC). Comparatively, both the isolates were able to make the plant sustain drought but with decreased shoot and root wet and dry weights, root volume, root shoot ratio, leaf number and chlorophyll content. However, significant difference was not observed between control plant without drought and inoculated + drought induced plants at 50% WHC. Control plants subjected to drought and without isolates could not survive 50% WHC drought severity. Plant responses to defend against reactive oxygen species (ROS) was more accelerated in the activity of enzymatic (increased -SOD, APOX, GPOX, MDA and decreased-GR and NR) and non-enzymatic (proline) antioxidants. Elevated morphological and biochemical status indicate the positive effect of the isolates compared to control without treatment.