Comparative chloroplast genome analyses of cultivated and wild Capsicum species shed light on evolution and phylogeny.

The chloroplast (cp.) genome, also known as plastome, plays crucial roles in plant survival, adaptation, and evolution. The stable genetic structure of cp. genomes provides an ideal system for investigating species evolution. We sequenced three complete cp. genome sequences of Capsicum species and analyzed them using sequences of various Capsicum species retrieved from the NCBI database. The cp. genome of Capsicum species maintains a well-preserved quadripartite structure consisting of two inverted repeats (IRs) flanked by a large single copy (LSC) region and a small single copy (SSC) region. The sizes of cp. genome sequences ranged from 156,583 bp (C. lycianthoides) to 157,390 bp (C.pubescens). A total of 127-132 unique genes, including 83-87 protein-coding, 36-37 tRNA, and eight rRNA genes, were predicted. Comparison of cp. genomes of 10 Capsicum species revealed high sequence similarity in genome-wide organization and gene arrangements. Fragments of trnT-UGU/trnL-UAA, ccsA, ndhD, rps12, and ycf1 were identified as variable regions, and nucleotide variability of LSC and SSC was higher than that of IR. Phylogenetic speciation analysis showed that the major domesticated C. annuum species were the most extensively divergent species and closely related to C. tovarii and C. frutescens. Analysis of divergent times suggested that a substantial range of speciation events started occurring ~ 25.79 million years ago (Mya). Overall, comparative analysis of cp. genomes of Capsicum species not only offers new insights into their genetic variation and phylogenetic relationships, but also lays a foundation for evolutionary history, genetic diversity, conservation, and biological breeding of Capsicum species.

Phytochemistry of ginsenosides: Recent advancements and emerging roles.

Ginsenosides, a group of tetracyclic saponins, accounts for the nutraceutical and pharmaceutical relevance of the ginseng (Panax sp.) herb. Owing to the associated therapeutic potential of ginsenosides, their demand has been increased significantly in the last two decades. However, a slow growth cycle, low seed production, and long generation time of ginseng have created a gap between the demand and supply of ginsenosides. The biosynthesis of ginsenosides involves an intricate network of pathways with multiple oxidation and glycosylation reactions. However, the exact functions of some of the associated genes/proteins are still not completely deciphered. Moreover, ginsenoside estimation and extraction using analytical techniques are not feasible with high efficiency. The present review is a step forward in recapitulating the comprehensive aspects of ginsenosides including their distribution, structural diversity, biotransformation, and functional attributes in both plants and animals including humans. Moreover, ginsenoside biosynthesis in the potential plant sources and their metabolism in the human body along with major regulators and stimulators affecting ginsenoside biosynthesis have also been discussed. Furthermore, this review consolidates biotechnological interventions to enhance the biosynthesis of ginsenosides in their potential sources and advancements in the development of synthetic biosystems for efficient ginsenoside biosynthesis to meet their rising industrial demands.

Proteomic Analysis Reveals a Critical Role of the Glycosyl Hydrolase 17 Protein in Panax ginseng Leaves under Salt Stress.

Ginseng, an important crop in East Asia, exhibits multiple medicinal and nutritional benefits because of the presence of ginsenosides. On the other hand, the ginseng yield is severely affected by abiotic stressors, particularly salinity, which reduces yield and quality. Therefore, efforts are needed to improve the ginseng yield during salinity stress, but salinity stress-induced changes in ginseng are poorly understood, particularly at the proteome-wide level. In this study, we report the comparative proteome profiles of ginseng leaves at four different time points (mock, 24, 72, and 96 h) using a label-free quantitative proteome approach. Of the 2484 proteins identified, 468 were salt-responsive. In particular, glycosyl hydrolase 17 (PgGH17), catalase-peroxidase 2, voltage-gated potassium channel subunit beta-2, fructose-1,6-bisphosphatase class 1, and chlorophyll a-b binding protein accumulated in ginseng leaves in response to salt stress. The heterologous expression of PgGH17 in Arabidopsis thaliana improved the salt tolerance of transgenic lines without compromising plant growth. Overall, this study uncovers the salt-induced changes in ginseng leaves at the proteome level and highlights the critical role of PgGH17 in salt stress tolerance in ginseng.

Prolonged Exposure to High Temperature Inhibits Shoot Primary and Root Secondary Growth in Panax ginseng.

High temperature is one of the most significant abiotic stresses reducing crop yield and quality by inhibiting plant growth and development. Global warming has recently increased the frequency of heat waves, which negatively impacts agricultural fields. Despite numerous studies on heat stress responses and signal transduction in model plant species, the molecular mechanism underlying thermomorphogenesis in Panax ginseng remains largely unknown. Here, we investigated the high temperature response of ginseng at the phenotypic and molecular levels. Both the primary shoot growth and secondary root growth of ginseng plants were significantly reduced at high temperature. Histological analysis revealed that these decreases in shoot and root growth were caused by decreases in cell elongation and cambium stem cell activity, respectively. Analysis of P. ginseng RNA-seq data revealed that heat-stress-repressed stem and root growth is closely related to changes in photosynthesis, cell wall organization, cell wall loosening, and abscisic acid (ABA) and jasmonic acid (JA) signaling. Reduction in both the light and dark reactions of photosynthesis resulted in defects in starch granule development in the storage parenchymal cells of the main tap root. Thus, by combining bioinformatics and histological analyses, we show that high temperature signaling pathways are integrated with crucial biological processes that repress stem and root growth in ginseng, providing novel insight into the heat stress response mechanism of P. ginseng.

Gibberellin Signaling Promotes the Secondary Growth of Storage Roots in Panax ginseng.

Gibberellins (GAs) are an important group of phytohormones associated with diverse growth and developmental processes, including cell elongation, seed germination, and secondary growth. Recent genomic and genetic analyses have advanced our knowledge of GA signaling pathways and related genes in model plant species. However, functional genomics analyses of GA signaling pathways in Panax ginseng, a perennial herb, have rarely been carried out, despite its well-known economical and medicinal importance. Here, we conducted functional characterization of GA receptors and investigated their physiological roles in the secondary growth of P. ginseng storage roots. We found that the physiological and genetic functions of P. ginseng gibberellin-insensitive dwarf1s (PgGID1s) have been evolutionarily conserved. Additionally, the essential domains and residues in the primary protein structure for interaction with active GAs and DELLA proteins are well-conserved. Overexpression of PgGID1s in Arabidopsis completely restored the GA deficient phenotype of the Arabidopsis gid1a gid1c (atgid1a/c) double mutant. Exogenous GA treatment greatly enhanced the secondary growth of tap roots; however, paclobutrazol (PCZ), a GA biosynthetic inhibitor, reduced root growth in P. ginseng. Transcriptome profiling of P. ginseng roots revealed that GA-induced root secondary growth is closely associated with cell wall biogenesis, the cell cycle, the jasmonic acid (JA) response, and nitrate assimilation, suggesting that a transcriptional network regulate root secondary growth in P. ginseng. These results provide novel insights into the mechanism controlling secondary root growth in P. ginseng.

Metabolomics for Age Discrimination of Ginseng Using a Multiplex Approach to HR-MAS NMR Spectroscopy, UPLC-QTOF/MS, and GC × GC-TOF/MS.

(1) Background: The ability to determine the age of ginseng is very important because the price of ginseng depends on the cultivation period. Since morphological observation is subjective, a new scientific and systematic method for determining the age of ginseng is required. (2) Methods: Three techniques were used for a metabolomics approach. High-resolution magic-angle-spinning nuclear magnetic resonance (HR-MAS NMR) spectroscopy was used to analyze powdered ginseng samples without extraction. Ultrahigh-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-QTOF/MS) and gas chromatography quadrupole time-of-fight mass spectrometry (GC-TOF/MS) were used to analyze the extracts of 4-, 5-, and 6-year-old ginseng. (3) Results: A metabolomics approach has the potential to discriminate the age of ginseng. Among the primary metabolites detected from NMR spectroscopy, the levels of fumarate and choline showed moderate prediction with an area under the curve (AUC) value of more than 0.7. As a result of UPLC-QTOF/MS-based profiling, 61 metabolites referring to the VIP (variable importance in the projection) score contributed to discriminating the age of ginseng. The results of GC×GC-TOF/MS showed clear discrimination of 4-, 5-, and 6-year-old ginseng using orthogonal partial least-squares discriminant analysis (OPLS-DA) to 100% of the discrimination rate. The results of receiver operating characteristic (ROC) analysis, 16 metabolites between 4- and 5-year-old ginseng, and 18 metabolites between 5- and 6-year-old ginseng contributed to age discrimination in all regions. (4) Conclusions: These results showed that metabolic profiling and multivariate statistical analyses can distinguish the age of ginseng. Especially, it is meaningful that ginseng samples from different areas had the same metabolites for age discrimination. In future studies, it will be necessary to identify the unknown variables and to collaboratively study with other fields the biochemistry of aging in ginseng.

Silencing of an α-dioxygenase gene, Ca-DOX, retards growth and suppresses basal disease resistance responses in Capsicum annum.

Alpha-dioxygenases (α-DOX) catalyzing the primary oxygenation of fatty acids to oxylipins were recently found in plants. Here, the biological roles of the pepper α-DOX (Ca-DOX) gene, which is strongly induced during non-host pathogen infection in chili pepper, were examined. Virus-induced gene silencing demonstrated that down-regulation of Ca-DOX enhanced susceptibility to bacterial pathogens and suppressed the hypersensitive response via the suppression of pathogenesis-related genes such as PR4, proteinase inhibitor II and lipid transfer protein (PR14). Ca-DOX-silenced pepper plants also exhibited more retarded growth with lower epidermal cell numbers and reduced cell wall thickness than control plants. To better understand regulation of Ca-DOX, transgenic Arabidopsis plants harboring the ß-glucuronidase (GUS) reporter gene driven from a putative Ca-DOX promoter were generated. GUS expression was significantly induced upon avirulent pathogen infection in transgenic Arabidopsis leaves, whereas GUS induction was relatively weak upon virulent pathogen treatment. After treatment with plant hormones, early and strong GUS expression was seen after treatment of salicylic acid, whereas ethylene and methyl jasmonate treatments produced relatively weak and late GUS signals. These results will enable us to further understand the role of α-DOX, which is important in lipid metabolism, defense responses, and growth development in plants.

De novo transcriptome assembly and the identification of gene-associated single-nucleotide polymorphism markers in Asian and American ginseng roots.

We performed de novo transcriptome sequencing for Panax ginseng and Panax quinquefolius accessions using the 454 GS FLX Titanium System and discovered annotation-based genome-wide single-nucleotide polymorphism (SNPs) using next-generation ginseng transcriptome data without reference genome sequence. The comprehensive transcriptome characterization with the mature roots of four ginseng accessions generated 297,170 reads for 'Cheonryang' cultivar, 305,673 reads for 'Yunpoong' cultivar, 311,861 reads for the G03080 breeding line, and 308,313 reads for P. quinquefolius. In transcriptome assembly, the lengths of the sample read were 156.42 Mb for 'Cheonryang', 161.95 Mb for 'Yunpoong', 165.07 Mb for G03080 breeding line, and 166.48 Mb for P. quinquefolius. A total of 97 primer pairs were designed with the homozygous SNP presented in all four accessions. SNP genotyping using high-resolution melting (HRM) analysis was performed to validate the putative SNP markers of 97 primer pairs. Out of the 73 primer pairs, 73 primer pairs amplified the target sequence and 34 primer pairs showed polymorphic melting curves in samples from 11 P. ginseng cultivars and one P. quinquefolius accession. Among the 34 polymorphic HRM-SNP primers, four primers were useful to distinguish ginseng cultivars. In the present study, we demonstrated that de novo transcriptome assembly and mapping analyses are useful in providing four HRM-SNP primer pairs that reliably show a high degree of polymorphism among ginseng cultivars.

De Novo Genome Assembly and Phylogenetic Analysis of Cirsium nipponicum.

Background: Cirsium nipponicum, a pharmaceutically valuable plant from the Asteraceae family, has been utilized for over 2000 years. Unlike other thistles, it is native to East Asia and found exclusively on Ulleung Island on the Korea Peninsula. Despite its significance, the genome information of C. nipponicum has remained unclear. Methods: In this study, we assembled the genome of C. nipponicum using both short reads from Illumina sequencing and long reads from Nanopore sequencing. Results: The assembled genome is 929.4 Mb in size with an N50 length of 0.7 Mb, covering 95.1% of BUSCO core groups listed in edicots_odb10. Repeat sequences accounted for 70.94% of the assembled genome. We curated 31,263 protein-coding genes, of which 28,752 were functionally annotated using public databases. Phylogenetic analysis of 11 plant species using single-copy orthologs revealed that C. nipponicum diverged from Cynara cardunculus approximately 15.9 million years ago. Gene family evolutionary analysis revealed significant expansion and contraction in genes involved in abscisic acid biosynthesis, late endosome to vacuole transport, response to nitrate, and abaxial cell fate specification. Conclusions: This study provides a reference genome of C. nipponicum, enhancing our understanding of its genetic background and facilitating an exploration of genetic resources for beneficial phytochemicals.

Comparative Analysis of Polyphenolic Compounds in Different Amaranthus Species: Influence of Genotypes and Harvesting Year.

Amaranth is a nutritionally valuable crop, as it contains phenolic acids and flavonoids, yielding diverse plant secondary metabolites (PSMs) like phytosterol, tocopherols, and carotenoids. This study explored the variations in the contents of seventeen polyphenolic compounds within the leaves of one hundred twenty Amaranthus accessions representing nine Amaranthus species. The investigation entailed the analysis of phenolic content across nine Amaranthus species, specifically A. hypochondriacus, A. cruentus, A. caudatus, A. tricolor, A. dubius, A. blitum, A. crispus, A. hybridus, and A. viridis, utilizing ultra performance liquid chromatography with photodiode array detection (UPLC-PDA). The results revealed significant differences in polyphenolic compounds among accessions in which rutin content was predominant in all Amaranthus species in both 2018 and 2019. Among the nine Amaranthus species, the rutin content ranged from 95.72 ± 199.17 µg g-1 (A. dubius) to 1485.09 ± 679.51 µg g-1 (A. viridis) in 2018 and from 821.59 ± 709.95 µg g-1 (A. tricolor) to 3166.52 ± 1317.38 µg g-1 (A. hypochondriacus) in 2019. Correlation analysis revealed, significant positive correlations between rutin and kaempferol-3-O-ß-rutinoside (r = 0.93), benzoic acid and ferulic acid (r = 0.76), and benzoic acid and kaempferol-3-O-ß-rutinoside (r = 0.76), whereas gallic acid showed consistently negative correlations with each of the 16 phenolic compounds. Wide variations were identified among accessions and between plants grown in the two years. The nine species and one hundred twenty Amaranthus accessions were clustered into six groups based on their seventeen phenolic compounds in each year. These findings contribute to expanding our understanding of the phytochemical traits of accessions within nine Amaranthus species, which serve as valuable resources for Amaranthus component breeding and functional material development.

The chromosome-level genome assembly of lance asiabell (Codonopsis lanceolata), a medicinal and vegetable plant of the Campanulaceae family.

Codonopsis lanceolata (2n = 2x = 16) belongs to the Campanulaceae family and is a valuable medicinal and vegetable plant primarily found in East Asia. Several studies have demonstrated its excellent pharmacological effects, for example in bronchial treatment. However, genomic information of C. lanceolata is scarce, hindering studies on crop improvement of the species. Here, we report a high-quality chromosome-level genome assembly of C. lanceolata based on a hybrid method using Nanopore long-read, Illumina short-read, and Hi-C data. The assembled genome was completed as 1,273 Mb (84.5% of the estimated genome size), containing eight pseudo-chromosomes, ranging from 101.3 to 184.3 Mb. The genome comprised of 71.3% repeat sequences and 46,005 protein-coding genes, of which 85.7% genes were functionally annotated. Completeness of the assembled genome and genes was assessed to be 97.5% and 90.4%, respectively, by Benchmarking Universal Single-Copy Orthologs analysis. Phylogenetic and synteny analysis revealed that C. lanceolata was closely related to Platycodon grandiflorus in the Campanulaceae family. Gene family evolution revealed significant expansion of related genes involved in saponin biosynthesis in the C. lanceolata genome. This is the first reference genome reported for C. lanceolata. The genomic data produced in this study will provide essential information for further research to improve this medicinal plant and will broaden the understanding of the Campanulaceae family.

Efficient Somatic Embryogenesis, Regeneration and Acclimatization of Panax ginseng Meyer: True-to-Type Conformity of Plantlets as Confirmed by ISSR Analysis.

Panax ginseng Meyer grows in east Russia and Asia. There is a high demand for this crop due to its medicinal properties. However, its low reproductive efficiency has been a hindrance to the crop's widespread use. This study aims to establish an efficient regeneration and acclimatization system for the crop. The type of basal media and strength were evaluated for their effects on somatic embryogenesis, germination, and regeneration. The highest rate of somatic embryogenesis was achieved for the basal media MS, N6, and GD, with the optimal nitrogen content (≥35 mM) and NH4+/NO3- ratio (1:2 or 1:4). The full-strength MS medium was the best one for somatic embryo induction. However, the diluted MS medium had a more positive effect on embryo maturation. Additionally, the basal media affected shooting, rooting, and plantlet formation. The germination medium containing 1/2 MS facilitated good shoot development; however, the medium with 1/2 SH yielded outstanding root development. In vitro-grown roots were successfully transferred to soil, and they exhibited a high survival rate (86.3%). Finally, the ISSR marker analysis demonstrated that the regenerated plants were not different from the control. The obtained results provide valuable information for a more efficient micropropagation of various P. ginseng cultivars.

A chromosome-level genome assembly of Korean mint (Agastache rugosa).

Agastache rugosa, also known as Korean mint, is a perennial plant from the Lamiaceae family that is traditionally used for various ailments and contains antioxidant and antibacterial phenolic compounds. Molecular breeding of A. rugosa can enhance secondary metabolite production and improve agricultural traits, but progress in this field has been delayed due to the lack of chromosome-scale genome information. Herein, we constructed a chromosome-level reference genome using Nanopore sequencing and Hi-C technology, resulting in a final genome assembly with a scaffold N50 of 52.15 Mbp and a total size of 410.67 Mbp. Nine pseudochromosomes accounted for 89.1% of the predicted genome. The BUSCO analysis indicated a high level of completeness in the assembly. Repeat annotation revealed 561,061 repeat elements, accounting for 61.65% of the genome, with Copia and Gypsy long terminal repeats being the most abundant. A total of 26,430 protein-coding genes were predicted, with an average length of 1,184 bp. The availability of this chromosome-scale genome will advance our understanding of A. rugosa's genetic makeup and its potential applications in various industries.

Response of nine triticale genotypes to different salt concentrations at the germination and early seedling stages.

Salinity stress poses a major challenge to agricultural productivity worldwide, and understanding their responses at the early growth stage is vital for devising strategies to cope with this stress. Therefore, to improve triticale productivity, this study investigated the salinity stress tolerance of different salt-tolerant triticale genotypes aiming to cultivate them on saline soils. To this end, salinity stress impacts on nine triticale genotypes, i.e., Zhongsi 1084, Gannong No. 2, Gannong No. 4, Shida No. 1, C6, C16, C23, C25 and C36 at germination and early seedling stages was evaluated. Each genotype was subjected to six treatments inducing control, 40, 80, 120, 160, and 200 mM NaCl treatments to study their effect on seedling and termination traits of the nine genotypes. Compared to the overall mean seedling vigor index, the seedling vigor index was higher in the genotypes Zhongsi 1084 and C6 (39% and 18.1%, respectively) and lower in Gannong No.2 (41%). Increasing NaCl concentrations negatively affected germination and seedling traits. Compared to other genotypes, Zhongsi 1084 had the highest mean germination rate, germination vigor index, germination percentage, mean daily germination and germination energy. It also showed the lowest relative salt injury. The relative salt injury was higher in the genotype Shida No. 1 than those in Gannong No. 2, Gannong No. 4, Shida No. 1, C16, and C36 genotypes. All genotypes exhibited desirable mean germination time except for line C6. High significant positive correlations were observed among germination rate, germination vigor index, germination percentage, mean daily germination, seedling vigor index, and root length. Principal component analysis (PCA) grouped the most desirable genotypes into two clusters. Our study determined salt stress tolerance of nine triticale genotypes at germination and early seedling stages. to select salt-tolerant genotypes that can be cultivated on saline soil or after salt irrigation.

CAPS markers using mitochondrial consensus primers for molecular identification of Panax species and Korean ginseng cultivars (Panax ginseng C. A. Meyer).

Cleaved amplified polymorphic sequence (CAPS) marker system using mitochondrial consensus primers was applied for molecular identification of Korean ginseng cultivars (Panax ginseng). Initially, a total of 34 primers were tested to six Korean ginseng cultivars and two foreign Panax species, P. quinquefolius and P. notoginseng. In the polymerase chain reaction (PCR) amplification results, four primers (mt7, mt11, mt13, and mt18) generated co-dominant polymorphic banding patterns discriminating the Korean ginseng cultivars from P. quinquefolius and P. notoginseng. In the CAPS analysis results, the majority of the cleaved PCR products also yielded additional latent polymorphisms between the Korean ginseng cultivars and two foreign Panax species. Specific latent CAPS polymorphisms for cultivar Gopoong and Chunpoong were detected from internal region amplified with mt9 primer by treating HinfI and Tsp509I endonucleases, respectively. Sequencing analysis revealed that the length of amplified region of Korean ginseng cultivars was 2,179 bp, and those of P. quinquefolius and P. notoginseng were 2,178 and 2,185 bp, respectively. Blast search revealed that the amplified region was a mitochondrial cytochrome oxidase subunit 2 (cox2) gene intron II region. Nineteen single nucleotide polymorphisms (SNP) including each specific SNP for Gopoong and Chunpoong, and three insertion and deletion (InDel) polymorphisms were detected by sequence alignment. The CAPS markers developed in this study, which are specific to Gopoong and Chunpoong, and between the Korean ginseng cultivars and two foreign Panax species, will serve as a practical and reliable tool for their identification, purity maintenance, and selection of candidate lines and cultivars.

Complete Chloroplast Genome of the Inverted Repeat-Lacking Species Vicia bungei and Development of Polymorphic Simple Sequence Repeat Markers.

Background: Vicia bungei is an economically important forage crop in South Korea and China. Although detailed genetic and genomic data can improve population genetic studies, conservation efforts, and improved breeding of crops, few such data are available for Vicia species in general and none at all for V. bungei. Therefore, the main objectives of this study were to sequence, assemble, and annotate V. bungei chloroplast genome and to identify simple sequence repeats (SSRs) as polymorphic genetic markers. Results: The whole-genome sequence of V. bungei was generated using an Illumina MiSeq platform. De novo assembly of complete chloroplast genome sequences was performed for the low-coverage sequence using CLC Genome Assembler with a 200-600-bp overlap size. Vicia bungei chloroplast genome was 130,796-bp long. The genome lacked an inverted repeat unit and thus resembled those of species in the inverted repeat-lacking clade within Fabaceae. Genome annotation using Dual OrganellarGenoMe Annotator (DOGMA) identified 107 genes, comprising 75 protein-coding, 28 transfer RNA, and 4 ribosomal RNA genes. In total, 432 SSRs were detected in V. bungei chloroplast genome, including 64 mononucleotides, 14 dinucleotides, 5 trinucleotides, 4 tetranucleotides, 233 pentanucleotides, 90 hexanucleotides, and 14 complex repeated motifs. These were used to develop 232 novel chloroplast SSR markers, 39 of which were chosen at random to test amplification and genetic diversity in Vicia species (20 accessions from seven species). The unweighted pair group method with arithmetic mean cluster analysis identified seven clusters at the interspecies level and intraspecific differences within clusters. Conclusion: The complete chloroplast genome sequence of V. bungei was determined. This reference genome should facilitate chloroplast resequencing and future searches for additional genetic markers using population samples. The novel chloroplast genome resources and SSR markers will greatly contribute to the conservation of the genus Vicia and facilitate genetic and evolutionary studies of this genus and of other higher plants.

Pseudo-Chromosomal Genome Assembly in Combination with Comprehensive Transcriptome Analysis in Agaricus bisporus Strain KMCC00540 Reveals Mechanical Stimulus Responsive Genes Associated with Browning Effect.

Agaricus bisporus is one of the world's most popular edible mushrooms, including in South Korea. We performed de novo genome assembly with a South Korean white-colored cultivar of A. bisporus, KMCC00540. After generating a scaffold-level genomic sequence, we inferred chromosome-level assembly by genomic synteny analysis with the representative A. bisporus strains H97 and H39. The KMCC00540 genome had 13 pseudochromosomes comprising 33,030,236 bp mostly covering both strains. A comparative genomic analysis with cultivar H97 indicated that most genomic regions and annotated proteins were shared (over 90%), ensuring that our cultivar could be used as a representative genome. However, A. bisporus suffers from browning even from only a slight mechanical stimulus during transportation, which significantly lowers its commercial value. To identify which genes respond to a mechanical stimulus that induces browning, we performed a time-course transcriptome analysis based on the de novo assembled genome. Mechanical stimulus induces up-regulation in long fatty acid ligase activity-related genes, as well as melanin biosynthesis genes, especially at early time points. In summary, we assembled the chromosome-level genomic information on a Korean strain of A. bisporus and identified which genes respond to a mechanical stimulus, which provided key hints for improving the post-harvest biological control of A. bisporus.

Volatile Compositions of Panax ginseng and Panax quinquifolium Grown for Different Cultivation Years.

The present study examined the volatile profiles of Panax ginseng (Korean ginseng) and Panax quinquefolium (American ginseng) grown for different cultivation years by using HS-SPME/GC-MS and determined the key discriminant volatile compounds by chemometric analysis including principal component analysis (PCA), hierarchical cluster analysis (HCA), and partial least squares-discrimination analysis (PLS-DA). Fifty-six compounds, including forty terpenes, eight alcohols, one alkane, one ketone, and one furan, were identified in the ginseng roots. The chemometric results identified two major clusters of American ginseng and Korean ginseng cultivars with distinct volatile compositions. The volatile compounds in fresh white ginseng roots were affected by the species, but the influence of different cultivation ages was ambiguous. The major volatile components of ginseng roots are terpenes, including monoterpenes and sesquiterpenes. In particular, panaginsene, ginsinsene, α-isocomene, and caryophyllene were predominant in Korean ginseng cultivars, whereas ß-farnesene levels were higher in American ginseng. The difference in volatile patterns between Panax ginseng and Panax quinquefolium could be attributed to the composition of sesquiterpenes such as ß-panaginsene, ginsinsene, caryophyllene, and ß-farnesene.

Development of CAPS Markers for Evaluation of Genetic Diversity and Population Structure in the Germplasm of Button Mushroom (Agaricus bisporus).

Agaricus bisporus is a globally cultivated mushroom with high economic value. Despite its widespread cultivation, commercial button mushroom strains have little genetic diversity and discrimination of strains for identification and breeding purposes is challenging. Molecular markers suitable for diversity analyses of germplasms with similar genotypes and discrimination between accessions are needed to support the development of new varieties. To develop cleaved amplified polymorphic sequences (CAPs) markers, single nucleotide polymorphism (SNP) mining was performed based on the A. bisporus genome and resequencing data. A total of 70 sets of CAPs markers were developed and applied to 41 A. bisporus accessions for diversity, multivariate, and population structure analyses. Of the 70 SNPs, 62.85% (44/70) were transitions (G/A or C/T) and 37.15% (26/70) were transversions (A/C, A/T, C/G, or G/T). The number of alleles per locus was 1 or 2 (average = 1.9), and expected heterozygosity and gene diversity were 0.0-0.499 (mean = 0.265) and 0.0-0.9367 (mean = 0.3599), respectively. Multivariate and cluster analyses of accessions produced similar groups, with F-statistic values of 0.134 and 0.153 for distance-based and model-based groups, respectively. A minimum set of 10 markers optimized for accession identification were selected based on high index of genetic diversity (GD, range 0.299-0.499) and major allele frequency (MAF, range 0.524-0.817). The CAPS markers can be used to evaluate genetic diversity and population structure and will facilitate the management of emerging genetic resources.

The complete mitochondrial genome of Panax ginseng (Apiales, Araliaceae): an important medicinal plant.

Ginseng (Panax ginseng C. A. Meyer) is a multifunctional medicinal herb used worldwide and is an economically important high-value crop in Korea. Here, we presented the mitochondrial genome of P. ginseng landrace 'Jakyung', which is one of the most common cultivars cultivated in Korean farms. The complete mitochondrial genome sequence was 464,661 bp in length and had a single circular form. The ginseng mitochondrial genome encoded 72 unique genes, including 45 protein-coding genes, 24 tRNA genes, and three rRNA genes. Nucleotide composition analysis revealed a GC content of 45.1%, with a slightly higher A + T bias (A, 27.1%; T, 27.8%; G, 22.5%; C, 22.6%). Phylogenetic analysis showed that P. ginseng was closely related to Daucus carota in the Apiales. This complete mitochondrial genome sequence of P. ginseng provides valuable genetic information for further studies of this important medicinal plant.