Influence of epigallocatechin-3-gallate (EGCG) and ascorbic acid (AsA) on heavy metal tolerance in plants

Abstract

Heavy metals induce reactive oxygen species (ROS) and damage of DNA or protein resulting in cell death and plant growth inhibition. It is important to investigate mechanism of detoxification and tolerance of heavy metals to improve plant growth under heavy metal stress. Here, we elucidated that the effect of epigallocatechin-3-gallate (EGCG), the major polyphenol in green tea, and ascorbic acid (AsA) on heavy metal tolerance in Arabidopsis and tobacco. Germination and seedling growth in Arabidopsis and tobacco were inhibited by Cd, Cu, Zn, Ni or Hg treatment with their concentration. Exogenous EGCG did not affect Cu tolerance but ameliorated the inhibition of seedling growth by Cd, Ni, Hg but Cu in Arabidopsis and tobacco. H2O2 and lipid peroxidation greatly increased by these metals but EGCG ameliorated them suggesting that EGCG plays a role as an antioxidant. On the other hand, AsA application remarkably enhanced the Hg-inhibited seedling growth of Arabidopsis and tobacco. When Arabidopsis seedlings were treated with AsA and Hg, higher chlorophyll and lower H2O2 were determined in comparison to Hg alone treatment. Our results suggest that EGCG and AsA could protect plant cells from heavy metal induced ROS mediated toxicity.