The Potential of Some Locally Grown Plants to Genetic Transformation with Cytochrome p450 and Their Use in Phytoremediation

To increase phytoremediation potential, Arabidopsis thaliana and Sesbania grandiflora were genetically
engineered with the rabbit cytochrome P450 enzyme. The P450 2E1 enzyme controls the ratelimiting step in the metabolism of multiple environmental pollutants, including Trichloroethylene (TCE), dichlorodiphenyltrichloroethane (DDT). The percentage of transformation increased at the less diluted cultures of Agrobacterium tumefaciens. Similarly, when bacterial concentration decreased, the chance of infected explants increased too and the concentration of A. tumefaciens culture was high at the time of infection. The concentration of DDT phytoextracted in this work ranged from 5.7 - 9.3 μg/ml in S. grandiflora and A. thaliana transgenic plants after 12 days. S. grandiflora transgenic lines showed more DDT absorption than A. thaliana transgenic plants. Trichloroethane (TCE) results showed a relationship between plant species and TCE metabolism. A. thaliana wild type and transgenic plants showed more translocation to Trichloroethanol (TCEOH) compared with Chloral (CH) while reverse thing happen in S. grandiflora. A. thaliana transgenic lines were more efficient in absorbing TCE in comparison with S. grandiflora transgenic lines. The ability of transgenic S. grandiflora plants were tested for their potential in remediation of metals (Potassium (K), Calcium (Ca), Manganese (Mn), Iron (Fe), Copper (Cu), Zinc (Zn), Brom (Br) and Lead (Pb)). Clearly, transgenic plants were more efficient achieving in 55, 59, 54, 52, 51, 54, 58 and 51% in comparison with non-transgenic plants. A. thaliana and S. grandiflora plants strongly expressed the enzyme P450 which is capable of translocating 90Sr, 238U and 137Cs from soils. Results also showed increased translocation (60, 70%) of 90Sr in transgenic S. grandiflora and A. thaliana respectively in comparison with wild type plants. A. thaliana transgenic lines showed an increased 238U translocation recording 90% and 80% for the F1 and F2 progeny respectively in comparison with wild type plants, while 238U concentration in soil decreased 50% and 60 % for the F1 and F2 progeny respectively. A. thaliana transgenic lines showed higher 137Cs translocation recording 70% in comparison with the wild type plant, and decreased to 30% in soil planted with transgenic A. thaliana.