Estimation of genetic variability and population structure in Ephedra gerardiana Wall. ex Stapf (Ephedraceae): An endangered and endemic high altitude medicinal plant

Abstract

Ephedra gerardiana is commonly known as ‘Gerard's Joint fir’, used in the indigenous systems as well as in modern systems of medicine. Almost every part of the plant possesses innumerable medicinal properties. Here we examined the genetic diversity and population structure of E. gerardiana employing Direct Amplification of Minisatellite DNA (DAMD) and Inter Simple Sequence Repeats (ISSR) methods. The cumulative (DAMD and ISSR) marker data revealed a high genetic diversity (P=90.84%, H=0.30, I=0.45) at species level than at population levels (P=62.43%, H=0.22, I=0.33), and moderate genetic differentiation (GST=0.27) among populations. Unweighted pair group method for arithmetic mean (UPGMA), Principle coordinate analysis (PCoA) and Bayesian clustering analysis revealed a significant population structure, and are in congruence with geographic distribution of the accessions. Mantel test revealed a significant correlation between geographic and genetic distances (r=0.86, P=0.007). Comparatively, high genetic diversity at species level than the population levels showed that these populations have evolved in response to their respective environments, and geographical isolation have played an important role in genetic differentiation and population structuring. However, increasing anthropogenic pressure on natural habitats of E. gerardiana, warrants immediate in-situ and ex-situ conservation measures to preserve diverse genotypes available in western Himalayan region for long term sustainability of E. gerardiana. To the best of our knowledge, present study seems to be the first endeavour to analyse genetic diversity and population structure of E. gerardiana using molecular markers.