Dendrobium huoshanense is used to treat various diseases in traditional Chinese medicine. Recent studies have identified active components. However, the lack of genomic data limits research on the biosynthesis and application of these therapeutic ingredients. To address this issue, we generated the first chromosome-level genome assembly and annotation of D. huoshanense. We integrated PacBio sequencing data, Illumina paired-end sequencing data, and Hi-C sequencing data to assemble a 1.285 Gb genome, with contig and scaffold N50 lengths of 598 kb and 71.79 Mb, respectively. We annotated 21,070 protein-coding genes and 0.96 Gb transposable elements, constituting 74.92% of the whole assembly. In addition, we identified 252 genes responsible for polysaccharide biosynthesis by Kyoto Encyclopedia of Genes and Genomes functional annotation. Our data provide a basis for further functional studies, particularly those focused on genes related to glycan biosynthesis and metabolism, and have implications for both conservation and medicine.

Dendrobium huoshanense, a traditional medicinal and food homologous plant, belongs to the family Orchidaceae and has a long history of medicinal use. It is reported that the stem of D. huoshanense has a variety of bioactive ingredients such as polysaccharides, flavonoids, sesquiterpenes, phenols, etc. These bioactive ingredients make D. huoshanense remarkable for its pharmacological effects on anti-tumor, immunomodulation, hepatoprotective, antioxidant, and anticataract activities. In recent years, its rich pharmacological activities have attracted extensive attention. However, there is no systematic review focusing on the chemical compositions and pharmacological effects of D. huoshanense. Therefore, the present review aims to summarize current research on the chemical compositions and pharmacological activities of D. huoshanense. This study provides valuable references and promising ideas for further investigations of D. huoshanense.

Polysaccharides are carbohydrate chains composed of linked monosaccharide units. Accumulating studies report that polysaccharides isolated from Dendrobium officinale have a variety of functions. However, the composition and anti-tumor activity of D. officinale grown in the Huoshan area are largely unknown. A polysaccharide (DOPA-1) was isolated from D. officinale by hot water extraction and ethanol precipitation, followed by purification via DEAE-cellulose and Sephadex G-100 chromatography. DOPA-1 was analyzed by infrared and nuclear magnetic resonance and then characterized by periodate oxidation and Smith degradation. The anti-tumor activity of DOPA-1 was then tested in HepG-2 cells. Our results show that DOPA-1 is mainly comprised of mannose, glucose, and galactose at a molar ratio of 1:0.42:0.27 and has an average molecular weight of 2.29 × 105 Da. Additionally, DOPA-1 inhibited HepG-2 cell growth in a dose-dependent manner. DOPA-1-treated HepG-2 cells also had increased reactive oxygen species (ROS) levels and decreased mitochondrial membrane potential. Furthermore, apoptosis was observed in DOPA-1-treated HepG-2 cells along with Bcl-2 downregulation and Bax upregulation at the protein level. Our findings suggest that DOPA-1 induces apoptosis in tumor cells via altered mitochondrial function, ROS production, and altered apoptosis-related protein expression. This bioactive polysaccharide could, therefore, potentially be further developed as an anti-tumor adjuvant drug.

Dendrobium huoshanense is a kind of precious herb with important medicinal and edible value in China, which is widely used in traditional Chinese medicine for various diseases. Recent studies have paid close attention to the genetic expression of the biosynthetic pathway of the main active components (polysaccharides, alkaloids, and flavonoids), and real-time polymerase chain reaction (qPCR) is one of the most widely used methods for doing so. However, so far, no reference gene selections have been reported in D. huoshanense. In this study, 15 reference gene candidates (GAPDH, eIF, EF-1α, PP2A, UBCE, RPL5, TBP, APT1, MDH, PTBP3, PEPC, CYP71, NCBP2, TIP41, and F-box) were selected and evaluated for their expression stability in D. huoshanense under various experimental conditions, including in different tissues (root, stem, and leaf), abiotic stresses (oxidative, drought, cold, and UV), and hormone treatment (methyl jasmonate) using three statistical programs (geNorm, NormFinder, and BestKeeper). Then, the RefFinder program was employed to comprehensively validate the stability of the selected reference genes. Finally, the expression profiles of the CESA and GMPP genes were further analyzed, and these results indicated that TBP, NCBP2, and CYP71 were the top three most stable reference genes after comprehensive comparison, which could be used as stable reference genes for normalizing the genes expression in D. huoshanense. This study described here provides the first data regarding on reference gene selection in D. huoshanense, which will be extremely beneficial for future research on the gene expression normalization in D. huoshanense.