EFFECT OF A COMMONLY USED VETERINARY ANTIBIOTIC ON OXIDATIVE STRESS AND ROOT TRANSPORTERS OF EDIBLE LEGUMES AND LEAFY CROPS

Abstract

Antibiotic accumulation in soil and plants is a rising problem in agriculture creating a serious threat to living organisms in the environment, hence needing huge attention. To this end, glasshouse pot experiments were conducted to simulate contamination by veterinary antibiotic at 150 mg kg-1 and 4800 mg kg-1 in a virgin soil in which lentil (Lens culinaris Medik.), chickpea (Cicer arietinum L.), arugula (Eruca sativa Mill.) and cress (Lepidium sativum L.) were grown, aiming at evaluating the potential toxicity of antibiotic in plants roots during their growth period. Biomarkers of toxicity such as malondialdehyde and proline levels and antioxidative enzyme activity (superoxide dismutase, SOD; catalase, CAT; and guaiacol peroxidase, POD) were analyzed in the roots of the four species. In addition, gene expression level of the antioxidant enzymes Cu/Zn-SOD and CAT4, IFS /IFR that are key enzymes in the isoflavone pathway, and four ABC transporters MRP2, MRP4, TT12, and PDR11 that are involved in detoxification processes were evaluated. Among all four vegetables, chickpea had the highest antioxidant activity with reduced lipid peroxidation in roots treated with the highest antibiotic concentration suggesting its antibiotic tolerance. Cu/Zn-SOD was not the key player in SOD activity. High antibiotic concentration inhibited the antioxidant activity in lentil, arugula, and cress implying their sensitivity. In treated arugula, SOD and POD activities decreased synergistically while CAT increased; whereas, in treated cress, POD and CAT were induced at low antibiotic concentration and inhibited with the high one. Gene expression displayed tolerance of chickpea and sensitivity of arugula to the antibiotic added. Our results reveal toxic effect of antibiotic on lentil, arugula, and cress with chickpea exhibiting higher tolerance to high antibiotic concentrations Among all four vegetables, chickpea had the highest antioxidant activity with reduced lipid peroxidation in roots treated with the highest antibiotic concentration suggesting its antibiotic tolerance. Cu/Zn-SOD was not the key player in SOD activity. High antibiotic concentration inhibited the antioxidant activity in lentil, arugula and cress implying their sensitivity. In treated arugula, SOD and POD activities decreased synergistically while CAT increased; whereas in treated cress, POD and CAT were induced at low antibiotic concentration and inhibited with the high one. Gene expression displayed tolerance of chickpea and sensitivity of arugula to the antibiotic added. Our results reveals toxic effect of antibiotic on lentil, arugula and cress with chickpea exhibiting higher tolerance to high antibiotic concentrations.