The Effect of Iron Deficiency on the Relative Expression of Genes Encoding Catalase, Ascorbate Peroxidase and Polyphenol Oxidase Enzymes in Bread Wheat

To evaluate the expression pattern of genes encoding antioxidant enzymes catalase, ascorbate peroxidase and polyphenol oxidase under iron deficiency conditions in Fe- efficient (Pishtaz) and -inefficient (Falat) bread wheat cultivars, a CRD (completely randomized design) based factorial experiment was conducted with three replications. The cultivars were grown under iron deficiency (Less than 1.5 mg Fe/kg soil) and compared with normal conditions (10 mg Fe/kg soil). The relative expression levels of the above-mentioned genes were measured using Real-time PCR technique in the leaves and roots of the cultivars at two growth stages: vegetative (one month after germination) and reproductive (30% of heading). The results revealed a remarkable enhancement in calatalse expression in the roots of both cultivars in the vegetatative stage but it was higher in Fe-efficient cultivar than -inefficient one. The expression of this gene was decreased in leaves at the same stage as well as in the roots of both cultivars in the vegetative stage. The expression level of ascorbate peroxidase gene in the reproductive stage in the roots of Fe-inefficient cultivar was higher than that of -efficient one. In the vegetative stage, the expression of this gene increased in the leaves and roots of Fe-efficient cultivar, but it was decresed in Fe-inefficient cultivar. The relative expression level of polyphenol oxidase gene in the vegetative stage under iron deficiency conditions in the leaf increased almost three times, compared to the roots, while the expression of this gene decreased in the reproductive stage in both leaves and roots. By increasing the expression of both catalase and ascorbate peroxidase genes in the roots of both cultivars in the reproductive stage under iron deficiency conditions, it seems that bread wheat cultivars might reduce the deletrious effects of stress and maintain yield through transferring much iron to the seeds in the seed filling stage. The findings of the present study may increase our understanding of the important role of genes encoding antioxidant enzymes in Fe deficiency stress conditions.