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Background: Panax species are important herbal medicinal plants in the Araliaceae family. Recently, we reported the complete chloroplast genomes and 45S nuclear ribosomal DNA sequences from seven Panax species, two (P. quinquefolius and P. trifolius) from North America and five (P. ginseng, P. notoginseng, P. japonicus, P. vietnamensis, and P. stipuleanatus) from Asia. Methods: We conducted phylogenetic analysis of these chloroplast sequences with 12 other Araliaceae species and comprehensive comparative analysis among the seven Panax whole chloroplast genomes. Results: We identified 1,128 single nucleotide polymorphisms (SNP) in coding gene sequences, distributed among 72 of the 79 protein-coding genes in the chloroplast genomes of the seven Panax species. The other seven genes (including psaJ, psbN, rpl23, psbF, psbL, rps18, and rps7) were identical among the Panax species. We also discovered that 12 large chloroplast genome fragments were transferred into the mitochondrial genome based on sharing of more than 90% sequence similarity. The total size of transferred fragments was 60,331 bp, corresponding to approximately 38.6% of chloroplast genome. We developed 18 SNP markers from the chloroplast genic coding sequence regions that were not similar to regions in the mitochondrial genome. These markers included two or three species-specific markers for each species and can be used to authenticate all the seven Panax species from the others. Conclusion: The comparative analysis of chloroplast genomes from seven Panax species elucidated their genetic diversity and evolutionary relationships, and 18 species-specific markers were able to discriminate among these species, thereby furthering efforts to protect the ginseng industry from economically motivated adulteration. Keywords: Araliaceae evolution, Chloroplast genome, dCAPS markers, Ginseng authentication, Panax species

Ilex is a monogeneric plant group (containing approximately 600 species) in the Aquifoliaceae family and one of the most commonly used medicinal herbs. However, its taxonomy and phylogenetic relationships at the species level are debatable. Herein, we obtained the complete chloroplast genomes of all 19 Ilex types that are native to Hong Kong. The genomes are conserved in structure, gene content and arrangement. The chloroplast genomes range in size from 157,119 bp in Ilex graciliflora to 158,020 bp in Ilex kwangtungensis. All these genomes contain 125 genes, of which 88 are protein-coding and 37 are tRNA genes. Four highly varied sequences (rps16-trnQ, rpl32-trnL, ndhD-psaC and ycf1) were found. The number of repeats in the Ilex genomes is mostly conserved, but the number of repeating motifs varies. The phylogenetic relationship among the 19 Ilex genomes, together with eight other available genomes in other studies, was investigated. Most of the species could be correctly assigned to the section or even series level, consistent with previous taxonomy, except Ilex rotunda var. microcarpa, Ilex asprella var. tapuensis and Ilex chapaensis. These species were reclassified; I. rotunda was placed in the section Micrococca, while the other two were grouped with the section Pseudoaquifolium. These studies provide a better understanding of Ilex phylogeny and refine its classification.

Summary Panax ginseng C. A. Meyer, reputed as the king of medicinal herbs, has slow growth, long generation time, low seed production and complicated genome structure that hamper its study. Here, we unveil the genomic architecture of tetraploid P. ginseng by de novo genome assembly, representing 2.98 Gbp with 59 352 annotated genes. Resequencing data indicated that diploid Panax species diverged in association with global warming in Southern Asia, and two North American species evolved via two intercontinental migrations. Two whole genome duplications (WGD) occurred in the family Araliaceae (including Panax) after divergence with the Apiaceae, the more recent one contributing to the ability of P. ginseng to overwinter, enabling it to spread broadly through the Northern Hemisphere. Functional and evolutionary analyses suggest that production of pharmacologically important dammarane‐type ginsenosides originated in Panax and are produced largely in shoot tissues and transported to roots; that newly evolved P. ginseng fatty acid desaturases increase freezing tolerance; and that unprecedented retention of chlorophyll a/b binding protein genes enables efficient photosynthesis under low light. A genome‐scale metabolic network provides a holistic view of Panax ginsenoside biosynthesis. This study provides valuable resources for improving medicinal values of ginseng either through genomics‐assisted breeding or metabolic engineering.

Ginseng represents a set of high-value medicinal plants of different species: Panax ginseng (Asian ginseng), Panax quinquefolius (American ginseng), Panax notoginseng (Chinese ginseng), Panax japonicus (Bamboo ginseng), and Panax vietnamensis (Vietnamese ginseng). Each species is pharmacologically and economically important, with differences in efficacy and price. Accordingly, an authentication system is needed to combat economically motivated adulteration of Panax products. We conducted comparative analysis of the chloroplast genome sequences of these five species, identifying 34-124 InDels and 141-560 SNPs. Fourteen InDel markers were developed to authenticate the Panax species. Among these, eight were species-unique markers that successfully differentiated one species from the others. We generated at least one species-unique marker for each of the five species, and any of the species can be authenticated by selection among these markers. The markers are reliable, easily detectable, and valuable for applications in the ginseng industry as well as in related research.

Background Various Panax ginseng cultivars exhibit a range of diversity for morphological and physiological traits. However, there are few studies on diversity of metabolic profiles and genetic background to understand the complex metabolic pathway in ginseng. Methods To understand the complex metabolic pathway and related genes in ginseng, we tried to conduct integrated analysis of primary metabolite profiles and related gene expression using five ginseng cultivars showing different morphology. We investigated primary metabolite profiles via gas chromatography–mass spectrometry (GC-MS) and analyzed transcriptomes by Illumina sequencing using adventitious roots grown under the same conditions to elucidate the differences in metabolism underlying such genetic diversity. Results GC-MS analysis revealed that primary metabolite profiling allowed us to classify the five cultivars into three independent groups and the grouping was also explained by eight major primary metabolites as biomarkers. We selected three cultivars (Chunpoong, Cheongsun, and Sunhyang) to represent each group and analyzed their transcriptomes. We inspected 100 unigenes involved in seven primary metabolite biosynthesis pathways and found that 21 unigenes encoding 15 enzymes were differentially expressed among the three cultivars. Integrated analysis of transcriptomes and metabolomes revealed that the ginseng cultivars differ in primary metabolites as well as in the putative genes involved in the complex process of primary metabolic pathways. Conclusion Our data derived from this integrated analysis provide insights into the underlying complexity of genes and metabolites that co-regulate flux through these pathways in ginseng.

The transfer of ancestral plastid genomes into mitochondrial genomes to generate mitochondrial plastid DNA (MTPT) is known to occur in plants, but its impacts on mitochondrial genome complexity and the potential for causing a false-positive DNA barcoding paradox have been underestimated. Here, we assembled the organelle genomes of Cynanchum wilfordii and C. auriculatum, which are indigenous medicinal herbs in Korea and China, respectively. In both species, it is estimated that 35% of the ancestral plastid genomes were transferred to mitochondrial genomes over the past 10 million years and remain conserved in these genomes. Some plastid barcoding markers co-amplified the conserved MTPTs and caused a barcoding paradox, resulting in mis-authentication of botanical ingredients and/or taxonomic mis-positioning. We identified dynamic and lineage-specific MTPTs that have contributed to mitochondrial genome complexity and might cause a putative barcoding paradox across 81 plant species. We suggest that a DNA barcoding guidelines should be developed involving the use of multiple markers to help regulate economically motivated adulteration.

Three Apiaceae species Ledebouriella seseloides, Peucedanum japonicum, and Glehnia littoralis are used as Asian herbal medicines, with the confusingly similar common name &ldquo, Bang-poong&rdquo, We characterized the complete chloroplast (cp) genomes and 45S nuclear ribosomal DNA (45S nrDNA) sequences of two accessions for each species. The complete cp genomes of G. littoralis, L. seseloides, and P. japonicum were 147,467, 147,830, and 164,633 bp, respectively. Compared to the other species, the P. japonicum cp genome had a huge inverted repeat expansion and a segmental inversion. The 45S nrDNA cistron sequences of the three species were almost identical in size and structure. Despite the structural variation in the P. japonicum cp genome, phylogenetic analysis revealed that G. littoralis diverged 5&ndash, 6 million years ago (Mya), while P. japonicum diverged from L. seseloides only 2&ndash, 3 Mya. Abundant copy number variations including tandem repeats, insertion/deletions, and single nucleotide polymorphisms, were found at the interspecies level. Intraspecies-level polymorphism was also found for L. seseloides and G. littoralis. We developed nine PCR barcode markers to authenticate all three species. This study characterizes the genomic differences between L. seseloides, P. japonicum, and G. littoralis, provides a method of species identification, and sheds light on the evolutionary history of these three species.

Ginsenosides are dammarane-type or triterpenoidal saponins that contribute to the various pharmacological activities of the medicinal herb Panax ginseng. The putative biosynthetic pathway for ginsenoside biosynthesis is known in P. ginseng, as are some of the transcripts and enzyme-encoding genes. However, few genes related to the UDP-glycosyltransferases (UGTs), enzymes that mediate glycosylation processes in final saponin biosynthesis, have been identified. Here, we generated three replicated Illumina RNA-Seq datasets from the adventitious roots of P. ginseng cultivar Cheongsun (CS) after 0, 12, 24, and 48 h of treatment with methyl jasmonate (MeJA). Using the same CS cultivar, metabolomic data were also generated at 0 h and every 12–24 h thereafter until 120 h of MeJA treatment. Differential gene expression, phylogenetic analysis, and metabolic profiling were used to identify candidate UGTs. Eleven candidate UGTs likely to be involved in ginsenoside glycosylation were identified. Eight of these were considered novel UGTs, newly identified in this study, and three were matched to previously characterized UGTs in P. ginseng. Phylogenetic analysis further asserted their association with ginsenoside biosynthesis. Additionally, metabolomic analysis revealed that the newly identified UGTs might be involved in the elongation of glycosyl chains of ginsenosides, especially of protopanaxadiol (PPD)-type ginsenosides.

Liriope platyphylla is herbaceous perennial plant belonging to the Asparagaceae family and widely used both as ornamental plant and herbal medicine. The complete chloroplast genome of L. platyphylla was 156,754 bp in length, which was composed of four distinct parts; a large single copy (LSC) of 85,118 bp, a small single copy (SSC) of 18,680 bp, and a pair of inverted repeat regions (IRa and IRb) of 26,478 bp. A total of 130 genes including 83 protein-coding genes, 39 tRNA genes and 8 rRNA genes were identified. The phylogenetic tree showed that L. platyphylla has a close relationship with other Nolinoideae plants, especially with Maianthemum dilatatum and Nolina atopocarpa.

Wolfiporia cocos have been used as diuretic, sedative, and tonic medicine. Although its medicinal effects were reported, its genomic information is rare. In this paper, we report the comple...

Rehmannia glutinosa is a plant used as traditional medicine for its various tonic effects in Korea and China. In this study, chloroplast genomes of two R. glutinosa were completed by de novo assembly using whole-genome Illumina sequence data. The length of chloroplast genomes of R. glutinosa collected from China and Korea was 153,680 bp and 153,499 bp, respectively. A total of 114 coding regions were predicted in both R. glutinosa including 80 protein-coding genes, 4 rRNA genes, and 30 tRNA genes. We identified abundant intra-species diversity of 87 InDels and 147 SNPs, among three R. glutinosa chloroplast genome sequences including one from GenBank. The phylogenetic analysis showed that these R. glutinosa were closely clustered with related Rehmannia species, separated from other Orobanchaceae and Scrophulariaceae species.

Magic Lily (Lycoris squamigera), belonging to the Amaryllidaceae family, is cultivated for ornamental and medicinal purposes. To characterize its genomic information, we obtained the complete chloroplast genome sequence of L. squamigera by assembling Illumina whole genome sequence data. The complete chloroplast genome is 158,482 bp in length which is composed of four unique regions, a large single copy region (LSC) of 86,454 bp, a small single copy region (SSC) of 18,500 bp, and a pair of inverted repeats (IR) of 26,764 bp. The genome annotation predicted 159 genes including 105 protein-coding genes, 46 tRNA genes, and 8 rRNA genes. Phylogenetic tree analysis revealed that L. squamigera clustered with Allium species belonging to the Amaryllidaceae family.

Hosta capitata (Koidz.) Nakai is an herbaceous perennial plant belonging to the Asparagaceae family and has become a popular ornamental plant. In this study, the chloroplast genome sequence of H. capitata was completed by de novo assembly with whole genome sequence data. The chloroplast genome of H. capitata is 156,416 bp in length, which is composed of a large single-copy (LSC) of 84,788 bp, a small single-copy (SSC) of 18,206 bp, and a pair of inverted repeat regions (IRa and IRb) of 26,711 bp, as four distinct parts. In total, 114 genes were identified including 80 protein-coding genes, 30 tRNA genes, and four rRNA genes. The phylogenetic analysis revealed that H. capitata has a close relationship with other Hosta species, H. minor and H. ventricosa, but is farther than the distance between them.

Lonicera japonica is a traditional medicinal plant well known for its anti-inflammatory effect. The complete chloroplast genome sequence of L. japonica collected from Korea was obtained by de novo assembly using whole genome sequence data. The chloroplast genome is 155,060 bp in length, containing 88,853 bp in a large single copy (LSC), 18,653 bp in a small single copy (SSC) and 23,777 bp in a pair of inverted repeats (IRs). A total of 112 genes including 78 protein-coding genes and 34 structural RNA genes were identified. The sequence comparison of two L. japonica collected from Korea and China revealed 48 single nucleotide polymorphisms (SNPs) and 45 insertions/deletions (InDels). In addition, phylogenetic analysis represented intraspecific diversity within L. japonica species collected in Korea and China.

In this study, complete chloroplast sequences of Artemisia gmelinii and Artemisia capillaris (the Asteraceae family), which have been used as herbal medicine in Korea, were characterized by de novo assembly with whole-genome sequence data. The genomes of A. gmelinii and A. capillaris were 151,318 bp and 151,056 bp in length, respectively. Both genomes harbored identical number of annotated genes, such as 80 protein coding genes, 4 rRNA genes and 30 tRNA genes. Phylogenetic tree revealed that both A. gmelinii and A. capillaris were closely grouped with other Artemisia species.

Eclipta prostrata is an herbal medicinal plant belonging to the Asteraceae family. In this study, complete chloroplast genome sequence of the E. prostrata was characterized by de novo assembly using whole genome sequence data. The genome of E. prostrata was 151,757 bp in length, which was composed of large single copy region of 83,285 bp, small single copy region of 18,346 bp and a pair of inverted repeat regions of 25,063 bp. The genome harboured 80 protein coding sequences, 30 tRNA genes and 4 rRNA genes. We confirmed close taxonomic relationship between E. prostrata and Helianthus annuus through phylogenetic analysis with chloroplast protein-coding genes.

Capsicum chinense is one of the domesticated pepper species and well known for its distinctive pungency. The complete chloroplast genome sequence of C. chinense was generated by de novo assembly using next generation sequencing data. The chloroplast genome is 156 807 bp long, containing large single-copy region of 87 290 bp and small single-copy region of 17 911 bp separated by a pair of inverted repeats of 25 803 bp. A total of 113 genes were predicted including 79 protein-coding genes, 30 tRNA genes and four rRNA genes. Phylogenomic analysis revealed that C. chinense chloroplast genome was most closely related to Capsicum annuum var. glabriusculum (American bird pepper), a wild progenitor of C. annuum.

In this study, a complete chloroplast genome sequence of Artemisia fukudo (Asteraceae family) was characterized by de novo assembly using whole genome sequence data. The chloroplast genome was 151,011 bp in length, comprising a large single-copy region of 82,751 bp, a small single copy region of 18,348 bp and a pair of inverted repeats of 24,956 bp. The genome contained 80 protein-coding genes, 4 rRNA genes and 30 tRNA genes. Phylogenetic tree revealed that A. fukudo was closely located in other Artemisia species, Artemisia montana and Artemisia frigida.

Taraxacum platycarpum and Taraxacum mongolicum are perennial plants utilized for medicinal purposes in the family Asteraceae. The complete chloroplast genome sequences of the two species were characterized by de novo assembly with whole genome sequencing data. The chloroplast genomes of T. platycarpum and T. mongolicum were 151,307 and 151,451 bp in length, respectively, and showed a typical quadripartite structure. The chloroplast genomes of both species contained the same number of genes, 79 protein-coding genes, 29 tRNA genes and 4 rRNA genes. Phylogenetic analysis indicated that the two Taraxacum species were grouped with T. officinale, all of which showed sister relationship with Lactuca sativa.

In this study, complete chloroplast genome sequences of Rhus chinensis was characterized by de novo assembly using whole genome sequence data. The chloroplast genome of R. chinensis were 149,011bp long, which was comprised of a large single copy region of 96,882 bp, a small single copy region of 18,647bp, and a pair of inverted repeats of 16,741 bp. The genome contained 77 protein-coding genes, four rRNA genes and 30 tRNA genes. Phylogenetic tree revealed that R. chinensis was closely grouped with Spondias species, S. tuberosa and S. bahiensis, belonging to the Anacardiaceae family.

Taraxacum officinale is a distributed weedy plant used as a traditional medicinal herb belonging to the family Asteraceae. The complete chloroplast genome of T. officinale was generated by de novo assembly with whole genome sequence data. The chloroplast genome was 151 324 bp in length, which consisted of a large single copy region of 83 895 bp and a short single copy region of 18 549 bp separated by a pair of inverted repeat regions of 24 440 bp. The chloroplast genome contained 79 protein-coding genes, 29 tRNA genes and four rRNA genes. Phylogenetic analysis revealed that T. officinale was closely related to Lactuca sativa.

Cynanchum auriculatum is a climbing vine belonging to the Apocynaceae family and shows very similar morphology to Cynanchum wilfordii, a medicinal plant. The complete chloroplast genome of C. auriculatum was generated by de novo assembly using the small amount of whole genome sequencing data. The chloroplast genome of C. auriculatum was 160 840 bp in length and consisted of four distinct regions, such as large single copy region (91 973 bp), small single copy region (19 667 bp), and a pair of inverted repeat regions (24 600 bp). The overall GC contents of the chloroplast genome were 37.8%. A total of 114 genes were predicted and included 80 protein-coding genes, 30 tRNA genes, and four rRNA genes. Phylogenetic analysis with the reported chloroplast genomes revealed that C. auriculatum is most closely related to Cynanchum wilfordii, a medicinal plant.

Cynanchum wilfordii (Maxim.) Hemsl. is a traditional medicinal herb belonging to the Asclepiadoideae subfamily, whose dried roots have been used as traditional medicine in Asia. The complete chloroplast genome of C. wilfordii was generated by de novo assembly using the small amount of whole genome sequencing data. The chloroplast genome of C. wilfordii was 161 241 bp long, composed of large single copy region (91 995 bp), small single copy region (19 930 bp) and a pair of inverted repeat regions (24 658 bp). The overall GC contents of the chloroplast genome was 37.8%. A total of 114 genes were annotated, which included 80 protein-coding genes, 30 tRNA genes and 4 rRNA genes. Phylogenetic analysis with the reported chloroplast genomes revealed that C. wilfordii is most closely related to Asclepias nivea (Caribbean milkweed) and Asclepias syriaca (common milkweed) within the Asclepiadoideae subfamily.