[Comparison of transcriptome of Atractylodes lancea rhizome and exploration of genes for sesquiterpenoid biosynthesis].

This study compared the transcriptome of Atractylodes lancea rhizome at different development stages and explored genes encoding the key enzymes of the sesquiterpenoid biosynthesis pathway. Specifically, Illumina NovaSeq 6000 was employed for sequencing the cDNA libraries of A. lancea rhizome samples at the growth stage(SZ), flowering stage(KH), and harvesting stage(CS), respectively. Finally, a total of 388 201 748 clean reads were obtained, and 16 925, 8 616, and 13 702 differentially expressed genes(DEGs) were identified between SZ and KH, KH and CS, and SZ and CS, separately. Among them, 53 genes were involved in the sesquiterpenoid biosynthesis pathways: 9 encoding 6 enzymes of the mevalonic acid(MVA) pathway, 15 encoding 7 enzymes of the 2-C-methyl-D-erythritol-4-phosphate(MEP) pathway, and 29 of sesquiterpenoid and triterpenoid biosynthesis pathway. Weighted gene co-expression network analysis(WGCNA) yielded 12 genes related to sesquiterpenoid biosynthesis for the SZ, 1 gene for the KH, and 1 gene for CS, and several candidate genes for sesquiterpenoid biosynthesis were discovered based on the co-expression network. This study laid a solid foundation for further research on the sesquiterpenoid biosynthesis pathway, analysis of the regulation mechanism, and mechanism for the accumulation of sesquiterpenoids in A. lancea.

A nucleotide signature for the identification of Pinelliae Rhizoma (Banxia) and its products.

BACKGROUND: Ensuring the authenticity of raw materials is a key step prior to producing Chinese patent medicines. Pinellia ternata (Thunb.) Breit. is the botanical origin of Pinelliae Rhizoma (Banxia), a traditional Chinese medicine used to treat cough, insomnia, nausea, inflammation, epilepsy, and so on. Unfortunately, authentic Pinelliae Rhizoma is often adulterated by morphologically indistinguishable plant material due to the insufficient regulatory procedures of processed medicinal plant products. Thus, it is important to develop a molecular assay based on species-specific nucleotide signatures and primers to efficiently distinguish authentic Pinelliae Rhizoma from its adulterants. METHODS AND RESULTS: The ITS2 region of 67 Pinelliae Rhizoma and its common adulterants were sequenced. Eight single nucleotide polymorphisms within a 28-43 bp stretch of ITS2 were used to develop six primer pairs to amplify these species-specific regions. We assayed 56 Pinelliae Rhizoma products sold on the Chinese market, including medicinal slices, powder and Chinese patent medicines, which revealed that about 66% of products were adulterated. The most common adulterants were Pinellia pedatisecta (found in 57% of the assayed products), Arisaema erubescens (9%), Typhonium giganteum (2%) and Typhonium flagelliforme (2%). CONCLUSIONS: A severe adulteration condition was revealed in the traditional medicine market. The species-specific nucleotide assays developed in this study can be applied to reliably identify Pinelliae Rhizoma and its adulterants, aiding in the authentication and quality control of processed products on the herbal market.

Differences in gene expression and endophytic bacterial diversity in Atractylodes macrocephala Koidz. rhizomes from different growth years.

Atractylodes macrocephala Koidz. (AMK) is widely used in traditional Chinese medicine owing to its pharmacological activity. Here, we aimed to characterize the differentially expressed genes (DEGs) of one- and three-year growth (OYG and TYG) rhizomes of AMK, combined with endophytic bacterial diversity analysis using high-throughput RNA sequencing. A total of 114 572 unigenes were annotated using six public databases. In all, 3570 DEGs revealed a clear difference, of which 936 and 2634 genes were upregulated and downregulated, respectively. The results of KEGG pathway analysis indicated that DEGs corresponding to terpenoid synthesis gene were downregulated in TYG rhizomes. In addition, 414 424 sequences corresponding to the 16S rRNA gene were divided into 1267 operational taxonomic units (OTUs). Moreover, the diversity of endophytic bacteria changed with species in the OYG (773) and TYG (1201) rhizomes at the OTU level, and Proteobacteria, Actinobacteria, and Bacteroidetes were the dominant phyla. A comparison of species differences among different growth years revealed that some species were significantly different, such as Actinomycetes, Variovorax, and Cloacibacterium. Interestingly, the decrease in the function-related metabolism of terpenoids and polyketides was correlated with the low expression of terpene synthesis genes in TYG rhizomes, as assessed using PICRUSt2. These data provide a scientific basis for elucidating the mechanisms underlying metabolite accumulation and endophytic bacterial diversity in relation to the growth years in AMK.

Metabolic fingerprinting for discrimination of DNA-authenticated Atractylodes plants using 1H NMR spectroscopy.

Identifying different species of the genus Atractylodes which are commonly used in Chinese and Japanese traditional medicine, using chromatographic approaches can be difficult. 1H NMR metabolic profiling of DNA-authenticated, archived rhizomes of the genus Atractylodes was performed for genetic and chemical evaluation. The ITS region of the nuclear rDNA was sequenced for five species, A. japonica, A. macrocephala, A. lancea, A. chinensis, and A. koreana. Our samples had nucleotide sequences as previously reported, except that part of the A. lancea cultivated in Japan had a type 5, hybrid DNA sequence. Principal component analysis (PCA) using 1H NMR spectra of extracts with two solvent systems (CD3OD, CDCl3) was performed. When CDCl3 extracts were utilized, the chemometric analysis enabled the identification and classification of Atractylodes species according to their composition of major sesquiterpene compounds. The 1H NMR spectra using CD3OD contained confounding sugar peaks. PCA removal of these peaks gave the same result as that obtained using CDCl3 and allowed species distinction. Such chemometric methods with multivariate analysis of NMR spectra will be useful for the discrimination of plant species, without specifying the index components and quantitative analysis on multi-components.

Transcriptome analysis of Curcuma wenyujin from Haikou and Wenzhou, and a comparison of the main constituents and related genes of Rhizoma Curcumae.

For more than a thousand years, Rhizoma Curcumae (known as E zhu), a Chinese herbal medicine, has been used to eradicate blood stasis and relieve aches. The plant Curcuma wenyujin, which is grown primarily in Wenzhou, China, is considered the best source of Rhizoma Curcumae. In this study, we sought to ascertain differences in transcript profiles of C. wenyujin grown in traditional (Wenzhou) and recently established (Haikou) production areas based on Illumina and RNA (RNA-seq) sequencing. We also examined differences in the main components of the volatile oil terpene; curcumin, polysaccharide, and starch constituents and related genes in the corresponding pathways, in C. wenyujin cultivated in the two production areas. We accordingly found that the essential oil (2.05%), curcumin (1.46%), and polysaccharide (8.90%) content in Wenzhou rhizomes was higher than that in the rhizomes of plants from Haikou (1.60%, 0.91%, and 6.15%, respectively). In contrast, the starch content of Wenzhou rhizomes (17.0%) was lower than that of Haikou rhizomes (23.8%). Furthermore, we detected significant differences in the oil components of Haikou and Wenzhou rhizomes, with curzerene (32.34%), curdione (21.35%), and germacrene B (9.39%) being the primary components of the essential oil derived from Wenzhou rhizomes, and curzerene (20.13%), curdione (14.73%), and cineole (9.76%) being the main constituents in Haikou rhizomes. Transcriptome and qPCR analyses revealed considerable differences in gene expression between Wenzhou and Haikou rhizomes. The expression of terpene, curcumin, and polysaccharide pathway-related genes in Wenzhou rhizomes was significantly up-regulated, whereas the expression of starch-associated genes was significantly down-regulated, compared with those in Haikou rhizomes. Difference in the content of terpene, curcumin, polysaccharides, and starch in rhizomes from the two production areas could be explained in terms of differences in expression of the related genes.

De novo transcriptome analysis of the critically endangered alpine Himalayan herb Nardostachys jatamansi reveals the biosynthesis pathway genes of tissue-specific secondary metabolites.

The study is the first report on de novo transcriptome analysis of Nardostachys jatamansi, a critically endangered medicinal plant of alpine Himalayas. Illumina GAIIx sequencing of plants collected during end of vegetative growth (August) yielded 48,411 unigenes. 74.45% of these were annotated using UNIPROT. GO enrichment analysis, KEGG pathways and PPI network indicated simultaneous utilization of leaf photosynthates for flowering, rhizome fortification, stress response and tissue-specific secondary metabolites biosynthesis. Among the secondary metabolite biosynthesis genes, terpenoids were predominant. UPLC-PDA analysis of in vitro plants revealed temperature-dependent, tissue-specific differential distribution of various phenolics. Thus, as compared to 25 °C, the phenolic contents of both leaves (gallic acid and rutin) and roots (p-coumaric acid and cinnamic acid) were higher at 15 °C. These phenolics accounted for the therapeutic properties reported in the plant. In qRT-PCR of in vitro plants, secondary metabolite biosynthesis pathway genes showed higher expression at 15 °C and 14 h/10 h photoperiod (conditions representing end of vegetative growth period). This provided cues for in vitro modulation of identified secondary metabolites. Such modulation of secondary metabolites in in vitro systems can eliminate the need for uprooting N. jatamansi from wild. Hence, the study is a step towards effective conservation of the plant.

SMRT- and Illumina-based RNA-seq analyses unveil the ginsinoside biosynthesis and transcriptomic complexity in Panax notoginseng.

Panax notoginseng is one of the most widely used traditional Chinese herbs with particularly valued roots. Triterpenoid saponins are mainly specialized secondary metabolites, which medically act as bioactive components. Knowledge of the ginsenoside biosynthesis in P. notoginseng, which is of great importance in the industrial biosynthesis and genetic breeding program, remains largely undetermined. Here we combined single molecular real time (SMRT) and Second-Generation Sequencing (SGS) technologies to generate a widespread transcriptome atlas of P. notoginseng. We mapped 2,383 full-length non-chimeric (FLNC) reads to adjacently annotated genes, corrected 1,925 mis-annotated genes and merged into 927 new genes. We identified 8,111 novel transcript isoforms that have improved the annotation of the current genome assembly, of which we found 2,664 novel lncRNAs. We characterized more alternative splicing (AS) events from SMRT reads (20,015 AS in 6,324 genes) than Illumina reads (18,498 AS in 9,550 genes), which contained a number of AS events associated with the ginsenoside biosynthesis. The comprehensive transcriptome landscape reveals that the ginsenoside biosynthesis predominantly occurs in flowers compared to leaves and roots, substantiated by levels of gene expression, which is supported by tissue-specific abundance of isoforms in flowers compared to roots and rhizomes. Comparative metabolic analyses further show that a total of 17 characteristic ginsenosides increasingly accumulated, and roots contained the most ginsenosides with variable contents, which are extraordinarily abundant in roots of the three-year old plants. We observed that roots were rich in protopanaxatriol- and protopanaxadiol-type saponins, whereas protopanaxadiol-type saponins predominated in aerial parts (leaves, stems and flowers). The obtained results will greatly enhance our understanding about the ginsenoside biosynthetic machinery in the genus Panax.

Full-length transcriptome sequencing and modular organization analysis of oleanolic acid- and dammarane-type saponins related gene expression patterns in Panax japonicus.

The saponins found in Panax japonicus, a traditional medicinal herb in Asia, exhibit high degrees of structural and functional similarity. In this study, metabolite analysis revealed that oleanolic acid-type and dammarane-type saponins were distributed unevenly in three tissues (rhizome_Y, rhizome_O, and secRoot) of P. japonicus. Single-molecule real-time (SMRT) sequencing and next generation sequencing (NGS) data revealed distinct and tissue-specific transcriptomic patterns relating to the production of these two types of saponins. In the co-expression network and hierarchical clustering analyses, one 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR) and two 1-deoxy-D-xylulose-5-phosphate synthase (DXS) etc. transcripts were found to be key genes associated with the biosynthesis of oleanolic acid and dammarane-type saponins in P. japonicus, respectively. In addition, cytochrome p450 (CYP) and UDP-glucuronosyltransferase (UGT) family proteins that serve as regulators of saponin biosynthesis-related genes were also found to exhibit tissue-specific expression patterns. Together these results offer a comprehensive metabolomic and transcriptomic overview of P. japonicus.

Comparative transcriptome analysis of rhizome nodes and internodes in Panax. japonicus var. major reveals candidate genes involved in the biosynthesis of triterpenoid saponins.

The rhizome of P. japonicus var. major, one of the important herbs in Traditional Chinese medicine (TCM), has been used as tonic and hemostatic drugs in Tujia and Miao ethnic groups of China for thousand years. In this study, comparative metabolite and transcriptome analysis of rhizome nodes and internodes of wild P. japonicus var. major was performed to reveal their different roles in the biosynthesis of triterpene saponins. The results showed that the node was the crucial section for the synthesis of ginsenosides in the rhizome. The content of oleanane-type ginsenosides in the node was much higher than those in the internode. Most isoprenoid biosynthesis-related genes were highly expressed in the node. And, candidate UDP-glycosyltransferase (UGT) genes were also found to be differentially expressed between node and internode. Our study will provide a better understanding of the metabolism of ginsenosides in the rhizome of P. japonicus var. major.

Integrated transcriptome and miRNA analysis uncovers molecular regulators of aerial stem-to-rhizome transition in the medical herb Gynostemma pentaphyllum.

BACKGROUND: Gynostemma pentaphyllum is an important perennial medicinal herb belonging to the family Cucurbitaceae. Aerial stem-to-rhizome transition before entering the winter is an adaptive regenerative strategy in G. pentaphyllum that enables it to survive during winter. However, the molecular regulation of aerial stem-to-rhizome transition is unknown in plants. Here, integrated transcriptome and miRNA analysis was conducted to investigate the regulatory network of stem-to-rhizome transition. RESULTS: Nine transcriptome libraries prepared from stem/rhizome samples collected at three stages of developmental stem-to-rhizome transition were sequenced and a total of 5428 differentially expressed genes (DEGs) were identified. DEGs associated with gravitropism, cell wall biosynthesis, photoperiod, hormone signaling, and carbohydrate metabolism were found to regulate stem-to-rhizome transition. Nine small RNA libraries were parallelly sequenced, and seven significantly differentially expressed miRNAs (DEMs) were identified, including four known and three novel miRNAs. The seven DEMs targeted 123 mRNAs, and six pairs of miRNA-target showed significantly opposite expression trends. The GpmiR166b-GpECH2 module involved in stem-to-rhizome transition probably promotes cell expansion by IBA-to-IAA conversion, and the GpmiR166e-GpSGT-like module probably protects IAA from degradation, thereby promoting rhizome formation. GpmiR156a was found to be involved in stem-to-rhizome transition by inhibiting the expression of GpSPL13A/GpSPL6, which are believed to negatively regulate vegetative phase transition. GpmiR156a and a novel miRNA Co.47071 co-repressed the expression of growth inhibitor GpRAV-like during stem-to-rhizome transition. These miRNAs and their targets were first reported to be involved in the formation of rhizomes. In this study, the expression patterns of DEGs, DEMs and their targets were further validated by quantitative real-time PCR, supporting the reliability of sequencing data. CONCLUSIONS: Our study revealed a comprehensive molecular network regulating the transition of aerial stem to rhizome in G. pentaphyllum. These results broaden our understanding of developmental phase transitions in plants.

Transcriptomic analysis in Anemone flaccida rhizomes reveals ancillary pathway for triterpene saponins biosynthesis and differential responsiveness to phytohormones.

Anemone flaccida Fr. Schmidt is a perennial medicinal herb that contains pentacyclic triterpenoid saponins as the major bioactive constituents. In China, the rhizomes are used as treatments for a variety of ailments including arthritis. However, yields of the saponins are low, and little is known about the plant's genetic background or phytohormonal responsiveness. Using one-quarter of the 454 pyrosequencing information from the Roche GS FLX Titanium platform, we performed a transcriptomic analysis to identify 157 genes putatively encoding 26 enzymes involved in the synthesis of the bioactive compounds. It was revealed that there are two biosynthetic pathways of triterpene saponins in A. flaccida. One pathway depends on ß-amyrin synthase and is similar to that found in other plants. The second, subsidiary ("backburner") pathway is catalyzed by camelliol C synthase and yields ß-amyrin as minor byproduct. Both pathways used cytochrome P450-dependent monooxygenases (CYPs) and family 1 uridine diphosphate glycosyltransferases (UGTs) to modify the triterpenoid backbone. The expression of CYPs and UGTs were quite different in roots treated with the phytohormones methyl jasmonate, salicylic acid and indole-3-acetic acid. This study provides the first large-scale transcriptional dataset for the biosynthetic pathways of triterpene saponins and their phytohormonal responsiveness in the genus Anemone.

The regulatory mechanism of chilling-induced dormancy transition from endo-dormancy to non-dormancy in Polygonatum kingianum Coll.et Hemsl rhizome bud.

KEY MESSAGE: We identified three dormant stages of Polygonatum kingianum and changes that occurred during dormancy transition in the following aspects including cell wall and hormones, as well as interaction among them. Polygonatum kingianum Coll.et Hemsl (P. kingianum) is an important traditional Chinese medicine, but the mechanism of its rhizome bud dormancy has not yet been studied systematically. In this study, three dormancy phases were induced under controlled conditions, and changes occurring during the transition were examined, focusing on phytohormones and the cell wall. As revealed by HPLC-MS (High Performance Liquid Chromatography-Mass Spectrometry) analysis, the endo- to non-dormancy transition was association with a reduced abscisic acid (ABA)/gibberellin (GA3) ratio, a decreased level of auxin (IAA) and an increased level of trans-zeatin (tZR). Transmission electron microscopy showed that plasmodesmata (PDs) and the cell wall of the bud underwent significant changes between endo- and eco-dormancy. A total of 95,462 differentially expressed genes (DEGs) were identified based on transcriptomics, and clustering and principal component analysis confirmed the different physiological statuses of the three types of bud samples. Changes in the abundance of transcripts associated with IAA, cytokinins (CTKs), GA, ABA, brassinolide (BR), jasmonic acid (JA), ethylene, salicylic acid (SA), PDs and cell wall-loosening factors were analysed during the bud dormancy transition in P. kingianum. Furthermore, nitrilase 4 (NIT4) and tryptophan synthase alpha chain (TSA1), which are related to IAA synthesis, were identified as hub genes of the co-expression network, and strong interactions between hormones and cell wall-related factors were observed. This research will provide a good model for chilling-treated rhizome bud dormancy in P. kingianum and cultivation of this plant.

[Effects of shading on key enzyme genesexpression and accumulation of saponins in Panax japonicus var. major].

To explore the effects of shading and the expression of key enzyme genes on the synthesis and accumulation of Panax japonicus var. major saponins, different shading treatments (0%, 30%,50%) of potted P. japonicus var. major were used as test materials, the expression of three key enzyme genes(CAS,DS,ß-AS) of leaves and rhizomes in different growth periods of P. japonicus var. major was determined by real-time quantitative PCR, the content of total saponins was determined by ultraviolet spectrophotometry. The results indicated that, in flowering stage, CAS,DS,ß-AS were highly expressed in the aerial parts of P. japonicus var. major, 30% shading treatment significantly inhibited the expression of CAS in leaves and promoted the expression of DS and ß-AS in stems, leaves and flowers, it was speculated that the main part of saponin synthesis was leaf in this stage. Both the expression levels of DS and ß-AS and changes in the content of total saponins in leaves showed a tendency of low-high-low throughout the growth cycle, correlation coefficient analysis showed that there was a positive correlation between them. Compared with control, the expression levels of DS and ß-AS and the content of total saponins were greatly enhanced under shading treatment, 30% shading treatment significantly promoted the accumulation of total saponins. Therefore, it is suggested that 30% shading treatment should be applied to the artificial cultivation of P. japonicus var. major, which is beneficial to the accumulation and quality improvement of saponins.

Identification and Characterization of Genes in the Curcuminoid Pathway of Curcuma zedoaria Roscoe.

BACKGROUND: Curcuminoid genes have an important role in the biosynthesis of curcumin, a valuable bioactive compound, in Curcuma species. However, there have not been any reports of these genes in Curcuma zedoaria. OBJECTIVE: The present work reports on the isolation of genes encoding enzymes in curcuminoid metabolic pathway and their expression in C. zedoaria. METHOD: The primers were designed from untranslation regions of DCS, CURS1, CURS2 and CURS3 genes which are involved in curcuminoid biosynthesis in C. longa to isolate the corresponding fulllength genes in C. zedoaria. RT-PCR amplification and HPLC analysis are used to estimate the expression of genes and biosynthesis of curcumin in both rhizome and callus. RESULTS: The results showed that all four genes from C. zedoaria (named CzDCS, CzCURS1, CzCURS2 and CzCURS3) and C. longa have a high identity (approximately 99%) and lengths of genes from C. zedoaria are 1382, 1240, 1288 and 1265 nu, respectively. CzCURS1, 2 and 3 genes have one intron while CzDCS has two introns. RT-PCR amplification indicated that curcuminoid genes expressed mRNA in rhizome and callus of C. zedoaria. Curcumin, a major component of curcuminoids, was also found in callus by HPLC analysis. CONCLUSION: The sequence information of DCS and CURS1-3 genes in C. zedoaria will be very valuable for a subsequent study on the effects of elicitors on the transcription of genes involved in curcuminoid biosynthesis pathway.

Comparative Transcriptome Analysis Identifies Putative Genes Involved in Dioscin Biosynthesis in Dioscorea zingiberensis.

Dioscorea zingiberensis is a perennial herb native to China. The rhizome of D. zingiberensis has long been used as a traditional Chinese medicine to treat rheumatic arthritis. Dioscin is the major bioactive ingredient conferring the medicinal property described in Chinese pharmacopoeia. Several previous studies have suggested cholesterol as the intermediate to the biosynthesis of dioscin, however, the biosynthetic steps to dioscin after cholesterol remain unknown. In this study, a comprehensive D. zingiberensis transcriptome derived from its leaf and rhizome was constructed. Based on the annotation using various public databases, all possible enzymes in the biosynthetic steps to cholesterol were identified. In the late steps beyond cholesterol, cholesterol undergoes site-specific oxidation by cytochrome P450s (CYPs) and glycosylation by UDP-glycosyltransferases (UGTs) to yield dioscin. From the D. zingiberensis transcriptome, a total of 485 unigenes were annotated as CYPs and 195 unigenes with a sequence length above 1000 bp were annotated as UGTs. Transcriptomic comparison revealed 165 CYP annotated unigenes correlating to dioscin biosynthesis in the plant. Further phylogenetic analysis suggested that among those CYP candidates four of them would be the most likely candidates involved in the biosynthetic steps from cholesterol to dioscin. Additionally, from the UGT annotated unigenes, six of them were annotated as 3-O-UGTs and two of them were annotated as rhamnosyltransferases, which consisted of potential UGT candidates involved in dioscin biosynthesis. To further explore the function of the UGT candidates, two 3-O-UGT candidates, named Dz3GT1 and Dz3GT2, were cloned and functionally characterized. Both Dz3GT1 and Dz3GT2 were able to catalyze a C3-glucosylation activity on diosgenin. In conclusion, this study will facilitate our understanding of dioscin biosynthesis pathway and provides a basis for further mining the genes involved in dioscin biosynthesis.

Establishment of the most comprehensive ITS2 barcode database to date of the traditional medicinal plant Rhodiola (Crassulacaee).

The roots and rhizomes of Rhodiola crenulata and R. rosea have been used worldwide as adaptogens for hundreds of years. However, rapid growth in demand has resulted in merchants using other species of Rhodiola as adulterants. Here, we surveyed 518 individuals representing 47 of the 55 species in the genus, including 253 R. crenulata individuals from 16 populations and 98 R. rosea individuals from 11 populations, to evaluate the utility of the internal transcribed spacer 2 (ITS2) barcode for identification of Rhodiola species. We detected six haplotypes in R. crenulata and only one haplotype in R. rosea. An obvious overlap between intra- and inter-specific distance was detected, and the authentication efficacy of ITS2, which was assessed by BLAST1, a nearest distance method, and a tree test, was much lower than in other groups. However, R. crenulata and R. rosea could be exactly identified. Analysis showed that the secondary structure of ITS2 differs in R. crenulata and its closest relatives. Our results demonstrated that both a mini barcode from ITS2 and the structure of ITS2 are effective markers for the identification of R. crenulata and R. rosea. This study represents the most comprehensive database of ITS2 barcodes in Rhodiola to date and will be useful in Rhodiola species identification.

Assessment of Genetic and Chemical Variability in Curcumae Longae Rhizoma (Curcuma longa) Based on DNA Barcoding Markers and HPLC Fingerprints.

Curcumae Longae Rhizoma (Curcuma longa L.) is an important traditional Chinese medicine with multiple beneficial effects. To elucidate the genetic and chemical differences among Curcumae Longae Rhizoma samples, three DNA barcoding markers (rbcL, matK, and ITS-LSU D1/D3) and HPLC fingerprinting were employed in this study. The discriminatory power of rbcL and matK was low, as they only detected one sequence type that showed 100% similarity with more than 20 congeneric species in the Barcode of Life Data Systems (BOLD) database. In contrast, ITS-LSU D1/D3 showed sufficient discriminatory power to precisely identify all of the market samples as C. longa L. in a BLAST search as well as differentiate each sample based on 2-10 ITS-LSU D1/D3 haplotypes with intragenomic variability (mean p-distance: 0.7%, range: 0-2.6%; mean number of differences: 9.6 sites, range: 0-38 sites). HPLC fingerprinting of 13 commercial samples showed a similarity that ranged from 0.769 to 0.996, indicating that the sample quality varied. A cluster analysis based on 5 common peak areas from the HPLC chromatogram resulted in two groups. Group I included 9 samples with a relatively high chemical content, and group II contained 4 samples with a low chemical content. A Mantel test revealed a low correlation (r=0.1721, p=0.047) between genetic and chemical differences. Our findings suggest that the integrated approach of ITS-LSU D1/D3 DNA barcoding and HPLC fingerprinting provides a comprehensive, precise, and convenient method to clarify the genetic and chemical differences in Curcumae Longae Rhizoma.

Subtractive transcriptome analysis of leaf and rhizome reveals differentially expressed transcripts in Panax sokpayensis.

In the present study, suppression subtractive hybridization (SSH) strategy was used to identify rare and differentially expressed transcripts in leaf and rhizome tissues of Panax sokpayensis. Out of 1102 randomly picked clones, 513 and 374 high quality expressed sequenced tags (ESTs) were generated from leaf and rhizome subtractive libraries, respectively. Out of them, 64.92 % ESTs from leaf and 69.26 % ESTs from rhizome SSH libraries were assembled into different functional categories, while others were of unknown function. In particular, ESTs encoding galactinol synthase 2, ribosomal RNA processing Brix domain protein, and cell division cycle protein 20.1, which are involved in plant growth and development, were most abundant in the leaf SSH library. Other ESTs encoding protein KIAA0664 homologue, ubiquitin-activating enzyme e11, and major latex protein, which are involved in plant immunity and defense response, were most abundant in the rhizome SSH library. Subtractive ESTs also showed similarity with genes involved in ginsenoside biosynthetic pathway, namely farnesyl pyrophosphate synthase, squalene synthase, and dammarenediol synthase. Expression profiles of selected ESTs validated the quality of libraries and confirmed their differential expression in the leaf, stem, and rhizome tissues. In silico comparative analyses revealed that around 13.75 % of unigenes from the leaf SSH library were not represented in the available leaf transcriptome of Panax ginseng. Similarly, around 18.12, 23.75, 25, and 6.25 % of unigenes from the rhizome SSH library were not represented in available root/rhizome transcriptomes of P. ginseng, Panax notoginseng, Panax quinquefolius, and Panax vietnamensis, respectively, indicating a major fraction of novel ESTs. Therefore, these subtractive transcriptomes provide valuable resources for gene discovery in P. sokpayensis and would complement the available transcriptomes from other Panax species.

Protocols for In Vitro Propagation, Conservation, Synthetic Seed Production, Embryo Rescue, Microrhizome Production, Molecular Profiling, and Genetic Transformation in Ginger (Zingiber officinale Roscoe.).

Ginger is a rhizomatous plant that belongs to the family Zingiberaceae. It is a herbaceous perennial but cultivated as annual, with crop duration of 7-10 months. Ginger is native to India and Tropical South Asia. The tuberous rhizomes or underground stems of ginger are used as condiment, an aromatic stimulant, and food preservative as well as in traditional medicine. Ginger is propagated vegetatively with rhizome bits as seed material. Cultivation of ginger is plagued by rhizome rot diseases, most of which are mainly spread through infected seed rhizomes. Micropropagation will help in production of disease-free planting material. Sexual reproduction is absent in ginger, making recombinant breeding very impossible. In vitro technology can thus become the preferred choice as it can be utilized for multiplication, conservation of genetic resources, generating variability, gene transfer, molecular tagging, and their utility in crop improvement of these crops.

Identification and analysis of miRNAs and their targets in ginger using bioinformatics approach.

MicroRNAs (miRNAs) are a large family of endogenous small RNAs derived from the non-protein coding genes. miRNA regulates the gene expression at the post-transcriptional level and plays an important role in plant development. Zingiber officinale is an important medicinal plant having numerous therapeutic properties. Its bioactive compound gingerol and essential oil posses important pharmacological and physiological activities. In this study, we used a homology search based computational approach for identifying miRNAs in Z. officinale. A total of 16 potential miRNA families (miR167, miR407, miR414, miR5015, miR5021, miR5644, miR5645, miR5656, miR5658, miR5664, miR827, miR838, miR847, miR854, miR862 and miR864) were predicted in ginger. Phylogenetic and conserved analyses were performed for predicted miRNAs. Thirteen miRNA families were found to regulate 300 target transcripts and play an important role in cell signaling, reproduction, metabolic process and stress. To understand the miRNA mediated gene regulatory control and to validate miRNA target predictions, a biological network was also constructed. Gene ontology and pathway analyses were also done. miR5015 was observed to regulate the biosynthesis of gingerol by inhibiting phenyl ammonia lyase (PAL), a precursor enzyme in the biosynthesis of gingerol. Our results revealed that most of the predicted miRNAs were involved in the regulation of rhizome development. miR5021, miR854 and miR838 were identified to regulate the rhizome development and the essential oil biosynthesis in ginger.