Assessment of Genetic Stability in Three Generations of In Vitro Propagated Jatropha curcas L. Plantlets Using ISSR Markers

Abstract

Tissue culture has been widely employed in Jatropha curcas L. for the clonal multiplication of superior genotypes. However, the evaluation of genetic stability is necessary to detect somaclonal variants. In this context, the present aim was to evaluate the genetic stability of J. curcas plantlets, obtained via indirect organogenesis, by means of ISSR markers. To supply the explant sources for in vitro propagation, the first generation of plants was produced from in vitro germination of J. curcas seeds. Fragments of cotyledonary leaves were inoculated into medium supplemented with 1.5 mg L−1 BAP and 0.05 mg L−1 of IBA for induction of callogenesis. The resulting calli were transferred to bud induction medium. Subsequently, the buds were cultured in medium for elongation, giving rise to the second generation of plants. These plants provided new buds, which were excised and subcultured in elongation medium, yielding a third generation of plants. To evaluate genetic stability in three plant generations, twelve ISSR primers were used, resulting in 124 bands showing 41.93 % of polymorphism. Increase was observed in the level of somaclonal variation (SV) over the generations. The present study reports, for the first time, the analysis of genetic stability in J. curcas plantlets regenerated via indirect organogenesis by means of ISSR markers. The results suggest that the indirect route is associated to higher levels of genetic instability, which also increased with successive subcultures. The ISSR markers were efficient in detecting SV, and the generated genetic variability may be useful for breeding programs.