RESUMEN
1-Deoxy-D-xylulose-5-phosphate synthase (DXS), the first key enzyme in 2-methyl-D-erythritol-4-phosphate (MEP) pathway, catalyzes the condensation of glyceraldehyde-3-phosphate with pyruvate to 1-deoxy-xylose-5-phosphate (DXP). In this study, PgDXS1, PgDXS2, and PgDXS3 genes were cloned from the root of Platycodon grandiflorum (P. grandiflorum). The open reading frame (ORF) of PgDXS1, PgDXS2, and PgDXS3 were 2 160, 2 208, and 2 151 bp in full length, encoding 719, 735, and 716 amino acids, respectively. Homologous alignment results showed a high identity of PgDXSs with DXS in Hevea brasiliensis, Datura stramonium and Stevia rebaudiana. The recombinant expression plasmids of pET-28a-PgDXSs were constructed and transformed into Escherichia coli (E. coli) BL21 (DE3) cells, and the induced proteins were successfully expressed. Subcellular localization results showed that PgDXS1 and PgDXS2 were mainly located in chloroplasts, and PgDXS3 was located in chloroplasts, nucleus and cytoplasm. The expression of three DXS genes in different tissues of two producing areas of P. grandiflorum were assayed via real-time fluorescence quantitative PCR, and the results showed that all of them were highly expressed in leaves of P. grandiflorum from Taihe. Under methyl jasmonate (MeJA) treatment, the expression levels of three PgDXS genes showed a trend of first decreasing and then increasing at different time points (3 - 48 h), and the activity of DXS showed a trend of first increasing and then decreasing in three tissues of P. grandiflorum. This study provides a reference for further elucidating the biological function of PgDXS in terpenoid synthesis pathway in P. grandiflorum.
RESUMEN
Growth year is one of the important factors for the quality of mountain cultivated ginseng (MCG). For age differentiation of MCG, rhizome extracts of ginseng aged from 11 to 15 years were analyzed using a non-targeted approach with ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS)-based on plant metabolomics technique. Multivariate statistical methods such as principal component analysis (PCA) and orthogonal partial least squared discrimination analysis (OPLS-DA) were used to compare the derived patterns among the samples. The results showed that the chemical constituents of MCG rhizome extracts of ginseng aged from 11 to 15 years were different. The data set was subsequently applied to metabolite selection by variable importance in the projection (VIP) for sophisticated classification with the optimal number of metabolites. The OPLS-DA model of MCG has a high interpretability and predictive capability, which established by selecting metabolites of MCG aged from 11 to 15 years. By this approach, MCG samples aged from 11 to 15 years, which are the most in demand in the Chinese ginseng market, can be precisely differentiated on the basis of selected metabolites. This proposed analytical method is fast, accurate, and reliable for discriminating the growth year of MCG. Moreover, this study supplies a new method for the age discrimination of other Chinese medicinal materials.
RESUMEN
Mountain cultivated ginseng (MCG), also called "Lin-Xia-Shan-Shen", is intentionally seeded and grows in mountainous forest but without any artificial management, which belongs to the herbaceous plants classified in the Araliaceae family and the genus Panax L. MCG has high medicinal value and wide range of pharmacological effects, which had been reported with many kinds of effective components, such as saponins, volatile oil, polysaccharides, protein, and inorganic elements. There is a phenomenon that something regards as real, shoddy, varying of quality in MCG market. Currently, a lot of measures are applied to the identification and evaluation of MCG. This paper summarizes the progress in study on the chemical constituents, the identification and evaluation of MCG, and provides the references for the further development, utilization, and quality control of MCG.
RESUMEN
In present study, an ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UHPLC-QTOF/MS)-based plant metabolomics approach was established to investigate the metabolic profiles of the leaves, main root, branch root, and rhizome of Mountain Cultivated Ginseng (MCG). The UHPLC-QTOF/MS data were subjected to principal component analysis (PCA) and orthogonal partial least squared discrimination analysis (OPLS-DA) to find the potential characteristic components of the four parts of MCG in a quick way. The four different parts could be separated into four different groups of phytochemicals according to the PCA scores. The chemical constituents in four parts of MCG were obviously different. The identities of 81 major peaks that were detected in the four parts of MCG and the potential markers were identified by comparison with the reference compounds or were tentatively assigned by matching the retention time,empirical molecular formula and fragment ions with those of the published compounds of the Panax species. This proposed analytical method is fast, accurate, and reliable for differentiating the different parts of MCG. Moreover, this study supplied a new method for the quality evaluation of other Chinese medicinal materials.