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

Abstract

Background: The increasing use of nanoparticles (NPs) may have negative impacts on both organisms and<span lang="EN">the environment. </span><br /> Objectives: The differential expression of mitochondrial manganese superoxide dismutase (<em>MnSOD</em>) gene in wheat in response to silver nitrate nanoparticles (AgNPs) and AgNO₃ was investigated.<br /> Materials and Methods: A quantitative Real-Time RT-PCR experiment was carried out with <em>MnSOD</em> 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.<br /> Results: The results of this study showed that both treatments cause changes in the expression pattern of the <em>MnSOD</em> gene. While 2 and 6 h following the beginning of the stress, <em>MnSOD</em> 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 AgNO₃and 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.<br /> Conclusion: Exposure to both AgNPs and Ag ions led to a significant increase in <em>MnSOD</em> expression, but AgNO₃ changed the <em>MnSOD</em> expression faster than AgNPs. Therefore, it is suggested that AgNO₃ has greater penetrability and effectiveness.