Cell cycle and mismatch repair genes as potential biomarkers in Arabidopsis thaliana seedlings exposed to silver nanoparticles.

The expression of cell cycle genes and DNA mismatch repair (MMR) genes were analyzed in Arabidopsis thaliana seedlings exposed to 0, 0.2, 0.5 and 1 mg/L of silver nanoparticles for 24, 48 and 72 h using real-time PCR. Significant up-regulation of AtPCNA1 was observed after 24 h exposure to 0.2 and 0.5 mg/L of silver nanoparticles. AtPCNA2 gene was up-regulated after 24, 48 and 72 h exposure to 0.5 and 1 mg/L of silver nanoparticles. AtMLH1 gene was up-regulated after 48 h exposure to 0.5 and 1 mg/L of silver nanoparticles and down-regulated after 72 h. Down-regulation of AtMSH2, AtMSH3, AtMSH6 and AtMSH7 mRNA was observed after exposure to all concentrations of silver nanoparticles for different time periods. Exposure to silver ions showed no significant change in the expression levels of AtPCNA and MMR genes. The results show that AtPCNA and MMR genes could be used as potential molecular biomarkers.