ABSTRACT
Dendrobium has been widely used not only as ornamental plants but also as food and medicines. The identification and evaluation of the genetic diversity of Dendrobium species support the conservation of genetic resources of endemic Dendrobium species. Uniquely identifying Dendrobium species used as medicines helps avoid misuse of medicinal herbs. However, it is challenging to identify Dendrobium species morphologically during their immature stage. Based on the DNA barcoding method, it is now possible to efficiently identify species in a shorter time. In this study, the genetic diversity of 76 Dendrobium samples from Southern Vietnam was investigated based on the ITS (Internal transcribed spacer), ITS2, matK (Maturase_K), rbcL (ribulose-bisphosphate carboxylase large subunit) and trnH-psbA (the internal space of the gene coding histidine transfer RNA (trnH) and gene coding protein D1, a polypeptide of the photosystem I reaction center (psaB)) regions. The ITS region was found to have the best identification potential. Nineteen out of 24 Dendrobium species were identified based on phylogenetic tree and Indel information of this region. Among these, seven identified species were used as medicinal herbs. The results of this research contributed to the conservation, propagation, and hybridization of indigenous Dendrobium species in Southern Vietnam.
ABSTRACT
Paphiopedilum delenatii is a native orchid of Vietnam with highly attractive floral traits. Unfortunately, it is now listed as a critically endangered species with a few hundred individuals remaining in nature. In this study, we performed next-generation sequencing of P. delenatii and assembled its complete chloroplast genome. The whole chloroplast genome of P. delenatii was 160,955 bp in size, 35.6% of which was GC content, and exhibited typical quadripartite structure of plastid genomes with four distinct regions, including the large and small single-copy regions and a pair of inverted repeat regions. There were, in total, 130 genes annotated in the genome: 77 coding genes, 39 tRNA genes, 8 rRNA genes, and 6 pseudogenes. The loss of ndh genes and variation in inverted repeat (IR) boundaries as well as data of simple sequence repeats (SSRs) and divergent hotspots provided useful information for identification applications and phylogenetic studies of Paphiopedilum species. Whole chloroplast genomes could be used as an effective super barcode for species identification or for developing other identification markers, which subsequently serves the conservation of Paphiopedilum species.
ABSTRACT
Paphiopedilum is among the most popular ornamental orchid genera due to its unique slipper flowers and attractive leaf coloration. Most of the Paphiopedilum species are in critical danger due to over-exploitation. They were listed in Appendix I of the Convention on International Trade in Endangered Species of Wild Fauna and Flora, which prevents their being traded across borders. While most Paphiopedilum species are distinctive, owing to their respective flowers, their vegetative features are more similar and undistinguished. Hence, the conservation of these species is challenging, as most traded specimins are immature and non-flowered. An urgent need exists for effective identification methods to prevent further illegal trading of Paphiopedilum species. DNA barcoding is a rapid and sensitive method for species identification, at any developmental stage, using short DNA sequences. In this study, eight loci, i.e., ITS, LEAFY, ACO, matK, trnL, rpoB, rpoC1, and trnH-psbA, were screened for potential barcode sequences on the Vietnamese Paphiopedilum species. In total, 17 out of 22 Paphiopedilum species were well identified. The studied DNA sequences were deposited to GenBank, in which Paphiopedilum dalatense accessions were introduced for the first time. ACO, LEAFY, and trnH-psbA were limited in amplification rate for Paphiopedilum. ITS was the best single barcode. Single ITS could be used along with nucleotide polymorphism characteristics for species discrimination. The combination of ITS + matK was the most efficient identification barcode for Vietnamese Paphiopedilum species. This barcode also succeeded in recognizing misidentified or wrongly-named traded samples. Different bioinformatics programs and algorithms for establishing phylogenetic trees were also compared in the study to propose quick, simple, and effective tools for practical use. It was proved that both the Bayesian Inference method in the MRBAYES program and the neighbor-joining method in the MEGA software met the criteria. Our study provides a barcoding database of Vietnamese Paphiopedilum which may significantly contribute to the control and conservation of these valuable species.
ABSTRACT
BACKGROUND: The long-term risk of patients with Kawasaki disease is not well defined. A great proportion of patients with Kawasaki disease have important variation of their coronary artery (CA) diameters, but the significance of this variation is not known. The aim of this study was to test the hypothesis that patients within the normal range of CA diameters but with important Z-score variation have a stronger inflammatory response and increased resistance to treatment than those without such Z-score variation. METHODS: A retrospective study was conducted in 197 patients with Kawasaki disease with serial echocardiograms up to 12 months after diagnosis. Patients with occult CA dilatation (variation > 2 Z-score units but within the normal range) were compared with patients with definite CA dilatation (Z score > 2.5) and with patients with normal CA for resistance to treatment and systemic inflammatory parameters. RESULTS: A total of 63 patients (32.0%) were identified with Z scores always within the normal range but with important variation of CA diameter during follow-up (occult dilatation). There was a strong statistically significant trend of increasing inflammatory marker levels across patient categories (normal > occult dilatation > definite dilatation). Furthermore, resistance to intravenous immunoglobulin therapy was significantly increased in patients with occult dilatation compared with patients with normal CAs (relative risk, 2.6; 95% confidence interval, 1.21-5.44; P = .006). CONCLUSIONS: The suggested definition of occult CA dilatation identified patients with CA involvement currently unrecognized per the current guidelines. These patients might be at a higher CA risk than previously thought.