植物基因工程修复土壤重金属污染研究进展

Phytoremediation technology is widely used for heavy metal pollution control in soil. However, slow growth rate, relatively low biomass and regional type of plants often limit the extensive application of these existing hyperaccumulators, searching better hyperaccumulators to complete the remediation is time-consuming and laborious. The application of genetic engineering in phytoremediation provides new idea for improving the phytoremediation efficiency. In this paper, the enhancement of phytoremediation for heavy metal contamination in soil by genetic engineering are reviewed. Moreover, the regulation genes for phytoremediation process are emphatically introduced, which includes: (1) The key genes, controlling the migration of heavy metals from the extracellular to the intracellular, are often related to zinc-iron regulatory proteins, yellow stripe-like proteins, and natural-resistance-associated marophage protein. They participate as carriers during the translocation and the uptake process of heavy metals in different tissues of plants. (2) The key genes, changing the location of heavy metals in cells, often regulate ATP-binding cassette transporter, cation diffusion facilitator family and P_1B type ATPase. They could improve the segregation ability of plants to heavy metals by controlling the intracellular transport of heavy metals. (3) The key genes related to phytochelatins and metallothionein, which reduce the toxicity to plants by forming stable chelates with heavy metals. All the regulation gene mentioned above reveal the entire process of heavy metal hypertolerance and hyperaccumulation characteristics. Hence it is suggested that reverse transcription used to improve expression of functional genes in the target plants might be better in the future, which is enable plants to grow in the natural environment. This method would regulate the balance of heavy metal content in plants, so as to overcome the shortcomings of poor environmental adaptability of hyperaccumulators.