Search Results (93)

Background/Objectives: Dendrobium officinale (D. officinale), an endangered ornamental and medicinal orchid, displays significant variability in its bioactive compounds depending on geographical and environmental factors. To decipher these influences, we investigated metabolic divergence across three cultivars (GN, LS, DX) cultivated in greenhouse and outdoor conditions using untargeted metabolomics. Methods: Metabolites extracted from stem and leaf tissues were analyzed via UHPLC-Q Exactive Orbitrap MS, and the raw data were processed using XCMS for peak alignment and quantification. Differentially abundant metabolites (DAMs) were identified by multivariate statistical analyses including PCA and OPLS-DA. Metabolic pathways were annotated using KEGG, HMDB, and LIPID Maps databases, with enrichment analysis and visualization performed via TBtools II and Hiplot. Results: Metabolite profiling and multivariate analysis revealed distinct chemotypes. The DX cultivar exhibited anthocyanin enrichment in its stems, correlating with a red pigmentation, while GN accumulated specific amino acid derivatives. Tissue-specific metabolic specialization was evident, with leaves displaying greater flavonoid diversity and stems prioritizing lipid and amino acid metabolism. Outdoor cultivation enhanced flavonoid biosynthesis, whereas greenhouse conditions favored alkaloid accumulation. Functional analysis identified both conserved pathways, like phenylpropanoid biosynthesis, and varietal-specific adaptations in amino acid and secondary metabolism. Notably, alkaloid levels declined sharply during plant defoliation. Conclusions: Our findings demonstrate that environmental factors and geographical origin synergistically shape the metabolic profiles of D. officinale. This provides a scientific basis for optimizing cultivation strategies—through targeted environmental adjustments and varietal selection—to enhance the yield of desired bioactive compounds. Full article

Dendrobium Sonia orchid cultivation constitutes a vital commercial industry in Thailand; however, production remains persistently threatened by fungal and bacterial diseases. This study proposes a robust automated framework for orchid disease classification under conditions characterized by high visual uncertainty. A comparative analysis was conducted across four Convolutional Neural Network (CNN) architectures: ResNet-50 and three lightweight counterparts—MobileNetV3-Large, EfficientNetV2-B0, and NASNet-Mobile. All models were optimized using transfer learning, Cosine Decay scheduling, and EarlyStopping on a real-world dataset acquired from commercial orchid farms in Thailand. Experimental results indicate that ResNet-50 attained the highest overall performance (Accuracy: 98.96%, Macro F1: 0.9894, AUC-ROC: 0.9996), while EfficientNetV2-B0 achieved comparable results among the lightweight architectures (Accuracy: 98.47%, Macro F1: 0.9846, AUC-ROC: 0.9985). Importantly, statistical evaluation using the Wilcoxon Signed-Rank Test across five independent trials revealed no statistically significant difference between ResNet-50 and all three lightweight models (p > 0.05). This confirms the practical viability of deploying compact architectures on mobile platforms within smart farming systems without sacrificing diagnostic accuracy. Moreover, integrating Grad-CAM++ enhances interpretability by producing visual explanations that align with expert pathological assessments. This transparency effectively mitigates decision-making ambiguity and strengthens farmer confidence in adopting AI-driven precision agriculture. Full article

Background/Objectives: The orchid Dendrobium devonianum Paxt., valued for its ornamental and medicinal properties, is widely used in horticulture, medicine, and food industries. Methods: This study investigated dynamic changes in aroma-active volatile organic compounds (VOCs) and associated gene expression in D. devonianum flowers across four developmental stages (bud, half bloom, full bloom, and aging) using headspace solid-phase microextraction, gas chromatography–mass spectrometry, and transcriptome analysis. Results: Floral VOCs, particularly volatile terpenoids and esters, were most abundant at full bloom. Among the 664 VOCs identified, α-hemelene, β-bisabolene, δ-naphthalene, perillyl alcohol, L-perillyl alcohol, terpinen-4-ol, 2-(4-methylphenyl)propan-2-ol, cis-3-hexenyl butyrate, and α-pinene were likely to contribute to floral scent. Terpene biosynthesis pathways played a pivotal role in floral fragrance formation. A comprehensive terpenoid biosynthesis pathway for D. devonianum floral scent was proposed, and eight genes encoding key regulatory enzymes were identified. Conclusions: These results provide new insights into terpenoid metabolism in Dendrobium and may guide future research on the utilization of floral scent. Full article

R2R3-MYB and bHLH transcription factors (TFs) are key regulators of floral secondary metabolism and epidermal development in flowering plants. Orchids exhibit remarkable floral diversity, which is critical for pollination success and ornamental value, yet the evolutionary and functional diversification of these TF families within the genus remains largely unexplored. Here, we conducted a comprehensive pan-genome dissection of R2R3-MYB and bHLH TF families across 18 Dendrobium species, integrating orthologs assignment, phylogenetics, duplication profiling, cis-regulatory annotation, and tissue-specific expression analysis. We identified 3074 R2R3-MYB and 2282 bHLH genes, classified into 69 and 61 orthologous gene groups (OGGs), respectively. Core OGGs accounted for two-thirds of both families, indicating strong evolutionary conservation, whereas variable OGGs reflected lineage-specific diversification. Phylogenetic analyses resolved R2R3-MYBs into 24 canonical subfamilies and revealed conserved heterogeneous expansion patterns in bHLH subfamilies. Promoter architectures of R2R3-MYB genes were enriched in hormone-, stress-, and light-responsive elements, whereas bHLH promoters were dominated by development-related motifs. Tissue-specific expression profiling in Dendrobium ‘Chao Praya Smile’ showed that floral bud-enriched genes were associated with flavonoid/anthocyanin biosynthesis, whereas root-enriched genes were linked to stress and hormone responses. Integration of pan-genomics and transcriptomics highlighted evolutionary trajectory and functional divergence between core and variable gene sets within Dendrobium. Our study establishes a comprehensive, genus-wide framework for understanding the evolutionary and functional characteristics of MYB–bHLH regulatory networks in Dendrobium. These findings provide valuable genetic resources and key candidate targets for functional characterization and molecular breeding, with important implications for genetic improvement of reproductive traits, floral quality, stress resistance, and ornamental and agronomic value in orchids. Full article

This study introduces an optimized and selective extraction methodology using dichloromethane/methanol (DCM/MeOH, 95:5, v/v) in combination with accelerated solvent extraction (ASE) for the targeted stilbenoid and phenanthrene derivatives from five orchid species: Cattleya nobilior (root), Cymbidium defoliatum (root and bulb), Dendrobium phalaenopsis (stem), Encyclia linearifolioides (leaf), and Phalaenopsis aphrodite (root). Sequential extraction was performed with hexane, followed by DCM/MeOH (95:5 and 1:1, v/v) under controlled temperatures (70 °C for hexane, 100 °C for DCM/MeOH), using three static cycles per stage. Chemical profiling by high-performance liquid chromatography with a diode-array-detector and tandem mass spectrometry (HPLC-DAD-MS/MS) enabled the identification of twenty specialized metabolites—seven stilbenoids and thirteen phenanthrenes—several reported here for the first time, including crepidatuol B, dendrosinen D, and coeloginanthridin. The analytical method showed excellent separation of structurally related phenolic compounds, demonstrating the efficiency of the extraction protocol and the selectivity of the solvent system. Many of the identification metabolites are known for cytotoxic, antioxidant, anti-inflammatory, and metabolic regulatory properties, while newly detected compounds remain unexplored and present promising candidates for future biological evaluation. The broad distribution of these metabolites across the studied orchids enhances the current understanding of their phytochemical diversity and suggests chemotaxonomic relevance within the Orchidaceae family. Importantly, the extraction strategy requires minimal plant material, offering ecological advantages when working with rare or endangered species. Overall, this environmentally conscious extraction approach provides a robust platform for metabolic discovery and supports future research in natural products chemistry, plant ecology, drug discovery, structure–activity relationships studies and biotechnological applications. Full article

Background/Objectives: Dendrobium officinale is a valuable medicinal orchid. However, the metabolic profiles of its leaves and flowers remain poorly characterized. This highlights the need for comprehensive analysis of stems, leaves, and flowers to reveal plant-part-specific bioactive compounds and expand whole-plant utilization. Methods: An integrative metabolomic approach based on UHPLC–MS/MS was employed to systematically characterize secondary metabolite profiles in different parts of D. officinale, including stems (DOS), leaves (DOL), and flowers (DOF). Results: A total of 761 metabolites, predominantly flavonoids (30.6%), alkaloids (20.2%), phenolic acids (12.2%), and terpenoids (9.3%), were identified. The most abundant metabolites were detected in DOF (634), followed by DOL (598) and DOS (586). Total flavonoid and alkaloid contents were the highest in DOF, reaching 0.86 and 0.62 mg·g⁻¹ DW, respectively. Screening identified 74 key active ingredients (KAI) and 83 active pharmaceutical ingredients (API) and demonstrated potential efficacy against six major human diseases. Among these, gardenoside and phloroglucinol were uniquely present in leaves, whereas 12 KAIs and 16 APIs were specific to DOF. Quercetin, a compound associated with more than 90 disease-related entries, was exclusively detected in DOF. Multivariate analyses revealed clear separation among the three plant parts. Furthermore, 15 metabolites with VIP > 1, including pinobanksin and naringenin, exhibited distinct plant-part-specific accumulation patterns. Additionally, potential plant-part-specific biomarkers were identified. Conclusions: This study presents a comprehensive plant-part-specific metabolomic profile of D. officinale, revealing that its flowers and leaves are particularly enriched in bioactive flavonoids and alkaloids. The findings reveal the remarkable metabolic diversity and functional potential of D. officinale, providing essential chemical insights that support the whole plant’s broader medicinal and biotechnological applications. Full article

The use of mycorrhizal fungi to enhance orchid seed germination and seedling growth is a promising approach for orchid propagation and conservation, but practical applications remain limited. In this study, we developed a direct seeding technique based on mycorrhizal symbiosis using Dendrobium officinale. Seeds were inoculated with two fungal strains, Serendipita officinale (SO) and Serendipita indica (SI), individually or in combination, and cultivated on three substrates to identify optimal fungus–substrate combinations. SO achieved the highest germination rate (52.9 ± 5.6%) at 30 days on substrate 1 but declined at later stages, while SI performed best on substrate 3 at 30 days (72.3 ± 6.7%) but was less effective after 90 days. The SO and SI mixture showed strong synergistic effects on substrate 1, with peak germination (48.7 ± 5.9%) and seedling formation (45.6 ± 5.1%) at 120 days. Substrates 1 and 3 significantly outperformed 2 (p < 0.05), with 1 promoting rapid early germination and 3 favoring long-term seedling establishment. In contrast, controls without fungi showed less than 5% for all indices, confirming the necessity of symbiotic fungi. Microscopic observations revealed typical orchid mycorrhizal structures and dynamic hyphal turnover, providing histological evidence of the symbiotic mechanism. These findings establish a practical framework for mycorrhizal-assisted propagation and contribute to the ecological cultivation and conservation of D. officinale. Full article

Dendrobium huoshanense, a rare and endangered medicinal orchid species endemic to Huoshan County, Anhui Province, faces a severe limit of wild resources. Its medicinal efficacy derives from unique chemical constituents, which vary significantly across cultivation modes. We systematically compared sensory properties and nutritional constituents (polysaccharides, flavonoids, alkaloids, bibenzyls, minerals, and free amino acids) between D. huoshanense in three cultivation modes—greenhouse cultivation, understory gravel cultivation, and wild-simulated cultivation. Additionally, the gastroprotective effects of wild-simulated cultivated D. huoshanense on gastric mucosal epithelial cells were evaluated. Results demonstrated that wild-simulated cultivation yielded significantly higher levels of nutritional constituents compared to gravel and greenhouse cultivation. Furthermore, wild-simulated cultivated D. huoshanense exhibited notable protective effects against gastric mucosal epithelial cell damage. This study not only elucidates the influence of cultivation modes on the chemical profile of D. huoshanense but also provides scientific evidence supporting its gastric protective properties, offering a foundation for its sustainable utilization and quality-oriented cultivation. Full article

The genetic improvement of Phalaenopsis-type Dendrobium, a valuable ornamental and medicinal orchid, is hindered by the lack of a complete reference genome. In this study, a transcriptome-based approach was employed to develop and validate insertion–deletion (InDel) markers for genetic analysis and variety identification. RNA-seq was performed on two distinct varieties, resulting in the de novo assembly of 156,108 unigenes. A bioinformatics pipeline was developed to identify 5083 high-quality InDel loci, from which 1029 potential markers were designed. Fifty primer pairs were selected and validated experimentally, with 84% successfully amplifying clear products, and 76% showing polymorphism. The polymorphism information content (PIC) of the markers ranged from 0.25 to 0.78, indicating their high potential for use in genetic diversity studies. These markers were used to classify 24 Phalaenopsis-type Dendrobium varieties into distinct genetic clusters. This work provides a scalable and robust platform for molecular breeding, DNA fingerprinting, and germplasm management in non-model species that lack a reference genome. By leveraging transcriptome data, these markers will contribute to the efficient genetic improvement of Dendrobium and other similar crops. Full article

Dendrobium officinale, a perennial epiphytic herb of the orchid family renowned for its ornamental value and diverse medicinal properties, has attracted considerable global attention due to its rarity and increasing market demand. However, large-scale cultivation has led to confusion regarding its germplasm resources and genetic backgrounds, posing significant challenges for the effective conservation, management, and utilization of D. officinale germplasm. In this study, we systematically analyzed the abundance and characteristics of simple sequence repeats (SSRs) and developed highly polymorphic genomic SSR markers using whole-genome resequencing (WGRS) data from 15 D. officinale genotypes. A total of 494,783 SSRs were identified in the “Niu2020” reference genome. Mononucleotide repeats were the most abundant motifs, followed by dinucleotide repeats, with A/T and AT/TA being the predominant types, respectively. Of the SSRs with unique flanking sequences (unique SSRs), 121,544 out of 388,553 (31.28%) were polymorphic across the 15 genotypes. The polymorphism information content (PIC) values of these SSRs ranged from 0.13 to 0.92, with an average of 0.59. Subsequently, 10,364 pairs of SSR primers were successfully designed from polymorphic SSR loci with PIC values ≥ 0.5 and major allele size differences ≥ 3 bp. Ultimately, 20 primer pairs were randomly selected for experimental validation. Of these, 18 successfully amplified the target fragments and exhibited high levels of polymorphism (PIC values ranged from 0.31 to 0.74), confirming the effectiveness and practical utility of the newly developed markers. The SSR fingerprints and polymorphic markers developed in this study provide a valuable resource and establish a robust technical foundation for enhancing the efficiency of cultivar identification, genetic research, and molecular breeding in D. officinale. Full article

Dendrobium is an orchid genus with high economic and ecological importance, but its taxonomy based on morphology remains controversial. Dendrobium linawianum, a critically endangered species with both ornamental and medicinal value, represents a key taxon within this genus. However, its phylogenetic relationship has long been unplaced due to similar morphological traits. Despite its conservation and taxonomic importance, its complete chloroplast genome has not been previously characterized. Here, we newly sequenced and assembled the complete chloroplast genome of D. linawianum. The 150,497 bp genome exhibits a typical quadripartite structure, encoding 119 genes. A total of 161 simple sequence repeats (SSRs) were identified, predominantly mononucleotide and dinucleotide motifs. Condon usage analysis revealed leucine as the most abundant amino acid. Phylogenetic analysis based on complete chloroplast genome sequences strongly supported the close relationship of D. linawianum with D. hercoglossum, D. thyrsiflorum, and D. moniliforme, resolving its taxonomic position within the genus. The complete chloroplast genomes successfully resolved the phylogenetic relationships among 35 Dendrobium species, demonstrating their efficacy as powerful molecular markers for resolving taxonomic ambiguities within this morphologically complex genus. Our findings provide a genomic foundation for precise species identification and molecular breeding of D. linawianum, and enhance understanding of phylogenetic relationships in this taxonomically challenging group. Full article

Dendrobium denneanum Kerr, Dendrobium denneanum Kerr, an orchid in the food-medicine homology catalog, is traditionally used for stomach-nourishing, yin-tonifying, and immunity-enhancing. While its preventive effect on acute gastric ulcers is confirmed, variations among genuine producing areas remain underexplored. This study comparatively analyzed components of D. denneanum from 22 habitats and their polysaccharides’ (DDP) anti-inflammatory/antioxidant activities. Results showed habitat-dependent active components: total sugar (20–51.49%), crude polysaccharide yield (0.29–1.76%), and total phenol (~3%). In vitro, all extracts exhibited dose-dependent scavenging of DPPH (IC₅₀: 0.99–2.11 mg/mL), ABTS (0.61–1.62 mg/mL), and hydroxyl radicals (1.02–2.18 mg/mL), with Habitats 5 and 7 showing the strongest activity. GPC, ion chromatography, and FT-IR revealed DDP had a 5–11 kDa molecular weight, dominated by glucose (49.67–84.73%), plus mannose (8.29–12.25%) and galactose (0.96–16.41%), with shared hydroxyl (3400 cm⁻¹) and β-glycosidic bond (890 cm⁻¹) features. In ethanol-induced gastric ulcer rats, DDP exerted dose-dependent protection: low doses (100 mg/kg/d) reduced ulcer index, increased SOD/GSH-Px (1.5–1.8-fold), decreased MDA (30–35%), and elevated PGE₂; high doses (400 mg/kg/d) further inhibited serum TNF-α/IL-6 (25–40%) and improved histopathology. Conclusion: Despite habitat-dependent component variations, DDP maintains consistent structures. This study first confirms DDP protects gastric mucosa via antioxidant-anti-inflammatory synergism, supporting its development as a natural gastroprotectant. Future work may focus on standardized cultivation and clinical translation. Full article

Dendrobium huoshanense, an endangered orchid species, is renowned for its polysaccharides with vast pharmacological significance in stems. Phosphomannomutase (PMM) critically regulates polysaccharide accumulation. Transcriptional regulation of DhPMM remains poorly characterized. This study employed a yeast one-hybrid (Y1H) system to identify upstream regulators of DhPMM. The 2.15 kb DhPMM promoter was cloned, revealing multiple stress- and hormone-responsive cis-elements (e.g., ABRE, MYC, ERF). A high-complexity Y1H library (3.60 × 10⁹ CFU) was constructed with insert sizes averaging 1–2 kb. Screening using aureobasidin A (AbA)-resistant Y1HGold [pAbAi-DhPMM] identified 11 candidate clones, including four transcription factor families (DOF, NAC, ERF, BES1). Interactions were rigorously confirmed by pairwise Y1H showing AbA-resistant growth and dual-luciferase assays demonstrating DhPMM activation. This represents the first functional cDNA library resource for D. huoshanense and identification of TFs interacting with DhPMM. The discovery of TFs belonging to DOF, NAC, ERF, and BES1 families as DhPMM regulators elucidated the transcriptional network underlying polysaccharide biosynthesis. This establishes a transcriptional framework for engineering polysaccharide biosynthesis in D. huoshanense. Full article

Dendrobium officinale, an orchid of significant medicinal and ornamental value, exhibits poorly characterized hormonal regulation of flower bud differentiation. To address this knowledge gap, we employed an integrated multi-omics approach combining physiological, transcriptomic, metabolomic, and network analyses to elucidate the molecular mechanisms underlying the coordinated action of 6-Benzylaminopurine (6-BA) and Gibberellin A3 (GA₃) in this critical developmental process. Our key findings reveal that combined 6-BA and GA₃ treatment significantly enhances flower bud differentiation and induces stage-specific fluctuations in soluble sugar, protein, and starch levels. Transcriptomic profiling identified 11,994 differentially expressed genes (DEGs), with DEGs specific to the hormone-treated stage showing pronounced enrichment in plant hormone signal transduction and plant–pathogen interaction pathways. Metabolomic analysis uncovered 18 stage-specific differential metabolites (DAMs) during hormone treatment, including GA₃, 6-BA, and OPDA, whose accumulation dynamics were strongly correlated with the progression of differentiation. Weighted gene co-expression network analysis (WGCNA) pinpointed key hub genes within the yellow module, notably transcription factors from the C2H2, bZIP, and NAC families. Their interaction network demonstrated significant correlation with the transcriptional regulation of hormone-responsive genes. Significantly, this study establishes the first molecular framework for 6-BA and GA₃ regulation of flower bud differentiation in D. officinale. We demonstrate a metabolomic–transcriptomic coordination network driven by these hormones, where key hub genes form regulatory modules with transcription factors. Dynamic shifts in endogenous hormones reinforce the flowering signal. These findings provide crucial molecular targets for precision flowering control and molecular breeding strategies in orchids. Full article

Combined abiotic stresses often impose greater challenges to plant survival than individual stresses. In this study, we focused on elucidating the physiological and molecular mechanisms underlying the response of Dendrobium huoshanense to combined salt and heat stress by integrating physiological, transcriptomic, and metabolomic analyses. Our results demonstrated that high temperature plays a dominant role in the combined stress response. Physiological assays showed increased oxidative damage under combined stress, accompanied by significant activation of antioxidant enzyme systems (SOD, POD, CAT). Metabolomic analysis revealed significant enrichment of glutathione metabolism and flavonoid biosynthesis pathways, with key antioxidants such as glutathione and naringenin chalcone accumulating under combined stress. Transcriptomic data supported these findings, showing differential regulation of stress-related genes, including those involved in reactive oxygen species scavenging and secondary metabolism. These results highlight a coordinated defense strategy in D. huoshanense, involving both enzymatic and non-enzymatic antioxidant systems to maintain redox homeostasis under combined stress. This study provides novel insights into the molecular mechanisms underlying combined stress tolerance and lays the foundation for improving stress resilience in medicinal orchids. Full article