Dendrobium officinale is an edible medicinal herb. Its flowers contain various nutrients and active compounds, the abundance of which differs significantly across developmental stages. However, the molecular mechanisms underlying these variations remain poorly understood. This study employed combined transcriptomic and metabolomic analyses to investigate changes in gene expression and metabolite concentrations in Dendrobium flowers and buds. The analysis identified 2767 differentially expressed genes between the bud (group B) and flower (group F) stages, with 902 up-regulated and 1865 down-regulated in group B relative to group F. The number of differentially abundant secondary metabolites was 221, including 113 up-regulated and 108 down-regulated metabolites. The differential metabolites primarily consisted of lipids and lipid-like molecules, organic heterocyclic compounds, organic acids, and their derivatives, phenylacetones and polyketides, organic oxides, benzene ring-type compounds, hydrocarbons, and alkaloids with their derivatives. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis of the differentially expressed genes and metabolites revealed enrichment in pathways related to phytohormone signaling, phenylpropanoid biosynthesis, and zeaxanthin biosynthesis. Verification of 15 genes through quantitative real-time PCR (qRT-PCR) confirmed the accuracy of the transcriptomic analysis. Taken together, these findings contribute to an improved understanding of the nutritional and pharmacological characteristics of Dendrobium officinale flowers at different developmental stages.

Tetrastigma hemsleyanum Diels et Gilg is a rare and wild medicinal resource. Metabolites, especially secondary metabolites, have an important influence on T. hemsleyanum adaptability and its medicinal quality. The metabolite proanthocyanidin (PA) is a polyphenol compound widely distributed in land plants, which can be used as antioxidants and anticancer agents. Here, we discovered that three types of PA accumulated in large amounts in purple leaves (PL), but not in green leaves (RG), based on widely non-targeted metabolomics. In addition, we further found that catechins and their derivatives, which are the structural units of PA, are also enriched in PL. Afterwards, we screened and obtained five key genes, DNR1/2, ANS, ANR and LAR closely related to PA biosynthesis through transcriptome analysis and found they were all highly expressed in PL compared to RG. Therefore, observed the regulatory relationship between the main compounds and genes network, and the PA metabolism regulatory pathway was complicated, which may be different to other species.

Tetrastigma hemsleyanum Diels et Gilg is a high-value edible and medicinal homologous plant, routinely grown under conventional field or greenhouse production systems across Asia. However, mislabeling of conventional products as the rarer (and more expensive) wild version may occur for financial gain. In this study, stable isotopes (δ¹³C, δ¹⁵N, δ²H, and δ¹⁸O) and metal contents (Cr, Cu, Ni, As, Cd, Pb) were used to characterize plant tissues (tuber root, stem, leaf) and corresponding soils originating from simulated-wild-cultivated (WC) and greenhouse-cultivated (GC) pot trials using the same soil. Carbon and nitrogen isotopes served as key indicators for distinguishing GC and WC products. Specifically, δ¹³C values of GC plant tissues were 1.4 to 2.4‰ more positive than those of WC plant tissues (p < 0.05), and δ¹⁵N values in GC tissues were 2.7 to 4.6‰ more positive than δ¹⁵N in WC tissues (p < 0.01). Lower δ¹⁵N values observed in WC products indicate slower nitrogen turnover compared with GC products. Soil metal concentrations had significant differences between the two cultivation systems, but only limited effects on metal bioconcentration factors (BCFs) and translocation factors (TFs) in T. hemsleyanum tissues. Pb and Cd concentrations in root tissues had large differences between cultivation systems, and carbon dynamics in GC plants were more negatively affected by Pb levels in soils. These findings provide the first investigation of T. hemsleyanum grown under different cultivation practices and establish a scientific basis for distinguishing other wild or simulated-wild labeled food and medicinal plant products from conventionally grown products in future studies.

Background/Objectives: To elucidate how flower retention regulates leaf quality formation in Dendrobium officinale and to provide a theoretical basis for high-quality leaf cultivation and high-value utilization of byproducts, D. officinale leaves were subjected to two treatments: flower retention (FR) and flower removal (FT). Methods: Quantitative analysis revealed significant differences in quality-related compounds between the two treatments. Specifically, the polysaccharide content in the FR group (8.72%) was significantly lower than that in the FT group (9.37%). Conversely, the FT group exhibited a significantly higher total flavonoid content (1.74%) compared to the FR group (1.41%). Additionally, the total phenol content in the FR group (0.90%) was significantly higher than that in the FT group (0.69%) (n = 3). Results: Compared with the FR group, the FT group exhibited significantly higher levels of total flavonoids, polysaccharides, tyrosine (Tyr), hydroxylysine (Hylys), lysine (Lys), histidine (His), and arginine (Arg). A total of 1999 (39.5%) of the 5062 annotated metabolites were accumulated significantly differently. The FT group was mainly characterized by upregulated secondary metabolites, including flavonoids. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis indicated that nucleotide metabolism, purine metabolism, aminoacyl-tRNA biosynthesis, and flavonoid biosynthesis were the core differential pathways. Furthermore, the differential metabolites exhibited a metabolic trade-off of “upregulated secondary metabolism and downregulated primary metabolism”. Conclusions: Our findings indicated that flower removal can significantly increase the active flavonoid components and amino acids in D. officinale leaves and optimize the quality of this medicinal leaf by regulating the source–sink relationship, carbon–nitrogen partitioning, and key metabolic pathways.