Expression pattern of catalase, ascorbate peroxidase and polyphenol oxidase encoding genes under soil Zn deficiency in bread wheat

A factorial experiment (based on completely randomized design) with three replications was conducted in greenhouse to investigate the effect of soil Zn deficiency on the genes expression of antioxidant enzymes catalase (CAT), ascorbate peroxidase (APX) and polyphenol oxidase (PPO) in Zn-efficient and -inefficient bread wheat cultivars. Bayat and Niknejad (Zn-efficient) and Hirmand and Karaj 1 (Zn-inefficient) cultivars were grown under soil Zn deficiency and normal conditions. The expression levels of three above-mentioned genes were measured using Real time PCR technique in leaf and root tissues of the cultivars at two growth stages: one month after germination (vegetative) and 30% of heading (reproductive). The results of variance analysis and mean comparison of treatments showed that the highest rate of CAT expression (5.74 fold) observed in Zn-efficient cultivars (Bayat and Niknejad) at reproductive stage under soil Zn deficiency conditions. Moreover, the expression levels of CAT and APX in leaves of Zn-efficient cultivars were more than those of inefficient cultivars under soil Zn deficiency. The highest expression level of PPO (5.62 fold) was obtained in the leaves of Bayat (Zn-efficient) cultivar under Zn deficiency conditions. Therefore, the results of the current study proposed the possible roles of the genes encoding three studied antioxidant enzymes in tolerance of Zn-efficient bread wheat cultivars against soil Zn deficiency.