Search Results (145)

Changes in environmental temperatures and water availability can disrupt plant–pollinator interactions by altering floral attractive and rewarding traits. Here, we investigated the effects of warming and drought on floral scent and rewards in Vaccinum corymbosum (an entomophilous crop), and how these changes affect pollinator behavior. Plants were exposed to two temperatures (24 °C and 28 °C) and two watering treatments (optimal watering, W+, and water stress, W−). We measured floral volatiles, pollen and nectar quantity, as well as the nutritional composition of pollen (C, carbon, and N, nitrogen percentage) and nectar (hexose-to-amino acids ratio). Bioassays with honeybees were conducted to assess responses to the attractive and rewarding traits specific to each treatment. Floral volatiles significantly increased at 28° W+; nevertheless, they declined under the combination of both warming and drought. Pollen and nectar production were only negatively affected by warming. Pollen’s nutritional composition was negatively affected by the interaction of both stresses, with greater reductions in % C and N occurring when both stresses were combined. We observed that the synthetic floral scent representing the blend emitted by flowers under 28° W+ conditions, at low concentrations, attracted the highest percentage of honeybees. Additionally, honeybees tended to visit artificial diets of pollen with a more nutritious composition (50% carbon and 6% nitrogen), as found in 24° W+. We showed that changes in the composition of floral scent and pollen in varieties of V. corymbosum affected pollinator preferences in laboratory bioassays. This study contributes to our understanding of how climate change may impact trophic interactions by showing that changes in floral traits are associated with alterations in pollinator preferences. 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

Geranyl diphosphate synthase (GPPS) is a key enzyme in the plant isoprenoid metabolic pathway and regulates the biosynthesis of volatile monoterpenes. It plays an important role in the biosynthesis of floral volatile terpenoids (FVTs) and inter-cultivar variation in snapdragon. Despite its importance in floral scent formation, the GPPS/GGPPS gene family in snapdragon (Antirrhinum majus L.) has not been systematically characterized. In this study, nine GPPS/GGPPS family members were identified at genome-wide level. These include six AmGPPS and three AmGGPPS genes. Phylogenetic analysis grouped them into distinct subfamilies. We further analyzed their chromosomal locations, gene structures, conserved protein motifs, and promoter cis-acting elements. These results revealed both conservation and functional divergence within the gene family. To explore their functional roles, we compared gene expression profiles at the full flowering stage. This comparison was performed between strongly scented cultivar (Am3) and the weakly scented cultivar (Am5). Among all candidates, AmGPPS6 showed the most significant differential expression. Further, functional validation was conducted using transient overexpression and virus-induced gene silencing (VIGS). Overexpression of AmGPPS6 significantly increased terpenoid production. Total floral volatile terpenoids (FVTs) increased by 1.4 fold. Both monoterpene and sesquiterpene emissions were enhanced. In contrast, silencing of AmGPPS6 markedly reduced the emission of key monoterpenes such as ocimene and its isomers. Sequence analysis showed that AmGPPS6 shares 67.04% identity with canonical GPPS small subunit (GPPS.SSU). However, it lacks the conserved catalytic DDx2-D motif. This suggests that AmGGPPS2 is not catalytically active. Instead, it likely functions through heterodimer with AmGGPPS2. This interaction is supported by coordinated transcriptional expression patterns. Additionally, natural sequence polymorphisms were identified in GPPS.SSU. These variations, rather than those in GPPS.LSU, appear to drive differences in monoterpense emission between cultivars. In conclusion, AmGPPS6 in a key regulator of floral scent biosynthesis in snapdragon. This study provides new insights into functional roles of GPPS/GGPPS genes. It also offers valuable gene targets for the molecular breeding of aromatic traits in ornamental plants. 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

To reveal how the characteristic flavor of jasmine tea is generated, this study analyzed the coordinated changes in sensory properties, chemical components, and aroma migration behavior during scenting. Sensory evaluation, biochemical assays, and headspace solid-phase microextraction–gas chromatography–mass spectrometry (HS-SPME-GC-MS) integrated with orthogonal partial least squares discriminant analysis (OPLS-DA) and relative odor activity value (rOAV) filtering were applied to tea samples before and after scenting. After scenting, aroma and taste scores increased significantly, and liquor color shifted from tender green to pale yellow. Amino acids and soluble sugars increased, while astringent substances such as tea polyphenols and catechins decreased. Key floral compounds, including cis-3-hexenyl benzoate and methyl anthranilate, were transferred from jasmine flowers to the tea base and enriched, likely contributing to the typical aroma profile. The retention rate of aroma in spent flowers was positively correlated with hydrophobicity (logP, r > 0.46, p < 0.01) and negatively with polarity (TPSA, r > −0.42, p < 0.05), suggesting regulation by hydrophobic partitioning. In contrast, aroma transfer to the tea base showed no simple correlation with any single physicochemical parameter, suggesting multi-factor regulation. This study provides insights into the scenting process and offers a theoretical reference for quality control in jasmine tea production. 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

This study involved developing a novel lemon flower-scented white tea (LT) through multiple aroma-imparting cycles, and taking an integrated approach to investigating its flavour formation mechanism. Sensory evaluation and electronic tongue analysis revealed that the LT exhibited more balanced taste characteristics, with significantly reduced bitterness and astringency, attributed to the decreased caffeine content and conversion of esterified catechins. Electronic nose and HS-SPME/GC-MS results confirmed that the LT had acquired a distinctive aroma characterised by floral and citrus notes, primarily originating from lemon flower volatiles such as methyl anthranilate and limonene. Multivariate statistical analysis identified 32 key differential compounds (variable importance in projection value > 1), with methyl anthranilate, β-ionone, and geraniol (relative odour activity value > 80) jointly forming the shared flavour base among teas. These findings demonstrate that lemon flower infusion can effectively enhance the sensory quality of white tea and provide theoretical support for the development of diverse floral teas. 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

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

Floral volatile terpenoids are known to play important roles in plant pollination biology by attracting animal pollinators, repelling antagonists, and enhancing resistance to potential microbial pathogens. The terpenoid blend emitted by a flower is usually plant-lineage specific and is primarily determined by a set of versatile terpene synthases (TPSs), which catalyze the final step of diverse terpenoid synthesis. The strongly scented flower of Jasminum sambac (L.) Aiton emits linalool and α-farnesene, which dominate the nocturnal floral VOCs, yet the corresponding TPSs have not been identified. Here, we show that four TPS enzymes are responsible for the synthesis of a mixture of volatile terpenoids in the flower, based on their highly correlated and almost exclusive expression in the petal, as well as their enzymatic characterizations in vitro and in Nicotiana benthamiana Domin. JsTPS01 (TPS-a) acts as a sesquiterpene synthase, producing τ-cadinol in yeast at levels that mirror its rhythmic expression in petals. JsTPS02 (TPS-b) carries a plastid-targeting transit peptide, localizes to chloroplasts/plastids, and converts geranyl diphosphate (GPP) to linalool with high affinity (K_m = 28.2 ± 3.4 µM). JsTPS03 is a TPS-b clade member that can convert farnesyl diphosphate (FPP) to farnesol with a K_m of 14.4 ± 5.9 μM in an in vitro assay using isolated yeast vehicles. JsTPS04 (TPS-e/f) exhibits dual targeting—cytosolic in protoplasts of Arabidopsis thaliana (L.) Heynh, but plastidic in J. sambac petals—and functions as a bifunctional mono-/sesqui-TPS, forming linalool from GPP (K_m = 2.5 ± 0.3 µM) and trans-nerolidol from FPP (K_m = 7.6 ± 0.6 µM). Transient expression in N. benthamiana leaves further confirmed its in-planta linalool production. Collectively, we identified four preferentially expressed terpene synthases that contribute to the production of linalool, τ-cadinol, trans-nerolidol, and farnesol in J. sambac. Full article

Cymbidium faberi Rolfe is a Chinese flower famous due to its beautiful floral pattern and strong floral scent and is also a threatened terrestrial orchid. Moreover, the traditional propagation method through tillers and symbiotic seed germination with the correct fungus under nature conditions could not meet conservation and commercial needs. Here, an efficient procedure for asymbiotic seed germination and in vitro seedlings development of C. faberi was successfully established through evaluation of time of seed collecting, seed pretreatments, light conditions and composition of culture media, respectively. Seed pretreatment with 1% NaClO for 30 min, dark culture on 1/4 MS medium containing 0.5 mg·L⁻¹ 6-BA and 0.1 mg·L⁻¹ NAA for 30 days and subsequent long day condition (14 h light/10 h dark photoperiod) culture on this medium for 30 days could obviously enhance the seed germination rate of C. faberi. The highest germination rate (85.0 ± 0.79%) was achieved when seeds were collected at 120 d after cross-fertilization, and then germination percentages progressively decreased. Furthermore, histological analyses from protocorm formation to seedling growth were explored. This study not only offers a reliable and scalable system for mass propagation to meet commercial and conservation demands but also serves as a foundational reference for physiological and molecular studies in Cymbidium and related orchids. Full article

Clematis L., a significant genus of climbing plants within the Ranunculaceae family, boasts widespread germplasm resources distributed across temperate to tropical regions globally, with Asia preserving particularly abundant native populations. This review systematically summarizes recent advances in Clematis research: in terms of physiological characteristics, the research focuses on the evolution of plant classification, chromosomal evolutionary features revealed by karyotype analysis, and studies on genetic diversity and phylogenetic relationships based on molecular markers; in breeding methods, it summarizes the two major technical systems of sexual and asexual reproduction; regarding ornamental traits, it emphasizes the molecular mechanisms of flower color and form development, and synthesizes breakthroughs in techniques for flowering period regulation and research on the biosynthesis pathways of floral scent metabolites; in the field of stress resistance mechanisms, it thoroughly examines physiological responses and molecular adaptation mechanisms under abiotic stresses such as UV radiation, drought, high temperature, and intense light, and outlines research progress on pathogen types of major diseases; in studies of medicinal value, it highlights the material basis and mechanisms of pharmacological activities including anti-inflammatory, analgesic, and antitumor effects. Through multidimensional comprehensive analysis, this review aims to elucidate the comprehensive development potential of Clematis, providing theoretical foundations and practical guidance for germplasm resource innovation, breeding of high-ornamental-value cultivars, and stress resistance applications. Full article

To address the challenge of monitoring the postharvest jasmine bloom stages during industrial tea scenting processes, this study proposes an efficient U-shaped Network (U-Net) model with frequency–spatial cross-attention (FSCA-EUNet) to resolve critical bottlenecks, including repetitive backgrounds and small interclass differences, caused by stacked jasmine flowers during factory production. High-resolution images of stacked jasmine flowers were first preprocessed and input into FSCA-EUNet, where the encoder extracted multi-scale spatial features and the FSCA module incorporated frequency-domain textures. The decoder then fused and refined these features, and the final classification layer output the predicted bloom stage for each image. The proposed model was designed as a “U-Net”-like structure to preserve multiscale details and employed a frequency–spatial cross-attention module to extract high-frequency texture features via a discrete cosine transform. Long-range dependencies were established by NonLocalBlook, located after the encoders in the model. Finally, a momentum-updated center loss function was introduced to constrain the feature space distribution and enhance intraclass compactness. According to the experimental results, the proposed model achieved the best metrics, including 95.52% precision, 95.42% recall, 95.40% F1-score, and 97.24% mean average precision, on our constructed dataset with only 878.851 K parameters and 15.445 G Floating Point Operations (FLOPs), and enabled real-time deployment at 22.33 FPS on Jetson Orin NX edge devices. The ablation experiments validated the improvements contributed by each module, which significantly improved the fine-grained classification capability of the proposed network. In conclusion, FSCA-EUNet effectively addresses the challenges of stacked flower backgrounds and subtle interclass differences, offering a lightweight yet accurate framework that enables real-time deployment for industrial jasmine tea scenting automation. Full article

Aroma is a crucial quality trait in ornamental flowers; however, the molecular mechanisms by which hormones regulate fragrance in Rhododendron remain poorly understood. In this study, Gibberellin (GA₃)-treated petals of Rhododendron fortunei Lindl were used as experimental materials to integrate volatile metabolomics with RNA-seq analysis, aiming to investigate aroma changes and their underlying molecular regulatory mechanisms. We cloned and characterized RfHMGR1, which encodes a key enzyme in the Mevalonate (MVA) pathway, and verified its function. Subcellular localization analysis showed that the Green Fluorescent Protein (GFP) signal of the RfHMGR1-GFP fusion protein was mainly distributed in the cytoplasm. Transient overexpression of RfHMGR1 in petals of two Rhododendron species (R. fortunei and Rhododendron hybrida) significantly increased the accumulation of the terpenoid linalool, whereas gene silencing reduced linalool accumulation. Furthermore, the purified recombinant RfHMGR1 protein exhibited HMGR-specific reductase activity in vitro. Our results confirmed that GA₃ regulates the terpenoid fragrance of R. fortunei by targeting the MVA pathway gene RfHMGR1. Collectively, these findings provide new insights into the fragrance regulation mechanisms in R. fortunei and identify molecular targets for breeding strategies aimed at improving floral scent. Full article