Effect of nickel on regeneration in Jatropha curcas L. and assessment of genotoxicity using RAPD markers

The aim of the present study was to determine the effect of nickel on shoot regeneration in tissue culture as well as to identify polymorphisms induced in leaf explants exposed to nickel through random amplified polymorphic DNA (RAPD). In vitro leaf explants of Jatropha curcas were grown in nickel amended Murashige and Skoog (MS) medium at four different concentrations (0, 0.01, 0.1, 1 mM) for 3 weeks. Percent regeneration, number of shoots produced and genotoxic effects were evaluated by RAPD using leaf explants obtained from the first three treatments following 5 weeks of their subsequent subculture in metal free MS medium. Percent regeneration decreased with increase in addition of nickel to the medium up to 14 days from 42.31% in control to zero in 1.0 mM. The number of shoot buds scored after 5 weeks was higher in control as compared to all other treatments except in one of the metal free subculture medium wherein the shoot number was higher in 0.01 mM treatment (mean = 7.80) than control (mean = 7.60). RAPD analysis produced only 5 polymorphic bands (3.225%) out of a total of 155 bands from 18 selected primers. Only three primers OPK-19, OPP-2, OPN-08 produced polymorphic bands. The dendrogram showed three groups A, B, and C. Group A samples showed 100% genetic similarity within them. Samples between groups B and C were more genetically distant from each other as compared to samples between groups A and B as well as groups A and C. Cluster analysis based on RAPD data correlated with treatments.