DNA damage in potato plants induced by cadmium, ethyl methanesulphonate and γ-rays

We have calibrated the alkaline protocol of the plant comet (Single Cell Gel Electrophoresis) assay as a method for detecting the extent of induced DNA damage in potato plants (Solanum tuberosurn L. cultivar Korela). After 2 and 24 h treatments of the rooted cuttings with the heavy metal cadmium (Cd2+), a dose-response increase in DNA damage was noted versus controls in root nuclei. With a 24h recovery period, the Cd2+ -induced DNA damage in roots increased significantly. No significant increase in DNA damage was demonstrated in leaf nuclei after 24h Cd2+ treatments, but continuous Cd2+ treatments for 2 weeks resulted in an increase in leaf DNA damage. This increase may be however associated with necrotic and apoptotic DNA fragmentation, as the affected plants had inhibited growth and distorted yellowish leaves. For comparison, the monofunctional alkylating agent ethyl methanesulphonate, and gamma-rays were assessed for induced DNA damage. Analysis of the accumulation of cadmium by inductively coupled plasma optical emission spectrometry demonstrates that roots accumulate almost 9-fold more cadmium than aboveground parts of the rooted potato cuttings. This may explain the absence of Cd2+ genotoxicity in leaves after short-term treatments. (c) 2007 Elsevier B.V. All rights reserved.