The role of glutathione in cell cycle regulation and the DNA damage response in cadmium-exposed Arabidopsis thaliana plants

Abstract

Many regions are affected by cadmium (Cd) contamination of the soil. Plants can take up this metal and in that way cadmium can enter the food chain. It can cause an increased production of ROS leading to oxidative stress. Elevated ROS levels can cause damage to DNA. Plants poses an antioxidative defense system to protect themselves against oxidative damage. An example of an antioxidative metabolite is glutathione (GSH).

Preliminary data show that upon stress conditions like Cd exposure, cell division in A. thaliana leaves is inhibited. Glutathione is known for its involvement in cell cycle regulation and plant responses to Cd, therefore the hypothesis of this project is that GSH is involved in cell cycle regulation in response to Cd exposure in A. thaliana. To test this hypothesis, several parameters related to cell cycle, oxidative stress and DNA damage are compared between WT and cad2-1 mutant A. thaliana plants grown in hydroponics and exposed to 5 µM Cd. Additionally, a screening method to identify Cd-sensitive A. thaliana mutants using 96-well plates was optimized.

The measured parameters were significantly affected upon Cd exposure in the mutant, emphasizing the involvement of GSH in the Cd-induced DNA damage response and cell cycle regulation. Similar responses where observed in other GSH-deficient mutants, meaning that the observed effects were due to decreased GSH levels. Additionally, the 96-well system can be used to identify Cd-sensitive mutants.