Gene expression and enzymatic activity of peroxidase and polyphenol oxidase in response to septoria tritici blotch disease

Many biotic and abiotic stresses bring about oxidative stress in plants. Peroxidase and polyphenol oxidase are among important antioxidant enzymes rendering a conservational role against variety of stressors. The present work was formulated in order to determine gene expression and enzymatic activities of the enzymes. For this aim, two various genotypes of bread wheat, i.e. Tajan and Promosing line#10, were subjected to an experiment under greenhouse condition; the former is susceptible and the latter is resistant to Septoria tritici (SG and RG, respectively). The plants were inoculated with S. tritici spores and the inoculated leaf samples were collected from the second leaf at different times (from 3-h to 21-d). Expression levels of POD and PPO genes were measured via qRT-PCR method. Moreover, enzymatic activities were specified after obtaining enzymatic extracts. The results acquired from determination of gene expressions revealed that SG experienced higher expression levels of POD genes than control sample except for the first and 21st days after inoculation. On the contrary, the gene’s transcripts were found to be higher in RG than control. In addition, the number of POD transcripts in SG was undermined by that in RG. PPO transcripts in SG increased 3 hours after inoculation followed by a considerable plunge compared with control sample. The transcripts were found to be more in RG than control sample peaking 10 days after inoculation. Furthermore, POD transcripts were detected to be higher in RG than SG at all times. Peroxidase activity in RG peaked after 21st day compared to control and SG. PPO activity was found to be higher in RG than control and SG at all times. It was concluded that PPO and POD enzymes seem to render considerable roles in resistance to STB.