Molecular and biochemical evaluation of two bread wheat cultivars (Triticum aestivum L.) under oxidative stress

Metal stress is one of the serious problems that restrict crop production around the world. Metal stress causes phenotypic, enzymatic and gene expression changes in plants. Mainly, the harmful effect of metal stress is created by producing a large amount of Reactive Oxygen Species (ROS). Although, high concentrations of ROS is deterioration but they can act as a signaling factor in fairly low concentrations.In this study, a factorial experiment was performed inthe form of randomized complete block design (RCBD) with three replications. Experimentalfactors dinclude silver nitrate(AgNO3) in three levels (0, 1, 2 mM) as factor for oxidative stressand DABCO as antioxidant in three levels (0, 10, 20 Mm) was applied on ″Falat″ and ″Tajan″ cultivars of wheat. The evaluated traitsinclude chlorophylla and b, index of cellular oxidative levels(TBARM) and gene expressions amount of metallothionein and glucanase. Our results illustrate that high levels (2 mM) of silver nitrate treatment alone, decreased the chlorophyll a, b content, as well as the TBARM increases. Also,based on the results, under stress conditions the expression of metallothionein and glucanase genes firstly increased and then with increasing of silver nitrate level reduced their expression in both cultivars The highest and lowest expression of Metallothionein and Glucanasegenes was happen in 1 mM and 2 mM silvernitrate treatments respectively. By knowing the role of the studied genes in response to oxidative burst, mechanisem of heavy metal effect was anlyzed. In addition, using of these genes in molecular or classic breeding program well approved.