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Chrysanthemum morifolium is a perennial herbaceous plant in the Asteraceae family that is used as a medicine and food owing to its superior pharmacological properties. Irrespective of its application, C. morifolium must be dried before use. Shade drying (YG) and heat drying (HG) are the two drying methods used in most origins. Given the abundance of flavonoids, phenolic acids, and terpenoids, the primary medicinal active constituents of C. morifolium, it is important to determine whether the composition and content of these compounds are altered during the drying processes. To test this, the changes in the chemical composition of C. morifolium flowers after YG and HG using full-spectrum, non-targeted LC/GC–MS−based metabolomics and, subsequently, the three indicator components of C. morifolium—chlorogenic acid, 3,5−dicaffeoylquinic acid, and luteolin−7−O−glucoside—were accurately quantified by HPLC. The results of the non-targeted metabolomics analysis revealed that YG- and HG-processed C. morifolium differed significantly with respect to chemical contents, especially flavonoids, phenolic acids, and terpenoids. The levels of the indicator components and their precursors also differed significantly between the YG and HG treatments. The contents of most of the flavonoids and key phenolic acids, terpenoids, and carbohydrates were higher with YG than with HG pre-treatment. These results revealed the changes in the chemical composition of C. morifolium during the YG and HG processes, thus providing a reference for the further optimization of the production and processing of chrysanthemums. [ABSTRACT FROM AUTHOR]

Plant-specific TEOSINTE BRANCHED1/CYCLOIDEA/PROLIFERATING CELL FACTOR (TCP) proteins play critical roles in plant development and stress responses; however, their functions in chrysanthemum (Chrysanthemum morifolium) have not been well-studied. In this study, we isolated and characterized the chrysanthemum TCP transcription factor family gene CmTCP13, a homolog of AtTCP13. This gene encoded a protein harboring a conserved basic helix–loop–helix motif, and its expression was induced by salinity stress in chrysanthemum plants. Subcellular localization experiments showed that CmTCP13 localized in the nucleus. Sequence analysis revealed the presence of multiple stress- and hormone-responsive cis-elements in the promoter region of CmTCP13. The heterologous expression of CmTCP13 in Arabidopsis plants enhanced their tolerance to salinity stress. Under salinity stress, CmTCP13 transgenic plants exhibited enhanced germination, root length, seedling growth, and chlorophyll content and reduced relative electrical conductivity compared with those exhibited by wild-type (WT) plants. Moreover, the expression levels of stress-related genes, including AtSOS3, AtP5CS2, AtRD22, AtRD29A, and AtDREB2A, were upregulated in CmTCP13 transgenic plants than in WT plants under salt stress. Taken together, our results demonstrate that CmTCP13 is a critical regulator of salt stress tolerance in plants. [ABSTRACT FROM AUTHOR]

Summary: Trichomes are specialized epidermal outgrowths covering the aerial parts of most terrestrial plants. There is a large species variability in occurrence of different types of trichomes such that the molecular regulatory mechanism underlying the formation and the biological function of trichomes in most plant species remain unexplored.Here, we used Chrysanthemum morifolium as a model plant to explore the regulatory network in trichome formation and terpenoid synthesis and unravel the physical and chemical roles of trichomes in constitutive defense against herbivore feeding.By analyzing the trichome‐related genes from transcriptome database of the trichomes‐removed leaves and intact leaves, we identified CmMYC2 to positively regulate both development of T‐shaped and glandular trichomes as well as the content of terpenoids stored in glandular trichomes. Furthermore, we found that the role of CmMYC2 in trichome formation and terpene synthesis was mediated by interaction with CmMYBML1. Our results reveal a sophisticated molecular mechanism wherein the CmMYC2–CmMYBML1 feedback inhibition loop regulates the formation of trichomes (non‐glandular and glandular) and terpene biosynthesis, collectively contributing to the enhanced resistance to Spodoptera litura larvae feeding.Our findings provide new insights into the novel regulatory network by which the plant synchronously regulates trichome density for the physical and chemical defense against herbivory. [ABSTRACT FROM AUTHOR]

Summary: In this study, a full factorial design with three temperature levels (20, 30 and 40 °C), three moisture content (MC) levels (8%, 15% and 22%), and four storage times (7, 14, 21 and 28 days) was used to investigate the changes of aflatoxins (AFs), active constituents, and antioxidant activities in Hangbaiju (HBJ, Chrysanthemum morifolium) after simulated inoculation with Aspergillus parasiticus. The results showed that AFs could be produced in the range of 20~30 °C and 8~22% MC after mould infection, but both mould growth and AFs production were inhibited under the tested MC condition at 40 °C. The analysis of variance (anova) indicated that the temperature, time, interaction between the temperature and time, and interaction between MC and time had significant effects on the total aflatoxins (AFTOT) accumulation. Under 20 and 30 °C, AFTOT in inoculated HBJ usually increased with the increase of MC and storage time, while its active constituents and antioxidant activities decreased with the increase of AFTOT under corresponding storage conditions. Pearson correlation analysis suggested that relatively stronger negative correlations were observed between luteolin‐7‐O‐glucoside (LUT7G), total phenolic content (TPC), total flavonoid content (TFC), and AFTOT. Grey correlation analysis (GCA) showed that antioxidant activity was highly linked to the content of active constituents, and the characteristic flavonoid LUT7G exhibited the highest grey correlation degrees (GCDs) in the three antioxidant activities. The AFTOT reached the highest level (31.15 μg kg−1) after 28 days of storage at 30 °C and 22% MC; meanwhile, LUT7G, TPC and TFC decreased by 93.66%, 20.77% and 55.50%, respectively, and all the three antioxidant activities indicated more than 25% reduction. This is the first study about the changes and relationships of AFTOT, active constituents and bioactivities in the medicinal food influenced by A. parasiticus under different storage conditions. These results provide important references to prevent AFs production and quality control for HBJ and other medicinal foods influenced by A. parasiticus in storage strategy. [ABSTRACT FROM AUTHOR]

The development of branching plays a pivotal role in the cultivation of ornamental chrysanthemums, as it dictates the ultimate morphology and quality of the plants. Strigolactones (SLs) are associated with apical dominance to indirectly inhibit shoot branching. Chrysanthemum morifolium 'Baltasar' in this study was subjected to treatment with three hormones: auxin (IAA), 6-BA, and GR24. Following the exogenous application of GR24 and IAA, a significant reduction in both the length and quantity of lateral buds on chrysanthemums was observed. Additionally, there was a notable down-regulation in the expression levels of CmPIN1 (associated with auxin transport) and CmIPT3, which is involved in cytokinin (CK) synthesis. After the application of 6-BA, there was a significant increase in both the length and quantity of lateral buds on chrysanthemums. Subsequently, the separate application of IAA and 6-BA to C. morifolium 'Baltasar' notably induced the expression of CmMAX1, a gene involved in the biosynthesis of strigolactones, and CmSMXL6, a gene associated with the signaling pathway of SLs, suggesting a negative regulatory role for SLs and auxin in chrysanthemum lateral buds, while CK demonstrated positive regulation. Cloning and expression analysis of CmSMXL6, a member of the D53/SMXL gene family in chrysanthemum, revealed its up-regulation following GR24 treatment, peaking at 9 h. The overexpression of CmSMXL6 in Arabidopsis thaliana promoted increased numbers of primary and secondary branches. In transgenic lines, genes associated with SLs synthesis (AtMAX1, AtMAX2, and AtMAX3) exhibited varying degrees of down-regulation, while the branching-inhibitory gene AtBRC1 also displayed decreased expression levels. These findings suggest that CmSMXL6 plays a role in promoting branching. [ABSTRACT FROM AUTHOR]

Introduction: Chrysanthemum morifolium Ramat. is a perennial herb in the Compositae family, often employed in traditional Chinese medicine due to its medicinal value. The planting of C. morifolium faces the challenges of continuous cropping, and intercropping is able to somewhat overcome the obstacles of continuous cropping. Methods: In our study, we designed two different C. morifolium-maize intercropping patterns, including C. morifolium-maize narrow-wide row planting (IS) and C. morifolium-maize middle row planting (IM). Compared with monoculture, the agronomic traits, yield, active ingredients, soil physicochemical properties, soil enzyme activities, and rhizosphere soil microbial communities of C. morifolium and maize were measured under the two C. morifolium-maize intercropping patterns. Results: The findings indicated that (1) Intercropping elevated the agronomic traits, yield, and active ingredients of C. morifolium, especially in C. morifoliummaize narrow-wide row planting pattern, which indicating that interspecific distance played an important role in intercropping system; (2) Intercropping enhanced soil physicochemical properties and enzyme activities of C. morifolium and maize; (3) Intercropping altered rhizosphere soil microbial communities of C. morifolium and maize, making microbial interrelationships more complex. (4) Intercropping could recruit a large number of beneficial microorganisms enrich in the soil, including Bacillus, Sphingomonas, Burkholderia-Caballeronia-Paraburkholderia, Chaetomium, and Ceratorhiza, which may increase the content of AN, NN, AvK, ExCa, AvCu, AvZn and other nutrients in soil and promoted the growth and quality of C. morifolium. Discussion: In summary, intercropping with maize could promote the accumulation of beneficial microorganisms in the soil, thus improving the overall growing environment, and finally realizing the growth and improvement of C. morifolium. [ABSTRACT FROM AUTHOR]

Abstract Background Chrysanthemum, one of the four major cut flowers all over the world, is very sensitive to salinity during cultivation. DNA binding with one finger (DOF) transcription factors play important roles in biological processes in plants. The response mechanism of CmDOF18 from chrysanthemum to salt stress remains unclear. Results In this study, CmDOF18 was cloned from Chrysanthemum morifolium, and its expression was induced by salinity stress. The gene encodes a 291-amino acid protein with a typical DOF domain. CmDOF18 was localized to the nucleus in onion epidermal cells and showed transcriptional activation in yeast. CmDOF18 transgenic plants were generated to identify the role of this gene in resistance to salinity treatment. Chrysanthemum plants overexpressing CmDOF18 were more resistant to salinity stress than wild-type plants. Under salinity stress, the malondialdehyde content and leaf electrolyte conductivity in CmDOF18-overexpressing transgenic plants were lower than those in wild-type plants, while the proline content, chlorophyll content, superoxide dismutase activity and peroxidase activity were higher than those in wild-type plants. The opposite findings were observed in gene-silenced plants compared with wild-type plants. The gene expression levels of oxidoreductase increased in CmDOF18-overexpressing transgenic plants but decreased in CmDOF18-SRDX gene-silenced transgenic plants. Conclusion In summary, we analyzed the function of CmDOF18 from chrysanthemum, which may regulate salinity stress in plants, possibly due to its role in the regulation of oxidoreductase.

Background: Chrysanthemum, one of the four major cut flowers all over the world, is very sensitive to salinity during cultivation. DNA binding with one finger (DOF) transcription factors play important roles in biological processes in plants. The response mechanism of CmDOF18 from chrysanthemum to salt stress remains unclear. Results: In this study, CmDOF18 was cloned from Chrysanthemum morifolium, and its expression was induced by salinity stress. The gene encodes a 291-amino acid protein with a typical DOF domain. CmDOF18 was localized to the nucleus in onion epidermal cells and showed transcriptional activation in yeast. CmDOF18 transgenic plants were generated to identify the role of this gene in resistance to salinity treatment. Chrysanthemum plants overexpressing CmDOF18 were more resistant to salinity stress than wild-type plants. Under salinity stress, the malondialdehyde content and leaf electrolyte conductivity in CmDOF18-overexpressing transgenic plants were lower than those in wild-type plants, while the proline content, chlorophyll content, superoxide dismutase activity and peroxidase activity were higher than those in wild-type plants. The opposite findings were observed in gene-silenced plants compared with wild-type plants. The gene expression levels of oxidoreductase increased in CmDOF18-overexpressing transgenic plants but decreased in CmDOF18-SRDX gene-silenced transgenic plants. Conclusion: In summary, we analyzed the function of CmDOF18 from chrysanthemum, which may regulate salinity stress in plants, possibly due to its role in the regulation of oxidoreductase. [ABSTRACT FROM AUTHOR]

FLOWERING LOCUS T (FT) is an important factor for integrating flowering signals through the photoperiod pathway, which significantly promotes flowering. Most chrysanthemum varieties are short-day plants, sensitive to the photoperiod, which limits their ornamental and annual production supply. In this study, we aim to analyze the nutrients and flowering-related genes of chrysanthemums with different photoperiod types and to clone and verify the function of the flowering-related gene CmFT. We found that the formation of floral buds requires the accumulation of starch while consuming soluble sugars and the expression patterns of flowering-related genes GIGANTEA (GI), CONSTANS (CO), and FT in C.morifolium ‘Zilian’ and C. morifolium ‘Zihongtuogui’ had a certain synchronization during floral buds differentiation according to our quantitative validation, and the expression levels of CmGI, CmCO and CmFT in C. morifolium ‘Zihongtuogui’ were higher than those in C. morifolium. ‘Zilian’ in the later stage of differentiation. CmFT was cloned from photosensitive chrysanthemums-C. morifolium ‘Zihongtuogui’ and polypeptide alignment and phylogenetic analysis showed that CmFT was clustered in FT-like subfamily. In further functional verification, we obtained two Arabidopsis transgenic lines. Our results showed that CmFT transgenic ft mutant lines can significantly accelerate flowering in Arabidopsis. Thus, we can initially confirm that CmFT plays an important role in promoting flowering, which may be the key reason for the photosensitivity of C. morifolium ‘Zihongtuogui’. Overall, the results of this study are of great importance in revealing the flowering mechanism of different photoperiod types of chrysanthemums. [ABSTRACT FROM AUTHOR]

• 14 light-responsive bHLH family genes were identified in leaves from the 'Nannongxuefeng' variety of cut Chrysanthemum morifolium. • These bHLH proteins harbored multiple conserved amino acid domains, exhibited E-box binding activity, and contained a highlight conserved His15-Glu19-Arg23 sequence in the basic region. • All members of this bHLH family other than bHLH4 were downregulated in response to a combination of white and blue light. The basic helix-loop-helix (bHLH) transcription factor (TF) family members are expressed across eukaryotic species, playing vital roles in growth and developmental processes. Transcriptome analysis in the current study revealed that the shade-tolerant 'Nannongxuefeng' variation of cut chrysanthemum contains 14 low-light stress-responsive bHLH family members. Subcellular localization studies show ten bHLH TFs are expressed in the nucleus, whereas the remaining four are extracellular proteins. These bHLH proteins included two conserved domains and a primary region with a highly conserved His15-Glu19-Arg23 sequence associated with target DNA binding. Residues 33 and 64 in the α-helical region were identified as hydrophobic leucine residues. Multiple conserved amino acids were evident in these bHLH proteins, which possess E-box binding functions and 20 sites with >85 % sequence conservation consistent with the characteristics typical of bHLH domains. Three enduring patterns associated with the bHLH protein family have been identified. The 14 genes were readily categorized into five groups. The bHLH2, bHLH12, and bHLH8 genes were promptly activated in response to a white and red light mixture. Except for bHLH4, all members of this family were downregulated in response to a combination of white and blue light, demonstrating a distinct pattern. Minimal expression of bHLH1-5, 9, 11, and 14 was observed in the presence of light. Except for bHLH4 and bHLH7, all members of the bHLH family are controlled by the circadian rhythm. These thorough examinations of the chrysanthemum bHLH TF family offer a basis for future investigations to explore the expression of these genes in more detail or unravel the molecular factors that influence plant responses to low light conditions. [ABSTRACT FROM AUTHOR]

Chrysanthemum morifolium is a valuable plant that contains a wide range of phytochemical compounds and exhibits various biological activities. Ethanol extracts from both the leaves and flowers of 17 different cultivars of C. morifolium were tested for antioxidant activities using the 2,2-diphenyl-1-picrylhydrazyl and 2,2′-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) assays and were quantitatively analyzed for 12 phenolic compounds using high-performance liquid chromatography with diode-array detection. We found that the 'Ford' and 'Raina' cultivars demonstrated strong antioxidant abilities and high phenolic compound contents compared to other cultivars, while the flowers of 'Cielo' and the leaves of 'White Cap' exhibited low antioxidant capacity in both assays. The 'Cielo' cultivar also displayed the lowest compound contents. Additionally, in most samples, 3,5-dicaffeoylquinic acid and 4,5-dicaffeoylquinic acid stood out as high-content compounds in the extracts. This study provides foundational knowledge that can be used for selecting appropriate C. morifolium cultivars for further research. Moreover, the 'Ford' and 'Raina' cultivars, containing high amounts of bioactive compounds and showing superior antioxidant ability, could be applied to produce health-beneficial products. [ABSTRACT FROM AUTHOR]

Fertilizer application is a decisive measure for the productivity of medicinal chrysanthemum plants. Therefore, determining the optimal doses of nutrients required for the growth and yield is crucial. In this study, we set out to investigate the effect of various nutrients on the growth, yield, and functional components of chrysanthemum under eight different fertilization levels at seedling, branching, and flowering growth periods. The results show that plant height, stem diameter, and leaf area under the balance fertilization treatment were the highest (82 cm, 0.78 cm, and 38.50 cm2, respectively), while the flower size and yield under the high potassium treatment were significantly increased compared to using balance fertilization. Chlorophyll content was also highest under the high potassium treatment. Moreover, plant defensive antioxidant peroxidase (POD) was responsive to low nitrogen treatment and low phosphorus treatment, while high potassium treatment enhanced the phenylalanine aminolase (PAL) activity and increased the content of flavonoids and chlorogenic acid in Chrysanthemum morifolium. In addition, low phosphorus treatment promoted the accumulation of flavonoids and chlorogenic acid content. Convincingly, the results show that growth, flowering, and functional indicators of chrysanthemum may thrive best under high potassium and balanced fertilization dosages, which will contribute to the development of a new economical chrysanthemum fertilizer ratio. [ABSTRACT FROM AUTHOR]

The shoot apical meristem culture has been used widely to produce virus-free plantlets which have the advantages of strong disease resistance, high yield, and prosperous growth potential. However, this virus-free plant will be naturally reinfected in the field. The physiological and metabolic responses in the reinfected plant are still unknown. The flower of chrysanthemum 'Hangju' is a traditional medicine which is unique to China. In this study, we found that the virus-free 'Hangju' (VFH) was reinfected with chrysanthemum virus B/R in the field. However, the reinfected VFH (RVFH) exhibited an increased yield and medicinal components compared with virus-infected 'Hangju' (VIH). Comparative analysis of transcriptomes was performed to explore the molecular response mechanisms of the RVFH to CVB infection. A total of 6223 differentially expressed genes (DEGs) were identified in the RVFH vs. the VIH. KEGG enrichment and physiological analyses indicated that treatment with the virus-free technology significantly mitigated the plants' lipid and galactose metabolic stress responses in the RVFH. Furthermore, GO enrichment showed that plant viral diseases affected salicylic acid (SA)-related processes in the RVFH. Specifically, we found that phenylalanine ammonia-lyase (PAL) genes played a major role in defense-related SA biosynthesis in 'Hangju'. These findings provided new insights into the molecular mechanisms underlying plant virus–host interactions and have implications for developing strategies to improve plant resistance against viruses. [ABSTRACT FROM AUTHOR]

The aim of this research was to study the impact of squalene synthase gene silencing on the features of transgenic chrysanthemum plants, and on the synthesis of some sesquiterpenes—caryophyllene, germacrene and farnesene. We have cloned chrysanthemum squalene synthase gene cDNA (CmSQS) and obtained five lines stably transformed with vector for CmSQS silencing. Silencing of CmSQS gene transcription was detected in all five transgenic lines, the decrease in the squalene content was found in three of them, by 1.8–2.0 times depending on the line. The content of triterpenes α- and β-amirin, derivatives of squalene, clearly correlated with its content in plants. The β-caryophyllene, germacrene D and β-farnesene were identified in chrysanthemum using GC-MS analysis; the content of these compounds in transgenic plants did not change appreciably compared to control ones. Silencing of squalene synthase had no effect on plants morphology. In two transgenic lines, a decrease in growth rate relative to non-transgenic plants was observed; the growth rate of three other lines did not differ from the control. Thus, in our experiments no well-defined relationship between CmSQS gene transcription level, the content of squalene and studied sesquiterpenes was found. The obtained data provide additional information on mechanisms of plant secondary metabolism regulation including the relation between β-caryophyllene, germacrene D and β-farnesene content with squalene synthesis level. [ABSTRACT FROM AUTHOR]

Plants have evolved complex mechanisms to reprogram growth in response to drought stress. In herbaceous perennial plant species, the rhizome, which is normally an organ for propagation and food storage, can also support plant growth in stressful environments, and allows the plant to perennate and survive stress damage. However, the mechanisms that regulate rhizome growth in perennial herbs during abiotic stresses are unknown. Here, we identified a chrysanthemum (Chrysanthemum morifolium) DEAD-box RNA helicase gene, CmRH56, that is specifically expressed in the rhizome shoot apex. Knock down of CmRH56 transcript levels decreased the number of rhizomes and enhanced drought stress tolerance. We determined that CmRH56 represses the expression of a putative gibberellin (GA) catabolic gene, GA2 oxidase6 (CmGA2ox6). Exogenous GA treatment and silencing of CmGA2ox6 resulted in more rhizomes. These results demonstrate that CmRH56 suppresses rhizome outgrowth under drought stress conditions by blocking GA biosynthesis.

Chrysanthemum morifolium ranks among the four highest-selling cut flowers worldwide. Gene editing is an important tool to research gene function, but efficient and precise genome-editing tools are not available for chrysanthemum. Here, we established a CRISPR/Cas9-mediated gene-editing system to explore gene functions and enhance the breeding of chrysanthemum. We used the Golden Gate Assembly system to construct CRISPR/Cas9 vectors for dual targeting of the Phytoene Dehydro (PDS) gene. To test the accuracy of sgRNA design, we initially used the transient CRISPR/Cas9 editing in plants (TCEP) method. Target gene expression in nine plants subjected to transient transfection was 19.1%–52% of the normal level, confirming the feasibility of target gene knockout. We carried out stable transformation; PCR and sequencing of the target sites showed that four of eight albino plants obtained had been stably edited at the target sites. We further assessed the editing efficiency of the system by targeting another gene, CmTGA1, chosen because of its potential importance in Chrysanthemum White Rust (CWR) disease progression. Our data indicates that combining transient and stable transformation improves the efficiency and success rate of genome fixed-point editing. The effective, heritable CRISPR/Cas9-mediated genome-editing system we have established here lays the foundation for functional gene studies and genetic improvement of C. morifolium.

Chrysanthemum morifolium is a perennial herbaceous plant in the Asteraceae family that is used as a medicine and food owing to its superior pharmacological properties. Irrespective of its application, C. morifolium must be dried before use. Shade drying (YG) and heat drying (HG) are the two drying methods used in most origins. Given the abundance of flavonoids, phenolic acids, and terpenoids, the primary medicinal active constituents of C. morifolium, it is important to determine whether the composition and content of these compounds are altered during the drying processes. To test this, the changes in the chemical composition of C. morifolium flowers after YG and HG using full-spectrum, non-targeted LC/GC–MS−based metabolomics and, subsequently, the three indicator components of C. morifolium—chlorogenic acid, 3,5−dicaffeoylquinic acid, and luteolin−7−O−glucoside—were accurately quantified by HPLC. The results of the non-targeted metabolomics analysis revealed that YG- and HG-processed C. morifolium differed significantly with respect to chemical contents, especially flavonoids, phenolic acids, and terpenoids. The levels of the indicator components and their precursors also differed significantly between the YG and HG treatments. The contents of most of the flavonoids and key phenolic acids, terpenoids, and carbohydrates were higher with YG than with HG pre-treatment. These results revealed the changes in the chemical composition of C. morifolium during the YG and HG processes, thus providing a reference for the further optimization of the production and processing of chrysanthemums.

Color fading caused by a decrease in anthocyanin accumulation during the post-flowering stage significantly affects postharvest quality of chrysanthemum. However, the underlying mechanism by which anthocyanin accumulation decreases during the post-flowering stage still unclear, which greatly restricts design of molecular breeding in chrysanthemum. Here, a chrysanthemum SG7 R2R3 MYB transcription factor (TF), CmMYB3-like, was identified to have a function in regulating anthocyanin biosynthesis during the post-flowering stage. Quantitative real time PCR (qRT-PCR) assays showed that the expression of CmMYB3-like was gradually downregulated when anthocyanin content increased during the flowering stage and was significantly upregulated during the post-flowering stage. Genetic transformation of chrysanthemum and dual-luciferase assays in N. benthamiana leaves showed that CmMYB3-like suppressed anthocyanin accumulation by inhibiting the transcription of CmCHS and CmANS directly and that of CmF3H indirectly. However, overexpression or suppression of CmMYB3-like did not affect the biosynthesis of flavones or flavonols. Genetic transformation of chrysanthemum revealed that the overexpression of CmMYB3-like inhibited anthocyanin accumulation, but its suppression prevented the decrease in anthocyanin accumulation during the post-flowering stage. Our results revealed a crucial role of CmMYB3-like in regulating the color of petals during the post-flowering stage and provided a target gene for molecular design breeding to improve the postharvest quality of chrysanthemum. [ABSTRACT FROM AUTHOR]

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The chrysanthemum DgLsL gene, homologous with tomato Ls, is one of the earliest expressed genes controlling axillary meristem initiation. In this study, the wild-type chrysanthemum (CW) and DgLsL-overexpressed line 15 (C15) were used to investigate the regulatory mechanism of axillary bud development in chrysanthemum. Transcriptome sequencing was carried out to detect the differentially expressed genes of the axillary buds 0 h, 24 h and 48 h after decapitation. The phenotypic results showed that the number of axillary buds of C15 was significantly higher than CW. A total of 9,224 DEGs were identified in C15-0 vs. CW-0, 10,622 DEGs in C15-24 vs. CW-24, and 8,929 DEGs in C15-48 vs. CW-48.GO and KEGG pathway enrichment analyses showed that the genes of the flavonoid, phenylpropanoids and plant hormone pathways appeared to be differentially expressed, indicating their important roles in axillary bud germination. DgLsL reduces GA content in axillary buds by promoting GA2ox expression. These results confirmed previous studies on axillary bud germination and growth, and revealed the important roles of genes involved in plant hormone biosynthesis and signal transduction, aiding in the study of the gene patterns involved in axillary bud germination and growth. [ABSTRACT FROM AUTHOR]

Chrysanthemum ( Chrysanthemum morifolium ) contains secondary metabolites, such as flavonoid compounds, especially luteolin-7-glucoside and quercetin-3-O-rhamnoside (quercitrin), in its tissues. Utilizing sucrose as an elicitor through callus culture presents an alternative method to enhance the production of secondary metabolites. This research aimed to determine the best sucrose concentration and harvest time for maximizing quercitrin content in chrysanthemum callus culture. The research employed a completely randomized design with four treatment groups: 0, 30, 45, and 60 g/l of sucrose added to MS medium containing 4 ppm 2,4-dichlorophenoxyacetic acid (2,4-D). Callus samples were harvested on the 15th and 30th days of culture. The observed parameters included callus morphology (color and texture), fresh weight, dry weight, the diameter of the callus, and quercitrin content analyzed using high-performance liquid chromatography. The results showed that all callus cultures exhibited intermediate textures and varied colors, predominantly shades of brown. The treatment involving 45 g/l of sucrose with a 30th-day harvest yielded the highest fresh weight, dry weight, and quercitrin content, namely 2.108 g, 0.051 g, and 0.437 mg/g DW, respectively. Notably, the quercitrin content exhibited a 63.67% increase compared to the control.

Abstract Background Black spot disease caused by the necrotrophic fungus Alternaria spp. is one of the most devastating diseases affecting Chrysanthemum morifolium. There is currently no effective way to prevent chrysanthemum black spot. Results We revealed that pre-treatment of chrysanthemum leaves with the methy jasmonate (MeJA) significantly reduces their susceptibility to Alternaria alternata. To understand how MeJA treatment induces resistance, we monitored the dynamics of metabolites and the transcriptome in leaves after MeJA treatment following A. alternata infection. JA signaling affected the resistance of plants to pathogens through cell wall modification, Ca2+ regulation, reactive oxygen species (ROS) regulation, mitogen‐activated protein kinase cascade and hormonal signaling processes, and the accumulation of anti-fungal and anti-oxidant metabolites. Furthermore, the expression of genes associated with these functions was verified by reverse transcription quantitative PCR and transgenic assays. Conclusion Our findings indicate that MeJA pre-treatment could be a potential orchestrator of a broad-spectrum defense response that may help establish an ecologically friendly pest control strategy and offer a promising way of priming plants to induce defense responses against A. alternata.

ABSTRACTThis study was aiming at the differences in the aroma, flavor compounds, and bioactivities of essential oil of Coreopsis tinctoria flower (CTFEO) and essential oil of Chrysanthemum morifolium flower (CMFEO). Both essential oils were extracted by steam distillation. Their flavor compositions were determined by GC-MS and the antioxidant, antibacterial, and anti-inflammatory activities were also evaluated. It was found that CTFEO possessed a special medicinal herb odor, which was obviously stronger than those of CMFEO. A preferred condition for steam distillation was flower powder–water ratio of 7.5:100 and extraction for more than 3.0 h. Interestingly, the main flavor compounds of CTFEO were determined as D-limonene (34.54%), cis-carveol (5.49%), trans-α-bergamotene (4.44%), and α-pinene (3.90%), which were quite different from those of CMFEO. CTFEO showed better antioxidant activities with IC50 value of 121.4 ± 9.8 μg/mL than those of CMFEO. It also exhibited stronger antibacterial effects than those of CMFEO, with minimal inhibitory concentrations (MICs) ranging from 0.183 to 1.412 mg/mL against six strains of bacteria. Moreover, CTFEO was also found to exhibit strong anti-inflammatory effects that reduced the LPS-induced RAW 264.7 cell mRNA expression of the cytokines IL-1β, IL-6, and TNF-α at a concentration of 10.0 μg/mL. All these results suggest that the aroma, flavor compounds, and bioactivities of the two essential oils were quite different and they could be used as tea, drink, and food additive in the food industry for further development.

Plant-specific TEOSINTE BRANCHED1/CYCLOIDEA/PROLIFERATING CELL FACTOR (TCP) proteins play critical roles in plant development and stress responses; however, their functions in chrysanthemum (Chrysanthemum morifolium) have not been well-studied. In this study, we isolated and characterized the chrysanthemum TCP transcription factor family gene CmTCP13, a homolog of AtTCP13. This gene encoded a protein harboring a conserved basic helix–loop–helix motif, and its expression was induced by salinity stress in chrysanthemum plants. Subcellular localization experiments showed that CmTCP13 localized in the nucleus. Sequence analysis revealed the presence of multiple stress- and hormone-responsive cis-elements in the promoter region of CmTCP13. The heterologous expression of CmTCP13 in Arabidopsis plants enhanced their tolerance to salinity stress. Under salinity stress, CmTCP13 transgenic plants exhibited enhanced germination, root length, seedling growth, and chlorophyll content and reduced relative electrical conductivity compared with those exhibited by wild-type (WT) plants. Moreover, the expression levels of stress-related genes, including AtSOS3, AtP5CS2, AtRD22, AtRD29A, and AtDREB2A, were upregulated in CmTCP13 transgenic plants than in WT plants under salt stress. Taken together, our results demonstrate that CmTCP13 is a critical regulator of salt stress tolerance in plants.

The development of branching plays a pivotal role in the cultivation of ornamental chrysanthemums, as it dictates the ultimate morphology and quality of the plants. Strigolactones (SLs) are associated with apical dominance to indirectly inhibit shoot branching. Chrysanthemum morifolium ‘Baltasar’ in this study was subjected to treatment with three hormones: auxin (IAA), 6-BA, and GR24. Following the exogenous application of GR24 and IAA, a significant reduction in both the length and quantity of lateral buds on chrysanthemums was observed. Additionally, there was a notable down-regulation in the expression levels of CmPIN1 (associated with auxin transport) and CmIPT3, which is involved in cytokinin (CK) synthesis. After the application of 6-BA, there was a significant increase in both the length and quantity of lateral buds on chrysanthemums. Subsequently, the separate application of IAA and 6-BA to C. morifolium ‘Baltasar’ notably induced the expression of CmMAX1, a gene involved in the biosynthesis of strigolactones, and CmSMXL6, a gene associated with the signaling pathway of SLs, suggesting a negative regulatory role for SLs and auxin in chrysanthemum lateral buds, while CK demonstrated positive regulation. Cloning and expression analysis of CmSMXL6, a member of the D53/SMXL gene family in chrysanthemum, revealed its up-regulation following GR24 treatment, peaking at 9 h. The overexpression of CmSMXL6 in Arabidopsis thaliana promoted increased numbers of primary and secondary branches. In transgenic lines, genes associated with SLs synthesis (AtMAX1, AtMAX2, and AtMAX3) exhibited varying degrees of down-regulation, while the branching-inhibitory gene AtBRC1 also displayed decreased expression levels. These findings suggest that CmSMXL6 plays a role in promoting branching.

[Objectives] This study was conducted to provide a theoretical basis for the extraction and comprehensive utilization of functional active components of Chrysanthemum morifolium polyphenols. [Methods] With C. morifolium as a raw material, polyphenols were extracted by water extraction. The extraction process of polyphenols were optimized by single factor tests on solid-liquid ratio, extracting time and times. Old rice wine selected as the base wine was added with C. morifolium polyphenol extract, honey, citric acid and other auxiliary materials to prepare a kind of chrysanthemum old rice wine. Through sensory analysis combined with fuzzy mathematics comprehensive evaluation method, the optimal formula of chrysanthemum old rice wine was determined, and the corresponding physicochemical indicators of the obtained chrysanthemum old rice wine were tested. [Results] The optimal soaking prods for C. morifolium was as flows: extraction time of 20 min, a solid-liquid ratio of C. morifolium to warm water at 1 : 40, extraction times of 3 times. The physical and chemical indicators of the chrysanthemum wine obtained from the above optimal formula were as flows: sugar content 5%, ethanol content 11 %, and pH value 4.04. The chrysanthemum old rice wine obtained was clear and transparent, and the fragrance of chrysanthemum was coordinated with the mellow aroma of rice wine. The taste was refreshing and suitable for the vast majority of people to drink. [Conclusions] The new type of chrysanthemum old rice wine combines the polyphenolic active substances in C. morifollum with the low ethanol content of old rice wine, which not only improves the utilization rate of C. morifollum, but also strengthens the health function of old rice wine products, improves the quality of old rice wine, and promotes the healthy and rapid development of the old rice wine industry. [ABSTRACT FROM AUTHOR]

Background: Black spot disease caused by the necrotrophic fungus Alternaria spp. is one of the most devastating diseases affecting Chrysanthemum morifolium. There is currently no effective way to prevent chrysanthemum black spot. Results: We revealed that pre-treatment of chrysanthemum leaves with the methy jasmonate (MeJA) significantly reduces their susceptibility to Alternaria alternata. To understand how MeJA treatment induces resistance, we monitored the dynamics of metabolites and the transcriptome in leaves after MeJA treatment following A. alternata infection. JA signaling affected the resistance of plants to pathogens through cell wall modification, Ca2+ regulation, reactive oxygen species (ROS) regulation, mitogen‐activated protein kinase cascade and hormonal signaling processes, and the accumulation of anti-fungal and anti-oxidant metabolites. Furthermore, the expression of genes associated with these functions was verified by reverse transcription quantitative PCR and transgenic assays. Conclusion: Our findings indicate that MeJA pre-treatment could be a potential orchestrator of a broad-spectrum defense response that may help establish an ecologically friendly pest control strategy and offer a promising way of priming plants to induce defense responses against A. alternata. [ABSTRACT FROM AUTHOR]

Chrysanthemum × morifolium Ramat. is a famous perennial herb with medicinal, edible, and ornamental purposes, but the occurrence of plant diseases can reduce its value. A serious disease that caused leaf spots in C. morifolium appeared in 2022 in Tongxiang City, Zhejiang Province, China. The C. morifolium leaves with brown spots were collected and used for pathogen isolation. By completing Koch's postulates, it was proven that the isolate had pathogenicity to infect C. morifolium. It was determined that the pathogen isolated from chrysanthemum leaves was Nigrospora oryzae, through morphology and a multilocus sequence analysis method using a combination of the internal transcribed spacer gene (ITS), beta-tubulin gene (TUB2), and translation elongation factor 1-alpha gene (TEF1-α). This is the first report of C. morifolium disease caused by N. oryzae in the world. Through dual culture assay on PDA plates, 12 strains of bacteria with antagonistic effects were selected from 231 strains from the C. morifolium phyllosphere, among which Bacillus siamensis D65 had the best inhibitory effect on N. oryzae growth. In addition, the components of a strain D65 fermentation broth were profiled by SPME-GC-Q-TOF analysis, providing a foundation for further application and research of biological control. [ABSTRACT FROM AUTHOR]

Chrysanthemum is one of the most commercially used ornamental flowering plants in the world. As chrysanthemum is self-incompatible, the propagation of identical varieties is carried out through cuttings rather than through seed. Axillary bud development can be controlled by changing the temperature; for instance, axillary bud development in some varieties is suppressed at high temperatures. In this study, we focused on the simultaneous axillary bud growth from multiple lines of chrysanthemum upon changing conditions from low to normal temperature. Transcriptome analysis was conducted on the Chrysanthemum morifolium cultivar 'Jinba' to identify the important genes for axillary bud development seen when moved from low-temperature treatment to normal cultivation temperature. We performed RNA-Seq analysis on plants after cold conditions in two-day time-course experiments. Under these settings, we constructed a transcriptome of 415,923 C. morifolium and extracted 7357 differentially expressed genes. Our understanding of Arabidopsis axillary meristem development and growth showed that at least 101 genes in our dataset were homologous to transcription factors involved in the biological process. In addition, six genes exhibited statistically significant variations in expression throughout conditions. We hypothesized that these genes were involved in the formation of axillary buds in C. morifolium after cold conditions. [ABSTRACT FROM AUTHOR]

Chrysanthemum morifolium is a valuable plant that contains a wide range of phytochemical compounds and exhibits various biological activities. Ethanol extracts from both the leaves and flowers of 17 different cultivars of C. morifolium were tested for antioxidant activities using the 2,2-diphenyl-1-picrylhydrazyl and 2,2′-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) assays and were quantitatively analyzed for 12 phenolic compounds using high-performance liquid chromatography with diode-array detection. We found that the ‘Ford’ and ‘Raina’ cultivars demonstrated strong antioxidant abilities and high phenolic compound contents compared to other cultivars, while the flowers of ‘Cielo’ and the leaves of ‘White Cap’ exhibited low antioxidant capacity in both assays. The ‘Cielo’ cultivar also displayed the lowest compound contents. Additionally, in most samples, 3,5-dicaffeoylquinic acid and 4,5-dicaffeoylquinic acid stood out as high-content compounds in the extracts. This study provides foundational knowledge that can be used for selecting appropriate C. morifolium cultivars for further research. Moreover, the ‘Ford’ and ‘Raina’ cultivars, containing high amounts of bioactive compounds and showing superior antioxidant ability, could be applied to produce health-beneficial products.

The shoot apical meristem culture has been used widely to produce virus-free plantlets which have the advantages of strong disease resistance, high yield, and prosperous growth potential. However, this virus-free plant will be naturally reinfected in the field. The physiological and metabolic responses in the reinfected plant are still unknown. The flower of chrysanthemum ‘Hangju’ is a traditional medicine which is unique to China. In this study, we found that the virus-free ‘Hangju’ (VFH) was reinfected with chrysanthemum virus B/R in the field. However, the reinfected VFH (RVFH) exhibited an increased yield and medicinal components compared with virus-infected ‘Hangju’ (VIH). Comparative analysis of transcriptomes was performed to explore the molecular response mechanisms of the RVFH to CVB infection. A total of 6223 differentially expressed genes (DEGs) were identified in the RVFH vs. the VIH. KEGG enrichment and physiological analyses indicated that treatment with the virus-free technology significantly mitigated the plants’ lipid and galactose metabolic stress responses in the RVFH. Furthermore, GO enrichment showed that plant viral diseases affected salicylic acid (SA)-related processes in the RVFH. Specifically, we found that phenylalanine ammonia-lyase (PAL) genes played a major role in defense-related SA biosynthesis in ‘Hangju’. These findings provided new insights into the molecular mechanisms underlying plant virus–host interactions and have implications for developing strategies to improve plant resistance against viruses.

Fertilizer application is a decisive measure for the productivity of medicinal chrysanthemum plants. Therefore, determining the optimal doses of nutrients required for the growth and yield is crucial. In this study, we set out to investigate the effect of various nutrients on the growth, yield, and functional components of chrysanthemum under eight different fertilization levels at seedling, branching, and flowering growth periods. The results show that plant height, stem diameter, and leaf area under the balance fertilization treatment were the highest (82 cm, 0.78 cm, and 38.50 cm2, respectively), while the flower size and yield under the high potassium treatment were significantly increased compared to using balance fertilization. Chlorophyll content was also highest under the high potassium treatment. Moreover, plant defensive antioxidant peroxidase (POD) was responsive to low nitrogen treatment and low phosphorus treatment, while high potassium treatment enhanced the phenylalanine aminolase (PAL) activity and increased the content of flavonoids and chlorogenic acid in Chrysanthemum morifolium. In addition, low phosphorus treatment promoted the accumulation of flavonoids and chlorogenic acid content. Convincingly, the results show that growth, flowering, and functional indicators of chrysanthemum may thrive best under high potassium and balanced fertilization dosages, which will contribute to the development of a new economical chrysanthemum fertilizer ratio.

Chrysanthemum morifolium L. cultivators in Pakistan have frequently detected that poor root cuttings of chrysanthemum caused poor anchorage of roots that results in shipping losses of these pot plants. Optimum concentration of appropriate auxins is used to promote effective rooting. Completely randomized design (CRD) is adopted and it consisted of five treatments including control and different concentration of both auxins viz. 1-Naphthalene acetic acid (50 mg/L,100 mg/L) and Indole-3-acetic acid (100 mg/L, 200 mg/L) on tip cuttings of chrysanthemum. In this experiment, 15 pots of 9-inch diameter were used which were filled with silt, leaf mould and well rotten farmyard manure (1:1:1). Three cuttings in each pot and a total of 45 cuttings were planted. Cuttings of each treatment were dipped for 3 minutes in respective solution before planting. Uprooting was done after 60 days of plantation the cuttings. NAA with 100 mg/L proved best treatments that produced maximum root length, number of roots, dry and fresh weights of roots, number of sprouted buds, number of leaves, leaves fresh weight and dry leaves weight as compared to other treatments and control. This data suggested that NAA can be successfully used to increase root and shoot parameters in chrysanthemum propagated by means of tip cuttings. [ABSTRACT FROM AUTHOR]

Brassinosteroids (BRs), a class of steroid phytohormones, play a critical role in plant growth and development. The DWF4 gene encodes a cytochrome P450 enzyme (CYP90B1), which is considered a rate-limiting enzyme in BR biosynthesis. Here, we identified a homologous gene of DWF4 in chrysanthemum, CmDWF4. This gene was predicted to encode 491 amino acid residues with a molecular weight of 56.2 kDa and an isoelectric point (pI) of 9.10. Overexpression of CmDWF4 in chrysanthemum was found to significantly increase growth rate, number, and length of lateral buds. Transcriptome analysis showed that multiple xyloglucan endotransglycosylase/hydrolase (XTH) family encoding genes associated with cell wall modification were up-regulated in CmDWF4-overexpressing lines. qRT-PCR assay confirmed the up-regulation of CmXTH6, CmXTH23, and CmXTH28 in CmDWF4-overexpression line. Overall, this work establishes a mechanism by which BR biosynthetic gene CmDWF4 promotes lateral bud outgrowth in chrysanthemum, possibly through regulating cell elongation and expansion. [ABSTRACT FROM AUTHOR]

[Objectives]The paper aimed to explore the function of chrysanthemum CmHB15-1 gene in regulating lignin synthesis. [Methods]Through homologous cloning, the CmHB15-1 gene was cloned by using Chrysanthemum morifolium’Jinba’cDNA as a template. The amino acid sequence alignment was conducted using DNAMAN 8.0 software. The pORE-R4-CmHB15-1-GFP vector was constructed and introduced into tobacco leaves for protein subcellular localization analysis. The transcriptional activation activity was analyzed by yeast hybridization assay. The expression level of CmHB15-1 gene in different tissues, and its potential downstream genes were analyzed by RT-qPCR. The role of CmHB15-1 in regulating the lignin synthesis was analyzed by generating CmHB15-1 overexpressing Arabidopsis thaliana. [Results]The open reading frame length of CmHB15-1 gene was 2 520 bp, encoding 839 amino acids. Putative protein relative molecular weight was 92.44×10~3with an isoelectric point of 6.46. CmHB15-1 protein had Homeobox, bZIP, START and MEKHLA domain. It was closely related to TcATHB-15 of Tanacetum cinerariifolium. Subcellular localization results showed that CmHB15-1 protein was located in the nucleus, and it had transcriptional activation activity. The expression level of CmHB15-1 gene was the highest in stems, and the expression level gradually increased from the top of the stem internode to the base of the stem internodes, and the expression level of CmHB15-1 gene was the highest in the base of the stem internode. The lignin content of CmHB15-1 transgenic A.thaliana line OE-20 and OE-23 increased by 15.98% and 17.99% respectively compared with the wild-type. The expressions of the lignin synthesis genes of phenylalanine ammonia lyase1 (PAL1), cinnamate 4-hydroxylase (C4H), 4-coumarate CoA ligase1 (4CL1),caffeoyl CoA O-methyltransferase1 (CCoAOMT1), ferulate 5-hydroxylase (F5H) were significantly upregulated in transgenic A.thaliana line. [Conclusions]CmHB15-1 gene was involved in regulating lignin biosynthesis. [ABSTRACT FROM AUTHOR]

Abstract Background Chrysanthemum virus B (CVB), a key member of the genus Carlavirus, family Betaflexiviridae, causes severe viral diseases in chrysanthemum (Chrysanthemum morifolium) plants worldwide. However, information on the mechanisms underlying the response of chrysanthemum plants to CVB is scant. Methods Here, an integrated next-generation sequencing and comparative transcriptomic analysis of chrysanthemum leaves was conducted to explore the molecular response mechanisms of plants to a Chinese isolate of CVB (CVB-CN) at the molecular level. Results In total, 4934 significant differentially expressed genes (SDEGs) were identified to respond to CVB-CN, of which 4097 were upregulated and 837 were downregulated. Gene ontology and functional classification showed that the majority of upregulated SDEGs were categorized into gene cohorts involved in plant hormone signal transduction, phenylpropanoid and flavonoid biosynthesis, and ribosome metabolism. Enrichment analysis demonstrated that ethylene pathway-related genes were significantly upregulated following CVB-CN infection, indicating a strong promotion of ethylene biosynthesis and signaling. Furthermore, disruption of the ethylene pathway in Nicotiana benthamiana, a model plant, using virus-induced gene silencing technology rendered them more susceptible to cysteine-rich protein of CVB-CN induced hypersensitive response, suggesting a crucial role of this pathway in response to CVB-CN infection. Conclusion This study provides evidence that ethylene pathway has an essential role of plant in response to CVB and offers valuable insights into the defense mechanisms of chrysanthemum against Carlavirus.

Key message: Chrysanthemum morifolium MYB3 factors are transcriptional activators for the regulation of flavonol biosynthesis. Flavonol was not only the critical secondary metabolite participating in the growth and development of plants but also the main active ingredient in medicinal chrysanthemum. However, few pieces of research revealed the transcriptional regulation of flavonol biosynthesis in Chrysanthemum morifolium. Here, we isolated two CmMYB3 transcription factors (CmMYB3a and CmMYB3b) from the capitulum of Chrysanthemum morifolium cv 'Hangju'. According to the sequence characteristics, the CmMYB3a and CmMYB3b belonged to the R2R3-MYB subgroup 7, whose members were often reported to regulate flavonol biosynthesis positively. CmMYB3a and CmMYB3b factors were identified to localize in the nucleus by subcellular localization assay. Besides, both of them have obvious transcriptional self-activation activity in their C-terminal. After the overexpression of CmMYB3 genes in Nicotiana benthamiana and Arabidopsis thaliana, the flavonol contents in plants were increased, and the expression of AtCHS, AtCHI, AtF3H, and AtFLS genes in A. thaliana was also improved. Interestingly, the CmMYB3a factor had stronger functions in improving flavonol contents and related gene expression levels than CmMYB3b. The interaction analysis between transcription factors and promoters suggested that CmMYB3 could bind and activate the promoters of CmCHI and CmFLS genes in C. morifolium, and CmMYB3a also functioned more powerfully. Overall, these results indicated that CmMYB3a and CmMYB3b work as transcriptional activators in controlling flavonol biosynthesis. [ABSTRACT FROM AUTHOR]

Chrysanthemum (Chrysanthemum morifolium) is an important ornamental and medicinal plant suffering from many viruses and viroids worldwide. In this study, a new carlavirus, tentatively named Chinese isolate of Carya illinoinensis carlavirus 1 (CiCV1-CN), was identified from chrysanthemum plants in Zhejiang Province, China. The genome sequence of CiCV1-CN was 8795 nucleotides (nt) in length, with a 68-nt 5′-untranslated region (UTR) and a 76-nt 3′-UTR, which contained six predicted open reading frames (ORFs) that encode six corresponding proteins of various sizes. Phylogenetic analyses based on full-length genome and coat protein sequences revealed that CiCV1-CN is in an evolutionary branch with chrysanthemum virus R (CVR) in the Carlavirus genus. Pairwise sequence identity analysis showed that, except for CiCV1, CiCV1-CN has the highest whole-genome sequence identity of 71.3% to CVR-X6. At the amino acid level, the highest identities of predicted proteins encoded by the ORF1, ORF2, ORF3, ORF4, ORF5, and ORF6 of CiCV1-CN were 77.1% in the CVR-X21 ORF1, 80.3% in the CVR-X13 ORF2, 74.8% in the CVR-X21 ORF3, 60.9% in the CVR-BJ ORF4, 90.2% in the CVR-X6 and CVR-TX ORF5s, and 79.4% in the CVR-X21 ORF6. Furthermore, we also found a transient expression of the cysteine-rich protein (CRP) encoded by the ORF6 of CiCV1-CN in Nicotiana benthamiana plants using a potato virus X-based vector, which can result in a downward leaf curl and hypersensitive cell death over the time course. These results demonstrated that CiCV1-CN is a pathogenic virus and C. morifolium is a natural host of CiCV1. [ABSTRACT FROM AUTHOR]

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Chrysanthemum Fusarium wilt, caused by the pathogenic fungus Fusarium oxysporum, severely reduces ornamental quality and yields. WRKY transcription factors are extensively involved in regulating disease resistance pathways in a variety of plants; however, it is unclear how members of this family regulate the defense against Fusarium wilt in chrysanthemums. In this study, we characterized the WRKY family gene CmWRKY8-1 from the chrysanthemum cultivar 'Jinba', which is localized to the nucleus and has no transcriptional activity. We obtained CmWRKY8-1 transgenic chrysanthemum lines overexpressing the CmWRKY8-1-VP64 fusion protein that showed less resistance to F. oxysporum. Compared to Wild Type (WT) lines, CmWRKY8-1 transgenic lines had lower endogenous salicylic acid (SA) content and expressed levels of SA-related genes. RNA-Seq analysis of the WT and CmWRKY8-1-VP64 transgenic lines revealed some differentially expressed genes (DEGs) involved in the SA signaling pathway, such as PAL, AIM1, NPR1, and EDS1. Based on Gene Ontology (GO) enrichment analysis, the SA-associated pathways were enriched. Our results showed that CmWRKY8-1-VP64 transgenic lines reduced the resistance to F. oxysporum by regulating the expression of genes related to the SA signaling pathway. This study demonstrated the role of CmWRKY8-1 in response to F. oxysporum, which provides a basis for revealing the molecular regulatory mechanism of the WRKY response to F. oxysporum infestation in chrysanthemum. [ABSTRACT FROM AUTHOR]

Chrysanthemum morifolium, an ornamental crop with diverse forms of inflorescence, is a good model for studying flower development in Asteraceae. However, the genetic background is complex and the mechanisms of regulating flower development are still unclear. Here, we identified two natural mutant lines of chrysanthemum and named them M1 and M2 according to the severity of the phenotype. Both lines showed defects in petal identity, and the petals of the M1 line had a mild phenotype: partially loss of petal identity and conversion of petals into green, leaf-like organs. The M2 line had severe phenotypes: in addition to severe petal defects, secondary inflorescences were produced in the capitulum to replace the normal ray and disc florets, which indicated a transformation of a flower meristem into an inflorescence meristem. Transcriptome sequencing of WT and M2 inflorescences was performed and found altered expression of floral organ development A, B and E class genes, where B and E class genes were significantly down-regulated. qRT-PCR analysis in both M1 and M2 lines revealed that the expression of three chrysanthemum class B genes CmAP3.1, CmAP3.2 and CmPI, was negatively correlated with phenotypic severity. This suggests that class B genes in chrysanthemum not only have conserved functions in determining petal identity but also were involved in the determinacy of the flower meristem. This study provides insights into the functions of class B genes in flower development, and is informative for dissecting the molecular mechanisms of flower development in chrysanthemum. [ABSTRACT FROM AUTHOR]

The purpose of the study was to establish a rapid analytical strategy to screen potential anti-inflammatory compounds from Flos Chrysanthemum flower. The enzyme assay was conducted to prescreen botanical extracts, in which Chrysanthemum morifolium aqueous extract (CME) displayed hyaluronidase (HAase) inhibitory activity in a dose-dependent manner with the values of 8.31, 24.25, and 66.51% at concentrations of 1.00, 2.00, and 4 0.00 mg/mL, respectively. Eight potential compounds targeting HAase (compounds 9, 10, 11, 13, 15, 17, 20 and 21) from CME were screened using ultrafiltration affinity liquid chromatography coupled with mass spectrometry (UF-LC-MS) technology. The well-known inhibitor, dipotassium glycyrrhizinate (DG), was used as a positive control and competitive ligand to eliminate false positives. Then, four of these potential components (compounds 9, 10, 17, and 21), namely eriodictyol-7-O-glucoside, luteoloside, apigenin-7-O-glucoside and diosmetin-7-O-glucoside, were distinguished as potent HAase specific inhibitor candidates with high BD and CBD values. The enzyme inhibitory activities of candidate compounds were verified using enzyme inhibition assay. At a concentration of 1000 μM, compounds 9, 10, 17, and 21 showed 40.15, 44.85, 18.04, and 24.15% inhibition of HAase, respectively. Furthermore, all the four compounds significantly decreased the production of nitric oxide (NO) and IL-6, and significantly suppressed the mRNA expression of inducible NO synthase (iNOS) and IL-1β in both murine and human macrophages.

This study was aiming at the differences in the aroma, flavor compounds, and bioactivities of essential oil of Coreopsis tinctoria flower (CTFEO) and essential oil of Chrysanthemum morifolium flower (CMFEO). Both essential oils were extracted by steam distillation. Their flavor compositions were determined by GC-MS and the antioxidant, antibacterial, and anti-inflammatory activities were also evaluated. It was found that CTFEO possessed a special medicinal herb odor, which was obviously stronger than those of CMFEO. A preferred condition for steam distillation was flower powder–water ratio of 7.5:100 and extraction for more than 3.0 h. Interestingly, the main flavor compounds of CTFEO were determined as D-limonene (34.54%), cis-carveol (5.49%), trans-α-bergamotene (4.44%), and α-pinene (3.90%), which were quite different from those of CMFEO. CTFEO showed better antioxidant activities with IC50 value of 121.4 ± 9.8 μg/mL than those of CMFEO. It also exhibited stronger antibacterial effects than those of CMFEO, with minimal inhibitory concentrations (MICs) ranging from 0.183 to 1.412 mg/mL against six strains of bacteria. Moreover, CTFEO was also found to exhibit strong anti-inflammatory effects that reduced the LPS-induced RAW 264.7 cell mRNA expression of the cytokines IL-1β, IL-6, and TNF-α at a concentration of 10.0 μg/mL. All these results suggest that the aroma, flavor compounds, and bioactivities of the two essential oils were quite different and they could be used as tea, drink, and food additive in the food industry for further development. [ABSTRACT FROM AUTHOR]

SUMMARY: Petals are the second floral whorl of angiosperms, exhibiting astonishing diversity in their size between and within species. This variation is essential for protecting their inner reproductive organs and attracting pollinators for fertilization. However, currently, the genetic and developmental control of petal size remains unexplored. Chrysanthemum (Chrysanthemum morifolium) belongs to the Asteraceae family, the largest group of angiosperms, and the extraordinary diversity of petal size in chrysanthemums makes it an ideal model for exploring the regulation mechanism of petal size. Here, we reveal that overexpression of a JAZ repressor CmJAZ1‐like exhibits decreased petal size compared to that of the wild‐type as a result of repressed cell expansion. Through further in‐depth exploration, we confirm an interaction pair between CmJAZ1‐like and the bHLH transcription factor CmBPE2. The inhibition of CmBPE2 expression negatively regulates petal size by downregulating the expression of genes involved in cell expansion. Furthermore, CmJAZ1‐like significantly reduced the activation ability of CmBPE2 on its target gene CmEXPA7 by directly interacting with it, thus participating in the regulation of petal size development in chrysanthemum. Our results will provide insights into the molecular mechanisms of petal size regulation in flowering plants. Significance Statement: This work is concerned with an important finding: CmJAZ1‐like interacts with CmBPE2 to repress its activation for CmEXPA7, thereby forming an antagonistic system to regulate chrysanthemum petal size. The regulation mediated by this interaction pair has not been identified in other plant species. The present study may potentially contribute to our understanding of the molecular mechanisms underlying petal growth in flowering plants. [ABSTRACT FROM AUTHOR]

SUMMARY: Chrysanthemum (Chrysanthemum morifolium) is well known as a photoperiod‐sensitive flowering plant. However, it has also evolved into a temperature‐sensitive ecotype. Low temperature can promote the floral transition of the temperature‐sensitive ecotype, but little is known about the underlying molecular mechanisms. Here, we identified MADS AFFECTING FLOWERING 2 (CmMAF2), a putative MADS‐box gene, which induces floral transition in response to low temperatures independent of day length conditions in this ecotype. CmMAF2 was shown to bind to the promoter of the GA biosynthesis gene CmGA20ox1 and to directly regulate the biosynthesis of bioactive GA1 and GA4. The elevated bioactive GA levels activated LEAFY (CmLFY) expression, ultimately initiating floral transition. In addition, CmMAF2 expression in response to low temperatures was directly activated by CmC3H1, a CCCH‐type zinc‐finger protein upstream. In summary, our results reveal that the CmC3H1–CmMAF2 module regulates flowering time in response to low temperatures by regulating GA biosynthesis in the temperature‐sensitive chrysanthemum ecotype. Significance Statement: Chrysanthemum (Chrysanthemum morifolium) is well known as a photoperiod‐sensitive flowering plant. However, it has also evolved a temperature‐sensitive ecotype whose regulatory mechanisms of flowering remain largely unknown. We show that the C3H1–MAF2 module contributes to floral transition by regulating the GA–LFY pathway. This study contributes to development of flowering time regulation technologies and breeding of new energy‐saving chrysanthemum cultivars. [ABSTRACT FROM AUTHOR]

As an ingredient in various foods, Chrysanthemum morifolium flower is popular due to its multiple health benefits. Pyrrolizidine alkaloids (PAs) are hepatotoxic secondary metabolites in Chrysanthemum family. Effects of high-pressure extraction (HPE) on PAs removal efficiency, as well as the retention efficiency of functional components, including chlorogenic acid, luteolin-7-β-D-glucopyranoside, 3,5-dicaffeyl quinic acid and total flavonoids, were investigated and optimized using response surface methodology (RSM). Pressure (0.1–200 MPa), numbers of cycles (1–5) and acetic acid concentration (0–10%) were chosen as the independent variables. The results indicated that the pressure was the most significant factors affecting all responses. The optimum HPE for removing Pas and retaining functional components were set at 124 MPa, with one cycle and with an acetic acid concentration of 10%. After comparing the experimental optimum values and predicted optimum values, the validity of RSM model was proved. [ABSTRACT FROM AUTHOR]

Background: Chrysanthemum virus B (CVB), a key member of the genus Carlavirus, family Betaflexiviridae, causes severe viral diseases in chrysanthemum (Chrysanthemum morifolium) plants worldwide. However, information on the mechanisms underlying the response of chrysanthemum plants to CVB is scant. Methods: Here, an integrated next-generation sequencing and comparative transcriptomic analysis of chrysanthemum leaves was conducted to explore the molecular response mechanisms of plants to a Chinese isolate of CVB (CVB-CN) at the molecular level. Results: In total, 4934 significant differentially expressed genes (SDEGs) were identified to respond to CVB-CN, of which 4097 were upregulated and 837 were downregulated. Gene ontology and functional classification showed that the majority of upregulated SDEGs were categorized into gene cohorts involved in plant hormone signal transduction, phenylpropanoid and flavonoid biosynthesis, and ribosome metabolism. Enrichment analysis demonstrated that ethylene pathway-related genes were significantly upregulated following CVB-CN infection, indicating a strong promotion of ethylene biosynthesis and signaling. Furthermore, disruption of the ethylene pathway in Nicotiana benthamiana, a model plant, using virus-induced gene silencing technology rendered them more susceptible to cysteine-rich protein of CVB-CN induced hypersensitive response, suggesting a crucial role of this pathway in response to CVB-CN infection. Conclusion: This study provides evidence that ethylene pathway has an essential role of plant in response to CVB and offers valuable insights into the defense mechanisms of chrysanthemum against Carlavirus. [ABSTRACT FROM AUTHOR]

Chrysanthemum × morifolium Ramat. is a famous perennial herb with medicinal, edible, and ornamental purposes, but the occurrence of plant diseases can reduce its value. A serious disease that caused leaf spots in C. morifolium appeared in 2022 in Tongxiang City, Zhejiang Province, China. The C. morifolium leaves with brown spots were collected and used for pathogen isolation. By completing Koch’s postulates, it was proven that the isolate had pathogenicity to infect C. morifolium. It was determined that the pathogen isolated from chrysanthemum leaves was Nigrospora oryzae, through morphology and a multilocus sequence analysis method using a combination of the internal transcribed spacer gene (ITS), beta-tubulin gene (TUB2), and translation elongation factor 1-alpha gene (TEF1-α). This is the first report of C. morifolium disease caused by N. oryzae in the world. Through dual culture assay on PDA plates, 12 strains of bacteria with antagonistic effects were selected from 231 strains from the C. morifolium phyllosphere, among which Bacillus siamensis D65 had the best inhibitory effect on N. oryzae growth. In addition, the components of a strain D65 fermentation broth were profiled by SPME-GC-Q-TOF analysis, providing a foundation for further application and research of biological control.

Chrysanthemum is one of the most commercially used ornamental flowering plants in the world. As chrysanthemum is self-incompatible, the propagation of identical varieties is carried out through cuttings rather than through seed. Axillary bud development can be controlled by changing the temperature; for instance, axillary bud development in some varieties is suppressed at high temperatures. In this study, we focused on the simultaneous axillary bud growth from multiple lines of chrysanthemum upon changing conditions from low to normal temperature. Transcriptome analysis was conducted on the Chrysanthemum morifolium cultivar ’Jinba’ to identify the important genes for axillary bud development seen when moved from low-temperature treatment to normal cultivation temperature. We performed RNA-Seq analysis on plants after cold conditions in two-day time-course experiments. Under these settings, we constructed a transcriptome of 415,923 C. morifolium and extracted 7357 differentially expressed genes. Our understanding of Arabidopsis axillary meristem development and growth showed that at least 101 genes in our dataset were homologous to transcription factors involved in the biological process. In addition, six genes exhibited statistically significant variations in expression throughout conditions. We hypothesized that these genes were involved in the formation of axillary buds in C. morifolium after cold conditions.