Differential Expression of Mitochondrial Manganese Superoxide Dismutase (SOD) in Triticum aestivum Exposed to Silver Nitrate and Silver Nanoparticles

Background: The increasing use of nanoparticles (NPs) may have negative impacts on both organisms andthe environment. Objectives: The differential expression of mitochondrial manganese superoxide dismutase (MnSOD) gene in wheat in response to silver nitrate nanoparticles (AgNPs) and AgNO3 was investigated. Materials and Methods: A quantitative Real-Time RT-PCR experiment was carried out with MnSOD gene using RNAs isolated from wheat shoots treated for 0, 2, 6, 12, and 24 h with 100 mg.L-1 of either AgNO3 or AgNPs. Results: The results of this study showed that both treatments cause changes in the expression pattern of the MnSOD gene. While 2 and 6 h following the beginning of the stress, MnSOD expression was up-regulated significantly, in response to AgNO3 (1.4 and 2.8 fold, respectively), in response to AgNPs, it was up-regulated significant only after 6 h (1.6 fold), compared with the control. The gene expression, after 12 h in response to AgNO3 and AgNPs were down-regulated significantly (0.7 and 0.8 fold, respectively), and in the next 12 h , the expression appeared to be similar to the control. Conclusion: Exposure to both AgNPs and Ag ions led to a significant increase in MnSOD expression, but AgNO3 changed the MnSOD expression faster than AgNPs. Therefore, it is suggested that AgNO3 has greater penetrability and effectiveness.