Expression pattern of HMA1, HMA2 and HMA9 genes under Zn deficiency conditions in bread wheat cultivars with different Zn uptake efficiency

Heavy metal associated (HMA) proteins are involved in zinc (Zn) uptake from soil and its transport in plants. To study the expression pattern of HMA1, HMA2 and HMA9 genes in Zn-efficient and Zn-inefficient bread wheat cultivars under zinc deficiency conditions, a factorial experiment in completely randomized design (CRD) with three replications was carried out in greenhouse. Two Zn-efficient (Hamoon) and -inefficient (Hirmand) cultivars were grown under Zn deficient and sufficient (5 mg Zn per kg soil) conditions and relative expression of the studied genes in root and leaf at two growth stages, one month after cultivation (vegetative stage) and 30 % flowering (reproductive stage) were measured by real time PCR technique. The results revealed that the highest increase in the expression of HMA1 (30.9 fold more than check) and HMA2 (13.65 fold more than check) genes were observed at reproductive stage in the leaf and root of Hamoon cultivar under Zn deficiency conditions, respectively. In contrast, the highest increase in the expression of HMA9 gene (48.83 fold more than check) was found in the root of Hamoon cultivar at vegetative stage. Also, there was not a significant difference between Zn-efficient and -inefficient cultivars in term of expression of this gene in the root at reproductive stage. In conclusion, the results of the current study showed that the expression of HMA1, HMA2 and HMA9 genes are involved in soil Zn deficiency tolerance in Zn-efficient bread wheat cultivars.