Studies On Genetic Diversity And Genetic Structure Of Rehmannia

Rehmannia genus belonging to Scrophulariaceae contains six kinds of perennial herb. All of the Rehmannia are endemic products in China, except R. glutinosa distributed in Japan and Korea. In order to investigate the genetic background of different species about Rehmannia, We developed SSR primers from EST database and studied population genetics about 47 Rehmannia wild populations, which cover natural geographic distribution of Rehmannia include 9 pairs of primers. Discussed geographical distribution patterns of genetic variation of Rehmannia and its impact, on this basis; We have presented to the protection policy recommendations for wild populations of Rehmannia.The main results are as follows:We developed 15 pairs of SSR primers which were used to amplification in partially Rehmannia populations. The results revealed that these primers have good versatility between Rehmannia species and richer polymorphism, and the mean of polymorphic information content (PIC) value is 0.71.Using 9 pairs of primers, we analyzed the genetic diversity of Rehmannia 47 natural populations of 901 individuals, the results showed genetic diversity of the R. glutinosa populations at a high level (Hpop=0.507, PPL=91.57%), while Genetic diversity of the other species in Rehmannia is quite low. It may be associated with molecular markers we used, on the other hand, which may related to the reproductive system and the habits. R. glutinosa, R. chingii and R. piasezkii all have low genetic differentiation level and the value of Gst are 0.2740,0.2442 and 0.2452 respectively, which may correlated with the value of gene flow between these three types. AMOVA analysis indicated that the genetic variation of Rehmannia 47 populations mainly come from populations, the proportion of 78.96% are fromthe genetic variation among populations of the total genetic variation, only 14.78% be out of population.Based on Nei (1987) genetic distance, cluster and principal component analysis, results supported that the 47 natural populations can be divided into two branches, R. glutinosa and R. solanifolia formed one distinct lineage, the other species including R. chingii, R. piasezkii And R. henryi were formed other group. It means tetraploid and diploid species were separated into two groups. In diploid populations, R. chingii was separated from other species and then became one group.By using IBD (Isolation by Distance) software, we calculated Rehmannia correlation analysis between geographic distance and genetic distance of Rehmannia populations, the results indicated that the correlation between geographic isolation distance and genetic distance were significantly in R. glutinosa populations (r=0.2568, P=0.027). As for the R. piasezkii populations, calculated results (r=0.676, P=0.001) revealed there were very closely correlation. For the Rehmannia chingii populations, the correlation between geographic distance and genetic distance (r=0.0537, p=0.3700) was not significant.