Detection of genotoxic effect of cadmium on tomato ( Lycopersicon esculentum Mill.) using RAPD markers

Abstract

Tomato ( Lycopersicon esculentum Mill.) seeds were germinated in Petri dishes for 7-10 days. Seedlings were transferred to pots, grown in greenhouse and Cadmium (Cd) treatments were applied at concentrations of 0.0, 10.0, 50.0, 70.0 and 100.0 µM for two weeks. Genomic DNA from tomato leaves was used for RAPD analysis using four random primers (OPB05, OPB07, OPB08, and OPB09). RAPD profiles showed great variations in banding patterns, particularly in intensity, number, thickness and mobility of the PCR generated fragments. Appearance of new RAPD markers may occur because some oligonucleotide priming sites could become accessible to primers due to changes in DNA sequence. Disappearance of some DNA fragments might be due to structural rearrangement in DNA caused by different types of DNA damage after exposure to cadmium pollution whi ch can change the number of binding sites of Taq polymerase. Structural rearrangements may also result in an increase in the intensity and thickness of some DNA fragments. The change in the mobility of DNA fragments might be the result of single strand conformational polymorphism (SSCP) that reveals differences in electrophoretic mobility between normal and mutant single strands of DNA. These results indicated that the genomic DNA template stability was affected by cadmium pollution. In other words, cadmium pollution can cause genotoxic effects on tomato plants that may be regarded as a bioindicator of environmental pollution.