Genetic diversity on guaiacol peroxidase activity in different species of wheat under salinity

Salinity is a limiting factor for growth, quality and yield of crops in arid and semi-arid regions in world as well as in Iran. Guiacol Peroxidase (GPX) is a glycoprotein that is located in the cytosol, cell wall, and vacuoles, and uses from the oxidation of phenolic compounds to decontaminate and decompose of H2O2. In addition to antioxidant activity, this enzyme also plays a role in growth regulation. In order to investigation the effect of salinity stress on GPX activity in wheat wild relatives, an factorial experiment based on randomized complete block design included three concentration of salinity (0, 25 and 35 dS/m) as the first factor and twenty-two accessions related to eleven wheat species as the second factor was conducted at three replications. The ANOVA results indicated significant effect of salinity and salinity × genotype interaction on GPX activity. In main effect mean comparison, the highest amount of GPX activity (53.4 unit/mg protein) was observed in Aegilops ovata (accession Kamyaran-Kermanshah) and then in Darya cultivar (salinity sensitive check cultivar). The lowest GPX activity (8.5 unit/mg protein) was observed in Aegilops speltoides accession Sarpolezahab. The comparison of means for salinity × genotype interaction showed that the highest and lowest activity of GPX was obtained in Aegilops umbellulata (accession Islamabad-Kermanshah, Seyah- Khor) and Aegilops speltoides (accession Gasre-Shirin) in salinity of 25 dS/m, respectively. Reducing GPX activity in some genotypes/accession may be due to an increase in ascorbate content.

Keywords:

Genetic diversity , GPX , Salinity , Wheat.