Phytoremediation of the herbicide simazine by p450 transgenic tobacco plants

The human Cytochrome P 450 CYPIA2 gene was introduced into tobacco plants (Nicotina tabacum cv. Virginia tobacco). CYP IA2 plants grown in soil clearly showed a healthy growth and tolerance to simazine, but non transgenic plants were completely damaged by the herbicides. The results proved that simazine was completely metabolized by the CYPIA2 transgenic plants to prevailingly non phytotoxic metabolites, the herbicide was biotransformed to a minor extent in non transgenic plants to metabolites with residual phytotoxicity. Thus, CYPIA2 tobacco plants can remove simazine herbicide from the soil, whereas non transgenic tobacco was damaged. The results revealed that in the NT tobacco plantlets and excised leaves, 32% and 50% respectively of the simazine absorbed by the tissues was metabolized into Des. The T-E plantlets metabolized 83% of the absorbed parent herbicide into different metabolites, while only 8.3% remained non-metabolized in the T-V plantlets. The main metabolite resulting from degradation of simazine by CYP1A2 transgenic plants was DiDes representing 41% (plantlets) and 37.3% (excised leaves) in case of T-E, and 35% (plantlets) and 60% (excised leaves) with T-V. Doses ranging between 4 and 40 mg simazine per plant were enough to inhibit the growth, finally causing the death for tobacco plants. When simazine was applied to the CYP1A2 transgenic tobacco plant (T-E and T-V) under similar conditions, the plants showed considerable resistance with all concentrations used.