Assessment of the genotoxicity of heavy metals in Phaseolus vulgaris L. as a model plant system by Random Amplified Polymorphic DNA (RAPD) analysis

Abstract

Impact assessments of environmental pollutants are important in eco-genotoxicology. A random amplified polymorphic DNA (RAPD) technique was used to detect genotoxicity-induced DNA damage in Phaseolus vulgaris L. from heavy metals at two different concentrations. The results from six 10-base pair (bp) random RAPD primers with 60–70% GC content used, showed a total of 295 RAPD fragments of 700–4000 bp in molecular size in the seedlings of untreated and treated samples, of which only 163 fragments were polymorphic. Polymorphisms became evident as the disappearance and/or appearance of DNA fragments in treated samples compared to the control. A dendrogram constructed using the Numerical Taxonomy and Multivariate Analysis System (NTSYSps), showed that the control group merged with groups treated with CuSO₄·5H₂O (150 mg L⁻¹) and MnSO₄·H₂O (150 mg L⁻¹) in a separate cluster. These groups were linked with all of the other samples treated with metals at concentrations of 150 mg L⁻¹ and CuSO₄·5H₂O and Cd(NO₃)₂ at concentrations of 350 mg L⁻¹. Finally, the samples treated with metals at concentrations of 350 mg L⁻¹ together with NiSO₄ at the concentration of 150 mg L⁻¹, clustered separately. The DNA polymorphism detected by RAPD analysis offered a useful biomarker assay for the detection of toxic chemicals genotoxicity in plant model systems.

Keywords:

• RAPD
• genotoxic effects
• Phaseolus vulgaris
• heavy metals