Genetic diversity and population structure assessment of Hellenia speciosa from Indian agro-ecological regions using inter-simple sequence repeat markers

Hellenia speciosa (J. Koenig) S. R. Dutta (Syn: Costus speciosus (J. Koenig) Sm.) is well known for its anti-diabetic properties and is in high demand for its steroidal sapogenin, diosgenin, which is used in the pharmaceutical industry for manufacturing steroidal drugs. The increasing demand for this plant has led to the depletion of its wild population. This study was conducted to reveal the genetic diversity of H. speciosa collected from various agro-ecological regions of India for use in devising conservational strategies, and cultivation and breeding programs. Twenty inter-simple sequence repeat markers yielded 304 products with 100% polymorphism demonstrating high genetic diversity. Nei ' s gene diversity and Shannon information indexes were estimated among the populations as 0.19 +/- 0.23 and 0.28 +/- 0.25, respectively. High genetic differentiation (G(ST) = 0.40) and low gene flow (N-m = 0.74) were observed, which corroborated with the analysis of molecular variance revealing maximum (86.75%) variance within populations. The unweighted pair group method with arithmetic mean analysis grouped all accessions into three major clusters. Principal component analysis showed that the first three components accounted for 30.66%, 4.54%, and 3.98% variation, respectively, and Bayesian clustering through structure showed the presence of two genetic population (K = 2). This study revealed high genetic diversity among the populations collected from high altitude compared to those from the plain. A positive but low correlation among genetic and geographic distances was obtained (r = 0.282, p < 0.0001). Identification of genetic diversity and intra population variation of a species are prime factors to take defined conservation strategies.