A collection of cultivated Liriope and Ophiopogon plants was established in 1996-1998 and subsequently hosted at a horticultural college. Uncertainties about the identification of the accessions, compounded by potential errors in propagation and labelling have led to waning confidence in the identities of the plants in the collection. The potential for using DNA barcoding to determine the species identities of the accessions was investigated. The DNA barcode regions of the plastid ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit gene (rbcL) and nuclear ribosomal internal transcribed spacer (nrITS) were amplified. DNA sequence analysis allowed the sequences of the accessions to be compared to reference sequences in public databases. A simple haplotype map of the characteristic polymorphic positions in the rbcL regions was used to clearly distinguish between the two genera and assign Ophiopogon accessions to individual species or sub-groups of species. The ITS sequence data confirmed these genus and species assignations and provided greater resolution to distinguish between closely related species. The combination of two DNA barcodes allowed most of the accessions to be assigned to individual species. This molecular verification confirmed the identity of about 70% of the accessions, with the remaining 30% demonstrating a range of mistaken identities at the species and genus levels.
Abstract The steno-endemic species of genus Decalepis are highly threatened by destructive wild harvesting. The medicinally important fleshy tuberous roots of Decalepis hamiltonii are traded as substitute, to meet the international market demand of Hemidesmus indicus . In addition, the tuberous roots of all three species of Decalepis possess similar exudates and texture, which challenges the ability of conventional techniques alone to perform accurate species authentication. This study was undertaken to generate DNA barcodes that could be utilized in monitoring and curtailing the illegal trade of these endangered species. The DNA barcode reference library was developed in BOLD database platform for candidate barcodes rbcL , matK , psbA-trnH , ITS and ITS2 . The average intra-specific variations (0–0.27%) were less than the distance to nearest neighbour (0.4–11.67%) with matK and ITS . Anchoring the coding region rbcL in multigene tiered approach, the combination rbcL + matK + ITS yielded 100% species resolution, using the least number of loci combinations either with PAUP or BLOG methods to support a character-based approach. Species-specific SNP position (230 bp) in the matK region that is characteristic of D . hamiltonii could be used to design specific assays, enhancing its applicability for direct use in CITES enforcement for distinguishing it from H . indicus .
The Mak-type Cdc2-like protein kinases are, a relatively uncharacterized group of proteins. Bvcrk2 encodes a plant Mak-type kinase. Its highest levels of expression occur in the secondary meristems of developing sugar beet storage organs, suggesting a role, in planta, in the regulation of cell division or early cell differentiation.
The potential value of DNA barcoding for the identification of medicinal plants and authentication of traded plant materials has been widely recognized; however, a number of challenges remain before DNA methods are fully accepted as an essential quality control method by industry and regulatory authorities. The successes and limitations of conventional DNA barcoding are considered in relation to important members of the Lamiaceae. The mint family (Lamiaceae) contains over one thousand species recorded as having a medicinal use, with many more exploited in food and cosmetics for their aromatic properties. The family is characterized by a diversity of secondary products, most notably the essential oils (EOs) produced in external glandular structures on the aerial parts of the plant that typify well-known plants of the basil (Ocimum), lavender (Lavandula), mint (Mentha), thyme (Thymus), sage (Salvia) and related genera. This complex, species-rich family includes widely cultivated commercial hybrids and endangered wild-harvested traditional medicines, and examples of potential toxic adulterants within the family are explored in detail. The opportunities provided by next generation sequencing technologies to whole plastome barcoding and nuclear genome sequencing are also discussed with relevant examples.
Low temperature presowing treatment (LTPST) of tomato seeds, var. Moneymaker, increases their rate of germination. During this treatment there is a large increase in nucleic acid content, especially rRNA, within the seeds. Denaturing gel electrophoresis indicates that the quality of this RNA improves during LTPST. Although replacement of fragmented rRNA may be an important prerequisite for successful germination, the data show that this is unlikely to be the immediate cause of more rapid seed germination. When compared with untreated controls during subsequent germination, treated seeds show reduced rates of nucleic acid accumulation and reduced RNA polymerase activity per unit DNA, implying that rRNA synthesis within these seeds is under some measure of stringent control. The association between nucleic acid metabolism and germination is discussed.
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