Boosting stress resilience of Arabidopsis by heterologous expression of a selenocysteine containing glutathione peroxidase

Various environmental stress conditions in plants lead to oxidative stress and trigger damage to macromolecules causing losses in the crop yield.

To better cope with oxidative stress via boosting the redox potential, and antioxidant activity, the RedoxBoost project aims to ectopically express the selenoprotein glutathione peroxidase from Chlamydomonas reinhardtii (Sec-CrGPX) in Arabidopsis thaliana. Selenoproteins entail a selenocysteine (Sec) amino acid, encoded by the UGA, which encodes stop codon in higher plants.

Thereby, selenoproteins are not present in higher plants but present in eubacteria, archaea, and eukaryotes including green algae.

Most of the known selenoproteins were involved in antioxidant activity, redox regulation and are more resistant to irreversible oxidation under severe oxidative stress than their cysteine homologs.

I hypothesize that heterologous expression of selenoproteins in higher plants might offer an excellent opportunity for harnessing plants against oxidative stress and hence develop more stress resilient plants. Glutathione peroxidase is one of the most abundant selenoproteins and known to protect cells from oxidative damage.

To achieve heterologous expression of Sec-CrGPX in Arabidopsis, initially a DNA assembly of whole Sec biosynthetic pathway and Sec-CrGPX will be transiently expressed in Nicotiana benthamiana to get a swift assessment on the feasibility of ectopic Sec-CrGPX expression in land plants. Then, these Sec-CrGPX DNA assemblies will be stably transformed in Arabidopsis.

RedoxBoost for the first-time will integrate the coding mechanism for Sec in higher plants.

Biochemical and physiological studies will be performed in transgenic Arabidopsis plants under different stress conditions to determine altered stress resilience.

In a changing environment where flooding, waterlogging conditions, and saline soils are becoming more frequent RedoxBoost presents a novel approach for development of stress resilient plants.