Search Results (4)

Taxillus chinensis (DC.) Danser is an important hemiparasitic medicinal plant whose propagation is severely limited by the desiccation sensitivity of its recalcitrant seeds. Dehydrins (DHNs), which protect plants against dehydration-induced stresses such as salinity, drought, and low temperatures, may play a critical role in protecting recalcitrant seeds. However, the role of DHNs in the seeds of T. chinensis remains unclear. In this study, a differentially expressed gene was identified from the seed transcriptome of T. chinensis and designated TcDHN1. Sequence alignment and phylogenetic analyses revealed that TcDHN1 encodes a dehydrin protein. Heterologous overexpression of TcDHN1 in Arabidopsis did not affect growth under normal conditions. Under salt, drought, and cold stresses, transgenic lines exhibited higher seed germination rates, longer primary roots, and improved seedling growth compared with wild-type (WT) plants. The transgenic lines showed significantly increased activities of antioxidant enzymes, including superoxide dismutase, catalase, and peroxidase. In addition, ectopic overexpression of TcDHN1 in Arabidopsis conferred enhanced tolerance to abiotic stresses compared to WT plants, accompanied by increased expression of the stress-responsive genes Responsive to Desiccation 29A (AtRD29A) and Heat Shock Protein 70-1 (AtHSP70-1). The above results indicate that TcDHN1 confers enhanced tolerance to abiotic stresses. This study provides a functional characterization of an abiotic stress-responsive gene from recalcitrant seeds and identifies a potential genetic resource for molecular breeding. This could potentially improve abiotic stress resistance in T. chinensis and related medicinal plants. Full article

Research on the chloroplast genome of parasitic plants is limited. In particular, the homology between the chloroplast genomes of parasitic and hyperparasitic plants has not been reported yet. In this study, three chloroplast genomes of Taxillus (Taxillus chinensis, Taxillus delavayi, and Taxillus thibetensis) and one chloroplast genome of Phacellaria (Phacellaria rigidula) were sequenced and analyzed, among which T. chinensis is the host of P. rigidula. The chloroplast genomes of the four species were 119,941–138,492 bp in length. Compared with the chloroplast genome of the autotrophic plant Nicotiana tabacum, all of the ndh genes, three ribosomal protein genes, three tRNA genes and the infA gene were lost in the three Taxillus species. Meanwhile, in P. rigidula, the trnV-UAC gene and the ycf15 gene were lost, and only one ndh gene (ndhB) existed. The results of homology analysis showed that the homology between P. rigidula and its host T. chinensis was low, indicating that P. rigidula grows on its host T. chinensis but they do not share the chloroplast genome. In addition, horizontal gene transfer was not found between P. rigidula and its host T. chinensis. Several candidate highly variable regions in the chloroplast genomes of Taxillus and Phacellaria species were selected for species identification study. Phylogenetic analysis revealed that the species of Taxillus and Scurrula were closely related and supported that Scurrula and Taxillus should be treated as congeneric, while species in Phacellaria had a close relationship with that in Viscum. Full article

The goal of this study was to identify and compare the main biomarkers of Taxillus chinensis from different hosts. A metabolomics approach utilizing ultra-pressure liquid chromatography coupled with tandem mass spectrometry (UPLC-MS), including cluster analysis, sample correlation analysis and orthogonal partial least squares discriminant analysis, was used to explore the flavonoid metabolites of Taxillus chinensis growing on different hosts. Results: The total flavonoids content (up to 30.08 mg/g) in Taxillus chinensis from Morus alba (CSG) was significantly higher than that from growth on Liquidambar formosana (CFG) or Clausena lansium (CHG) (p < 0.01). There were 23 different metabolites between CSG and CHG, 23 different metabolites between CSG and CFG, and 19 different metabolites between CHG and CFG. The results demonstrated that different hosts exerted a large influence on the metabolites of Taxillus chinensis; it was found that CSG differed from CFG and CHG in eleven metabolic compounds, ten of which were upregulated and one of which was downregulated. Most of these metabolites derive from compounds contained in the host plant, white mulberry (Morus alba); many feature potent anti-cancer effects. Differences in host can influence the type and abundance of flavonoids in parasitic plants such as Taxillus chinensis, which is of great significance to researchers seeking to understand the formation mechanism of Taxillus chinensis metabolites. Therefore, attention should be paid to the species of host plant when studying the Taxillus chinensis metabolome. Plants grown on Morus alba offer the greatest potential for the development of new anti-cancer drugs. Full article

Taxilli Herba (TH) is a well-known traditional Chinese medicine (TCM) with a wide range of clinical application. However, there is a lack of comprehensive research on its chemical composition in recent years. At the same time, Taxillus chinensis (DC) Danser is a semi parasitic plant with abundant hosts, and its chemical constituents varies due to hosts. In this study, the characterization of chemical constituents in TH was analyzed by ultra-fast liquid chromatography coupled with triple quadrupole-time of flight tandem mass spectrometry (UFLC-Triple TOF-MS/MS). Moreover, partial least squares discriminant analysis (PLS-DA) was applied to reveal the differential constituents in TH from different hosts based on the qualitative information of the chemical constituents. Results showed that 73 constituents in TH were identified or tentatively presumed, including flavonoids, phenolic acids and glycosides, and others; meanwhile, the fragmentation pathways of different types of compounds were preliminarily deduced by the fragmentation behavior of the major constituents. In addition, 23 differential characteristic constituents were screened based on variable importance in projection (VIP) and p-value. Among them, quercetin 3-O-β-D-glucuronide, quercitrin and hyperoside were common differential constituents. Our research will contribute to comprehensive evaluation and intrinsic quality control of TH, and provide a scientific basis for the variety identification of medicinal materials from different hosts. Full article