Effect of Imidacloprid on Bacterial Soil Isolate Bacillus weihenstephanensis

Imidacloprid is a chloronicotinyl insecticide used widely to control biting and sucking in‐ sects. The over accumulation of this pesticide in environment requires higher awareness about this pesticide. Present investigation was carried out to analyze the effect of imida‐ cloprid on antioxidant enzymes such as superoxide dismutase, catalase and peroxidase in soil isolate Bacillus weihenstephanensis isolated after laboratory and field studies on the toxic effect of imidacloprid. Further, the genes for the three enzymes involved in the anti‐ oxidant defense process in soil isolate Bacillus weihenstephanensis were sequenced and identified. Study on the effect of 10–7 to 10–3 molar concentrations of imidacloprid for a period of 24, 48, 72 and 96 h on three antioxidant enzymes superoxide dismutase, catalase and peroxidase in Bacillus weihenstephanensis showed that there was an increase in the ac‐ tivity of all the three antioxidant enzymes. The enzyme activity increased with an in‐ crease in the concentration of insecticide proving that the inhibitory effect is dosedependent. Further, sequencing revealed that Fe/MnSOD (sod A), hydroxyperoxidase HP(II) (Kat E) and glutathione peroxidase genes were expressed in response to stress in‐ duced by imidacloprid treatment in Bacillus weihenstephanensis. The present investigation indicates that imidacloprid induces the expression of antioxidant enzymes in the soil iso‐ late Bacillus weihenstephanensis. The synthesis of antioxidant enzymes may be helping Ba‐ cillus weihenstephanensis in resisting the toxic effects of imidacloprid.