Assessment of tumor inducing potential of lead using crown gall tumor disc bioassay

The exposure of human beings to the compounds of lead (such as commercially important lead acetate) via different routes (including inhalation, ingestion, skin contact etc.) poses severe health risks. The present study involved the application of crown gall tumor assay using potato discs, to check the tumor inducing potential of lead acetate. Though originally designed for estimation of antitumor activity of various test compounds/plant extracts, this assay has recently been used for analysis of tumor inducing potential of different environmental samples. The experiment was divided into two sets to check the tumor induction by different concentrations of lead acetate alone and in combination with Agrobacterium tumefaciens. The controls used in the present study were A. tumefaciens alone and only discs. The study revealed that number of tumors induced in potato discs treated with different concentrations of lead alone (29.8–49.2) and in combination with A. tumefaciens (36.4–50.8) were significantly higher than the negative control (2.4). The increase in number of tumors was significantly higher in the discs which were treated with lead in combination with culture than the culture alone which indicates that the presence of lead enhanced the expression of Ti-plasmid of A. tumefaciens. Thus, the present study indicates that lead acetate has a significant tumor inducing potential and crown gall tumor disc bioassay can be used as a potential and reliable tool for screening the tumor inducing potential of various test agents.