Gene expression analysis of metallothionein and mineral elements uptake in tomato (Solanum lycopersicum) exposed to cadmium

Abstract

Heavy metals such as Cd are considered to be the most important pollutants in soil contamination. Cd is a non-essential element adversely affecting plant growth and development, and it has caused some physiological and molecular changes. Metallothioneins (MTs) are low molecular weight, cysteine-rich, and metal binding proteins. In this study, we aimed to evaluate the MT gene expression levels and minerals uptake in the tissues of Solanum lycopersicum exposed to Cd. The transcriptional expression of the MT genes was determined by real-time quantitative PCR. The MT genes were regulated by the Cd and the mineral elements uptake changed tissue type and applied doses. The MT1 and MT2 transcript levels increased in the roots, the leaves and the fruits of the tomato. The MT3 and MT4 transcript pattern changed according to the tissue types. The Cd treatment on the growth medium increased the Mg, Ca, and Fe content in both the leaves and fruits of the tomato. However, the Cd affected the mineral levels in the roots depending on the mineral types and doses. Also, the Cd content increased in the roots, the leaves, and the fruits of the tomato, respectively. The results presented in this study show that Cd has synergistic and/or antagonistic effects on minerals depending on the tissue types. These results indicate that the MT1 and MT2 expression pattern increased together with the Mg, Ca, and Fe content in both the leaves and the fruits of the tomato.