Engineering tobacco to remove mercury from polluted soil.

Area of Science:

• Biotechnology
• Environmental Science
• Plant Science

Background:

• Mercury contamination poses significant environmental and health risks.
• Existing transgenic tobacco for mercury removal have limitations, such as mercury release or low accumulation.
• Bioremediation using plants offers a sustainable approach to detoxify mercury-polluted soils.

Purpose of the Study:

• To develop novel transgenic tobacco lines with enhanced mercury accumulation and resistance.
• To evaluate the efficacy of two engineered tobacco lines, Ntk-7 and Ntp-36, in mercury-contaminated soil.
• To assess the potential of these engineered plants for practical mercury bioremediation.

Main Methods:

• Construction of two transgenic tobacco lines, Ntk-7 (merT-merP-merB1-merB2-ppk) and Ntp-36 (merT-merP-merB1-merB2-pcs1), incorporating mercury resistance genes from Pseudomonas K-62 and plant-specific genes.
• Verification of abundant expression of all introduced foreign genes.
• Assessment of mercury resistance and accumulation in Ntk-7 and Ntp-36 compared to wild-type tobacco under organic mercury and mercuric ion exposure.
• Quantification of mercury content in plant tissues, particularly roots, grown in mercury-polluted soil.

Main Results:

• Both Ntk-7 and Ntp-36 exhibited significantly higher mercury resistance than wild-type tobacco.
• Transgenic lines demonstrated substantially greater mercury accumulation capacity compared to the wild type.
• Ntp-36 showed superior mercury accumulation from soil, with root concentrations reaching up to 251 μg/g in polluted soil.
• Engineered tobacco successfully accumulated and retained mercury within the plant tissues.

Conclusions:

• Engineered tobacco lines Ntk-7 and Ntp-36 possess enhanced mercury resistance and accumulation capabilities.
• The Ntp-36 line is particularly promising for effective mercury bioremediation due to its high accumulation capacity and retention.
• This study presents the first evidence of engineered tobacco accumulating and retaining mercury from soil, highlighting its potential for environmental cleanup.