Dissertation
Dissertation > Biological Sciences > Botany > Plant Cell Genetics > Plant Genetic Engineering

Study on Phytodegradation of Organophosphorus Compounds by Transgenic Plants Expressing a Bacterial Organophosphorus Hydrolase

Author WangXiaoXue
Tutor WuNingFeng
School Chinese Academy of Agricultural Sciences
Course Biochemistry and Molecular Biology
Keywords organophosphorus hydrolase phytoremediation transgenic plant Methyl parathion
CLC Q943.2
Type Master's thesis
Year 2007
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Organophosphorus (OP) compounds which widely used as pesticides in agriculture caused broad-area pollution to environment. However, the economic and effective method for such pollutant treatment is absent. In this work, we expressed a bacterial organophosphorus hydrolase (OPH) gene in tobacco plants. The expression vector was constructed, and the final expression cassette, containing CaMV 35S promoter, the extensin sequence, ophc2 and nos termination sequence, was designated pBI-E-ophc2. The signal sequence from carrot extensin facilitated OPHC2 extracellular expression. The transformation resulted in 101 independent TO generation Kanamycin-resistant plants. Of the 101 lines, 80 were shown to have the transgene by PCR. 24 of the randomly selected 60 transgenic plants were positive in western blot analysis. The assay of enzyme activity showed that transgenic plants could secrete OPH into the growth medium. The results of Methyl parathion (Mep) toxicity and plant tolerance studies indicated that transgenic plants found to be resistance to Mep phytotoxicity, producing shoot and root biomasses greater than those of wild-type plants. The analysis of Mep degradation in growth medium and plant tissue revealed that the transgenic plants degrade Mep to very low level compared with the wild type plants after 14 days’ growth in 0.02% (v/v) Mep medium (0.5% agar). The results on our work suggest that transgenic plants successfully expressed the OPH gene and the remediation function of transgenic plants has been demonstrated, which will provide a new strategy for OP pollutant decontamination.

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