Search Results (109)

Taiwanofungus camphoratus, an edible and medicinal fungus endemic to Taiwan, produces a distinctive and complex fragrance during mycelial growth, indicating its potential as a source of natural flavor compounds for food and cosmetic applications. However, few research efforts have focused on changes in its flavor-related metabolites and the related underlying molecular mechanisms remain largely unexplored. In this study, we found that the water extract of Cinnamomum camphora leaves (CC water extract) markedly stimulated T. camphoratus mycelial growth, increasing biomass by 29.7% in liquid fermentation. Integrated transcriptomics, UPLC-based metabolomics and HS-SPME-GC-MS analyses revealed that CC water extract could enhance metabolic fluxes through glycolysis, the pentose phosphate pathway, and galactose metabolism, thereby supporting mycelial growth and the accumulation of flavor-related metabolites. Specifically, CC water extract promoted the abundance of metabolites associated with mushroom-like, floral, and fruity aroma profiles, together with sweet taste-related metabolites. These findings provide new insights into optimizing the liquid fermentation processes and flavor profiles of T. camphoratus mycelia, providing a reference for better utilizing this valuable fungal resource. Full article

Objectives: This study aims to provide a theoretical basis for a deeper understanding of the transcriptional regulatory network underlying the formation of Primula forbesii floral scent, and also offers important genetic resources for the molecular improvement of floral scent traits in Primula species. Methods: Using the P. forbesii cultivar ‘Pink violet’ as experimental material, we cloned PfbHLH131 and analyzed its expression pattern. We also validated its function via virus-induced gene silencing (VIGS) and used gas chromatography–mass spectrometry (GC-MS) to analyze changes in floral aroma components in silenced plants. Additionally, we detected the expression levels of key structural genes involved in floral aroma biosynthesis in silenced plants via qRT-PCR to elucidate the regulatory role of PfbHLH131 in the biosynthesis of P. forbesii floral aroma. Results: The cloned PfbHLH131 open reading frame is 922 bp in length, encoding a total of 307 amino acids, and contains a bHLH_AtBPE_like domain characteristic of the bHLH gene family. Quantitative real-time PCR (qRT-PCR) revealed that PfbHLH131 is highly expressed in floral organs, peaking during full bloom. Subcellular localization studies indicated that it is localized to the nucleus. VIGS-mediated transient silencing of PfbHLH131 significantly reduced the release of terpenoid and phenylpropanoid floral odor compounds and suppressed the expression of multiple key structural genes in both synthetic pathways. Conclusions: PfbHLH131 is a positive regulator of scent biosynthesis in P. forbesii. Full article

Seasonal variation in aroma quality is critical for commercial grading of Xinyang Maojian (XYMJ) green tea, and how seasonal changes shape its volatile composition and aroma profile remains unclear. This study investigated the volatile profiles of XYMJ harvested in spring, summer, and autumn using headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) and odor activity value (OAV) analysis. A total of 93 volatile compounds were identified, with alkenes, alcohols, and esters being the most numerous chemical classes. Total volatile content decreased significantly seasonally (p < 0.05), being highest in spring (1716.68 μg/kg), followed by summer (1566.72 μg/kg) and autumn (1378.21 μg/kg). PCA and PLS-DA clearly distinguished seasons. Using a dual-filtering strategy (variable importance in the projection > 1.0 and p < 0.01), 14 differential volatile metabolites were identified as core seasonal markers. Geraniol, cis-jasmone, and indole were identified as key drivers of the premium floral fragrance in spring XYMJ, while cis-3-hexenyl hexanoate and linalool peaked in the summer harvest. OAV results and cross-modal sensory interaction principles suggest that the superior flavor of spring XYMJ arises from both higher aromatic intensity and an optimized aroma-taste balance. These findings provide useful insights into the seasonal variations in the metabolic and chemical profiles of XYMJ, enhancing our understanding of the biochemical markers associated with its production timeline. Full article

This study introduced freeze-withering to resolve the conflict in traditional Taiping Kuihong black tea processing, where rolling enhances flavor but damages the integrity of the leaf shape. Using sensory evaluation, high-performance liquid chromatography, and gas chromatography–mass spectrometry, the effects of three freezing treatments (−20 °C, −80 °C, and liquid nitrogen at −196 °C) were analyzed and compared with traditional withering (CK). The results demonstrated that low-temperature treatments better preserved the morphological integrity of ‘two leaves and one bud.’ Compared to the CK group, the −20 °C low-temperature treatment group had a significantly higher proportion of esters among the volatile compounds in Taiping Kuihong black tea. Key floral fragrance components were abundant, while grassy undertones were greatly decreased. Concurrently, this group had the highest levels of theaflavins and TF/TR ratios. The −80 °C treatment was highly effective in preserving thearubigins; however, it resulted in a less complex fragrance profile with a reduced theaflavin level. Liquid nitrogen treatment caused aberrant accumulation of theabrownins, poor aroma harmony, and the lowest theaflavin level. This study indicates that −20 °C freezing withering is the best method for harmonizing the appearance and internal quality of Taiping Kuihong, giving critical evidence for targeted processing of unique black teas. Full article

Magnolia cavaleriei var. platypetala ‘Tanchun’ is a newly registered flower variety in China, known for its characteristic floral aroma that intensifies toward full bloom. However, the composition of the volatiles of this aromatic flower remains uncharacterized. Here, we compared the volatile organic compound composition of Tanchun through gas chromatography–mass spectrometry and comparative transcriptome sequencing analyses of the stamen (S), pistil (P), and petals (T) during flower development, i.e., the bud (S1), semi-opened (S2), and bloom (S3) stages. We present a first comprehensive profile of 1395 metabolites from Tanchun’s floral organs. Terpenoids (26.2%) constituted the largest chemical group, followed by esters (17.52%), nitrogen compounds (9.83%), hydrocarbons (8.11%), alcohols (7.97%), aldehydes (6.53%), and others. We found that volatile organic compound (VOC) accumulation was both spatiotemporal and stage-specific. The S1 and S2 transition was characterized by scent notes of green, herbal, and waxy aromas, while the S2 and S3 shift exhibited a richer profile of fruity, sweet, and creamy notes, primarily in petals. A comparative VOC and transcriptomic analysis revealed that petals activate pathways for structural expansion and precursor mobilization, stamens enhance lipid and terpenoid metabolism, and pistils maintain a conserved profile. Importantly, the S1 and S2 transition in petals establishes the biochemical foundation by activating acyl-CoA, phenylpropanoid, and terpenoid synthesis pathways, which enables the activation of the butanoate metabolism pathway at S3, leading to the production of ester-rich compounds that define the floral scent. The transition to full bloom involves a shift to energy-efficient volatile biosynthesis, supported by carbohydrate restructuring and phytohormonal regulation. Our results provide the first comprehensive volatilome and transcriptome resource for ‘Tanchun’, revealing a highly efficient, multi-stage strategy for floral fragrance biosynthesis. This work lays a molecular foundation for future horticultural improvement and biotechnological applications in the flavor and fragrance industries. 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

This study aimed to provide a comprehensive characterization of floral volatile organic compounds (VOCs), perform systematic comparative analysis among multiple fragrant camellias, and establish a classification framework based on aroma components for cultivars derived from Camellia Sect. Theopsis. Volatile compounds were analyzed from 21 fragrant camellias using headspace solid-phase microextraction coupled with gas chromatography–time-of-flight mass spectrometry (HS-SPME-GC-TOFMS), followed by cluster and correlation analyses. A total of 51 volatile compounds were identified, including 20 alcohols, 15 aldehydes, and five esters, among which 27 were designated as major aroma components. Alcohols were the dominant class, and phenylethyl alcohol was detected in all cultivars, with a relative abundance ranging from 1.30% to 45.86%. Certain compounds, such as eugenol and 2-pentylfuran, exhibited cultivar-specific enrichment. Cluster analysis revealed a high degree of similarity in volatile profiles, with the strongest correlation observed between Camellia ‘Himenoka’ and Camellia ‘Minato-no-haru’ (r = 0.97). This similarity may be associated with a shared parental background, particularly the frequent use of Camellia lutchuensis in breeding. These findings provide a systematic understanding of floral VOC composition and offer a chemical basis for the utilization of Camellia Sect. Theopsis germplasm in fragrance-oriented breeding. Full article

This study investigated the aroma characteristics of three grades of raw tea leaves and their corresponding jasmine tea products from Guangxi, China. Aromatic profiles of jasmine tea varieties were analysed using two-dimensional gas chromatography-olfactory-mass spectrometry (GC×GC-O-MS), stir bar sorptive extraction (SBSE), and descriptive sensory evaluation. Chemometric methods were applied to compare sensory scores with instrumental data. Volatile compound concentrations and relative odour activity values (r-OAVs) were calculated. The results indicated significant differences in base tea leaf quality: high-grade tea leaf G1 exhibited pure, sweet characteristics, serving as an excellent aroma-absorbing carrier. The scenting process significantly imparted jasmine fragrance to the finished product, although its efficacy was constrained by tea leaf grade. GH1 finished tea exhibited a fresh, vibrant, and rich aroma with a sweet, mellow fragrance and high floral integration. In contrast, GH3, due to its inferior base material quality, yielded a weak aroma after scenting with limited quality improvement. The initial quality of the tea base is the fundamental determinant of the upper limit of the finished jasmine tea’s sensory quality, while the scenting process is the core means of shaping its signature floral aroma. The combination of high-quality tea leaves and precise scenting techniques is essential for developing the fresh, vibrant, and rich flavour profile of premium jasmine tea. This study reveals that the flavour formation of jasmine tea originates from the foundational quality of the tea leaves, providing a theoretical basis for monitoring the aroma quality of jasmine tea produced from different grades of tea leaves. Full article

Fragrance lotus (Nymphaea hybrid) is a tropical interspecific cultivar characterized by large flowers and high scent intensity, offering dual potential for ornamental commerce and natural fragrance extraction. Floral scent determines both economic value and pollinator attraction, yet the biosynthetic organs and metabolic routes remain undocumented. To fill this gap, single flowers of the high-aroma cultivar ‘Eldorado’ at full anthesis were dissected into petal (PE), stamen (ST) and pistil (PI); each organ was subjected to untargeted LC-MS/MS metabolomics and Illumina RNA-seq. Organ-specific gene–metabolite co-expression networks were constructed by pairwise integration of transcript and metabolite matrices. All three organs formed distinct clusters in principal-component space. Compared with PE, 6221, 3352 and 5891 differentially expressed genes (DEGs) together with 30, 24 and 39 differentially accumulated metabolites (DAMs) were identified in ST, PI and PE, respectively. The phenylpropanoid biosynthesis pathway (map00940) was the only route simultaneously enriched at both transcript and metabolite levels; 59 DEGs mapped to this pathway co-linearly with three scent-related DAMs. ST contained the highest concentration of scent-active volatiles; phenylalanine ammonia-lyase (PAL), cinnamate-4-hydroxylase (C4H), 4-coumarate-CoA ligase (4CL) and benzaldehyde reductase (BAR) were all significantly up-regulated in this organ, driving the accumulation of p-coumaric acid that is subsequently channeled into benzyl alcohol via side-chain cleavage and BAR-mediated reduction, thereby generating the characteristic fragrance of Nymphaea. This study provides the first organ-level resolution of scent biosynthesis and metabolic flux partitioning in fragrance lotus, furnishing molecular targets for directed aroma improvement and efficient natural fragrance extraction. Full article

Waterlily (Nymphaea L.), a globally renowned aquatic ornamental plant, is prized for its aesthetic flowers and intense floral fragrance. However, the molecular mechanisms underlying floral scent biosynthesis in waterlily remain poorly characterized, and integrated analyses of dynamic volatile emission patterns and their associated biosynthetic pathways are lacking. In this study, we combined headspace solid-phase microextraction/gas chromatography–mass spectrometry (HS-SPME/GC-MS) with transcriptome sequencing (RNA-seq) to investigate the composition, emission dynamics, and biosynthesis of volatile organic compounds (VOCs) in the stamens of Nymphaea ‘Paul Stetson’ across three developmental stages. A total of 671 VOCs, classified into 14 categories, were identified. Transcriptome analysis revealed 47,951 differentially expressed genes (DEGs). Integrative omics analysis demonstrated correlated DEGs and differentially accumulated volatiles were significantly enriched in pathways related to phenylpropanoid biosynthesis, terpenoid backbone biosynthesis, diterpenoid biosynthesis, and ubiquinone/other terpenoid-quinone biosynthesis. Five candidate functional genes exhibiting strong positive correlations with VOC accumulation levels were identified, three of which are implicated in terpenoid biosynthesis. These findings provide a theoretical foundation for elucidating aroma composition and biosynthesis in waterlily and offer novel avenues for the genetic improvement of fragrance traits for ornamental, beverage, and cosmetic applications. Full article

The color and scent of flowers are vital ornamental attributes influenced by a complex interaction of metabolic and transcriptional mechanisms. Comparative analyses were performed to determine the molecular rationale for these features in Hydrangea arborescens, between the white-flowered variety ‘Annabelle’ (An) and its pink-flowered variant ‘Pink Annabelle’ (PA). Gas chromatography–mass spectrometry (GC–MS) detected 25 volatile organic compounds (VOCs) in ‘An’ and 21 in ‘PA’, with 18 chemicals common to both types. ‘An’ exhibited somewhat higher VOC diversity, whereas ‘PA’ emitted much bigger quantities of benzenoid and phenylpropanoid volatiles, including benzaldehyde, benzyl alcohol, and phenylethyl alcohol, resulting in a more pronounced floral scent. UPLC–MS/MS metabolomic analysis demonstrated obvious clustering of the two varieties and underscored the enrichment of phenylpropanoid biosynthesis pathways in ‘PA’. Transcriptomic analysis revealed 11,653 differentially expressed genes (DEGs), of which 7633 were elevated and linked to secondary metabolism. Key biosynthetic genes, including PAL, 4CL, CHS, DFR, and ANS, alongside transcription factors such as MYB—specifically TRINITY_DN5277_c0_g1, which is downregulated in ‘PA’ (homologous to AtMYB4, a negative regulator of flavonoid biosynthesis)—and TRINITY_DN23167_c0_g1, which is significantly upregulated in ‘PA’ (homologous to AtMYB90, a positive regulator of anthocyanin synthesis), as well as bHLH, ERF, and WRKY (notably TRINITY_DN25903_c0_g1, highly upregulated in ‘PA’ and homologous to AtWRKY75, associated with jasmonate pathway), demonstrating a coordinated activation of color and fragrance pathways. The integration of metabolomic and transcriptome data indicates that the pink-flowered ‘PA’ variety attains its superior coloring and aroma via the synchronized transcriptional regulation of the phenylpropanoid and flavonoid pathways. These findings offer novel molecular insights into the genetic and metabolic interplay of floral characteristics in Hydrangea. Full article

Pollination syndromes reflect the convergence of floral traits among plants sharing the same pollinator guild. However, bee-pollinated orchids exhibit striking variation in color and size. This diversity reflects the multiple reward strategies that evolved within the family, each interacting differently with bee sensory biases. Here, we tested whether the complex floral visual displays of orchids differ in signal identity and intensity among reward systems. We also considered intrafloral modularity, measured as the color differentiation among flower parts, and color–size integration. For this, we measured and modeled floral morphometric and reflectance data from sepals, petals, lip tips, and lip bases under bee vision from 95 tropical Epidendroid species to compare chromatic and achromatic contrasts, spectral purity, and mean reflectance across wavebands, plus flower and display size, among reward systems. Reward types included 19 food-deceptive, 8 nectar-offering, 10 oil-offering, 11 fragrance-offering, and 47 orchid species of unknown reward strategy. Principal component analyses on 34 color and 9 size variables summarized major gradients of visual trait variation: first component (19.1%) represented overall green-red reflectance and achromatic contrasts, whereas the second (16.5%) captured chromatic contrast–size covariation. Reward systems differed mostly in signal identity rather than signal intensity. Flower chromatic contrasts presented strong integration with flower size, while achromatic contrasts were negatively associated with display size. While deceptive and nectar-offering orchids tend toward larger solitary flowers with bluer and spectrally purer displays, oil- and fragrance-offering orchids tend toward smaller, brownish, or yellow to green flowers, with larger inflorescences. Rewardless orchids presented more achromatically conspicuous signals than rewarding orchids, but smaller displays. Orchid species clustered by reward both in PCA spaces and in bee hexagon color space. Deceptive orchids were typically associated with UV + White colors, oil orchids with UV + Yellow lip tips, and fragrance orchids with UV-Black lip bases and UV-Green lip tips. Together, these results indicate that orchid reward systems promote qualitative rather than quantitative differentiation in visual signals, integrating display color and size. These long-evolved distinct signals potentially enable foraging bees to discriminate among resource types within the community floral market. Our results demonstrate that color and flower display size are important predictors of reward strategy, likely used by foraging bees for phenotype-reward associations, thus mediating the evolution of floral signals. Full article

Paeonia lactiflora Pall. is a perennial herbaceous plant widely renowned for its floral ornamental appeal, distinctive pleasant scent, and utilization in folk remedies. Roots and barks are traditionally used in Chinese medicine for various properties, including anti-inflammatory, antioxidant, antibacterial, anticancer, cardiovascular, and neuroprotective effects. Considering the growing interest and demand in the pharmaceutical and cosmetic fields for sustainable and bioactive botanical derivatives, this study aimed to apply NADES (natural deep eutectic solvents) extraction on fresh flowers of Paeonia lactiflora Pall. The purpose was to obtain a natural, multifunctional, and ready-to-use cosmetic ingredient with concurrent antioxidant activity, antimicrobial functionalities, and olfactive properties. The eutectic systems selected in this study were composed of betaine as the hydrogen bond acceptor and glycerol and/or sorbitol as the hydrogen bond donors. These eutectic systems under microwave activation led to a rapid extraction, from peony fresh flowers, of considerable phenolic amounts (from 33.0 to 34.4 mg of gallic acid equivalents per gram of fresh flowers), which confer to the whole NADES-based extract an excellent radical scavenging activity (around 87.5%, compared to Trolox) and a pleasant fragrance, due to the extraction of some characteristic volatile compounds, as confirmed by GC-MS analysis. Antimicrobial assays against different Gram-positive and Gram-negative strains demonstrated good inhibitory activity of the sample against multidrug-resistant Staphylococcus species (MIC ranging from 0.9 to 14.5 mg/mL) and against Enterococcus species (from 28.8 to 57.8 mg/mL). Furthermore, results on different Staphylococcus aureus strains disclosed additional interesting anti-biofilm properties. Preliminary long-term studies (up to 9 months) on these combined properties highlighted the stabilizing effect of NADESs on the active metabolites, confirming their potential as natural and functional ingredients that could be directly incorporated into pharmaceutical and cosmetic formulations, offering enhanced efficacy and improved stability. Full article

Cymbidium sinense is a highly valued ornamental orchid renowned for its strong floral fragrance. In this study, dihydro-β-ionone was identified as a major volatile compound in C. sinense ‘Qi Hei’. Its emission increased progressively during flower development and was predominantly released from the sepals and petals. Transcriptome analysis of flowers at three developmental stages led to the identification of four double-bond reductase genes, designated CsDBR1–CsDBR4. Spatiotemporal expression profiling demonstrated that transcript levels of CsDBRs were highest in sepals and petals, showing a significant positive correlation with dihydro-β-ionone accumulation (p < 0.05). Heterologous expression in Escherichia coli and subsequent in vitro enzymatic assays confirmed that recombinant CsDBR1, CsDBR2, and CsDBR4 proteins catalyze the conversion of β-ionone to dihydro-β-ionone, whereas CsDBR3 exhibited no detectable activity. Transient expression in Nicotiana benthamiana leaves further verified the in planta function of CsDBR1, CsDBR2, and CsDBR4, resulting in elevated production of dihydro-β-ionone upon infiltration of β-ionone. Substrate specificity assays revealed that CsDBR2 and CsDBR4 also reduced 1-octen-3-one, 3-nonen-2-one, and pulegone. Collectively, these findings demonstrate that CsDBR1, CsDBR2, and CsDBR4 are key enzymes responsible for dihydro-β-ionone biosynthesis in C. sinense, providing a genetic foundation for molecular breeding aimed at improving floral fragrance in orchids. Full article

Molecular odor prediction represents a fundamental challenge in computational chemistry with significant applications in fragrance design, food science, and chemical safety assessment. While traditional Quantitative Structure–Activity Relationship (QSAR) methods rely on hand-crafted molecular descriptors, recent advances in graph neural networks (GNNs) enable direct end-to-end learning from molecular graph structures. However, systematic comparison between these approaches for multi-label odor prediction remains limited. This study presents a comprehensive evaluation of traditional QSAR methods compared with modern GNN approaches for multi-label molecular odor prediction. Using the GoodScent dataset containing 3304 molecules with six high-frequency odor types (fruity, green, sweet, floral, woody, herbal), we systematically evaluate 23 model configurations across traditional machine learning algorithms (Random Forest, SVM, GBDT, MLP, XGBoost, LightGBM) with three feature-processing strategies and three GNN architectures (GCN, GAT, NNConv). The results demonstrate that GNN models achieve significantly superior performance, with GCN achieving the highest macro F1-score of 0.5193 compared to 0.4766 for the best traditional method (MLP with basic preprocessing), representing a 24.1% relative improvement. Critically, we discover that threshold optimization is essential for multi-label chemical classification. These findings establish GNNs as the preferred approach for molecular property prediction tasks and provide crucial insights for handling class imbalance in chemical informatics applications. Full article