Determination of content of metallothionein and low molecular mass stress peptides in transgenic tobacco plants

Phytoremediation is a process that utilizes plants to remove, transfer, stabilize, or destroy pollutants in soil, sediment, and groundwater. Plants used for such purposes have several requirements. Genetic engineering these plants could be an effective tool used to acquire features needed for such purposes within a substantial amount of time. This paper aims to utilize electrochemical techniques to analyze transgenic tobacco and, thus, to reveal their heavy metals phytoremediation potential. Total thiol and metallothionein (MT) quantities were determined in the control and transgenic tobacco plants. The total content of thiols in transgenic plants varied within the range of 561 to 1,671 μg g⁻¹. Furthermore, the determination of MT was done on transgenic tobacco plants. The level of human MT in transgenic tobacco plants varied between 25 and 95 μg g⁻¹. However, a plant cell protects itself by synthesizing low molecular mass thiols such as reduced glutathione and phytochelatins to protect itself against heavy metals toxicity. The most important thiols, cysteine (Cys), glutathione (GSH), oxidised glutathione (GSSG) and phytochelatin 2 (PC2), were determined in the non-transgenic and transgenic tobacco plants by high performance liquid chromatography with electrochemical detection. Tobacco plants synthesizing the highest amount of metallothionein have the highest basal level of phytochelatin 2 as well as reduced glutathione and free cysteine. It clearly follows from the results obtained that the biosynthesis of particular thiols is mutually linked, which contributes to a better protection of a transgenic plant against heavy metals effects.