Search Results (28)

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

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

Blue light (BL) is a key environmental signal influencing plant flowering, yet its role in floral development beyond the transition phase remains underexplored. This review provides a comprehensive synthesis of current research on BL-mediated floral development, with a particular emphasis on horticultural crops grown in a controlled environment. Unlike prior reviews that focus primarily on floral induction, this article systematically examines BL’s effects on later stages of flowering, including floral organ morphogenesis, sex expression, bud abortion, flower opening, scent emission, coloration, pollination, and senescence. Drawing on evidence from both model plants (e.g., Arabidopsis thaliana) and crop species, this review identifies key photoreceptors, hormonal regulators, and signaling components involved in BL responses. It also highlights species-specific and context-dependent outcomes of BL manipulation, proposes mechanistic hypotheses to explain conflicting findings, and outlines critical knowledge gaps. By integrating molecular, physiological, and environmental perspectives, this review offers a framework for optimizing BL applications to improve flowering traits and postharvest quality in horticultural production systems. Full article

The MADS-box transcription factors play essential roles in various processes of plant growth and development. Here, we identified 107 MADS-box genes in Osmanthus fragrans Lour. genome (OfMADS), encoding proteins ranging from 61 to 608 amino acids. Phylogenetic analysis classified these genes into five subfamilies: MIKC*, MIKCC, Mα, Mβ, and Mγ, with conserved motif architectures within subfamilies. Tandem and whole-genome duplications were identified as key drivers of OfMADS expansion. Cis-regulatory element analysis revealed enrichment for hormone response and developmental regulatory motifs, implicating roles in growth and flowering processes. Transcriptome dynamics across six floral developmental stages (bolting to petal shedding) uncovered 78 differentially expressed OfMADS genes, including 16 exhibiting flower-specific expressions. Integrated metabolome profiling demonstrated robust correlations between critical OfMADS regulators and scent metabolites. This nexus suggests a potential role of these OfMADS in regulating specialized metabolite biosynthesis pathways. Our multi-omics study provides insights into the regulatory hierarchy of OfMADS in coordinating floral morphogenesis and the accumulation of economically significant metabolites in O. fragrans. These findings establish a foundation for subsequent functional validation and molecular breeding of horticultural traits. Full article

Flower fragrance is a crucial ornamental and economic trait of Dendrobium chrysotoxum, and the most abundant and diverse aroma-active compounds are terpenes. Terpene synthase (TPS) is the ultimate enzyme for the biosynthesis of various types of terpenes, and TPS genes were identified as the key regulators governing the spatiotemporal release of volatile terpene compounds. Until recently, the TPS gene family in D. chrysotoxum has remained largely unexplored. Our study characterizes the TPS genes in D. chrysotoxum and identifies 37 DcTPS gene family members. It helped identify the DcTPS genes, gene characteristics, the phylogeny relationship, conserved motif location, gene exon/intron structure, cis-elements in the promoter regions, protein–protein interaction (PPI) network, tissue specific expression and verification of the expression across different flowering stages and floral organs. Three highly expressed DcTPS genes were cloned, and their functions were verified using a transient expressed in tobacco leaves. Further functional verification showed that the proteins encoded by these genes were enzymes involved in monoterpene synthesis, and they were all involved in the synthesis of linalool. This study comprehensively expatiates on the TPS gene family members in D. chrysotoxum for the first time. These data will help us gain a deeper understanding of both the molecular mechanisms and the effects of the TPS genes. Furthermore, the discovery that three TPS-b genes (DcTPS 02, 10, 32) specifically drive linalool-based scent in D. chrysotoxum, will provide new insights for expanding the TPS-b subfamily in orchids and identifying the linalool synthases contributing to orchid fragrance. Full article

LBD transcription factors are critical regulators of plant growth and development. Recent studies highlighted their significant role in the transcriptional regulation of plant growth and metabolism. Thus, identifying the CeLBD gene in Cymbidium ensifolium, a species abundant in floral scent metabolites, could provide deeper insights into its functional significance. A total of 34 LBD genes were identified in C. ensifolium. These CeLBDs fell into two major groups: Class I and Class II. The Class I group contained 30 genes, while the Class II group included only 4 genes. Among the 30 Class I genes, several genes in the Ie branch exhibited structural variations or partial deletions (CeLBD20 and CeLBD21) in the coiled-coil motif (LX₆LX₃LX₆L). These changes may contribute to the difficulty in root hair formation in C. ensifolium. The variations may prevent normal transcription, leading to low or absent expression, which may explain the fleshy and corona-like root system of C. ensifolium without prominent lateral roots. The expansion for CeLBDs was largely due to special WGD events in orchids during evolution, or by segmental duplication and tandem duplication. CeLBDs in different branches exhibit similar functions and expression characteristics. Promoter analysis enriched environmental response elements, such as AP2/ERF, potentially mediating the specific expression of CeLBDs under different stresses. CeLBDs were predicted to interact with multiple transcription factors or ribosomal proteins, forming complex regulatory networks. CeLBD20 was localized in the cytoplasm, it may act as a signaling factor to activate other transcription factors. CeLBD6 in Class II was significantly up-regulated under cold, drought, and ABA treatments, suggesting its role in environmental responses. Furthermore, metabolic correlation analysis revealed that its expression was associated with the release of major aromatic compounds, such as MeJA. These findings offer valuable insights for further functional studies of CeLBD genes in C. ensifolium. Full article

Lilies (Lilium spp.) are renowned for their diverse and captivating floral scents, which are highly valued both commercially and ornamentally. This review provides a comprehensive overview of recent advancements in the identification, biosynthesis, and regulation of fragrance components in lily flowers. Various volatile organic compounds (VOCs) that contribute to the unique scents of different lily species and cultivars, including terpenoids, benzenoids/phenylpropanoids, and fatty acid derivatives, are discussed. The release patterns of these compounds from different floral tissues and at different developmental stages are examined, highlighting the significant role of tepals. Detection methods such as gas chromatography–mass spectrometry (GC-MS) and sensory analysis are evaluated for their effectiveness in fragrance research. Additionally, the biosynthetic pathways of key fragrance compounds are explored, focusing on the terpenoid and benzenoid/phenylpropanoid pathways and the regulatory mechanisms involving transcription factors and environmental factors. This review also addresses the influence of genetic and environmental factors on fragrance production and proposes future research directions to enhance the aromatic qualities of lilies through selective genetic and breeding approaches. Emphasis is placed on the potential applications of these findings in the floral industry to improve the commercial value and consumer appeal of lily flowers. Full article

Flowers are plant structures characteristic of the phylum Angiosperms composed of organs thought to have emerged from homologous structures to leaves in order to specialize in a distinctive function: reproduction. Symmetric shapes, colours, and scents all play important functional roles in flower biology. The evolution of flower symmetry and the morphology of individual flower parts (sepals, petals, stamens, and carpels) has significantly contributed to the diversity of reproductive strategies across flowering plant species. This diversity facilitates attractiveness for pollination, protection of gametes, efficient fertilization, and seed production. Symmetry, the establishment of body axes, and fate determination are tightly linked. The complex genetic networks underlying the establishment of organ, tissue, and cellular identity, as well as the growth regulators acting across the body axes, are steadily being elucidated in the field. In this review, we summarise the wealth of research already at our fingertips to begin weaving together how separate processes involved in specifying organ identity within the flower may interact, providing a functional perspective on how identity determination and axial regulation may be coordinated to inform symmetrical floral organ structures. Full article

Heat shock factors (HSFs) are the key regulators of heat stress responses and play pivotal roles in tissue development and the temperature-induced regulation of secondary metabolites. In order to elucidate the roles of HSFs in Cymbidium ensifolium, we conducted a genome-wide identification of CeHSF genes and predicted their functions based on their structural features and splicing patterns. Our results revealed 22 HSF family members, with each gene containing more than one intron. According to phylogenetic analysis, 59.1% of HSFs were grouped into the A subfamily, while subfamily HSFC contained only two HSFs. And the HSF gene families were differentiated evolutionarily between plant species. Two tandem repeats were found on Chr02, and two segmental duplication pairs were observed on Chr12, Chr17, and Chr19; this provided evidence for whole-genome duplication (WGD) events in C. ensifolium. The core region of the promoter in most CeHSF genes contained cis-acting elements such as AP2/ERF and bHLH, which were associated with plant growth, development, and stress responses. Except for CeHSF11, 14, and 19, each of the remaining CeHSFs contained at least one miRNA binding site. This included binding sites for miR156, miR393, and miR319, which were responsive to temperature and other stresses. The HSF gene family exhibited significant tissue specificity in both vegetative and floral organs of C. ensifolium. CeHSF13 and CeHSF15 showed relatively significant expression in flowers compared to other genes. During flower development, CeHSF15 exhibited markedly elevated expression in the early stages of flower opening, implicating critical regulatory functions in organ development and floral scent-related regulations. During the poikilothermic treatment, CeHSF14 was upregulated over 200-fold after 6 h of heat treatment. CeHSF13 and CeHSF14 showed the highest expression at 6 h of low temperature, while the expression of CeHSF15 and CeHSF21 continuously decreased at a low temperature. The expression patterns of CeHSFs further confirmed their role in responding to temperature stress. Our study may help reveal the important roles of HSFs in plant development and metabolic regulation and show insight for the further molecular design breeding of C. ensifolium. Full article

Long non-coding RNAs (lncRNAs) have emerged as curial regulators of diverse biological processes in plants. Jasmine (Jasminum sambac) is a world-renowned ornamental plant for its attractive and exceptional flower fragrance. However, to date, no systematic screening of lncRNAs and their regulatory roles in the production of the floral fragrance of jasmine flowers has been reported. In this study, we identified a total of 31,079 novel lncRNAs based on an analysis of strand-specific RNA-Seq data from J. sambac flowers at different stages. The lncRNAs identified in jasmine flowers exhibited distinct characteristics compared with protein-coding genes (PCGs), including lower expression levels, shorter transcript lengths, and fewer exons. Certain jasmine lncRNAs possess detectable sequence conservation with other species. Expression analysis identified 2752 differentially expressed lncRNAs (DE_lncRNAs) and 8002 DE_PCGs in flowers at the full-blooming stage. DE_lncRNAs could potentially cis- and trans-regulate PCGs, among which DE_lincRNAs and their targets showed significant opposite expression patterns. The flowers at the full-blooming stage are specifically enriched with abundant phenylpropanoids and terpenoids potentially contributed by DE_lncRNA cis-regulated PCGs. Notably, we found that many cis-regulated DE_lncRNAs may be involved in terpenoid and phenylpropanoid/benzenoid biosynthesis pathways, which potentially contribute to the production of jasmine floral scents. Our study reports numerous jasmine lncRNAs and identifies floral-scent-biosynthesis-related lncRNAs, which highlights their potential functions in regulating the floral scent formation of jasmine and lays the foundations for future molecular breeding. Full article

Wintersweet (Chimonanthus praecox (L.) Link, Calycanthaceae) is an esteemed ornamental flowering shrub known for its distinct blooming period in winter, vibrant color petals, and captivating floral fragrance. Basic helix-loop-helix (bHLH) transcription factors (TFs) play pivotal roles as key regulators in secondary metabolites biosynthesis, growth, and development in plants. However, the systematic analysis of the bHLH family members and their role in the regulation of floral traits in Wintersweet remains insufficiently understood. To bridge this knowledge gap, we conducted a comprehensive genome-wide analysis of the C. praecox bHLH (CpbHLH) gene family, identifying a total of 131 CpbHLH genes across 11 chromosomes. Phylogenetic analysis classified these CpbHLH genes into 23 subfamilies, wherein most members within the same subfamily exhibited analogous intron/exon patterns and motif composition. Moreover, the expansion of the CpbHLH gene family was primarily driven by segmental duplication, with duplicated gene pairs experiencing purifying selection during evolution. Transcriptomic analysis revealed diverse expression patterns of CpbHLH genes in various tissues and distinct stages of Wintersweet flower development, thereby suggesting their involvement in a diverse array of physiological processes. Furthermore, yeast 2-hybrid assay demonstrated interaction between CpbHLH25 and CpbHLH59 (regulators of floral scent and color) as well as with CpbHLH112 and CpMYB2, suggesting potential coordinately regulation of secondary metabolites biosynthesis in Wintersweet flowers. Collectively, our comprehensive analysis provides valuable insights into the structural attributes, evolutionary dynamics, and expression profiles of the CpbHLH gene family, laying a solid foundation for further explorations of the multifaceted physiological and molecular roles of bHLH TFs in Wintersweet. Full article

Primula forbesii Franch. is a unique biennial herb with a strong floral fragrance, making it an excellent material for studying the aroma characteristics of the genus Primula. The floral scent is an important ornamental trait that facilitates fertilization. However, the molecular mechanism regulating the floral scent in Primula is unknown. In order to better understand the biological mechanisms of floral scents in this species, this study used RNA sequencing analysis to discuss the first transcriptome sequence of four flowering stages of P. forbesii, which generated 12 P. forbesii cDNA libraries with 79.64 Gb of clean data that formed 51,849 unigenes. Moreover, 53.26% of the unigenes were annotated using public databases. P. forbesii contained 44 candidate genes covering all known enzymatic steps for the biosynthesis of volatile terpenes, the major contributor to the flower’s scent. Finally, 1-deoxy-d-xylulose 5-phosphate synthase gene of P. forbesii (PfDXS2, MK370094), the first key enzyme gene in the 2-c-methyl-d-erythritol 4-phosphate (MEP) pathway of terpenoids, was cloned and functionally verified using virus-induced gene silencing (VIGs). The results showed that PfDXS2-silencing significantly reduced the relative concentrations of main volatile terpenes. This report is the first to present molecular data related to aroma metabolites biosynthesis pathways and the functional characterization of any P. forbesii gene. The data on RNA sequencing provide comprehensive information for further analysis of other plants of the genus Primula. Full article

Many species of the Dendrobium genus are traditional Chinese herbal medicine and ornamental plants. Flower fragrance is one of the most important horticultural ornamental characters and plays a crucial role in the ecology, economy, and aesthetics of plants. However, the volatile constituents and key regulatory genes related to floral biosynthesis are poorly understood. In this experiment, the flowers from two species of Dendrobium with high-scent smells, Dendrobium moniliforme (L.) Sw. (D. moniliforme), and light-scent smells, Dendrobium nobile “H1” (D. “H1”), were selected. The aim of this study was to explore the key gene expression profiles of floral biosynthesis by combining volatile constituent determination and transcriptome analysis in two different Dendrobium species. Physiological determination results showed that 60 volatile compounds were identified in D. moniliforme and 52 volatile compounds were identified in D. ‘H1’ flowers in four flowering stages, and the full bloom stage was the most complicated stage because there were 41 and 33 volatile compounds, respectively. These compounds belong to terpenes, aromatics, fatty acids, nitrogenous compounds, ketones, alcohols, and alkanes, respectively. The components identified in the gynandrium and petals revealed that the petals were probably the most important sites affecting the release of volatiles. The relative content of terpene compounds was the highest, with 77.25% (D. moniliforme) and 50.38% (D. “H1”), respectively. Transcriptome analysis showed that differentially expressed genes (DEGs) were highly enriched in terpenoid backbone biosynthesis and that four linalool synthetase (LIS) genes were up-regulated in high-scent smell species. This study is helpful to explore the key genes of flower fragrance and provides a theoretical basis for further understanding of the regulatory molecular functions of floral synthesis and release, as well as for the cultivation of new aromatic species. Full article

This review presents a systematic analysis of the studies on volatiles in Dendrobium. Among the various components, aromatic terpenes are a crucial component in the development of the aromatic characteristics of Dendrobium and other plants. Recent advancements in detection and sequencing technology have resulted in a considerable rise in research on the biosynthetic processes of aromatic terpenes in Dendrobium and other flowering plants. Nevertheless, the inquiry into the precise means by which plants regulate the proportion of diverse aromatic terpenes in their floral scent, thereby preserving their olfactory traits, requires further investigation. A conjecture on the botanical perfumer mechanism, which condensed the findings of earlier studies, was put forward to address this area of interest. Specific transcription factors likely govern the coordinated expression of multiple key terpene synthase (TPS) genes during the flowering stage of plants, thereby regulating the proportional biosynthesis of diverse aromatic terpenes and sustaining the distinctive aromatic properties of individual plants. This review serves as a significant theoretical reference for further investigations into aromatic volatile compounds in Dendrobium. Full article

Light is an important environmental signal that governs plant growth, development, and metabolism. Constitutive photomorphogenic 1 (COP1) is a light signaling component that plays a vital role in plant light responses. We isolated the COP1 gene (LoCOP1) from the petals of Lilium ‘Siberia’ and investigated its function. The LoCOP1 protein was found to be the most similar to Apostasia shenzhenica COP1. LoCOP1 was found to be an important factor located in the nucleus and played a negative regulatory role in floral scent production and emission using the virus-induced gene silencing (VIGS) approach. The yeast two-hybrid, β-galactosidase, and bimolecular fluorescence complementation (BiFC) assays revealed that LoCOP1 interacts with LoMYB1 and LoMYB3. Furthermore, light modified both the subcellular distribution of LoCOP1 and its interactions with LoMYB1 and MYB3 in onion cells. The findings highlighted an important regulatory mechanism in the light signaling system that governs scent emission in Lilium ‘Siberia’ by the ubiquitination and degradation of transcription factors via the proteasome pathway. Full article