Background
The internal transcribed spacer 2 (ITS2) region of nuclear ribosomal DNA is regarded as one of the candidate DNA barcodes because it possesses a number of valuable characteristics, such as the availability of conserved regions for designing universal primers, the ease of its amplification, and sufficient variability to distinguish even closely related species. However, a general analysis of its ability to discriminate species in a comprehensive sample set is lacking.

/pdf/use-of-its2-region-as-the-universal-dna-barcode-for-plants-4r9vsndamf.pdf

Use of ITS2 Region as the Universal DNA Barcode for Plants and Animals

DNA barcoding is currently a widely used and effective tool that enables rapid and accurate identification of plant species; however, none of the available loci work across all species Because single-locus DNA barcodes lack adequate variations in closely related taxa, recent barcoding studies have placed high emphasis on the use of whole-chloroplast genome sequences which are now more readily available as a consequence of improving sequencing technologies While chloroplast genome sequencing can already deliver a reliable barcode for accurate plant identification it is not yet resource-effective and does not yet offer the speed of analysis provided by single-locus barcodes to unspecialized laboratory facilities Here, we review the development of candidate barcodes and discuss the feasibility of using the chloroplast genome as a super-barcode We advocate a new approach for DNA barcoding that, for selected groups of taxa, combines the best use of single-locus barcodes and super-barcodes for efficient plant identification Specific barcodes might enhance our ability to distinguish closely related plants at the species and population levels

/pdf/plant-dna-barcoding-from-gene-to-genome-ygp80h814k.pdf

Plant DNA barcoding: From gene to genome

Medicinal plants are globally valuable sources of herbal products, and they are disappearing at a high speed. This article reviews global trends, developments and prospects for the strategies and methodologies concerning the conservation and sustainable use of medicinal plant resources to provide a reliable reference for the conservation and sustainable use of medicinal plants. We emphasized that both conservation strategies (e.g. in situ and ex situ conservation and cultivation practices) and resource management (e.g. good agricultural practices and sustainable use solutions) should be adequately taken into account for the sustainable use of medicinal plant resources. We recommend that biotechnical approaches (e.g. tissue culture, micropropagation, synthetic seed technology, and molecular marker-based approaches) should be applied to improve yield and modify the potency of medicinal plants.

/pdf/conservation-and-sustainable-use-of-medicinal-plants-3cr53p4qye.pdf

Conservation and sustainable use of medicinal plants: problems, progress, and prospects.

Plant tissue culture as an important tool for the continuous production of active compounds including secondary metabolites and engineered molecules. Novel methods (gene editing, abiotic stress) can improve the technique. Humans have a long history of reliance on plants for a supply of food, shelter and, most importantly, medicine. Current-day pharmaceuticals are typically based on plant-derived metabolites, with new products being discovered constantly. Nevertheless, the consistent and uniform supply of plant pharmaceuticals has often been compromised. One alternative for the production of important plant active compounds is in vitro plant tissue culture, as it assures independence from geographical conditions by eliminating the need to rely on wild plants. Plant transformation also allows the further use of plants for the production of engineered compounds, such as vaccines and multiple pharmaceuticals. This review summarizes the important bioactive compounds currently produced by plant tissue culture and the fundamental methods and plants employed for their production.

/pdf/in-vitro-plant-tissue-culture-means-for-production-of-5cvlep1j9n.pdf

In vitro plant tissue culture: means for production of biological active compounds

The past couple of decades have witnessed global resurgence of herbal-based health care. As a result, the trade of raw drugs has surged globally. Accurate and fast scientific identification of the plant(s) is the key to success for the herbal drug industry. The conventional approach is to engage an expert taxonomist, who uses a mix of traditional and modern techniques for precise plant identification. However, for bulk identification at industrial scale, the process is protracted and time-consuming. DNA barcoding, on the other hand, offers an alternative and feasible taxonomic tool box for rapid and robust species identification. For the success of DNA barcode, the barcode loci must have sufficient information to differentiate unambiguously between closely related plant species and discover new cryptic species. For herbal plant identification, matK, rbcL, trnH-psbA, ITS, trnL-F, 5S-rRNA and 18S-rRNA have been used as successful DNA barcodes. Emerging advances in DNA barcoding coupled with next-generation sequencing and high-resolution melting curve analysis have paved the way for successful species-level resolution recovered from finished herbal products. Further, development of multilocus strategy and its application has provided new vistas to the DNA barcode-based plant identification for herbal drug industry. For successful and acceptable identification of herbal ingredients and a holistic quality control of the drug, DNA barcoding needs to work harmoniously with other components of the systems biology approach. We suggest that for effectively resolving authentication challenges associated with the herbal market, DNA barcoding must be used in conjunction with metabolomics along with need-based transcriptomics and proteomics.

https://www.onlinelibrary.wiley.com/doi/pdf/10.1111/pbi.12419

DNA barcoding: an efficient tool to overcome authentication challenges in the herbal market.

DNA barcoding is a rapidly developing frontier technology that is gaining worldwide attention. Here, seven regions (psbA-trnH, matK, ycf5, rpoC1, rbcL, ITS2, and ITS) with potential for use as DNA barcodes were tested for their ability to identify 300 samples of 192 species from 72 genera of the family Rutaceae. To evaluate each barcode’s utility for species authentication, PCR amplification efficiency, genetic divergence, and barcoding gaps were assessed. We found that the ITS2 region exhibited the highest inter-specific divergence, and that this was significantly higher than the intra-specific variation in the “DNA barcoding gap” assessment and Wilcoxon two-sample tests. The ITS2 locus had the highest identification efficiency among all tested regions. In a previous study, we found that ITS2 was able to discriminate a wide range of plant taxa, and here we confirmed that ITS2 was also able to discriminate a number of closely related species. Therefore, we propose that ITS2 is a promising candidate barcode for plant species identification.

Assessment of candidate plant DNA barcodes using the Rutaceae family

Background
Many medicinal plants are increasingly endangered due to overexploitation and habitat destruction. To provide reliable references for conservation planning and regional management, this study focuses on large-scale distribution prediction of Rheum tanguticum Maxim. ex Balf (Dahuang).

/pdf/tcmgis-ii-based-prediction-of-medicinal-plant-distribution-1oy0lxedwx.pdf

TCMGIS-II based prediction of medicinal plant distribution for conservation planning: a case study of Rheum tanguticum

Magnoliaceae species have high ornamental and medicinal importance, but they are morphologically similar. DNA barcoding has been regarded as a rapid and effective approach for species identification. To determine the efficiency of expedient identification in Magnoliaceae species by DNA barcoding, in this study, we collected 83 samples belonging to 68 species in 10 genera of Magnoliaceae. Candidate DNA regions (i.e., psbA-trnH, matK, rbcL, ITS, ITS2, rpoB, and rpoC1) were amplified and sequenced for the evaluation of their PCR amplification, sequencing efficiency, intra- and inter-specific divergence and barcoding gap by sequence alignment and Kimura 2-Parameter (K2P) distance analysis, and the rate of correct identification was assessed by BLAST analysis. The results showed that psbA-trnH and matK exhibited high performance in efficiency of PCR amplification and the rate of successful sequencing, followed by rbcL. Associated with the analysis of 199 sequences for 96 species in 9 genera of Magnoliaceae retrieved from GenBank, it was discovered that psbA-trnH was highest in inter-specific divergence and rate of correct identification, indicating its efficiency in the identification of Magnoliaceae species. Besides, matK was also easy to amplify and had high rate of correct identification, suggesting its potential to distinguish Magnoliaceae species. This study indicates that DNA barcoding provides an effective technique for the expedient identification of morphologically similar species, and it is a powerful aid to the conventional methods for species identification.

/pdf/expedient-identification-of-magnoliaceae-species-by-dna-11t5yvr946.pdf

Expedient identification of Magnoliaceae species by DNA barcoding

Medicinal plants are globally valuable sources of herbal products, and they are disappearing at a high speed. This article reviews global trends, developments and prospects for the strategies and methodologies concerning the conservation and sustainable use of medicinal plant resources to provide a reliable reference for the conservation and sustainable use of medicinal plants. We emphasized that both conservation strategies (e.g. in situ and ex situ con‑ servation and cultivation practices) and resource management (e.g. good agricultural practices and sustainable use solutions) should be adequately taken into account for the sustainable use of medicinal plant resources. We recom‑ mend that biotechnical approaches (e.g. tissue culture, micropropagation, synthetic seed technology, and molecular marker‑based approaches) should be applied to improve yield and modify the potency of medicinal plants.

Hua Yu

Papers

Conservation and sustainable use of medicinal plants: problems, progress, and prospects.

Assessment of candidate plant DNA barcodes using the Rutaceae family

TCMGIS-II based prediction of medicinal plant distribution for conservation planning: a case study of Rheum tanguticum

Expedient identification of Magnoliaceae species by DNA barcoding

Conservation and sustainable use of medicinal plants: problems, progress,