| Species diversity and evolutionary potential are the foundation of survival and development of species themselves in the nature. Preserving species diversity and genetic diversity in species is protecting biodiversity in the ecosystem. The abundant genetic diversity is the substantial basis for species to adapt to environmental changes. The more genetic diversity or variation is possessed within species, the larger the ability of adapting to environment of species will be. In order to take effective measures to preserve genetic resources of survival and development for human being, genetic diversity and genetic structure of species, including the.magnitude of genetic variation among and within species, temporal and spatial distribution, and the relationships between species and environment should be further studied.Salvia miltiorrhiza Bunge, which belongs to Salvia genus, Labiatae family, is perennial herbage. Its dry radix and rootstalk have been using for Chinese traditional medicine for treating stasis, gall and delirium, and so on. Since 1970, with the decrease of wild S. miltiorrhiza resource, the demand for S. miltiorrhiza has exceeded its supply; so many areas in China began to cultivate S. miltiorrhiza. So far, cultivated S. miltiorrhiza has become the main raw materials source. As one of important wild origins of S.miltiorrhiza, Shandong Province has plentiful wild resources, but because of lack of the realization of preserving biological resource and awareness of persistent utilization, and the promotion of economical profit, wild S. miltiorrhiza is dug by the local people without continency, and the valuable genetic diversity of S. miltiorrhiza reduces year-by-year. Therefore, it is urgent to find out the genetic status of S. miltiorrhiza in Shandong Province to provide theoretic reference for preserving, domestication, genetic improvement and breeding for this important Chinese medicine.In high plants, chloroplast DNA has conservative coding region and relative-variable noncoding region. In some noncoding regions:of chloroplast DNA, relative-higher nucleotide replacement exists, making higher genetic variation among species and within species, so these noncoding regions have been used extensively to infer plant phylogenies and population structures. Among them, chloroplast psbA-trnH intergenic spacer is the most useful region for phylogenetic and biogeographic research. It locates between psbA gene and trnH gene and its average length is about 450bp. Because of indels, the length of this region is variable among plants. The two terminal sequences of this fragment are 75 bp conservative sequences, so it is easy to design usual primers.In this study, based on the sequence polymorphism of chloroplast psbA-trnH intergenic spacer region, the genetic structure of 3 wild populations and 1 cultivated population of S. miltiorrhiza from Shandong Province was studied. The results indicated that a total of 10 haplotypes were discovered from 80 samples, and 0.024 of nucleotide diversity were estimated, the cladogram of haplotypes classified 10 haplotypes into 2 major clusters, and each consisted of the haplotypes from 4 populations; Nei's gene diversity was 0.284, Shannon's information index was 0.406, and the percentage of polymorphic loci was 70%; the total genetic diversity was 0.905 and the within-population diversity was 0.747, interpopulation differentiation was 0.175; between different population pair, the genetic differentiation ranged from 0.017 to 0.1990, and gene flow ranged from 2.013 to 28.912; AMOVA revealed that 5% of the total genetic variation was partitioned among populations. The results revealed a high level of genetic diversity but low level of genetic differentiation in S. miltiorrhiza and confirmed that the genetic difference of the species existed mainly within population. In addition, the result also suggested that the cultivated S. miltiorrhiza of Shandong Province had complicated origin, and retained plentiful genetic diversity. |
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