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

Development and authentication of Panax ginseng cv. Sunhong with high yield and multiple tolerance to heat damage, rusty roots and lodging

Ginseng (Panax ginseng) has been used as a valuable medicinal plant in Asia, and the demand for ginseng production for health functional food is increasing worldwide after the COVID-19 crisis. Although a number of cultivars have been developed to increase ginseng production, none of them were widely cultivated in Korea because they could not resist various environmental stresses while being grown in one place for at least 4 years. To address this, Sunhong was developed as a ginseng cultivar with high yield and multiple stress tolerance by pure line selection. Sunhong showed high yield and heat tolerance comparable to Yunpoong, a representative high-yielding cultivar, and exhibited 1.4 times lower prevalence of rusty roots than Yunpoong, suggesting that Sunhong can keep its high yield and quality during long-term cultivation. In addition, distinct color and lodging resistance were expected to increase the convenience of cultivation. To supply pure seeds to farmers, we also established a reliable high-throughput authentication system for Sunhong and seven ginseng cultivars through genotyping-by-sequencing (GBS) analysis. The GBS approach enabled to identify a sufficient number of informative SNPs in ginseng, a heterozygous and polyploid species. These results contribute to the improvement of yield, quality, and homogeneity, and therefore promote the ginseng industry.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13580-023-00526-x.

Discrimination of Panax ginseng from counterfeits using single nucleotide polymorphism: A focused review

Discrimination of plant species, cultivars, and landraces is challenging because plants have high phenotypic and genotypic resemblance. Panax ginseng is commonly referred to as Korean ginseng, which contains saponins with high efficacy on cells, and has been reported to be worth billions in agroeconomic value. Korean ginseng's increasing global agroeconomic value includes additional species and cultivars that are not Korean ginseng but have physical characteristics close to it. This almost unidentifiable physical characteristic of Korean ginseng-like species is discriminated via molecular markers. Single nucleotide polymorphism (SNP), found across the plant species in abundance, is a valuable tool in the molecular mapping of genes and distinguishing a plant species from adulterants. Differentiating the composition of genes in species is quite evident, but the varieties and landraces have fewer differences in addition to single nucleotide mismatch. Especially in the exon region, there exist both favorable and adverse effects on species. With the aforementioned ideas in discriminating ginseng based on molecular markers, SNP has proven reliable and convenient, with advanced markers available. This article provides the simplest cost-effective guidelines for experiments in a traditional laboratory setting to get hands-on SNP marker analysis. Hence, the current review provides detailed up-to-date information about the discrimination of Panax ginseng exclusively based on SNP adding with a straightforward method explained which can be followed to perform the analysis.

Cynanchum auriculatum Royle ex Wight., Cynanchum bungei Decne. and Cynanchum wilfordii (Maxim.) Hemsl.: Current Research and Prospects

Cynanchum auriculatum Royle ex Wight. (CA), Cynanchum bungei Decne. (CB) and Cynanchum wilfordii (Maxim.) Hemsl. (CW) are three close species belonging to the Asclepiadaceous family, and their dry roots as the bioactive part have been revealed to exhibit anti-tumor, neuroprotection, organ protection, reducing liver lipid and blood lipid, immunomodulatory, anti-inflammatory, and other activities. Until 2021, phytochemistry investigations have uncovered 232 compounds isolated from three species, which could be classified into C21-steroids, acetophenones, terpenoids, and alkaloids. In this review, the morphology characteristics, species identification, and the relationship of botany, extraction, and the separation of chemical constituents, along with the molecular mechanism and pharmacokinetics of bioactive constituents of three species, are summarized for the first time, and their phytochemistry, pharmacology, and clinical safety are also updated. Moreover, the direction and limitation of current research on three species is also discussed.

De novo assembly and Transcriptome characterization of an endemic species of Vietnam, Panax vietnamensis Ha et Grushv., including the development of EST-SSR markers for population genetics

BACKGROUND

Understanding the genetic diversity in endangered species that occur inforest remnants is necessary to establish efficient strategies for the species conservation, restoration and management. Panax vietnamensis Ha et Grushv. is medicinally important, endemic and endangered species of Vietnam. However, genetic diversity and structure of population are unknown due to lack of efficient molecular markers.

RESULTS

In this study, we employed Illumina HiSeq™ 4000 sequencing to analyze the transcriptomes of P. vietnamensis (roots, leaves and stems). Raw reads total of 23,741,783 was obtained and then assembled, from which the generated unigenes were 89,271 (average length = 598.3191 nt). The 31,686 unigenes were annotated in different databases i.e. Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, Nucleotide Collection (NR/NT) and Swiss-Prot for functional annotation. Further, 11,343 EST-SSRs were detected. From 7774 primer pairs, 101 were selected for polymorphism validation, in which; 20 primer pairs were successfully amplified to DNA fragments and significant amounts of polymorphism was observed within population. The nine polymorphic microsatellite loci were used for population structure and diversity analyses. The obtained results revealed high levels of genetic diversity in populations, the average observed and expected heterozygosity were HO = 0.422 and HE = 0.479, respectively. During the Bottleneck analysis using TPM and SMM models (p < 0.01) shows that targeted population is significantly heterozygote deficient. This suggests sign of the bottleneck in all populations. Genetic differentiation between populations was moderate (FST = 0.133) and indicating slightly high level of gene flow (Nm = 1.63). Analysis of molecular variance (AMOVA) showed 63.17% of variation within individuals and 12.45% among populations. Our results shows two genetic clusters related to geographical distances.

CONCLUSION

Our study will assist conservators in future conservation management, breeding, production and habitats restoration of the species.

DNA barcoding as a valuable molecular tool for the certification of planting materials in bamboo

DNA barcodes developed for selected commercially important bamboo species can be utilized for the certification of planting stock in bamboo nurseries in absence of discriminatory features at the juvenile stage. Planting materials such as micropropagated plantlets, rhizome transplants and culm cuttings, generated at nursery level are directly procured for establishment of commercial plantations without any further verification. Very often misidentification and mixing up occur at nursery level and the error is not discovered until several years have passed. The present study evaluated the potentiality of seven Consortium for Barcode of Life (CBOL) recommended standard DNA barcode regions in commercially important bamboo species of India. Among the analyzed barcode regions, multiple sequence alignment (MSA) of psbA-trnH barcode region showed species-specific nucleotide differences in the studied bamboo taxa. The major nucleotide changes observed were transitions/transversions as well as insertions/deletions of nucleotides. Even though species-specific mononucleotide differences could be identified for most of the studied bamboo taxa, a small amount of sequence similarities were found in some of the Dendrocalamus and Bambusa species, which were grouped together in tree-based analysis. In subtribe Melocanninae, Ochlandra travancorica, Melocanna baccifera and M. clarkei showed unique species-specific psbA-trnH barcodes. Similarly, in the genus Oxytenanthera, unique species-specific psbA-trnH barcodes were obtained for O. monadelpha and O. parvifolia. Thus psbA-trnH barcode region generated distinct species-specific barcodes for commercial bamboo species in genera Bambusa, Dendrocalamus, Melocanna, Oxytenanthera as well as Ochlandra. Any national certification agency set up for the purpose can utilize psbA-trnH DNA barcode region to tag species identity and to establish the authenticity of multiplied planting materials in bamboos.

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.

Molecular discrimination of Panax ginseng cultivar K-1 using pathogenesis-related protein 5 gene

Background

The mixed-cultivation of different Panax ginseng cultivars can cause adverse effects on stability of yield and quality. K-1 is a superior cultivar with good root shape and stronger disease resistance. DNA markers mined from functional genes are clearly desirable for K-1, as they may associate with major traits and can be used for marker-assisted selection to maintain the high quality of Korean ginseng.

Methods

Five genes encoding pathogenesis-related (PR) proteins of P. ginseng were amplified and compared for polymorphism mining. Primary, secondary, and tertiary structures of PR5 protein were analyzed by ExPASy-ProtParam, PSSpred, and I-TASSER methods, respectively. A coding single nucleotide polymorphism (SNP)–based specific primer was designed for K-1 by introducing a destabilizing mismatch within the 3′ end. Allele-specific polymerase chain reaction (PCR) and real-time allele-specific PCR assays were conducted for molecular discrimination of K-1 from other cultivars and landraces.

Results

A coding SNP leading to the modification of amino acid residue from aspartic acid to asparagine was exploited in PR5 gene of K-1 cultivar. Bioinformatics analysis showed that the modification of amino acid residue changed the secondary and tertiary structures of the PR5 protein. Primer KSR was designed for specific discrimination of K-1 from other ginseng cultivars and landraces. The developed real-time allele-specific PCR assay enabled easier automation and accurate genotyping of K-1 from a large number of ginseng samples.

Conclusion

The SNP marker and the developed real-time allele-specific PCR assay will be useful not only for marker-assisted selection of K-1 cultivar but also for quality control in breeding and seed programs of P. ginseng.

The Multivariate Regression Statistics Strategy to Investigate Content-Effect Correlation of Multiple Components in Traditional Chinese Medicine Based on a Partial Least Squares Method

Amultivariate regression statisticstrategy was developed to clarify multi-components content-effect correlation ofpanaxginseng saponins extract and predict the pharmacological effect by components content. In example 1, firstly, we compared pharmacological effects between panax ginseng saponins extract and individual saponin combinations. Secondly, we examined the anti-platelet aggregation effect in seven different saponin combinations of ginsenoside Rb1, Rg1, Rh, Rd, Ra3 and notoginsenoside R1. Finally, the correlation between anti-platelet aggregation and the content of multiple components was analyzed by a partial least squares algorithm. In example 2, firstly, 18 common peaks were identified in ten different batches of panax ginseng saponins extracts from different origins. Then, we investigated the anti-myocardial ischemia reperfusion injury effects of the ten different panax ginseng saponins extracts. Finally, the correlation between the fingerprints and the cardioprotective effects was analyzed by a partial least squares algorithm. Both in example 1 and 2, the relationship between the components content and pharmacological effect was modeled well by the partial least squares regression equations. Importantly, the predicted effect curve was close to the observed data of dot marked on the partial least squares regression model. This study has given evidences that themulti-component content is a promising information for predicting the pharmacological effects of traditional Chinese medicine.