The Research Of Heavy Metal Accumulation In Plants By Combining IaaM And ACC Deaminase Expression

Global industrialization has resulted in the release of large amounts of heavy metal into environments, causing serious environmental problems and posing a threat to human health. The use of hyperaccumulator plants to absorb and degrade contaminant ?Phytoremediation, has received increasing attention in recent years. The plants used in phytoremediation is required to accumulate large amounts of trace elements in the shoot and exhibit a high rate of biomass production. But most of the heavy metal hyperaccumulators in natural are small and slow growing, in order to improve the efficiency of remediation, the introduction of novel traits into high biomass plants in a transgenic approach is a promising strategy for the development of effective phytoremediation. In this experiment, we introduced the iaaM and ACC deaminase gene into tobacco and Petunia Hybrida, to see if the transgenic plants can tolerate and concentrate high levels of heavy metals.The expression of iaaM gene can promote the growth of Petunia Hybrida, transgenic plants grow more quickly than control plants. The heavy metal resistance and accumulation tests suggested that the iaaM-expressing Petunia Hybrida can accumulate more of cobalt and copper than wild type plants, but became hypersensitive to cobalt and copper poison. Transformed Petunia Hybrida with both iaaM and ACC deaminase gene can accumulate large amounts of cobalt and show significant resistance to cobalt and copper. On MS rooting medium with 126//M cobalt, the transgenic Petunia Hybrida take root normally, after four weeks of growth on MS medium supplemented with 168/^M cobalt, 1.5-fold more cobalt was accumulated in shoots than wild plants.The experiment of heavy metal resistance and accumulation in nutrient solution suggested, transformant tobacco with iaaM and ACC deaminase gene can tolerate and concentrate high levels of copper, cadmium and lead. When growing on sand supplemented with ISQwM cadmium, the shoots of transgenic tobacco accumulated 1119.1 mg ?kg^cadmium, reached the standard of hyperaccmulator and the growth of the root system has not received obvious restrain. When growing on soil supplenmented with different copper concentratin, the iaaM-expressing tobacco can accumulate more of copper, but showed enhanced copper sensitivity. Transgenic tobacco expressing the iaaM andACC deaminase accumulated more of copper element and show enhanced resistance to copper poison, The transgenic tobacco can grow on soil supplemented with 2.37mM copper, which showed 1.5-fold increase compared with wild plants.Heavy metal resistance and accumulation and PCR result indicated that the iaaM gene and ACC deaminase gene were indeed integrated into the tobacco and Petunia Hybrida genome. The expression of iaaM gene can promote the plant growth, so as to absorb more of elements. Co-expression of iaaM and ACC deaminase genes can tolerate and accumulate high content of heavy metals, improve the efficiency of phytoremendiation.