The release of harmful wastes via different industrial activities is the main cause of heavy
metal toxicity. The present study was conducted to assess the effects of heavy metal stress on the
plant growth traits, antioxidant enzyme activities, chlorophyll content and proline content of Sesbania
sesban with/without the inoculation of heavy-metal-tolerant Bacillus gibsonii and B. xiamenensis. Both
PGP strains showed prominent ACC-deaminase, indole acetic acid, exopolysaccharides production
and tolerance at different heavy metal concentrations (50–1000 mg/L). Further, in a pot experiment,
S. sesban seeds were grown in contaminated and noncontaminated soils. After harvesting, plants
were used for the further analysis of growth parameters. The experiment comprised of six different
treatments. The effects of heavy metal stress and bacterial inoculation on the plant root length;
shoot length; fresh and dry weight; photosynthetic pigments; proline content; antioxidant activity;
and absorption of metals were observed at the end of the experiment. The results revealed that
industrially contaminated soils distinctly reduced the growth of plants. However, both PGPR strains
enhanced the root length up to 105% and 80%. The shoot length was increased by 133% and 75%,
and the fresh weight was increased by 121% and 129%. The proline content and antioxidant enzymes
posed dual effects on the plants growing in industrially contaminated soil, allowing them to cope
with the metal stress, which enhanced the plant growth. The proline content was increased up to
190% and 179% by the inoculation of bacterial strains. Antioxidant enzymes, such as SOD, increased
to about 216% and 245%, while POD increased up to 48% and 49%, respectively. The results clearly
show that the utilized PGPR strains might be strong candidates to assist S. sesban growth under
heavy metal stress conditions. We highly suggest these PGPR strains for further implementation in
field experiments.