Genotoxicity assessment of some selected chemicals on Tomato (Solanum lycopersicum)

Abstract

Genotoxic effects are considered among the most serious of the possible potential side effects of agrochemicals. Data of genotoxicity and carcinogenicity of insecticides and chemical fertilizers are rather controversial, depending on the genetic system or the assay used. Therefore, in present study, the genotoxicity profile of two agrochemicals viz insecticide 'YUJO' (Cholrpyrifos + Cypermethrin) and chemical fertilizer Boron 11 was evaluated with two genotoxicity assays using two different genetic systems. First assay was cytological assay which was conducted using root tips of non-target plant Allium cepa at three different conc. of each of the tested agrochemicals. The parameters evaluated in cytological assay were number of cells in dividing stage, mitotic indices (MI), % mitodepressive (MD) effect and chromosomal aberrations (CA) on A. cepa roots exposed to 0.2%, 0.6% and 1.0 % concentrations of the insecticide Yujo, and 0.25%, 0.75% and 1.25% conc. of Boron11. The results demonstrated that Yujo showed genotoxicity whereas Boron 11 showed both cyto as well as genotoxicity towards A. cepa meristematic cells, inducing chromosomal changes. Second assay i.e. molecular assay was performed with 20 ISSR primers using leaves of tomato plant, extracted after 2 days, 4 days and 6 days of the exposure to different conc. of both the test chemicals. The mutagenic activity of the active compounds was demonstrated by the detection of DNA changes in inter-simple sequence repeat (ISSR) markers in the treated cells compared to the control. The ISSR profiles showed a great variation in banding patterns, particularly in intensity, number, thickness and mobility of the generated DNA fragments by the used primers. There was a reduction of GTS value in comparison to control. Together, these results contribute to a better understanding of the damage caused by these substances in living organisms and reveal a promising strategy for prospective studies of the toxic effects of selected agrochemicals. Keywords : Cholrpyrifos + Cypermethrin, Boron 11, Mitotic Index (MI), mitodepressive (MD) effect, chromosomal aberrations (CA), A. cepa ,Tomato, Mutagenicity, ISSR, Genomic Template Stability (GTS), PIC value, RP value