The effect of drought stress on the expression of genes TaMOR, TaNAC۶۹-۱ and TaExpb۲۳ in different bread wheat (Triticum aestivum L.) cultivars

For evaluating the effects of TaMOR, TaNAC۶۹-۱ and TaExpb۲۳ expression on root system architecture and drought tolerance of wheat, ۱۰ bread wheat varieties were compared through germination test, pot experiment and field trial. In germination test, genotypes were evaluated under ۰, -۳ and -۶ bar osmotic potentials. In the pot experiment genotypes were compared at ۵۰%, ۷۵% and ۱۰۰% field capacity (FC) irrigation regime. In the field trial, genotypes were grown under well-watered and rain fed conditions. Based on the results of this experiment, it was concluded that water deficit had a significant effect on all traits except for seminal root numbers. Significant genotypic differences were observed for all traits indicating the presence of genetic variability among the genotypes. Correlation coefficients showed that TaMOR gene expression had a positive correlation with plant yield under ۷۵% FC stress (r=۰.۷۳۳*). TaNAC۶۹-۱ gene expression had positive correlations with plant yield and plant biomass under ۵۰% FC (r=۰.۶۳۴* and r=۰.۷۱۱*). TaNAC۶۹-۱ gene expression also showed a positive correlation with root numbers under ۵۰% FC condition (r=۰.۶۲۲*). TaNAC۶۹-۱ gene expression also showed a positive correlation with seminal root angle (r=۰.۶۴۸*) under severe stress. TaExpb۲۳ expression showed positive correlation with plant yield and biomass under ۷۵% FC (r=۰.۶۶۳* and r=۰.۷۲۳*). Based on the results of this experiment, it was concluded that under different stress levels, TaMOR, TaNAC۶۹-۱ and TaExpb۲۳ gene expressions had significant correlations with traits. Due to significant G×E interactions, it was also concluded that the effect of expression of TaMOR, TaNAC۶۹-۱ and TaExpb۲۳ genes on traits is different under distinct stress levels.

Keywords:

Gene expression , Root system architecture , Drought Tolerance , Water deficit