Effect of rhizobacterium Bacillus sp. Sn14 on Sorghum bicolor plants grown in cadmium polluted soil

The effect of the cadmium-resistant rhizobacterium Bacillus sp. Sn14 on the physiological and biochemical parameters of Sorghum bicolor (L.) Moench. under cadmium stress was studied. We assessed the effects of heavy metal and bacterization on dry biomass production, photosynthetic pigment content, plant antioxidant enzyme activity (catalase, superoxide dismutase, ascorbate peroxidase, glutathione reductase, and glutathione-S-transferase), and cadmium accumulation in sorghum plants. The effect of cadmium was manifested by the inhibition of plant growth, decrease in the content of photosynthetic pigments, and increase in the protein content and activity of antioxidant enzymes in shoots, but not in roots. Bacterization of plants with the Bacillus sp. Sn14 strain contributed to overcoming cadmium stress by the plant: an increase in sorghum root biomass, protein, and photosynthetic pigments content was observed. The rhizobacterium Bacillus sp. Sn14 enhanced the phytoaccumulation of cadmium, increasing its translocation from roots to shoots by 63%, which led to an increase in the purification of soil by bacterized plants up to 31% compared to non-bacterized plants (9%). Thus, the use of the Bacillus sp. Sn14 strain to reduce the phytotoxic effect of cadmium and enhance its phytoaccumulation by sorghum was demonstrated.