Genetic diversity and population structure of Gynostemma pentaphyllun

Objective The genetic diversity and population structure of Gynostemma pentaphyllun were investigated to give the rise to theoretical foundation for its resources protection and rational utilization. Methods Six pairs of SSR primers were screened in 28 natural populations of 426 individuals to calculate the genetic parameters of G. pentaphyllun, and further then cluster analysis was carried out. Results The genetic diversity of G. pentaphyllun was low: the average value of the percentage of polymorphic loci(PPL) and Nei's genetic diversity index(He) was 58.33% and 0.18, respectively. The values of Shannon index(I) within different populations were ranged from 0.02 to 0.50. AMOVA revealed that genetic variation mainly existed among the populations(inter-populations was 78.86%, intra-populations was 21.14%). Furthermore, it possessed the significant population genetic differentiation(FST = 0.673) with low level of gene flow(Nm = 0.142). The outcomes of cluster analysis indicated there were distinct genetic relationships and genetic structures within different ploidys of G. pentaphyllun. Conclusion The populations of G. pentaphyllun exist a low level of genetic diversity and clear genetic structure. We suggest that it is necessary to employ in-situ conservation for the natural populations of G. pentaphyllun with higher genetic diversity, while for the populations which contain specific genotypes, it is better to combine ex-situ conservation with in-situ conservation in protection.