Anthocyanins in Floral Colors: Biosynthesis and Regulation in Chrysanthemum Flowers

Characterization of key genes in anthocyanin and flavonoid biosynthesis during floral development in Rosa canina L

This study investigates the transition of Rosa canina L. petals from pink to white, driven by genetic and biochemical factors. It characterizes the expression of ten key genes involved in anthocyanin and flavonoid biosynthesis across five developmental stages, correlating gene expression with flavonoid and anthocyanin concentrations and colorimetric changes. Initially, the petals exhibit a rich flavonoid profile, dominated by Rutin and Kaempferol derivatives. The peak anthocyanin concentration, corresponding to the deepest color saturation, occurs in the subsequent stage. Advanced chromatographic analyses identify key flavonoids persisting into the final white petal stage. Notably, the ANS gene shows a dramatic 137.82-fold increase in expression at the final stage, indicating its crucial role in petal color maturation despite the absence of visible pigmentation. The study provides a comprehensive characterization of the genetic and biochemical mechanisms underlying petal pigmentation, suggesting that reduced anthocyanin synthesis and increased flavonol concentration led to white petals. It also highlights the roles of other genes such as PAL, CCD1, FLS, CHI, CHS, UFGT, F3H, DFR, and RhMYB1, indicating that post-translational modifications and other regulatory mechanisms may influence anthocyanin stability and degradation.

Floral Response to Heat: A Study of Color and Biochemical Adaptations in Purple Chrysanthemums

Chrysanthemums are among the world's most popular cut flowers, with their color being a key ornamental feature. The formation of these colors can be influenced by high temperatures. However, the regulatory mechanisms that control the fading of chrysanthemum flower color under high-temperature stress remain unclear. This study investigates the impact of high temperatures on the color and biochemical responses of purple chrysanthemums. Four purple chrysanthemum varieties were exposed to both normal and elevated temperature conditions. High-temperature stress elicited distinct responses among the purple chrysanthemum varieties. 'Zi Feng Che' and 'Chrystal Regal' maintained color stability, whereas 'Zi Hong Tuo Gui' and 'Zi lian' exhibited significant color fading, particularly during early bloom stages. This fading was associated with decreased enzymatic activities, specifically of chalcone isomerase (CHI), dihydroflavonol 4-reductase (DFR), and anthocyanidin synthase (ANS), indicating a critical period of color development under heat stress. Additionally, the color fading of 'Zi Lian' was closely related to the increased activity of the peroxidase (POD) and polyphenol oxidase (PPO). Conversely, a reduction in β-glucosidase (βG) activity may contribute significantly to the color steadfastness of 'Zi Feng Che'. The genes Cse_sc027584.1_g010.1 (PPO) and Cse_sc031727.1_g010.1 (POD) might contribute to the degradation of anthocyanins in the petals of 'Zi Hong Tuo Gui' and 'Zi Lian' under high-temperature conditions, while simultaneously maintaining the stability of anthocyanins in 'Zi Feng Che' and 'Chrystal Regal' at the early bloom floral stage. The findings of this research provide new insights into the physiological and biochemical mechanisms by which chrysanthemum flower color responds to high-temperature stress.

Natural biosynthesis, pharmacological applications, and sustainable biotechnological production of ornamental plant-derived anthocyanin: beyond colorants and aesthetics

Flowers have long been admired for their aesthetic qualities and have even found their way to be included in the human diet. Among the many chemical compounds found in flowers, anthocyanins stand out for their versatile applications in the food, cosmetic, and nutraceutical industries. The biosynthetic pathway of anthocyanins has been thoroughly studied in certain flower species, leading to the detection of key regulatory genes that can be controlled to enhance the production of anthocyanins via biotechnological methods. Nevertheless, the quantity and form of anthocyanins found in natural sources differ, both qualitatively and quantitatively, depending on the ornamental plant species. For this reason, research on in vitro plant cultures has been conducted for years in an attempt to comprehend how these essential substances are produced. Different biotechnological systems, like in vitro plant cell, organ, and tissue cultures, and transgenic approaches, have been employed to produce anthocyanins under controlled conditions. However, multiple factors influence the production of anthocyanins and create challenges during large-scale production. Metabolic engineering techniques have also been utilized for anthocyanin production in microorganisms and recombinant plants. Although these techniques are primarily tested at lab- and pilot-scale, limited studies have focused on scaling up the production. This review analyses the chemistry and biosynthesis of anthocyanin along with the factors that influence the biosynthetic pathway. Further emphasis has been given on strategies for conventional and non-conventional anthocyanin production along with their quantification, addressing the prevailing challenges, and exploring ways to ameliorate the production using the in vitro plant cell and tissue culture systems and metabolic engineering to open up new possibilities for the cosmetic, pharmaceutical, and food industries.

Genome assembly and multi-omic analyses reveal the mechanisms underlying flower color formation in Torenia fournieri

Torenia fournieri Lind. is an ornamental plant that is popular for its numerous flowers and variety of colors. However, its genomic evolutionary history and the genetic and metabolic bases of flower color formation remain poorly understood. Here, we report the first T. fournieri reference genome, which was resolved to the chromosome scale and was 164.4 Mb in size. Phylogenetic analyses clarified relationships with other plant species, and a comparative genomic analysis indicated that the shared ancestor of T. fournieri and Antirrhinum majus underwent a whole genome duplication event. Joint transcriptomic and metabolomic analyses identified many metabolites related to pelargonidin, peonidin, and naringenin production in rose (TfR)-colored flowers. Samples with blue (TfB) and deep blue (TfD) colors contained numerous derivatives of petunidin, cyanidin, quercetin, and malvidin; differences in the abundances of these metabolites and expression levels of the associated genes were hypothesized to be responsible for variety-specific differences in flower color. Furthermore, the genes encoding flavonoid 3-hydroxylase, anthocyanin synthase, and anthocyanin reductase were differentially expressed between flowers of different colors. Overall, we successfully identified key genes and metabolites involved in T. fournieri flower color formation. The data provided by the chromosome-scale genome assembly establish a basis for understanding the differentiation of this species and will facilitate future genetic studies and genomic-assisted breeding.

Genome-Wide Analysis of MYB Gene Family in Chrysanthemum ×morifolium Provides Insights into Flower Color Regulation

MYBs constitute the second largest transcription factor (TF) superfamily in flowering plants with substantial structural and functional diversity, which have been brought into focus because they affect flower colors by regulating anthocyanin biosynthesis. Up to now, the genomic data of several Chrysanthemum species have been released, which provides us with abundant genomic resources for revealing the evolution of the MYB gene family in Chrysanthemum species. In the present study, comparative analyses of the MYB gene family in six representative species, including C. lavandulifolium, C. seticuspe, C. ×morifolium, Helianthus annuus, Lactuca sativa, and Arabidopsis thaliana, were performed. A total of 1104 MYBs, which were classified into four subfamilies and 35 lineages, were identified in the three Chrysanthemum species (C. lavandulifolium, C. seticuspe, and C. ×morifolium). We found that whole-genome duplication and tandem duplication are the main duplication mechanisms that drove the occurrence of duplicates in CmMYBs (particularly in the R2R3-MYB subfamily) during the evolution of the cultivated chrysanthemums. Sequence structure and selective pressure analyses of the MYB gene family revealed that some of R2R3-MYBs were subjected to positive selection, which are mostly located on the distal telomere segments of the chromosomes and contain motifs 7 and 8. In addition, the gene expression analysis of CmMYBs in different organs and at various capitulum developmental stages of C. ×morifolium indicated that CmMYBS2, CmMYB96, and CmMYB109 might be the negative regulators for anthocyanin biosynthesis. Our results provide the phylogenetic context for research on the genetic and functional evolution of the MYB gene family in Chrysanthemum species and deepen our understanding of the regulatory mechanism of MYB TFs on the flower color of C. ×morifolium.

Cloned genes and genetic regulation of anthocyanin biosynthesis in maize, a comparative review

Anthocyanins are plant-based pigments that are primarily present in berries, grapes, purple yam, purple corn and black rice. The research on fruit corn with a high anthocyanin content is not sufficiently extensive. Considering its crucial role in nutrition and health it is vital to conduct further studies on how anthocyanin accumulates in fruit corn and to explore its potential for edible and medicinal purposes. Anthocyanin biosynthesis plays an important role in maize stems (corn). Several beneficial compounds, particularly cyanidin-3-O-glucoside, perlagonidin-3-O-glucoside, peonidin 3-O-glucoside, and their malonylated derivatives have been identified. C1, C2, Pl1, Pl2, Sh2, ZmCOP1 and ZmHY5 harbored functional alleles that played a role in the biosynthesis of anthocyanins in maize. The Sh2 gene in maize regulates sugar-to-starch conversion, thereby influencing kernel quality and nutritional content. ZmCOP1 and ZmHY5 are key regulatory genes in maize that control light responses and photomorphogenesis. This review concludes the molecular identification of all the genes encoding structural enzymes of the anthocyanin pathway in maize by describing the cloning and characterization of these genes. Our study presents important new understandings of the molecular processes behind the manufacture of anthocyanins in maize, which will contribute to the development of genetically modified variants of the crop with increased color and possible health advantages.

Integrative metabolome and transcriptome analyses reveal the coloration mechanism in Camellia oleifera petals with different color

BACKGROUND

Camellia olelfera petals are colorful, and have high ornamental value. However, the color formation mechanism of C. olelfera petals with different color is still unclear. In our study, WGCNA method was applied to integrate metabolites and transcriptomes to investigate the coloration mechanism of four C. olelfera cultivars with different petal colors.

RESULTS

Here, a total of 372 flavonoids were identified (including 27 anthocyanins), and 13 anthocyanins were significantly differentially accumulated in C. olelfera petals. Among them, cyanidin-3-O-(6''-O-p-Coumaroyl) glucoside was the main color constituent in pink petals, cyanidin-3-O-glucoside, cyanidin-3-O-galactoside, cyanidin-3-O-rutinoside, and cyanidin-3-O-(6''-O-malonyl) glucoside were the main contributors to candy pink petals, and peonidin-3-O-glucoside was the important color substance responsible for the red petals of C. oleifera. Furthermore, six structural genes (Co4CL1, CoF3H1, CoF3'H, CoANS, CoUGT75C1-4, and CoUGT75C1-5), three MYBs (CoMYB1, CoMYB4, and CoMYB44-3), three bHLHs (CobHLH30, CobHLH 77, and CobHLH 79-1), and two WRKYs (CoWRKY7 and CoWRKY22) could be identified candidate genes related to anthocyanins biosynthesis and accumulation, and lead to the pink and red phenotypes. The regulatory network of differentially accumulated anthocyanins and the anthocyanins related genes in C. olelfera petals were established.

CONCLUSIONS

These findings elucidate the molecular basis of the coloration mechanisms of pink and red color in C. olelfera petals, and provided valuable target genes for future improvement of petals color in C. olelfera.

Coloration differences in three Camellia reticulata Lindl. cultivars: 'Tongzimian', 'Shizitou' and 'Damanao'

Camellia reticulata Lindl., also known as Yunnan Camellia, is an important ornamental plant in China, especially for its large and stunning flowers. A comprehensive understanding of their coloration mechanisms can aid breeders in developing new cultivars and improving their ornamental value; however, it is still unclear in Yunnan Camellia, especially in mixed-color flowers. In this study, we conducted metabolic and transcriptomic comparison analyses to investigate the coloration differences in three Yunnan Camellia cultivars: C. reticulata 'Shizitou' (SZT), C. reticulata 'Damanao' (MN), and C. reticulata 'Tongzimian' (TZM). Our results revealed that the initial flowering stage may play a critical role in the color change of MN. Metabolome analysis demonstrated that cyanidin was the primary anthocyanin in SZT and MN's red region, while its content was low in TZM and MN's white region. According to the transcriptome analysis, the anthocyanins biosynthesis pathway was reconstructed in Yunnan Camellia, and the low expression of CHS was detected in TZM and MN's white region, while ANR maintained a high expression level, which may lead to the low content of cyanidin in them. Transcription factors MYBs, bHLH, and bZIP may play a key role in regulating anthocyanin-structural genes. The co-expression analysis showed that the meristem tissue may play a crucial role in the formation of the mixed white-red color in MN. Our study enriched the genetic basis of flower coloration differences in Yunnan Camellia which will be a valuable genomic resource to understanding the biology of coloration formation and for breeding the Camellia cultivars.

Sucrose-delaying flower color fading associated with delaying anthocyanin accumulation decrease in cut chrysanthemum

As fresh ornamental crops, vase life and post-harvested quality of cut flowers have attracted much attention. Flower color fading is the prominent defect in red and purple cut flowers, especially in cut chrysanthemum which have a relative long vase life. Here, the effect of sucrose on change in anthocyanin contents during the vase life of 'Dante Purple' cut chrysanthemum was studied. Results showed that 500 mM sucrose as holding solution could significantly delay the decrease in anthocyanin content and maintain the ornamental value for as long as 38 vase days. Moreover, the sucrose also increased the flower diameter, soluble sugar contents and total antioxidant capacity, while decreasing the malondialdehyde contents. Further studies suggested that the transcript levels of anthocyanin biosynthetic genes and transcription factors, CmMYB6 and CmMYB#7, had continuously decreased during the vase life. The changes in these genes expression patterns was retarded by the sucrose treatment, except for CmMYB#7 which is a repressor of anthocyanin biosynthesis gene expression. The decline in relative expression of CmMYB#7 was accelerated by sucrose. These results have supplied clues to study the mechanism whereby sucrose serves as a signal molecule to regulate anthocyanin biosynthesis.

Chromosome-level genome assembly and annotation of Zicaitai (Brassica rapa var. purpuraria)

Zicaitai is a seasonal vegetable known for its high anthocyanin content in both stalks and leaves, yet its reference genome has not been published to date. Here, we generated the first chromosome-level genome assembly of Zicaitai using a combination of PacBio long-reads, Illumina short-reads, and Hi-C sequencing techniques. The final genome length is 474.12 Mb with a scaffold N50 length of 43.82 Mb, a BUSCO score of 99.30% and the LAI score of 10.14. Repetitive elements accounted for 60.89% (288.72 Mb) of the genome, and Hi-C data enabled the allocation of 430.87 Mb of genome sequences to ten pseudochromosomes. A total of 42,051 protein-coding genes were successfully predicted using multiple methods, of which 99.74% were functionally annotated. Notably, comparing the genome of Zicaitai with seven other species in the Cruciferae family revealed strong conservation in terms of gene numbers and structures. Overall, the high-quality genome assembly provides a critical resource for studying the genetic basis of important agronomic traits in Zicaitai.

Designing of future ornamental crops: a biotechnological driven perspective

With a basis in human appreciation of beauty and aesthetic values, the new era of ornamental crops is based on implementing innovative technologies and transforming symbols into tangible assets. Recent advances in plant biotechnology have attracted considerable scientific and industrial interest, particularly in terms of modifying desired plant traits and developing future ornamental crops. By utilizing omics approaches, genomic data, genetic engineering, and gene editing tools, scientists have successively explored the underlying molecular mechanism and potential gene(s) behind trait regulation such as floral induction, plant architecture, stress resistance, plasticity, adaptation, and phytoremediation in ornamental crop species. These signs of progress lay a theoretical and practical foundation for designing and enhancing the efficiency of ornamental plants for a wide range of applications. In this review, we briefly summarized the existing literature and advances in biotechnological approaches for the improvement of vital traits in ornamental plants. The future ornamental plants, such as light-emitting plants, biotic/abiotic stress detectors, and pollution abatement, and the introduction of new ornamental varieties via domestication of wild species are also discussed.

Low LdMYB12 expression contributes to petal spot deficiency in Lilium davidii var. unicolor

Petal spots are widespread in plants, they are important for attracting pollinators and as economic traits in crop breeding. However, the genetic and developmental control of petal spots has seldom been investigated. To further clarify the development of petal spots formation, we performed comparative transcriptome analysis of Lilium davidii var. unicolor and Lilium davidii petals at the full-bloom stage. In comparison with the parental species L. davidii, petals of the lily variety L. davidii var. unicolor do not have the distinct anthocyanin spots. We show that among 7846 differentially expressed genes detected, LdMYB12 was identified as a candidate gene contributing to spot formation in lily petals. The expression level of LdMYB12 in the petals of L. davidii was higher than that in L. davidii var. unicolor petals. Moreover, overexpression of LdMYB12 led to the appearance of spots on the petals of L. davidii var. unicolor, accompanied by increased expression of anthocyanin synthesis-related genes. Taken together, these results indicate that abnormal expression of LdMYB12 contributes to petal spot deficiency in L. davidii var. unicolor.

Metabolomics Analysis Reveals the Accumulation Patterns of Flavonoids and Volatile Compounds in Camellia oleifera Petals with Different Color

To systematically and comprehensively investigate the metabolic characteristics of coloring substances and floral aroma substances in Camellia oleifera petals with different colors, ultrahigh-performance liquid chromatography-mass spectrometry (UPLC-MS/MS) and headspace solid phase microextraction and gas chromatography-mass spectrometry (HS-SPME-GC-MS) metabolomics methods were applied to determine the metabolic profiles of white, candy-pink and dark-red petals. The results revealed that 270 volatile organic compounds were detected, mainly terpenoids, heterocyclic, esters, hydrocarbons, aldehydes, and alcohols, in which phenylethyl alcohol, lilac alcohol, and butanoic acid, 1-methylhexyl ester, hotrienol, alpha-terpineol and 7-Octen-4-ol, 2-methyl-6-methylene-, (S)-, butanoic acid, 2-methyl-, 2-methylbutyl ester, 2,4-Octadienal, (E,E)- could act as the floral scent compounds. A total of 372 flavonoid compounds were identified, and luteolin, kaempferol, cyanidin and peonidin derivatives were considered as the main coloring substances for candy-pink and dark-red petal coloration. In conclusion, this study intuitively and quantitatively exhibited the variations in flower color and floral scent of C. oleifera petal with different colors caused by changes in variations of flavonoids and volatile organic compound composition, and provided useful data for improving the sensory quality and breeding of C. oleifera petals.

A Green Approach to Natural Dyes in Dye-Sensitized Solar Cells

Solar cells are pivotal in harnessing renewable energy for a greener and more sustainable energy landscape. Nonetheless, eco-friendly materials for solar cells have not been as extensive as conventional counterparts, highlighting a significant area for further investigation in advancing sustainable energy technologies. This study investigated natural dyes from cost-effective and environmentally friendly blueberries and mulberries. These dyes were utilized as alternative sensitizers for dye-sensitized solar cells (DSSCs). Alongside the natural dyes, a green approach was adopted for the DSSC design, encompassing TiO2 photoanodes, eco-friendly electrolytes, and green counter-electrodes created from graphite pencils and candle soot. Consequently, the best-optimized dye sensitizer was mulberry, with an output power of 13.79 µW and 0.122 µW for outdoor and indoor environments, respectively. This study underscored the feasibility of integrating DSSCs with sensitizers derived from readily available food ingredients, potentially expanding their applications in educational kits and technology development initiatives.

Integrated Metabolome and Transcriptome Analysis of Petal Anthocyanin Accumulation Mechanism in Gloriosa superba 'Rothschildiana' during Different Flower Development Stages

Flower color is a key ornamental trait in plants. The petals of Gloriosa superba 'Rothschildiana' petals undergo a color transformation from yellow to red during their development, but the molecular mechanism of this process remains unexplored. This study examines the anthocyanin profiles and gene expression patterns of 'Rothschildiana' petals across four developmental stages: bud (S1), initial opening (S2), half opening (S3), and full opening stage (S4). A total of 59 anthocyanins were identified with significant increases in cyanidin-3,5-O-diglucoside, cyanidin-3-O-glucoside, pelargonidin-3-O-glucoside, and pelargonidin-3,5-O-diglucoside levels observed during petal maturation. Transcriptome analysis revealed 46 differentially expressed genes implicated in flavonoid and anthocyanin biosynthesis. Additionally, three gene modules were found to be associated with anthocyanin accumulation throughout flower development. Expression levels of genes associated with auxin, abscisic acid, brassinosteroid signaling, and transcription factors such as NACs and WRKYs underwent significant changes and exhibited strong correlations with several flavonoid and anthocyanin biosynthetic genes in these modules. These findings offer novel insights into the molecular underpinnings of flower color variation and lay the groundwork for the improvement of G. superba.

Phytochemicals, therapeutic benefits and applications of chrysanthemum flower: A review

Chrysanthemum is a flowering plant belonging to a genus of the dicotyledonous herbaceous annual flowering plant of the Asteraceae (Compositae) family. It is a perpetual flowering plant, mostly cultivated for medicinal purposes; generally, used in popular drinks due to its aroma and flavor. It is primarily cultivated in China, Japan, Europe, and United States. These flowers were extensively used in various healthcare systems and for treating various diseases. Chrysanthemum flowers are rich in phenolic compounds and exhibit strong properties including antioxidant, antimicrobial, anti-inflammatory, anticancer, anti-allergic, anti-obesity, immune regulation, hepatoprotective, and nephroprotective activities. The main aim of the present review was to investigate the nutritional profile, phytochemistry, and biological activities of flowers of different Chrysanthemum species. Also, a critical discussion of the diverse metabolites or bioactive constituents of the Chrysanthemum flowers is highlighted in the present review. Moreover, the flower extracts of Chrysanthemum have been assessed to possess a rich phytochemical profile, including compounds such as cyanidin-3-O-(6″-O-malonyl) glucoside, delphinidin 3-O-(6" -O-malonyl) glucoside-3', rutin, quercetin, isorhamnetin, rutinoside, and others. These profiles exhibit potential health benefits, leading to their utilization in the production of supplementary food products and pharmaceutical drugs within the industry. However, more comprehensive research studies/investigations are still needed to further discover the potential benefits for human and animal utilization.

Characterization Variation of the Differential Coloring Substances in Rapeseed Petals with Different Colors Using UPLC-HESI-MS/MS

Rapeseed's (Brassica napus L.) colorful petals have important ornamental values. However, the mechanisms of regulating petals coloration in rapeseed are still unknown. In our study, we investigated the key differential coloring substances in nine rapeseed cultivars with different petal colors, and 543 metabolites were detected and characterized through UPLC-HESI-MS/MS. Among them, the kinds and contents of flavonols, flavones, and anthocyanidins were the main contributors to petals' coloration. Tamarixetin-, quercetin-, butin-, naringenin- and luteolin-derivates were the main pigment bases in white and yellow petals. Peonidin-3,5-O-diglucoside, peonidin-3-O-(6″-O-caffeoyl)glucoside, and quercetin-derivatives were the main coloring substances in pink petals. Acylated cyanidin derivatives might lead to a series of different purple petal colors. Glycosylated anthocyanins were responsible for the coloration of rapeseed red petals, and peonidin-3-O-glucoside and kaempferol-derivatives were mainly detected from the red petals. These results provide comprehensive insights into the difference in flavonoid metabolites in rapeseed petals with different colors and supply theoretical supports for the breeding of novel colorful rapeseed cultivars.

Involvement of a MYB Transcription Factor in Anthocyanin Biosynthesis during Chinese Bayberry (Morella rubra) Fruit Ripening

Anthocyanin is a class of water-soluble flavonoids found in Chinese bayberry (Morella rubra) that is not only responsible for the variety of colors visible in nature but also has numerous health-promoting benefits in humans. Through comparative transcriptomics, we isolated and identified a transcription factor (TF) of the R2R3-MYB type, MrMYB9, in order to explore the anthocyanin biosynthesis pathway in red and white Chinese bayberries. MrMYB9 transcript was positively correlated with anthocyanin level and anthocyanin biosynthetic gene expression during Chinese bayberry fruit maturation (R-values in the range 0.54-0.84, p < 0.05). Sequence analysis revealed that MrMYB9 shared a similar R2R3 domain with MYB activators of anthocyanin biosynthesis in other plants. MrMYB9 substantially transactivated promoters of anthocyanin biosynthesis-related EBGs (MrCHI, MrF3'H, and MrANS) and LBGs (MrUFGT) upon co-expression of the AtEGL3 gene. Our findings indicated that MrMYB9 may positively modulate anthocyanin accumulation in Chinese bayberry.

PlgMYBR1, an R2R3-MYB transcription factor, plays as a negative regulator of anthocyanin biosynthesis in Platycodon grandiflorus

Floral color plays a major role in pollinator specificity, and changes in color may result in pollinator shifts and pollinator-mediated speciation. In the purple flowers of Platycodon grandiflorus, anthocyanins are the major pigment metabolites, whereas white flowers result due to the absence of anthocyanins. The lack of anthocyanins may be due to the inhibition of the anthocyanin biosynthesis pathway. However, the molecular mechanism of anthocyanin biosynthesis in P. grandiflorus is not fully understood. Hence, we identified R2R3-MYB transcription factor, PlgMYBR1, as a negative regulator for anthocyanin biosynthesis using sequence homology and tissue-specific expression pattern analyses. A heterologous co-expression assay suggested that PlgMYBR1 inhibited the function of AtPAP1 (Arabidopsis thaliana production of anthocyanin pigment 1), indicating that PlgMYBR1 plays as a repressor of anthocyanin biosynthesis in P. grandiflorus. Our results provide a foundation for future efforts to understand the anthocyanin biosynthesis in P. grandiflorus and, thereby, to improve flower color through genetic engineering.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-023-03490-6.

Green synthesis of ZnFe2O4@ZnO nanocomposites using Chrysanthemum spp. floral waste for photocatalytic dye degradation

The occurrence of textile dyeing wastewater discharged into the environment has been recently increasing, resulting in harmful effects on living organisms and human health. The use of green nanoparticles for water decontamination has received much attention. Floral waste can be extracted with the release of natural compounds, which act as reducing and stabilizing agents during the biosynthesis of nanoparticles. Herein, we report the utilization of Chrysanthemum spp. floral waste extract to synthesize green ZnFe₂O₄@ZnO (ZFOZx) nanocomposites for the photocatalytic degradation of Congo red under solar light irradiation. The various molar ratio of ZnFe₂O₄ (0-50%) was incorporated into ZnO nanoparticles. The surface area of green ZFOZx nanocomposites was found to increase (7.41-42.66 m² g^-1) while their band gap energy decreased from 1.98 eV to 1.92 eV. Moreover, the results exhibited the highest Congo red dye degradation efficiency of 94.85% at a concentration of 5.0 mg L^-1, and a catalyst dosage of 0.33 g L^-1. The ^•O₂^- reactive species played a vital role in the photocatalytic degradation of Congo red dye. Green ZFOZ3 nanocomposites had good recyclability with at least three cycles, and an excellent stability. The germination results showed that wastewater treated by ZFOZ3 was safe enough for bean seed germination. We expect that this work contributes significantly to developing novel green bio-based nanomaterials for environmental remediation as well as reducing the harm caused by flower wastes.

UHPLC-QTOF-MS-based untargeted metabolomics and mineral element analysis insight into the geographical differences of Chrysanthemum morifolium Ramat cv. "Hangbaiju" from different origins

Chrysanthemum morifolium Ramat cv. "Hangbaiju" (HBJ), known as one of the "eight flavors of Zhejiang", is commonly used as a classical tea material for both food and medicine over three thousand years in China. The quality of HBJ is closely related to its geographical origins. However, the mechanism underlying the geographical differences of HBJ remains to be elucidated. In this study, an untargeted metabolomic strategy based on UHPLC-QTOF-MS was established to discover the differential metabolites in HBJ samples from four different origins and explore the possible relationship with mineral elements in planting soils by chemometric analysis. Eight compounds were screened and identified as the key differential metabolites in HBJ samples from different origins. Among them, four important pharmacodynamic compounds including L-arginine, rutin, chlorogenic acid and apigenin-7-O-glucoside are the most abundant in HBJ samples from Tongxiang region, which suggests that HBJ planted in Tongxiang has higher medicinal values. Pearson correlation analysis revealed that the contents of soil mineral elements are positively correlated with those of chlorogenic acid, rutin, apigenin-7-O-glucoside in HBJ samples. Furthermore, an interrelationship model based on random forest algorithm was established to successfully predict the contents of differential metabolites in HBJ samples by soil mineral elements. All these results indicated that the contents of differential metabolites in HBJ samples seemed to be affected by soil mineral elements and therefore resulted in the geographical differences of HBJ.

The Flavonoid Biosynthesis and Regulation in Brassica napus: A Review

Brassica napus is an important crop for edible oil, vegetables, biofuel, and animal food. It is also an ornamental crop for its various petal colors. Flavonoids are a group of secondary metabolites with antioxidant activities and medicinal values, and are important to plant pigmentation, disease resistance, and abiotic stress responses. The yellow seed coat, purple leaf and inflorescence, and colorful petals of B. napus have been bred for improved nutritional value, tourism and city ornamentation. The putative loci and genes regulating flavonoid biosynthesis in B. napus have been identified using germplasms with various seed, petal, leaf, and stem colors, or different flavonoid contents under stress conditions. This review introduces the advances of flavonoid profiling, biosynthesis, and regulation during development and stress responses of B. napus, and hopes to help with the breeding of B. napus with better quality, ornamental value, and stress resistances.

Genome-Scale Identification, Classification, and Expression Profiling of MYB Transcription Factor Genes in Cinnamomum camphora

The camphor tree (Cinnamomum camphora (L.) Presl.) is the representative species of subtropical evergreen broadleaved forests in eastern Asia and an important raw material for essential oil production worldwide. Although MYBs have been comprehensively characterized and their functions have been partially resolved in many plants, it has not been explored in C. camphora. In this study, 121 CcMYBs were identified on 12 chromosomes in the whole genome of C. camphora and found that CcMYBs were mainly expanded by segmental duplication. They were divided into 28 subgroups based on phylogenetic analysis and gene structural characteristics. In the promoter regions, numerous cis-acting elements were related to biological processes. Analysis of RNA sequencing data from seven tissues showed that CcMYBs exhibited different expression profiles, suggesting that they have various roles in camphor tree development. In addition, combined with the correlation analysis of structural genes in the flavonoid synthesis pathway, we identified CcMYBs from three subgroups that might be related to the flavonoid biosynthesis pathway. This study systematically analyzed CcMYBs in C. camphora, which will set the stage for subsequent research on the functions of CcMYBs during their lifetime and provide valuable insights for the genetic improvement of camphor trees.

Towards the Improvement of Ornamental Attributes in Chrysanthemum: Recent Progress in Biotechnological Advances

Incessant development and introduction of novel cultivars with improved floral attributes are vital in the dynamic ornamental industry. Chrysanthemum (Chrysanthemum morifolium) is a highly favored ornamental plant, ranking second globally in the cut flower trade, after rose. Development of new chrysanthemum cultivars with improved and innovative modifications in ornamental attributes, including floral color, shape, plant architecture, flowering time, enhanced shelf life, and biotic and abiotic stress tolerance, is a major goal in chrysanthemum breeding. Despite being an economically important ornamental plant, the application of conventional and molecular breeding approaches to various key traits of chrysanthemum is hindered owing to its genomic complexity, heterozygosity, and limited gene pool availability. Although classical breeding of chrysanthemum has resulted in the development of several hundreds of cultivars with various morphological variations, the genetic and transcriptional control of various important ornamental traits remains unclear. The coveted blue colored flowers of chrysanthemums cannot be achieved through conventional breeding and mutation breeding due to technical limitations. However, blue-hued flower has been developed by genetic engineering, and transgenic molecular breeding has been successfully employed, leading to substantial progress in improving various traits. The recent availability of whole-genome sequences of chrysanthemum offers a platform to extensively employ MAS to identify a large number of markers for QTL mapping, and GWAS to dissect the genetic control of complex traits. The combination of NGS, multi-omic platforms, and genome editing technologies has provided a tremendous scope to decipher the molecular and regulatory mechanisms. However, the application and integration of these technologies remain inadequate for chrysanthemum. This review, therefore, details the significance of floral attributes, describes the efforts of recent advancements, and highlights the possibilities for future application towards the improvement of crucial ornamental traits in the globally popular chrysanthemum plant.

C3H Expression Is Crucial for Methyl Jasmonate Induction of Chicoric Acid Production by Echinacea purpurea (L.) Moench Cell Suspension Cultures

Echinacea purpurea (L.) Moench is one of the most economically important medicinal plants, cultivated worldwide for its high medicinal value and with several industrial applications in both pharmaceutical and food industries. Thanks to its various phytochemical contents, including caffeic acid derivatives (CADs), E. purpurea extracts have antioxidant, anti-inflammatory, and immuno-stimulating properties. Among CADs, chicoric acid is one of the most important compounds which have shown important pharmacological properties. The present research was aimed at optimizing the production of chicoric acid in E. purpurea cell culture. Methyl jasmonate (MeJa) at different concentrations and for different duration of treatments was utilized as elicitor, and the content of total polyphenols and chicoric acid was measured. Several genes involved in the chicoric acid biosynthetic pathway were selected, and their expression evaluated at different time points of cell culture growth. This was performed with the aim of identifying the most suitable putative molecular markers to be used as a proxy for the early prediction of chicoric acid contents, without the need of expensive quantification methods. A correlation between the production of chicoric acid in response to MeJa and an increased response to oxidative stress was also proposed.

PhUGT78A22, a novel glycosyltransferase in Paeonia 'He Xie', can catalyze the transfer of glucose to glucosylated anthocyanins during petal blotch formation

BACKGROUND

Flower color patterns play an important role in the evolution and subsequent diversification of flowers by attracting animal pollinators. This interaction can drive the diversity observed in angiosperms today in many plant families such as Liliaceae, Paeoniaceae, and Orchidaceae, and increased their ornamental values. However, the molecular mechanism underlying the differential distribution of anthocyanins within petals remains unclear in Paeonia.

RESULTS

In this study, we used an intersectional hybrid between the section Moutan and Paeonia, hereafter named Paeonia 'He Xie', which has purple flowers with dark purple blotches. After Ultra-high performance liquid chromatography-diode array detector (UPLC-DAD) analysis of blotched and non-blotched parts of petals, we found the anthocyanin content in the blotched part was always higher than that in the non-blotched part. Four kinds of anthocyanins, namely cyanidin-3-O-glucoside (Cy3G), cyanidin-3,5-O-glucoside (Cy3G5G), peonidin-3-O-glucoside (Pn3G), and peonidin-3,5-O-glucoside (Pn3G5G) were detected in the blotched parts, while only Cy3G5G and Pn3G5G were detected in the non-blotched parts. This suggests that glucosyltransferases may play a vital role in the four kinds of glucosylated anthocyanins in the blotched parts. Moreover, 2433 differentially expressed genes (DEGs) were obtained from transcriptome analysis of blotched and non-blotched parts, and a key UDP-glycosyltransferase named PhUGT78A22 was identified, which could use Cy3G and Pn3G as substrates to produce Cy3G5G and Pn3G5G, respectively, in vitro. Furthermore, silencing of PhUGT78A22 reduced the content of anthocyanidin 3,5-O-diglucoside in P. 'He Xie'.

CONCLUSIONS

A UDP-glycosyltransferase, PhUGT78A22, was identified in P. 'He Xie', and the molecular mechanism underlying differential distribution of anthocyanins within petals was elucidated. This study provides new insights on the biosynthesis of different kinds of anthocyanins within colorful petals, and helps to explain petal blotch formation, which will facilitate the cultivar breeding with respect to increasing ornamental value. Additionally, it provides a reference for understanding the molecular mechanisms responsible for precise regulation of anthocyanin biosynthesis and distribution patterns.

The genus Chrysanthemum: Phylogeny, biodiversity, phytometabolites, and chemodiversity

The ecologically and economically important genus Chrysanthemum contains around 40 species and many hybrids and cultivars. The dried capitulum of Chrysanthemum morifolium (CM) Ramat. Tzvel, i.e., Flos Chrysanthemi, is frequently used in traditional Chinese medicine (TCM) and folk medicine for at least 2,200 years. It has also been a popular tea beverage for about 2,000 years since Han Dynasty in China. However, the origin of different cultivars of CM and the phylogenetic relationship between Chrysanthemum and related Asteraceae genera are still elusive, and there is a lack of comprehensive review about the association between biodiversity and chemodiversity of Chrysanthemum. This article aims to provide a synthetic summary of the phylogeny, biodiversity, phytometabolites and chemodiversity of Chrysanthemum and related taxonomic groups, focusing on CM and its wild relatives. Based on extensive literature review and in light of the medicinal value of chrysanthemum, we give some suggestions for its relationship with some genera/species and future applications. Mining chemodiversity from biodiversity of Chrysanthemum containing subtribe Artemisiinae, as well as mining therapeutic efficacy and other utilities from chemodiversity/biodiversity, is closely related with sustainable conservation and utilization of Artemisiinae resources. There were eight main cultivars of Flos Chrysanthemi, i.e., Hangju, Boju, Gongju, Chuju, Huaiju, Jiju, Chuanju and Qiju, which differ in geographical origins and processing methods. Different CM cultivars originated from various hybridizations between multiple wild species. They mainly contained volatile oils, triterpenes, flavonoids, phenolic acids, polysaccharides, amino acids and other phytometabolites, which have the activities of antimicrobial, anti-viral, antioxidant, anti-aging, anticancer, anti-inflammatory, and closely related taxonomic groups could also be useful as food, medicine and tea. Despite some progresses, the genetic/chemical relationships among varieties, species and relevant genera have yet to be clarified; therefore, the roles of pharmacophylogeny and omics technology are highlighted.

HPLC-FLD analysis of amino acids content in Chrysanthemum morifolium

Chrysanthemum morifolium (Asteraceae family) have long been used as a tonic, antioxidant, antipyretic, analgesic, sedative, antitumor, neuroprotector, hepatoprotector and cardioprotector agent. This species should be reconsidered as possible sources of many biocompounds, especially amino acids. Thus, the aim of this study was to validate the chromatographic method for detection of amino acids and their identification in flowers and leaves of Ch. morifolium of variant Pectoral. HPLC-FLD method was evaluated in terms of linearity, precision, repeatability, accuracy, LOD and LOQ. The calibration curves of all analytical standards of amino acids were linear (R2 &gt; 0.99) over the range of 0.015–0.625 μmol/mL, the LODs and the LOQs were in the range of 0.001–0.096 µg/mL and 0.004–0.321 µg/mL, respectively. During the HPLC-FLD assay ten amino acids in free form and fifteen amino acids after hydrolysis in Ch. morifolium flowers were identified. Besides, twelve amino acids were detected in free form and fourteen amino acids after hydrolysis in Ch. morifolium leaves. The results of HPLC-FLD analysis showed that the predominant amino acid was L-proline in both types of herbal raw materials. Its total content was 31.67±0.02 μg/mg in Ch. morifolium flowers and 18.56±0.02 μg/mg in Ch. morifolium leaves. This phytochemical study confirms that flowers and leaves of Ch. morifolium (Pectoral) are rich sources of amino acids and can exhibit a wide range of pharmacological activities.

A Comparative Study of Flavonoids and Carotenoids Revealed Metabolite Responses for Various Flower Colorations Between Nicotiana tabacum L. and Nicotiana rustica L

Tobacco is a model plant for studying flower coloration. Flavonoids and carotenoids were reported to contribute to the flower color in many plants. We investigated the mechanism underlying flower color formation in tobacco by comparing the profiling flavonoids and carotenoids between various species Nicotiana tabacum L. and Nicotiana rustica L., as their flowers commonly presented red (pink) and yellow (orange), respectively. The metabolomes were conducted by UPLC-ESI-MS/MS system. The main findings were as follows: (1) A total of 31 flavonoids and 36 carotenoids were identified in all four cultivars involved in N. tabacum and N. rustica. (2) Flavonoids and carotenoids tended to concentrate in the red flowers (N. tabacum) and yellow flowers (N. rustica), respectively. (3) About eight flavonoids and 12 carotenoids were primarily screened out for metabolic biomarkers, such as the robust biomarker involving kaempferol-3-o-rut, quercetin-glu, rutin, lutein, and β-carotene. This is the first research of systematic metabolome involving both flavonoids and carotenoids in tobacco flower coloration. The metabolic mechanism concluded that flavonoids and carotenoids mainly contributed to red (pink) and yellow (orange) colors of the tobacco flowers, respectively. Our finding will provide essential insights into characterizing species and modifying flower color in tobacco breeding through genetic improvement or regulation of featured metabolic synthesis.

Why Black Flowers? An Extreme Environment and Molecular Perspective of Black Color Accumulation in the Ornamental and Food Crops

Pollinators are attracted to vibrant flower colors. That is why flower color is the key agent to allow successful fruit set in food or ornamental crops. However, black flower color is the least attractive to pollinators, although a number of plant species produce black flowers. Cyanidin-based anthocyanins are thought to be the key agents to induce black color in the ornamental and fruit crops. R2R3-MYB transcription factors (TFs) play key roles for the tissue-specific accumulation of anthocyanin. MYB1 and MYB11 are the key TFs regulating the expression of anthocyanin biosynthesis genes for black color accumulation. Post-transcriptional silencing of flavone synthase II (FNS) gene is the technological method to stimulate the accumulation of cyanidin-based anthocyanins in black cultivars. Type 1 promoter of DvIVS takes the advantage of FNS silencing to produce large amounts of black anthocyanins. Exogenous ethylene application triggers anthocyanin accumulation in the fruit skin at ripening. Environment cues have been the pivotal regulators to allow differential accumulation of anthocyanins to regulate black color. Heat stress is one of the most important environmental stimulus that regulates concentration gradient of anthocyanins in various plant parts, thereby affecting the color pattern of flowers. Stability of black anthocyanins in the extreme environments can save the damage, especially in fruits, caused by abiotic stress. White flowers without anthocyanin face more damages from abiotic stress than dark color flowers. The intensity and pattern of flower color accumulation determine the overall fruit set, thereby controlling crop yield and human food needs. This review paper presents comprehensive knowledge of black flower regulation as affected by high temperature stress, and the molecular regulators of anthocyanin for black color in ornamental and food crops. It also discusses the black color-pollination interaction pattern affected by heat stress for food and ornamental crops.

Integrated transcriptome and metabolome profiling of Camellia reticulata reveal mechanisms of flower color differentiation

Camellia reticulata (Lindl.) is an important ornamental plant in China. Long-term natural or artificial selections have resulted in diverse phenotypes, especially for flower colors. Modulating flower colors can enhance the visual appeal and economic value in ornamental plants. In this study, we investigated the molecular mechanisms underlying flower color differentiation in C. reticulata. We performed a combined transcriptome and metabolome analysis of the petals of a popular variety C. reticulata (HHYC) (red), and its two cultivars "Xuejiao" (XJ) (pink) and "Tongzimian" (TZM) (white). Targeted metabolome profiling identified 310 flavonoid compounds of which 18 anthocyanins were differentially accumulated among the three samples with an accumulation pattern of HHYC > XJ > TZM. Likewise, transcriptome analysis showed that carotenoid and anthocyanin biosynthetic structural genes were mostly expressed in order of HHYC > XJ > TZM. Two genes (gene-LOC114287745765 and gene-LOC114289234) encoding for anthocyanidin 3-O-glucosyltransferase are predicted to be responsible for red coloration in HHYC and XJ. We also detected 42 MYB and 29 bHLH transcription factors as key regulators of anthocyanin-structural genes. Overall, this work showed that flavonoids, particularly anthocyanins contents are the major determinants of flower color differentiation among the 3 C. reticulata samples. In addition, the main regulatory and structural genes modulating anthocyanin contents in C. reticulata have been unveiled. Our results will help in the development of Camellia varieties with specific flower color and quality.

The biochemical and molecular investigation of flower color and scent sheds lights on further genetic modification of ornamental traits in Clivia miniata

Clivia miniata is renowned for its evergreen and strap-like leaves, whereas its floral color and scent are lacking diversity. Here, anthocyanin, volatile terpene, and carotenoid metabolisms were integrally investigated in C. miniata flowers. The results showed that pelargonidins and lutein might cooperate to confer orange or yellow color to C. miniata flowers, but only a trace amount of (+)-limonene was detected. The expression levels of CmF3'H and CmDFR appeared to be responsible for the ratio of cyanidin and pelargonidin derivatives in C. miniata, and the low expression of CmF3'H was responsible for the lack of cyanidins in flowers. Moreover, the CmF3'H promoter could not be activated by CmMYBAs, suggesting that it was controlled by novel regulators. Only two CmTPSs were functional, with CmTPS2 responsible for (+)-limonene synthesis, contributing to the monotonous flower volatile terpenes of C. miniata. CmCCD1a and CmCCD1b were able to cleave carotenoids at the 5,6 (5',6'), and 9,10 (9',10') positions to generate volatile apocarotenoids, whereas the substrates found in low-quantities or specific subcellular localizations of CmCCD1s might constrain volatile apocarotenoid release. Consequently, activating F3'H and introducing novel F3'5'H or versatile TPS may be effective ways to modify the floral color and scent, respectively. Alternatively, modifying the carotenoid flux or CCD1 localization might affect floral color and scent simultaneously. Taking these results together, the present study provides a preliminary deciphering of the genetic constraints underlying flower color and scent development, and proposes possible schemes for further genetic modification of ornamental traits in C. miniata and other plants.

The Compositional Aspects of Edible Flowers as an Emerging Horticultural Product

Edible flowers are becoming very popular, as consumers are seeking healthier and more attractive food products that can improve their diet aesthetics and diversify their dietary sources of micronutrients. The great variety of flowers that can be eaten is also associated with high variability in chemical composition, especially in bioactive compounds content that may significantly contribute to human health. The advanced analytical techniques allowed us to reveal the chemical composition of edible flowers and identify new compounds and effects that were not known until recently. Considering the numerous species of edible flowers, the present review aims to categorize the various species depending on their chemical composition and also to present the main groups of compounds that are usually present in the species that are most commonly used for culinary purposes. Moreover, special attention is given to those species that contain potentially toxic or poisonous compounds as their integration in human diets should be carefully considered. In conclusion, the present review provides useful information regarding the chemical composition and the main groups of chemical compounds that are present in the flowers of the most common species.

Transcriptome-based analysis reveals that the biosynthesis of anthocyanins is more active than that of flavonols and proanthocyanins in the colorful flowers of Lagerstroemia indica

Mechanisms associated with the control of flower color in crape myrtle varieties have yet to be sufficiently elucidated, which has tended to hamper the use of modern molecular and genetic strategies in the breeding programs for this plant. The whole transcriptome of four L. indica varieties characterized by different flower colors (white, light purple, deep purplish pink, and strong red) was sequenced, and we performed bioinformatic, quantitative PCR, and co-expression analyses of R2R3 MYB transcription factor and anthocyanin/flavonol pathway genes. We obtained a total of 49,980 transcripts with full-length coding sequences. Both transcriptome and qPCR analyses revealed that anthocyanin/flavonol pathway genes were differentially expressed among the four different flowers types, with the expression of LiPAL, LiCHS, LiCHI, LiDFR, LiANS/LDOX, and LiUFGT being induced in colorful flowers, whereas that of LiF3´5´H, LiFLS, and LiLAR was found to be inhibited. Base on phylogenetic analysis, seven R2R3 MYB transcriptional factors were identified as putative regulators of flower color. The molecular characteristics and co-expression patterns indicated that these MYBs differentially modulate their target genes, with two probably acting as activators, three as repressors, and one contributing to the regulation of vacuolar pH. The findings of this study indicate that the anthocyanin biosynthesis is more active than the flavonol and proanthocyanin in the colorful flowers. These observations provide new genomic information on L. indica and contribute gene resources for the flower color-targeted breeding of crape myrtle.

Recent Progress in Enhancing Fungal Disease Resistance in Ornamental Plants

Fungal diseases pose a major threat to ornamental plants, with an increasing percentage of pathogen-driven host losses. In ornamental plants, management of the majority of fungal diseases primarily depends upon chemical control methods that are often non-specific. Host basal resistance, which is deficient in many ornamental plants, plays a key role in combating diseases. Despite their economic importance, conventional and molecular breeding approaches in ornamental plants to facilitate disease resistance are lagging, and this is predominantly due to their complex genomes, limited availability of gene pools, and degree of heterozygosity. Although genetic engineering in ornamental plants offers feasible methods to overcome the intrinsic barriers of classical breeding, achievements have mainly been reported only in regard to the modification of floral attributes in ornamentals. The unavailability of transformation protocols and candidate gene resources for several ornamental crops presents an obstacle for tackling the functional studies on disease resistance. Recently, multiomics technologies, in combination with genome editing tools, have provided shortcuts to examine the molecular and genetic regulatory mechanisms underlying fungal disease resistance, ultimately leading to the subsequent advances in the development of novel cultivars with desired fungal disease-resistant traits, in ornamental crops. Although fungal diseases constitute the majority of ornamental plant diseases, a comprehensive overview of this highly important fungal disease resistance seems to be insufficient in the field of ornamental horticulture. Hence, in this review, we highlight the representative mechanisms of the fungal infection-related resistance to pathogens in plants, with a focus on ornamental crops. Recent progress in molecular breeding, genetic engineering strategies, and RNAi technologies, such as HIGS and SIGS for the enhancement of fungal disease resistance in various important ornamental crops, is also described.

Genetic Differentiation in Anthocyanin Content among Berry Fruits

Anthocyanins are widely distributed secondary metabolites that play an essential role in skin pigmentation of many plant organs and microorganisms. Anthocyanins have been associated with a wide range of biological and pharmacological properties. They are also effective agents in the prevention and treatment of many chronic diseases. Berries are particularly abundant in these compounds; therefore, their dietary intake has health-promoting effects. The aim of this study was to identify and determine the anthocyanin content in selected species and cultivars of berry fruits, such as raspberry, blackberry, red currant, blackcurrant, and highbush blueberry, widely consumed by Europeans. The concentrations of anthocyanins were determined by HPLC, identifying individual compounds: cyanidin-3-O-glucoside, pelargonidin-3-O-glucoside, delphinidin-3-O-glucoside, delphinidin-3-O-rutinoside, cyanidin-3-O-rutinoside, delphinidin-3-O-galactoside, cyanidin-3-O-galactoside, and malvidin-3-O-galactoside. The experimental data showed that the selected species and cultivars of berry fruits differ significantly in the contents of anthocyanins. Among all species tested, blackberry and blackcurrant were characterized significantly by the highest content of anthocyanins (sum), while the lowest content was found in red currant fruits. Additionally, the content of individual anthocyanin compounds in particular species and cultivars was also different. Considering the high content of anthocyanins and their potential positive impact on human health and protection against disease, berries should be part of healthy nutrition.

Regulation of MYB Transcription Factors of Anthocyanin Synthesis in Lily Flowers

Flower color is the decisive factor that affects the commercial value of ornamental flowers. Therefore, it is important to study the regulation of flower color formation in lily to discover the positive and negative factors that regulate this important trait. In this study, MYB transcription factors (TFs) were characterized to understand the regulatory mechanism of anthocyanin biosynthesis in lily. Two R2R3-MYB TFs, LvMYB5, and LvMYB1, were found to regulate anthocyanin biosynthesis in lily flowers. LvMYB5, which has an activation motif, belongs to the SG6 MYB protein subgroup of Arabidopsis thaliana. Transient expression of LvMYB5 indicated that LvMYB5 can promote coloration in Nicotiana benthamiana leaves, and that expression of LvMYB5 increases the expression levels of NbCHS, NbDFR, and NbANS. VIGS experiments in lily petals showed that the accumulation of anthocyanins was reduced when LvMYB5 was silenced. Luciferase assays showed that LvMYB5 can promote anthocyanin synthesis by activating the ANS gene promoter. Therefore, LvMYB5 plays an important role in flower coloration in lily. In addition, the transient expression experiment provided preliminary evidence that LvMYB1 (an R2R3-MYB TF) inhibits anthocyanin synthesis in lily flowers. The discovery of activating and inhibitory factors related to anthocyanin biosynthesis in lily provides a theoretical basis for improving flower color through genetic engineering. The results of our study provide a new direction for the further study of the mechanisms of flower color formation in lilies.