Enhanced expression of superoxide dismutase, phenylalanine ammonia-lyase and bZIP33 transcription factor encoding genes under Zn deficiency conditions in bread wheat (Triticum aestivum L.)

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 expression levels of genes encoding superoxide dismutase (SOD) and phenylalanine ammonia-lyase (PAL) antioxidant enzymes and bZIP33 transcription factor in Zn-efficient and -inefficient bread wheat cultivars.Bayat(Zn-efficient) and Hirmand (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 of the cultivars at two growth stages, one month after germination (vegetative) and 30% of heading (reproductive). The results of analysis of variance and mean comparisons of the treatments showed that the increased expression of SOD gene in vegetative and reproductive stages in Zn-efficient (Bayat) cultivar is more than that of Zn-inefficient (Hirmand) cultivar.The highest expression of PAL (50.56 fold) was observed in root of Zn-efficient (Bayat) cultivar at vegetative stage, butno significant difference was observed for PAL gene expression between Zn-efficient and -inefficient cultivars in both leaf and root tissues.The expression level of bZIP33 in the leaf of Zn-efficient cultivar (Bayat) under Zn deficiency conditions was more than that of Zn-inefficient cultivar, while no significant difference was found for the expression of this gene between Zn-efficient and in-efficient cultivars in root. Therefore, the results of this study demonstrated that SOD, PAL and bZIP33genes (probably through activation of Zn transporter genes) are involved in tolerance to soil Zn deficiency stress in Zn-efficient bread wheat cultivar.