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

The increasing use of nanoparticles (NPs) may have negative impacts on both organisms andthe environment.
The differential expression of mitochondrial manganese superoxide dismutase (MnSOD) gene in wheat in response to silver nitrate nanoparticles (AgNPs) and AgNO3 was investigated.
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.
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.
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.