Differential expression of antioxidants, Fe and Zn transporter genes in wheat under Pb stress

Abstract

Wheat (Triticum aestivum L.) is an important crop of the world and is considered as an essential food for one third of the world's population. Wheat yield and productivity are affected by many heavy metals including lead (Pb). In order to determine the genetic response of wheat against Pb stress, wheat was grown hydroponically with three different levels of Pb stress: 0, 75 and 225 µM. Total RNA was extracted from the leaves of two wheat cultivars 'Galaxy-13' and 'Punjab-11' in order to determine the expression of genes involved in detoxifying oxidative stress such as glutathione S-transferase (GST), glutathione reductase (GR), phospholipase Dα (PLDα) and zinc (Zn) transporter 8 precursor (ZIP8) and iron (Fe) regulatory transporter1 (IRT1). In silico characterization was performed to determine the sequence similarity of genes of this study in wheat and other crop plants. The results showed an increase in GST, GR and PLDα genes expression under severe stress conditions in both cultivars and the high expression of these genes could be important to protect cells from oxidative stress. Moreover, these genes could detoxify most of the secondary reactive oxygen species which are produced due to Pb stress. However, ZIP8 gene expression was high under mild stress condition while IRT1 gene expression was low in response to severe stress. In conclusion, high expression of GST, GR and PLDα genes could help wheat to survive under Pb stress and one or more of these genes could be used to screen Pb sensitive and resistant cultivars as well as in genetic transformation to develop Pb resistant wheat.