POTENTIAL OF NATIVE TRICHODERMA HARZIANUM TO TOLERATE AND REMEDIATE OF ORGANOPHOSPHATE PESTICIDES USED IN AGRICULTURE FIELDSONAM SHAHEEN AND S. KRISHNA SUNDARI
Pesticide toxicity has become a major threat to human health and ecosystem, due to heavy and repeated inputs in agriculture fields and persistent nature of this chemical compound in the agriculture fields. Monocrotophos and dimethoate belongs to organophosphate group of pesticides are known to have a significant adverse impact on human health directly affect CNS. Thus, there is a need to metabolize these compounds in the environment and removal of the residual amount of them. With this aim we have studied the tolerance and break down of environment through rhizoremediation methods. Tolerance of native isolate Trichoderma harzianum towards monocrotophos and dimethoate enrichment was studied through assays (plate assay/ liquid culture) at concentrations ranging from 0-2000 mg/l. At 1500mg/l concentration of dimethoate pesticide we observed isolates exhibiting 100% growth and afterwards the growth was reduced to 89% at 2000 mg/l. With monocrotophos the isolate showed constant growth till 1250 mg/l and afterwards it was reduced to 37% at 2000 mg/l concentration on solid agar plate. However, in liquid media isolate with dimethoate showed maximum growth only till 500 mg/ml concentration an initial increase in growth (dry weight) attaining and subsequently reduction upto 54% at 2000mg/l concentration however there was a negative growth impact with increasing pesticides concentration varied with the type of pesticides, with monocrotophos there was a progressive growth reduction which reached to 31% at 2000 mg/l concentration. Additionally, Trichoderma harzianum was observed to prefer monocrotophos and dimethoate as nitrogen source in minimal condition. Isolate Trichoderma harzianum recorded production of degradative enzyme of acid phosphate enzyme activity was 0.65 U/min/ml in culture treated dimethoate and alkaline phosphitase activity was 0.55 U/min/ml by culture treated with monocrotophos. Esterase activity was shown 14 U/min/ml in culture treated with monocrotophos. The native Trichoderma harzianum was not only able to endure higher pesticides concentration but can also offer a safe natural way for the removal of pesticides residue.