Unveiling the aesthetic secrets: exploring connections between genetic makeup, chemical, and environmental factors for enhancing/improving the color and fragrance/aroma of Chimonanthus praecox.

Floral color and scent profiles vary across species, geographical locations, and developmental stages. The exclusive floral color and fragrance of Chimonanthus praecox is contributed by a range of endogenous chemicals that distinguish it from other flowers and present amazing ornamental value. This comprehensive review explores the intricate interplay of environmental factors, chemicals and genes shaping the flower color and fragrance of Chimonanthus praecox. Genetic and physiological factors control morpho-anatomical attributes as well as pigment synthesis, while environmental factors such as temperature, light intensity, and soil composition influence flower characteristics. Specific genes control pigment synthesis, and environmental factors such as temperature, light intensity, and soil composition influence flower characteristics. Physiological processes including plant hormone contribute to flower color and fragrance. Hormones, notably ethylene, exert a profound influence on varioustraits. Pigment investigations have spotlighted specific flavonoids, including kaempferol 3-O-rutinoside, quercetin, and rutin. Red tepals exhibit unique composition with cyanidin-3-O-rutinoside and cyanidin-3-O-glucoside being distinctive components. Elucidating the molecular basis of tepal color variation, particularly in red and yellow varieties, involves the identification of crucial regulatory genes. In conclusion, this review unravels the mysteries of Chimonanthus praecox, providing a holistic understanding of its flower color and fragrance for landscape applications. This comprehensive review uniquely explores the genetic intricacies, chemical and environmental influences that govern the mesmerizing flower color and fragrance of Chimonanthus praecox, providing valuable insights for its landscape applications. This review article is designed for a diverse audience, including plant geneticists, horticulturists, environmental scientists, urban planners, and students, offering understandings into the genetic intricacies, ecological significance, and practical applications of Chimonanthus praecox across various disciplines. Its appeal extends to professionals and enthusiasts interested in plant biology, conservation, and industries dependent on unique floral characteristics.

Integrating network pharmacology and experimental verification to explore the mucosal protective effect of Chimonanthus nitens Oliv. Leaf Granule on ulcerative colitis.

ETHNOPHARMACOLOGICAL RELEVANCE: Chimonanthus nitens Oliv. Leaf Granule (COG) is a commonly used clinical preparation of traditional Chinese medicine for the treatment of cold, but there are folk reports that it can treat diarrhea and other gastrointestinal diseases. Therefore, the mechanism of COG in the treatment of ulcerative colitis with diarrhea as the main symptom needs to be studied. AIM OF THE STUDY: Combined network pharmacology and experimental validation to explore the mechanism of COG in the treatment of ulcerative colitis. MATERIALS AND METHODS: First, the main components of COG were characterized by liquid chromatography-mass spectrometry (LC-MS); subsequently, a network pharmacology approach was used to screen the effective chemical components and action targets of COG to construct a target network of COG for the treatment of ulcerative colitis (UC). The protein-protein interaction network (PPI) and literature reports were combined to identify the potential targets of COG for the treatment of UC. Finally, the predicted results of network pharmacology were validated by animal and cellular experiments. RESULTS: 19 components of COG were characterized by LC-MS, among which 10 bioactive components could act on 377 potential targets of UC. Key therapeutic targets were collected, including SRC, HSP90AA1, PIK3RI, MAPK1 and ESR1. KEGG results are enriched in pathways related to oxidative stress. Molecular docking analysis showed good binding activity of main components and target genes. Animal experiments showed that COG significantly relieved the colitis symptoms in mice, regulated the Treg/Th17 balance, and promoted the secretion of IL-10 and IL-4, along with the inhibition of IL-1ß and TNF-α. Additionally, COG reduced the apoptosis of colon epithelial cells, and significantly improved the levels of SOD, MAO, GSH-px, and inhibited MDA, iNOS, eNOS in colon. Also, it increased the expression of tight junction proteins such as ZO-1, Claudin1, Occludin and E-cadherin. In vitro experiments, COG inhibited the oxidative stress and inflammatory injury of HCT116 cells induced by LPS. CONCLUSIONS: Combining network pharmacology and in vitro and in vivo experiments, COG was verified to have a good protective effect in UC, which may be related to enhancing antioxidation in colon tissues.

Wintersweet (Chimonanthus praecox) toxicity in 5 sheep.

Two sheep presented with acute tonic-clonic seizures, opisthotonos, absent pupillary light reflexes and abnormal vital signs within 18 hours after observed consumption of leaves from an ornamental shrub later identified as wintersweet (Chimonanthus praecox). Despite symptomatic treatment, both sheep died. Three other sheep that consumed the plant died after displaying similar clinical signs, resulting in 2 deaths the prior evening and 1 recovery the next morning. Gross necropsy and histologic findings were diagnostically inconclusive. Rumen contents tested positive for the alkaloid calycanthine, a centrally-acting convulsant known to be present in wintersweet. Case reports of calycanthine toxicity in ruminants are limited, with no detailed reports published in the United States. Calycanthine has been isolated from the seeds, flowers, and leaves of the plant. Wintersweet is part of the family Calycanthaceae that including 3 species native to North America, all of which pose a neurologic risk to ruminants if consumed.

Genome-wide identification and analysis of the evolution and expression pattern of the SBP gene family in two Chimonanthus species.

BACKGROUND: Chimonanthus praecox and Chimonanthus salicifolius are closely related species that diverged approximately six million years ago. While both C. praecox and C. salicifolius could withstand brief periods of low temperatures of - 15 °C. Their flowering times are different, C. praecox blooms in early spring, whereas C. salicifolius blooms in autumn. The SBP-box (SQUAMOSA promoter-binding protein) is a plant-specific gene family that plays a crucial vital role in regulating plant flowering. Although extensively studied in various plants, the SBP gene family remains uncharacterized in Calycanthaceae. METHODS AND RESULTS: We conducted genome-wide identification of SBP genes in both C. praecox and C. salicifolius and comprehensively characterized the chromosomal localization, gene structure, conserved motifs, and domains of the identified SBP genes. In total, 15 and 18 SBP genes were identified in C. praecox and C. salicifolius, respectively. According to phylogenetic analysis, the SBP genes from Arabidopsis, C. praecox, and C. salicifolius were clustered into eight groups. Analysis of the gene structure and conserved protein motifs showed that SBP proteins of the same subfamily have similar motif structures. The expression patterns of SBP genes were analyzed using transcriptome data. The results revealed that more than half of the genes exhibited lower expression levels in leaves than in flowers, suggesting their potential involvement in the flower development process and may be linked to the winter and autumn flowering of C. praecox and C. salicifolius. CONCLUSION: Thirty-three SBPs were identified in C. praecox and C. salicifolius. The evolutionary characteristics and expression patterns were examined in this study. These results provide valuable information to elucidate the evolutionary relationships of the SBP family and help determine the functional characteristics of the SBP genes in subsequent studies.

Genome-Wide Identification and Expression Analysis of the bHLH Transcription Factor Family in Wintersweet (Chimonanthus praecox).

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.

CpCAF1 from Chimonanthus praecox Promotes Flowering and Low-Temperature Tolerance When Expressed in Arabidopsis thaliana.

CCR4-associated factor I (CAF1) is a deadenylase that plays a critical role in the initial step of mRNA degradation in most eukaryotic cells, and in plant growth and development. Knowledge of CAF1 proteins in woody plants remains limited. Wintersweet (Chimonanthus praecox) is a highly ornamental woody plant. In this study, CpCAF1 was isolated from wintersweet. CpCAF1 belongs to the DEDDh (Asp-Glu-Asp-Asp-His) subfamily of the DEDD (Asp-Glu-Asp-Asp) nuclease family. The amino acid sequence showed highest similarity to the homologous gene of Arabidopsis thaliana. In transgenic Arabidopsis overexpressing CpCAF1, the timing of bolting, formation of the first rosette, and other growth stages were earlier than those of the wild-type plants. Root, lateral branch, rosette leaf, and silique growth were positively correlated with CpCAF1 expression. FLOWERING LOCUS T (FT) and SUPPRESSOROF OVEREXPRESSION OF CO 1 (SOC1) gene expression was higher while EARLY FLOWERING3 (ELF3) and FLOWERING LOCUS C (FLC) gene expression of transgenic Arabidopsis was lower than the wild type grown for 4 weeks. Plant growth and flowering occurrences were earlier in transgenic Arabidopsis overexpressing CpCAF1 than in the wild-type plants. The abundance of the CpCAF1 transcript grew steadily, and significantly exceeded the initial level under 4 °C in wintersweet after initially decreasing. After low-temperature exposure, transgenic Arabidopsis had higher proline content and stronger superoxide dismutase activity than the wild type, and the malondialdehyde level in transgenic Arabidopsis was decreased significantly by 12 h and then increased in low temperature, whereas it was directly increased in the wild type. A higher potassium ion flux in the root was detected in transgenic plants than in the wild type with potassium deficiency. The CpCAF1 promoter was a constitutive promoter that contained multiple cis-acting regulatory elements. The DRE, LTR, and MYB elements, which play important roles in response to low temperature, were identified in the CpCAF1 promoter. These findings indicate that CpCAF1 is involved in flowering and low-temperature tolerance in wintersweet, and provide a basis for future genetic and breeding research on wintersweet.

Sesquiterpenoids from the leaves of Chimonanthus nitens.

Two new sesquiterpenoids (1 and 3), one new natural product (2), and two known compounds (4 and 5) were isolated from the leaves of Chimonanthus nitens. Their structures were elucidated by spectroscopic analysis, and the absolute configuration of compound 3 was determined by the X-ray single-crystal diffraction analysis. The cytotoxicity of compounds 1-5 was evaluated at three concentrations on two human breast cancer cell lines (MDA-MB-468 and MDA-MB-231) by MTT assay. As a result, we found that the cytotoxicity was weak even with a concentration of these compounds up to 100 µM.

Overexpression of a Senescence-Related Gene CpSRG1 from Wintersweet (Chimonanthus praecox) Promoted Growth and Flowering, and Delayed Senescence in Transgenic Arabidopsis.

Plant senescence is a complex process that is controlled by developmental regulation and genetic programs. A senescence-related gene CpSRG1, which belongs to the 2OG-Fe(II) dioxygenase superfamily, was characterized from wintersweet, and the phylogenetic relationship of CpSRG1 with homologs from other species was investigated. The expression analysis by qRT-PCR (quantitative real-time PCR) indicated that CpSRG1 is abundant in flower organs, especially in petals and stamens, and the highest expression of CpSRG1 was detected in stage 6 (withering period). The expression patterns of the CpSRG1 gene were further confirmed in CpSRG1pro::GUS (ß-glucuronidase) plants, and the activity of the CpSRG1 promoter was enhanced by exogenous Eth (ethylene), SA (salicylic acid), and GA3 (gibberellin). Heterologous overexpression of CpSRG1 in Arabidopsis promoted growth and flowering, and delayed senescence. Moreover, the survival rates were significantly higher and the root lengths were significantly longer in the transgenic lines than in the wild-type plants, both under low nitrogen stress and GA3 treatment. This indicated that the CpSRG1 gene may promote the synthesis of assimilates in plants through the GA pathway, thereby improving growth and flowering, and delaying senescence in transgenic Arabidopsis. Our study has laid a satisfactory foundation for further analysis of senescence-related genes in wintersweet and wood plants. It also enriched our knowledge of the 2OG-Fe(II) dioxygenase superfamily, which plays a variety of important roles in plants.

CpMAX1a, a Cytochrome P450 Monooxygenase Gene of Chimonanthus praecox Regulates Shoot Branching in Arabidopsis.

Strigolactones (SLs) are a class of important hormones in the regulation of plant branching. In the model plant Arabidopsis, AtMAX1 encodes a cytochrome P450 protein and is a crucial gene in the strigolactone synthesis pathway. Yet, the regulatory mechanism of MAX1 in the shoot branching of wintersweet (Chimonanthus praecox) remains unclear. Here we identified and isolated three MAX1 homologous genes, namely CpMAX1a, CpMAX1b, and CpMAX1c. Quantitative real-time PCR (qRT-PCR) revealed the expression of CpMAX1a in all tissues, being highest in leaves, whereas CpMAX1b was only expressed in stems, while CpMAX1c was expressed in both roots and stem tips. However, CpMAX1a's expression decreased significantly after decapitation; hence, we verified its gene function. CpMAX1a was located in Arabidopsis chloroplasts. Overexpressing CpMAX1a restored the phenotype of the branching mutant max1−3, and reduced the rosette branch number, but resulted in no significant phenotypic differences from the wild type. Additionally, expression of AtBRC1 was significantly upregulated in transgenic lines, indicating that the CpMAX1a gene has a function similar to the homologous gene of Arabidopsis. In conclusion, our study shows that CpMAX1a plays a conserved role in regulating the branch development of wintersweet. This work provides a molecular and theoretical basis for better understanding the branch development of wintersweet.

Synthesis and Antifungal Activity of Chimonanthus praecox Derivatives.

To search for efficient agricultural antifungal lead compounds, 39 Chimonanthus praecox derivatives were designed, synthesized, and evaluated for their antifungal activities. The structures of target compounds were fully characterized by 1H NMR, 13C NMR, and MS spectra. The preliminary bioassays revealed that some compounds exhibited excellent antifungal activities in vitro. For example, the minimum inhibitory concentration (MIC) of compound b15 against Phytophthora infestans was 1.95 µg mL-1, and the minimum inhibitory concentration (MIC) of compound b17 against Sclerotinia sclerotiorum was 1.95 µg mL-1. Therefore, compounds b15 and b17 were identified as the most promising candidates for further study.

Chimonanthus salicifolius attenuated vascular remodeling by alleviating endoplasmic reticulum stress in spontaneously hypertensive rats.

Chimonanthus salicifolius (CS), the leaves of Chimonanthus salicifolius S. Y. Hu., is an effective tea to prevent and treat hypertension in China. This study aimed to explore the effect and mechanism of CS in the protection against vascular remodeling in hypertension. Spontaneously hypertensive rats (SHRs) were orally administered with aqueous extracts of CS for 6 months. The blood pressure and morphological changes of the aorta were measured. Their mechanisms were studied by combining chemical identification, network pharmacology analysis and validation in vivo. Hypertensive rats showed an impaired vascular structure and dyslipidemia as illustrated by the increase of the vascular media thickness and collagen deposition in the aorta. CS treatment exhibited significant beneficial effects on blood pressure control and aortal morphology. A total of 21 compounds from CS were identified, which were linked to 106 corresponding targeted genes for vascular remodeling. The network pharmacology predicted that CS prevented vascular remodeling through the endoplasmic reticulum stress pathway. The in vivo experiments further showed that CS treatment upregulated Glucose-Regulated Protein 78 and downregulated CCAAT-enhancer-binding protein homologous protein at both mRNA and protein levels, paralleling reduced apoptotic cells in the arterial wall. Additionally, CS diminished the low-density lipoprotein cholesterol levels, total cholesterol contents and triglyceride/high-density lipoprotein cholesterol ratios in the sera of SHRs, which might also contribute to its protection of vessels. Collectively, CS protects against vascular modeling by suppressing endoplasmic reticulum stress-related apoptosis in hypertension, and it could be a potential agent for the prevention and treatment of vascular modeling.

Proteomics and metabolomics reveal the mechanism underlying differential antioxidant activity among the organs of two base plants of Shiliang tea (Chimonanthus salicifolius and Chimonanthus zhejiangensis).

The leaves and branches of Chimonanthus salicifolius and Chimonanthus zhejiangensis are the base ingredients of Shiliang tea. In this study, proteomics and metabolomics were performed to understand the molecular mechanisms underlying antioxidant activity (AA) in the leaves and branches of the two species. Stress and redox related proteins are differentially expressed among organs. The abundance of isoprenoid pathway-related proteins is higher in leaves while the abundance of phenylpropanoid and flavonoid pathway-related proteins is higher in branches in both species. Metabolomics revealed the flavonoid composition and demonstrated that procyanidins are more abundant in branches. Superoxide dismutase (SOD), glutathione peroxidase (GSH-PX), and AA are stronger in branches than leaves. Overall, branches might contribute to redox homeostasis through SOD/GSH-PX and flavonoids. Furthermore, the high level of AA of branches might be largely due to their increased accumulation of procyanidins.

The red flower wintersweet genome provides insights into the evolution of magnoliids and the molecular mechanism for tepal color development.

Wintersweet (Chimonanthus praecox) is one of the most important ornamental plants. Its color is mainly determined by the middle tepals. However, the molecular mechanisms underlying the intriguing flower color development among different wintersweet groups are still largely unknown. In addition, wintersweet belongs to magnoliids, and the phylogenetic position of magnoliids remains to be determined conclusively. Here, the whole genome of red flower wintersweet, a new wintersweet type, was sequenced and assembled with high quality. The genome comprised 11 super-scaffolds (chromosomes) with a total size of 737.03 Mb. Based on the analyses of the long branch attraction, incomplete lineage sorting, sparse taxon sampling, and other factors, we suggest that a bifurcating tree may not fully represent the complex early diversification of the angiosperms and that magnoliids are most likely sister to the eudicots. The wintersweet genome appears to have undergone two whole-genome duplication (WGD) events: a recent WGD event representing an independent event specific to the Calycanthaceae and an ancient WGD event shared by Laurales. By integrating genomic, transcriptomic, and metabolomic data, CpANS1 and the transcription factor CpMYB1 were found to play key roles in regulating tepal color development, whereas CpMYB1 needs to form a complex with bHLH and WD40 to fully perform its regulatory function. The present study not only provides novel insights into the evolution of magnoliids and the molecular mechanism for flower color development, but also lays the foundation for subsequent functional genomics study and molecular breeding of wintersweet.

CpBBX19, a B-Box Transcription Factor Gene of Chimonanthus praecox, Improves Salt and Drought Tolerance in Arabidopsis.

Zinc-finger proteins are important transcription factors in plants, responding to adversity and regulating the growth and development of plants. However, the roles of the BBX gene family of zinc-finger proteins in wintersweet (Chimonanthus praecox) have yet to be elucidated. In this study, a group IV subfamily BBX gene, CpBBX19, was identified and isolated from wintersweet. Quantitative real-time PCR (qRT-PCR) analyses revealed that CpBBX19 was expressed in all tissues and that expression was highest in cotyledons and inner petals. CpBBX19 was also expressed in all flower development stages, with the highest expression detected in early initiating bloom, followed by late initiating bloom and bloom. In addition, the expression of CpBBX19 was induced by different abiotic stress (cold, heat, NaCl, and drought) and hormone (ABA and MeJA) treatments. Heterologous expression of CpBBX19 in Arabidopsis thaliana (Arabidopsis) enhanced the tolerance of this plant to salt and drought stress as electrolyte leakage and malondialdehyde (MDA) concentrations in transgenic Arabidopsis after stress treatments were significantly lower than those in wild-type (WT) plants. In conclusion, this research demonstrated that CpBBX19 plays a role in the abiotic stress tolerance of wintersweet. These findings lay a foundation for future studies on the BBX gene family of wintersweet and enrich understanding of the molecular mechanism of stress resistance in wintersweet.

Carotenoid Cleavage Dioxygenase Genes of Chimonanthus praecox, CpCCD7 and CpCCD8, Regulate Shoot Branching in Arabidopsis.

Strigolactones (SLs) regulate plant shoot development by inhibiting axillary bud growth and branching. However, the role of SLs in wintersweet (Chimonanthus praecox) shoot branching remains unknown. Here, we identified and isolated two wintersweet genes, CCD7 and CCD8, involved in the SL biosynthetic pathway. Quantitative real-time PCR revealed that CpCCD7 and CpCCD8 were down-regulated in wintersweet during branching. When new shoots were formed, expression levels of CpCCD7 and CpCCD8 were almost the same as the control (un-decapitation). CpCCD7 was expressed in all tissues, with the highest expression in shoot tips and roots, while CpCCD8 showed the highest expression in roots. Both CpCCD7 and CpCCD8 localized to chloroplasts in Arabidopsis. CpCCD7 and CpCCD8 overexpression restored the phenotypes of branching mutant max3-9 and max4-1, respectively. CpCCD7 overexpression reduced the rosette branch number, whereas CpCCD8 overexpression lines showed no phenotypic differences compared with wild-type plants. Additionally, the expression of AtBRC1 was significantly up-regulated in transgenic lines, indicating that two CpCCD genes functioned similarly to the homologous genes of the Arabidopsis. Overall, our study demonstrates that CpCCD7 and CpCCD8 exhibit conserved functions in the CCD pathway, which controls shoot development in wintersweet. This research provides a molecular and theoretical basis for further understanding branch development in wintersweet.

Six new cadinane-type sesquiterpenoids from the leaves of Chimonanthus nitens Oliv.

Six new cadinane-type sesquiterpenoids, named Chimnitensin A-F (1-6) were isolated from the leaves of Chimonanthus nitens Oliv. Their structures were elucidated by comprehensive spectroscopic analyses and comparison with structurally related known analogues. In vitro MTT assay showed that all six compounds had cytotoxicity against two selected human breast cancer cell lines (MDA-MB-468 and MDA-MB-231), which indicate their potential of developing into anticancer drugs.

Digestive properties and effects of Chimonanthus nitens Oliv polysaccharides on antioxidant effects in vitro and in immunocompromised mice.

The study was aimed to investigate the simulated digestion behavior of the bioactive polysaccharides from Chimonanthus nitens Oliv (COP1), antioxidant activity in vitro, and prevention against cyclophosphamide (CP) induced oxidative damage in mice. The results showed that COP1 were 18.843 kDa, and consisted of arabinose (56.6 mol%), galactose (24.9 mol%), xylose (11.1 mol%), and glucose (7.4 mol%). Gastrointestinal digestion significantly improved the radical (DPPH, OH, and ABTS+) scavenging activities of COP1. Meanwhile, administration of COP1 (150, 300, and 600 mg/kg, continuous 16 days) prevented hepatotoxicity in CP-induced mice (reducing liver index and transaminase levels, alleviating liver damage). COP1 also attenuated oxidative stress as evident from as shown by reduced levels of MDA and enhanced activity of antioxidant enzymes (CAT, SOD, and GSH-Px). In addition, COP1 regulated the Nrf2/Keap1 signaling pathway in CP-treated mice, decreasing the upstream factor Keap1 and increasing the upstream factor Nrf2, which in turn enhanced the expression of downstream factors (NQO1, HO-1, GSH-Px, SOD1, and CAT). COP1 also protected the body from CP-induced oxidative damage by down-regulating Bax and caspase3 in the apoptosis pathway and up-regulating Bcl-2 mRNA levels. Overall, COP1 might be harnessed as an effective natural antioxidant for medical and food industries.

Comparative transcriptomic profiling reveals the regulation of terpenoid biosynthesis in Sinocalycanthus chinensis.

Sinocalycanthus chinensis, a diploid (2n = 22) deciduous shrub, belongs to the Calycanthaceae family of magnoliids and is rich secondary metabolites, such as terpenoids. However, the regulation of terpenoid biosynthesis in S. chinensis is largely unknown. In this study, comparative transcriptome analyses were performed in the bark, branches, leaves, and flowers. KEGG enrichment analysis revealed that the terpenoid biosynthesis and cytochrome P450 pathways were significantly enriched in the four tissues. Twelve terpenoid backbone biosynthesis-related genes were identified, and eight terpene synthases (TPSs) were reassembled based on independent transcriptomes from the four tissues. Phylogenetic analysis of the TPSs showed high sequence similarity between S. chinensis and Arabidopsis, and these TPSs were classified into three subfamilies. Moreover, 39 phytohormone response-related genes, including 5 abscisic acid (ABA) receptors, 25 auxin response factors, 3 gibberellin (GA) response genes, 5 ethylene response genes, and 1 jasmonic acid (JA) response gene were analyzed. Most phytohormone pathway-related genes were upregulated in the flowers and downregulated in the leaves. The endogenous indole acetic acid (IAA) content was higher in the flowers than in the other comparisons. Our results provide an opportunity to reveal the regulation of terpenoid biosynthesis in S. chinensis.

Overexpression of CpWRKY75 from Chimonanthus praecox Promotes Flowering Time in Transgenic Arabidopsis.

WRKY transcription factors play critical roles in the physiological processes of plants. Although the roles of WRKYs have been characterized in some model plants, their roles in woody plants, especially wintersweet (Chimonanthus praecox), are largely unclear. In this study, a wintersweet WRKY gene named CpWRKY75 belonging to group IIc was isolated and its characteristics were identified. CpWRKY75 is a nucleus-localized protein, and exhibited no transcriptional activation activity in yeast. CpWRKY75 was highly expressed in flowers at different bloom stages. Ectopic expression of CpWRKY75 significantly promoted the flowering time of transgenic Arabidopsis (Arabidopsis thaliana), as determined by the rosette leaf number and first flower open time. The expression levels of flowering-related genes were quantified by qRT-PCR, and the results suggested that CpWRKY75 had obvious influence on the expression level of MICRORNA156C (MIR156C), SQUAMOSA PROMOTER BINDING PROTEIN-LIKE3 (SPL3) and SQUAMOSA PROMOTER BINDING PROTEIN-LIKE 9 (SPL9), FLOWERING LOCUS T (FT), LEAFY (LFY), SUPPRESSOR OF OVEREXPRESSION OF CO 1 (SOC1), APETALA1 (AP1), CAULIFLOWER (CAL), and FRUITFULL (FUL). These results suggest that CpWRKY75 might have a flowering time regulation function, and additionally provide a new gene resource for the genetic engineering of woody flowering plants.

An integral insight into pollen wall development: involvement of physical processes in exine ontogeny in Calycanthus floridus L., with an experimental approach.

We aimed to understand the underlying mechanisms of development in the sporopollenin-containing part of the pollen wall, the exine, one of the most complex cell walls in plants. Our hypothesis is that distinct physical processes, phase separation and micellar self-assembly, underpinexine development by taking the molecular building blocks, determined and synthesised by the genome, through several phase transitions. To test this hypothesis, we traced each stage of microspore development in Calycanthus floridus with transmission electron microscopy and then generated in vitro experimental simulations corresponding to every developmental stage. The sequence of structures observed within the periplasmic space around developing microspores starts with spherical units, which are rearranged into columns to then form rod-like units (the young columellae) and, finally, white line centred endexine lamellae. Phase separation precedes each developmental stage. The set of experimental simulations, obtained as self-assembled micellar mesophases formed at the interface between lipid and water compartments, was the same: spherical micelles; columns of spherical micelles; cylindrical micelles; and laminate micelles, separated by gaps, resembling white-lined lamellae. Thus, patterns simulating structures observed at the main stages of exine development in C. floridus were obtained from in vitro experiments, and hence purely physicochemical processes can construct exine-like patterns. This highlights the important part played by physical processes that are not under direct genomic control and share influence on the emerging ultrastructure with the genome during exine development. These findings suggest that a new approach to ontogenetic studies, including a consideration of physical factors, is required for a better understanding of developmental processes.