RAPD AND ISSR ANALYSES REVEAL LOW LEVELS OF GENETIC DIVERSITY IN PHYLLANTHUS AMARUS

Kizhanelli (Phyllanthus amarus) is a very popular Indian medicinal plant known for its antihepatotoxic (liver-protecting) activity due to two lignan phytochemicals named phyllanthin and hypophyllanthin. In the present investigation, an attempt was made to assess the extent of genetic diversity in Phyllanthus amarus and two of its related species, P. debilis and P. virgatus, using RAPD and ISSR markers. A collection of 54 genotypes of P. amarus and 3 genotypes each of P. debilis and P. virgatus from different districts of Tamil Nadu, India, were surveyed with 16 RAPD and 8 ISSR primers. The average polymorphism of RAPD and ISSR markers was 68.2% and 69.7%, respectively, across the 54 genotypes of P. amarus, which increased to 96.5% and 97.5%, respectively, with the inclusion of genotypes from P. debilis and P. virgatus. Similarity, matrices were generated from RAPD and ISSR marker data separately and also from the combined marker data using Jaccard’s coefficient, and dendrograms were constructed based on UPGMA clustering. The cluster analysis carried out to group the 54 genotypes of P. amarus based on RAPD and ISSR markers did not establish a clear-cut pattern according to collection sites. However, the cluster analysis across the 60 genotypes of all 3 species involved in the study revealed a clear cut grouping of genotypes at the species level. Both RAPD and ISSR markers separated P. virgatus from the two other species, P. amarus and P. debilis.