Characterization of polymorphic microsatellite loci in cultivated and wildPanax ginseng

Genetic population structure of the Vietnamese ginseng (Panax vietnamensis Ha et Grushv.) detected by microsatellite analysis

Abstract Panax vietnamensis Ha et Grushv. is a precious medicinal species native to the tropical forests of Vietnam. Due to habitat loss and over-harvesting, this species is endangered in Vietnam. To conserve the species, we investigated genetic variability and population structure using nine microsatellites for 148 individuals from seven populations across the current distribution range of P. vietnamensis in Vietnam. We determined a moderate genetic diversity within populations (HO = 0.367, HE = 0.437) and relatively low population differentiation (the Weir and Cockerham index of 0.172 and the Hedrick index of 0.254) and showed significant differentiation (P < 0.05), which suggested fragmented habitats, over-utilization and over-harvesting of P. vietnamensis. Different clustering methods revealed that individuals were grouped into two major clusters, which were associated with gene flow across the geographical range of P. vietnamensis. This study also detected that ginseng populations can have undergone a recent bottleneck. We recommend measures in future P. vietnamensis conservation and breeding programs.

Review: Molecular techniques to assess genetic variation within and between Panax ginseng and Panax quinquefolius

A variety of methods have been used to examine genetic differences in P. ginseng and P. quinquefolius. They have shown genetic differences within populations of P. ginseng (within and between elite cultivars, landraces and wild accessions), within populations of P. quinquefolius (within and between wild and cultivated accessions) and between P. ginseng and P. quinquefolius as well as other Panax species. Some examples of their applications have been to show that some elite cultivars are not uniform, there are possible founder effects in certain populations, there has been the spread of cultivated types into wild populations, relative diversity differs between different populations and identification of the source and purity of commercial samples. More work in the use of molecular markers for ginseng are needed, however, particularly the use of Next Generation Sequencing. Potential applications are the use of sequence analysis for genetic selection, breeding to develop new cultivars and providing traceability from field to consumer. Research on molecular markers in ginseng has lagged compared to other crops probably because of less of an emphasis on breeding for cultivar development and relatively small areas of production. The many potential benefits for ginseng production have yet to be realized.

Genetic diversity among cultivated and wild Panax ginseng populations revealed by high-resolution microsatellite markers

Background

Ginseng (Panax ginseng Meyer) is one of the world's most valuable medicinal plants with numerous pharmacological effects. Ginseng has been cultivated from wild mountain ginseng collections for a few hundred years. However, the genetic diversity of cultivated and wild ginseng populations is not fully understood.

Methods

We developed 92 polymorphic microsatellite markers based on whole-genome sequence data. We selected five markers that represent clear allele diversity for each of their corresponding loci to elucidate genetic diversity. These markers were applied to 147 individual plants, including cultivars, breeding lines, and wild populations in Korea and neighboring countries.

Results

Most of the 92 markers displayed multiple-band patterns, resulting from genome duplication, which causes confusion in interpretation of their target locus. The five high-resolution markers revealed 3 to 8 alleles from each single locus. The proportion of heterozygosity (H_e) ranged from 0.027 to 0.190, with an average of 0.132, which is notably lower than that of previous studies. Polymorphism information content of the markers ranged from 0.199 to 0.701, with an average of 0.454. There was no statistically significant difference in genetic diversity between cultivated and wild ginseng groups, and they showed intermingled positioning in the phylogenetic relationship.

Conclusion

Ginseng has a relatively high level of genetic diversity, and cultivated and wild groups have similar levels of genetic diversity. Collectively, our data demonstrate that current breeding populations have abundant genetic diversity for breeding of elite ginseng cultivars.

Applications of molecular markers in the discrimination of Panax species and Korean ginseng cultivars (Panax ginseng)

The development of molecular markers is one of the most useful methods for molecular breeding and marker-based molecular associated selections. Even though there is less information on the reference genome, molecular markers are indispensable tools for determination of genetic variation and identification of species with high levels of accuracy and reproducibility. The demand for molecular approaches for marker-based breeding and genetic discriminations in Panax species has greatly increased in recent times and has been successfully applied for various purposes. However, owing to the existence of diverse molecular techniques and differences in their principles and applications, there should be careful consideration while selecting appropriate marker types. In this review, we outline the recent status of different molecular marker applications in ginseng research and industrial fields. In addition, we discuss the basic principles, requirements, and advantages and disadvantages of the most widely used molecular markers, including restriction fragment length polymorphism, random amplified polymorphic DNA, sequence tag sites, simple sequence repeats, and single nucleotide polymorphisms.