Isolation and characterization of a gene encoding farnesyl diphosphate synthase from \(\textit{Panax vietnamensis}\) Ha et Grushv

Panax vietnamensis Ha et Grushv. is a species of the genus Panax native to Central Vietnam, containing a family of triterpene saponins named ginsenosides. This group of biomolecules possesses valuable therapeutic properties against cancer, hepatitis, diabetes, inflammation as well as stress and anxiety. Farnesyl diphosphate synthase (FPS) is a key enzyme participating in the ginsenoside biosynthesis pathway. In this study, a FPS gene from P. vietnamensis (PvFPS) was isolated and characterized. The PvFPS cDNA contained an open reading frame of 1032 bp, encoding a polypeptide chain of 342 amino acid residues. Nucleotide sequence comparison showed that FPS was highly conserved among most species, with two Aspartate-rich motifs responsible for product chain length determination strongly sustained. PvFPS was closely related to those of the same genera and order and differed from those from other kingdoms. PvFPS expression was detected at a greater level in root tissues than in leaves in all ages. Our findings provided information concerning the properties of a crucial gene in the ginsenoside biosynthesis, thus enhancing our understanding of this important pathway.

Genome-wide characterization and analysis of WRKY transcription factors in Panax ginseng

Background Panax ginseng is a well-known medicinal plant worldwide. As an herbal medicine, ginseng is also known for its long lifecycle, which can reach several decades. WRKY proteins play regulatory roles in many aspects of biological processes in plants, such as responses to biotic or abiotic stress, plant development, and adaptation to environmental challenges. Genome-wide analyses of WRKY genes in P. ginseng have not been reported. Results In this study, 137 PgWRKY genes were identified from the ginseng genome. Phylogenetic analysis showed that the PgWRKYs could be clustered into three primary groups and five subgroups. Most of the PgWRKY gene promoters contained several kinds of hormone- and stress-related cis-regulatory elements. The expression patterns of PgWRKY genes in 14 different tissues were analyzed based on the available public RNA-seq data. The responses of the PgWRKY genes to heat, cold, salt and drought treatment were also investigated. Most of the PgWRKY genes were expressed differently after heat treatment, and expression trends changed significantly under drought and cold treatment but only slightly under salt treatment. The coexpression analysis of PgWRKY genes with the ginsenoside biosynthesis pathway genes identified 11 PgWRKYs that may have a potential regulatory role in the biosynthesis process of ginsenoside. Conclusions This work provides insights into the evolution, modulation and distribution of the WRKY gene family in ginseng and extends our knowledge of the molecular basis along with modulatory mechanisms of WRKY transcription factors in ginsenoside biosynthesis.

Optimization of Protein Isolation and Label-Free Quantitative Proteomic Analysis in Four Different Tissues of Korean Ginseng

Korean ginseng is one of the most valuable medicinal plants worldwide. However, our understanding of ginseng proteomics is largely limited due to difficulties in the extraction and resolution of ginseng proteins because of the presence of natural contaminants such as polysaccharides, phenols, and glycosides. Here, we compared four different protein extraction methods, namely, TCA/acetone, TCA/acetone–MeOH/chloroform, phenol–TCA/acetone, and phenol–MeOH/chloroform methods. The TCA/acetone–MeOH/chloroform method displayed the highest extraction efficiency, and thus it was used for the comparative proteome profiling of leaf, root, shoot, and fruit by a label-free quantitative proteomics approach. This approach led to the identification of 2604 significantly modulated proteins among four tissues. We could pinpoint differential pathways and proteins associated with ginsenoside biosynthesis, including the methylerythritol 4–phosphate (MEP) pathway, the mevalonate (MVA) pathway, UDP-glycosyltransferases (UGTs), and oxidoreductases (CYP450s). The current study reports an efficient and reproducible method for the isolation of proteins from a wide range of ginseng tissues and provides a detailed organ-based proteome map and a more comprehensive view of enzymatic alterations in ginsenoside biosynthesis.

Changes in the Leaf Physiological Characteristics and Tissue-Specific Distribution of Ginsenosides in Panax ginseng During Flowering Stage Under Cold Stress

Panax ginseng is a valuable traditional herbal medicine material with numerous applications. Ginsenosides are the key bioactive compounds in ginseng. Cold stress can activate stress tolerance mechanisms that regulate biomass and biosynthesis in ginseng tissue. In this study, the effects of short- and long-term cold stress (5°C) on the physiological characteristics, tissue-specific ginsenoside distributions, and ginsenoside synthesis gene expressions of 3-year-old P. ginseng during the flowering period were investigated. Short-term cold stress significantly reduced ginseng biomass (root fresh weight and dry weight), and increased malondialdehyde, proline, soluble sugar, and soluble protein concentrations. Superoxide dismutase, peroxidase, and catalase activities also increased significantly under cold stress. With prolongation of the cold stress period, all antioxidant enzyme activity decreased. The protopanaxatriol-type ginsenoside concentrations in the taproots (phloem and xylem) and fibrous roots, as well as the protopanaxadiol-type ginsenoside concentrations in the leaves, increased significantly under short-term cold stress. The key genes (SE, DS-II, CYP716A52v2, and CYP716A53v2) involved in the ginsenoside biosynthesis pathway were significantly positively correlated with the ginsenoside accumulation trends. Thus, short-term cold stress can stimulate membrane lipid peroxidation, in turn stimulating the antioxidant enzyme system to alleviate oxidative damage and increasing the expression of key enzyme genes involved in ginsenoside biosynthesis. During agricultural production, protopanaxadiol/protopanaxatriol ratios could be manipulated by low-temperature storage or treatments.