Anthocyanins In Petals Research Articles

Intelligent locust bean gum-k-carrageenan nanofibrous mats with Rosa canina petal anthocyanins and chitosan nanoparticles: Preparation, characterization, and application for monitoring of beef meat freshness

The objectives of the present experiment were to add Rosa canina petal extract (RCE, 3.5%) and chitosan nanoparticles (CNP, 1.5%) into the locust bean gum-kappa-carrageenan (LBG-KC) nanofiber mats and to examine their utilization for the freshness tracking of beef meat during the 6-day storage period. The surface morphology analysis of nanofibers using the scanning electron microscope showed that all developed nanofibers were cylindrical, uniformly disordered network structures with smooth surfaces. The tensile strength, elongation at break, water vapor permeability, water solubility, and moisture content of RCE/CNP-loaded nanofiber mats were recorded to be 10.00–31.77 MPa, 16.55%–22.98%, 5.04–9.18 × 10‾5 g mm/m2 h Pa, 3.80%–10.08%, and 2.10%–4.89%, respectively. The LBG-KC + RCE 3.5% and LBG-KC + RCE 3.5% + CNP 1.5% nanofibers were red, dark blue, green, and brown at pH values 1–6, 7–8, 9, and 10–12, respectively. After 4 days of beef meat storage at refrigerated conditions, the total viable count, pH, and total volatile basic nitrogen were 7.24 log CFU/g, 7.11, and 28.89 mg N/100 g, respectively. Moreover, on the 0th day, the pH-sensitive indicators presented a white color and after 4 days of meat storage, the indicator color changed to dark blue, which could indicate beef meat spoilage.

Carrageenan-based functional films hybridized with carbon dots and anthocyanins from rose petals for smart food packaging applications

Multifunctional smart biopolymeric films were fabricated using rose petal anthocyanin (RPA) and carrageenan (CAR) doped with rose petal-derived carbon dots (RP-CDs). Response surface-optimized RPA showed the highest total anthocyanins and radical scavenging ability. Produced RP-CD exhibited UV absorption and high fluorescence with antibacterial/antioxidant abilities. Enrichment with 2 % RP-CD and 5 % RPA in the CAR matrix results in improved physicochemical, i.e., water contact angle, water vapor permeability, and UV-blocking properties of the fabricated material. Results showed that nanocomposite films scavenged radicals better than the neat CAR films. Zeta potential, FTIR, SEM, and XPS suggested improved compatibility/stability and enhanced elemental configuration of RP-CDs/RPA additives in the CAR polymer matrix. Perishable food packaging (minced pork and shrimp) demonstrated that nanocomposite films work efficiently and non-destructively and are promising tools for monitoring real-time freshness through interpretable visual changes from red to yellow. The CAR/RP-CDs/RPA-based nanocomposite indicator films are expected to be applied as various smart packaging materials. These films possess the ability to promptly detect changes in quality, preserve the quality, and prolong the shelf life of packaged foods.

Peppermint essential oil enhances the vase life of Dendrobium orchids

To extend the vase life of cut flowers, there is now a trend of using plant essential oils in place of synthetic chemicals, as they are fully biodegradable, more eco-friendly, and safer. The objective of this study was to examine the possible application and postharvest quality effects of three plant essential oils namely, ginger (Zingiber officinale Roscoe), peppermint (Mentha piperita L.), and citronella (Cymbopogon nardus Rendle), as natural vase solution for cut Dendrobium flowers. Peppermint essential oil showed promise as a holding solution for extending the vase life of Dendrobium orchids. To confirm vase life extension, emulsions containing peppermint essential oil at concentrations of 50 and 100 μg mL−1 combined with 4 % glucose to formulate holding solutions applied to Dendrobium orchids. Vase life, some biochemical changes, electrolyte leakage, total microbial count in the holding solution, and physical condition via scanning electron microscopy (SEM) were evaluated over a period of 25 days. The three major compounds in peppermint essential oil were identified as menthol (33.24 %), 1-menthone (18.91 %) and menthofuran (14.85 %). The essential oil was applied in emulsion form as a holding solution. Treatment with 4 % glucose and either 50 or 100 μg mL−1 peppermint essential oil prolonged the vase life of Dendrobium orchids to up to 28 days. Scanning electron microscopy on Day 7 showed that the xylem vessels of treated orchids remained clear, suggesting reduced microbial plugging at the stalk end. Similarly, on Day 20, a reduced microbial cell count was observed for treated orchids (<1 log CFU mL−1) in comparison with controls (7.20 ± 0.04 log CFU mL−1). Finally, the essential oil improved flower quality by helping preserve petal membrane stability and petal anthocyanin content. Our results suggest the application of peppermint essential oil as a novel alternative to chemicals used in holding solutions for extending the vase life of Dendrobium orchids.

Smart nano-inks based on natural food colorant for screen-printing of dynamic shelf life of shrimp

Intelligent packaging embedded with food freshness indicators can monitor food quality and be deployed for food safety and cutting food waste. The innovative nano-inks for dynamic shelf-life printing based on natural food colorant with application in real-time monitoring of shrimp freshness were prepared. Co-assembly of saffron petal anthocyanin (SPA) with hydrophobic curcumin (Cur) into chitin nano-scaffold (particle sizes around 26 ± 8 nm) could deliver hindering SPA leaching, confirmed by FT-IR, FE-SEM, AFM, and color stability test. The best response to pH-sensitivity was found in a ratio of (1:4) Cur/SPA (30% (v/w) in ChNFs that was correlated with the chemical and microbial changes of shrimp during shrimp freshness. However, smart screen-printed inks signified higher responsiveness to pH changes than FFI films. Therefore, smart-printed indicators introduced the excellent potential for a short response time, easy, cost-effective, eco-friendly, co-assembly, great color stabilities, and lifetime for nondestructively freshness monitoring foods and supplements.

Integrated Metabolomic and Transcriptomic Profiles Provide Insights into the Mechanisms of Anthocyanin and Carotenoid Biosynthesis in Petals of Medicago sativa ssp. sativa and Medicago sativa ssp. falcata.

The petals of Medicago sativa ssp. sativa and M. sativa ssp. falcata are purple and yellow, respectively. Free hybridization between M. sativa ssp. sativa and M. sativa ssp. falcata has created hybrids with various flower colors in nature. Moreover, the flower colors of alfalfa are closely correlated with yield, nutritional quality, stress tolerance and other agronomic characteristics. To elucidate the underlying mechanisms of flower color formation in M. sativa ssp. sativa and M. sativa ssp. falcata, we conducted an integrative analysis of the transcriptome and metabolome of alfalfa with three different petal colors (purple, yellow and cream). The metabolic profiles suggested that anthocyanins and carotenoids are the crucial pigments in purple and yellow flowers, respectively. A quantitative exploration of the anthocyanin and carotenoid components indicated that the accumulations of cyanidin, delphinidin, peonidin, malvidin, pelargonidin and petunidin derivatives are significantly higher in purple flowers than in cream flowers. In addition, the content of carotenes (phytoene, α-carotene and β-carotene) and xanthophylls (α-cryptoxanthin, lutein, β-cryptoxanthin, zeaxanthin, antheraxanthin and violaxanthin derivatives) was markedly higher in yellow flowers than in cream flowers. Furthermore, we found that delphinidin-3,5-O-diglucoside and lutein were the predominant pigments accumulated in purple and yellow flowers, respectively. The transcriptomic results revealed that twenty-five upregulated structural genes (one C4H, three 4CL, twelve CHS, two CHI, one F3H, one F3'H, one F3'5'H and four DFR) are involved in the accumulation of anthocyanins in purple flowers, and nine structural genes (two PSY, one ZDS, two CRTISO, two BCH, one ZEP and one ECH) exert an effect on the carotenoid biosynthesis pathway in yellow flowers. The findings of this study reveal the underlying mechanisms of anthocyanin and carotenoid biosynthesis in alfalfa with three classic flower colors.

Development of guar gum-pectin nanofiber mats containing Papaver rhoeas petal anthocyanins and cellulose nanocrystals for real-time visual detection of lamb meat freshness

The aims of the current experiment were to encapsulate Papaver rhoeas petal extract (PRE, 5 %) and cellulose nanocrystals (CNC, 1 %) into the guar gum-pectin (GG-PE) nanofibers through the electrospinning technique and evaluate their application for spoilage monitoring of fresh lamb meat during an 8-day storage period. Tensile strength, elongation at break, water vapor permeability, moisture content, and water solubility of GG-PE nanofiber mats containing CNC 1 % and PRE 5 % were 4.54–14.85 MPa, 3.60 %–10.75 %, 6.32–15.23 × 10‾4 g mm/m2 h Pa, 7.99 %–14.32 %, and 3.71 %–6.13 %, respectively. The color of GG-PE-PRE 5 % and GG-PE-CNC 1 %-PRE 5 % nanofiber mats changed from red to dark violet, green, and brown colors with increasing pH from 1 to 5 to 6–8, 9–10, and 11–12, respectively. The total volatile basic nitrogen, pH, total viable count, and psychrotrophic bacterial count of lamb meat increased to 28.49 mg N/100 g, 7.23, 7.38 log CFU/g, and 6.52 log CFU/g after four days of refrigerated storage conditions, respectively. The GG-PE-PRE 5 % and GG-PE-CNC 1 %-PRE 5 % nanofiber mats exhibited evident color changes from white color (fresh) to dark violet color (spoiled) during lamb meat storage at refrigerated conditions, confirming the applicability of fabricated nanofiber mats as pH-sensitive indicators.

Rosa Indica flower petal anthocyanin mediated biogenic synthesis of PdNPs: Catalyst intended for the Suzuki-Miyaura reactions

In the present work, theRosa Indicaflowerpetals anthocyanin extract has been employed as a “green” natural source for the synthesis and topping of noble metal nanoparticles [palladium nanoparticles (PdNPs)]. TheRosa Indicaflowerpetals anthocyanin extract effectively replaces the toxic chemicals and stabilizers. The formed PdNPs were exposed to their structural properties examination by the Ultraviolet–Visible absorption, Energy-dispersive X- ray and Fourier TransformInfrared spectroscopic analysis. The diffractionpattern of the PdNPs@ rose-anthocyanin to the X-ray recognizes their crystalline nature. In addition, the detailed analysis of the X-ray pattern and microscopic images ofFESEM, TEM reveals that formed PdNP@ rose-anthocyanin possesses FCC crystal lattice with average dimensions of the particle ∼ 12 nm. The EDS analysis shows that the PdNPs@ rose-anthocyanin contains ∼ 80 wt% PdNPs. Further, the PdNP@ rose-anthocyanin were efficiently catalyses the Suzuki-Miyaura cross-coupling (CC) reactions between an aryl halide and phenylboronic acid in the presence of K2CO3 as a suitable base. To catalyse the reaction, PdNPs@ rose-anthocyanin works as heterogeneous catalyst in the absence of heating. Moreover, it provides a good to high yield of the corresponding coupled products under aerobic conditions with optimum reaction time in the aqueous medium, particularly at room temperature with a virtuous Turnover number relative to several synthesized PdNPs. Further, the catalyst PdNP@ rose-anthocyanin shows righteous catalytic activity without significant loss in its efficiency up to four reusable cycles.

A Simple Colorimetric Volatile Nitrogen and Hydrogen Sulfide Indicator Based on Filter Paper and Saffron Petal Anthocyanins to Monitor Fish Spoilage in Intelligent Packaging

A Simple Colorimetric Volatile Nitrogen and Hydrogen Sulfide Indicator Based on Filter Paper and Saffron Petal Anthocyanins to Monitor Fish Spoilage in Intelligent Packaging

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.

Intelligent double-layer polymers based on carboxymethyl cellulose-cellulose nanocrystals film and poly(lactic acid)-Viola odorata petal anthocyanins nanofibers to monitor food freshness

The present study was conducted with the aim of fabricating smart bilayer polymers based on carboxymethyl cellulose-cellulose nanocrystals film and poly(lactic acid)-Viola odorata extract nanofibers (CMC-CNC and PLA-VOE) for freshness monitoring of Pacific white shrimps, minced lamb meat, chicken fillets, and rainbow trout fillets, during refrigerated storage conditions. The fabricated indicators based on CMC-PLA-VOE 5%, CMC-CNC 1%-PLA-VOE 5%, and CMC-CNC 3%-PLA-VOE 5% presented remarkable color changes in pH 1–12 buffer solutions, including red at pH 1–6, violet at pH 7–8, green at pH 9–10, and brown at pH 11–12. Significantly lower water vapor permeability and oxygen transmission rate of prepared polymers were found in comparison with the control groups (P < 0.05). Regarding the monitoring of food samples in real-time, the samples spoiled after 3 days, evidenced by total viable count, psychrotrophic bacterial count, total volatile basic nitrogen, and pH values of 7.17–7.54 log CFU/g, 5.68–6.23 log CFU/g, 25.14–28.12 mg N/100 g, and 7.10–7.66, respectively. Meanwhile, the noticeable color change of prepared indicators from white to violet (day 3) and finally dark violet (day 7) was observed, indicating a potential application in intelligent packaging for real-time control of the freshness of perishable food samples.

Comparative transcriptome analysis and flavonoid profiling of floral mutants reveals CmMYB11 regulating flavonoid biosynthesis in chrysanthemum

Flavonoids, of which the major groups are flavones, flavonols, and anthocyanins, confer a variety of colors on plants. Bud sports with variation of floral colors occur occasionally during chrysanthemum cultivation. Although it has been reported that methylation at the promoter of CmMYB6 was related to anthocyanin contents, the regulatory networks of flavonoid biosynthesis still remain largely unknown in mutation of chrysanthemum. We compared phenotypes, pigment composition and transcriptomes in two chrysanthemum cultivars, ‘Anastasia Dark Green’ and ‘Anastasia Pink’, and regenerated bud sports of these cultivars with altered floral colors. Increased anthocyanins turned the ‘Anastasia Dark Green’ mutant red, while decreased anthocyanins turned the ‘Anastasia Pink’ mutant white. Moreover, total flavonoids were reduced in both mutants. Multiple flavonoid biosynthetic genes and regulatory genes encoding MYBs and bHLHs transcription factors were differentially expressed in pairwise comparisons of transcriptomes in ‘Anastasia Dark Green’ or ‘Anastasia Pink’ and their mutants at different flowering stages. Among these regulatory genes, the expression patterns of CmMYB6 and CmbHLH2 correlated to changes of anthocyanin contents, and down-regulation of CmMYB11 correlated to decreased total flavonoid contents in two mutants. CmMYB11 was shown to directly activate the promoter activities of CmCHS2, CmCHI, CmDFR, CmANS, CmFNS, and CmFLS. Furthermore, overexpression of CmMYB11 increased both flavonols and anthocyanins in tobacco petals. Our work provides new insights into regulatory networks involved in flavonoid biosynthesis and coloration in chrysanthemum.

Identification and Expression Analysis of DFR Gene Family in Brassica napus L.

Dihydroflavonol 4-reductase (DFR) is a key enzyme in the flavonoid biosynthetic pathway and is essential for the formation of plants' color. In this study, 26 BnDFR genes were identified using 6 Arabidopsis DFR genes as reference. The physicochemical properties, subcellular localization, and conserved structure of BnDFR proteins were analyzed; the evolutionary relationship, collinearity analysis, and expression characteristics of BnDFR genes were studied; and the correlation between the expression level of BnDFR genes and anthocyanin content in rape petals were analyzed. The results showed that the 26 BnDFRs were located in chloroplasts, cytoplasm, nuclei, and mitochondria, distributed on 17 chromosomes, and divided into 4 groups; members of the same group have a similar function, which may be related to the environmental response elements and plant hormone response elements. Intraspecific collinearity analysis showed 51 pairs of collinear genes, and interspecific collinearity analysis showed 30 pairs of collinear genes. Analysis of the expression levels of BnDFRs and anthocyanin content in different color rape petals showed that BnDFR6 and BnDFR26 might play an important role in the synthesis of anthocyanins in rape petals. This provides theoretical guidance for further analysis of the anthocyanin anabolism mechanism involved in the DFR gene in Brassica napus.

Transcription factor NnMYB5 controls petal color by regulating GLUTATHIONE S-TRANSFERASE2 in Nelumbo nucifera.

Lotus (Nelumbo spp.) is an important aquatic ornamental genus in the family Nelumbonaceae comprising only two species: N. lutea with yellow flowers and N. nucifera with red or white flowers. The petal color variations between these two species have previously been associated with the potential activities of FLAVONOL SYNTHASE (FLS) and MYB5. However, the underlying genetic mechanisms of flower color divergence within the N. nucifera species remains unclear. Here, quantitative trait locus mapping led to the identification of MYB5, a candidate gene controlling petal color in N. nucifera. Genotyping of 213 natural lotus accessions revealed an 80-kb presence/absence variant (PAV) of the NnMYB5 gene that is associated with petal color variation. Transcriptome analysis, dual-luciferase and yeast one-hybrid assays showed that NnMYB5 could directly activate the anthocyanin transporter gene GLUTATHIONE S-TRANSFERASE2 (NnGST2). Heterologous expression of NnGST2 in Arabidopsis (Arabidopsis thaliana) and its overexpression in lotus petals induced anthocyanin accumulation. Deletion of the 80-kb PAV within NnMYB5 inactivated NnGST2 expression and blocked anthocyanin accumulation in white N. nucifera petals. In contrast, the anthocyanin deficiency of N. lutea occurred due to pseudogenized NlMYB5 alleles. Our results establish a regulatory link between NnMYB5 and NnGST2 in petal anthocyanin accumulation and demonstrate the independent mechanisms controlling flower coloration in Nelumbo.

Transcription factors TgbHLH42-1 and TgbHLH42-2 positively regulate anthocyanin biosynthesis in Tulip (Tulipa gesneriana L.).

The floral coloration of tulip flowers is one of the most prominent traits contributing to its high ornamental value. The molecular mechanisms of petal coloration remain elusive in tulip species. In this study, we performed comparative metabolome and transcriptome analyses using four tulip cultivars with distinguished petal colors. Four types of anthocyanins were identified, including cyanidin derivatives and pelargonidin derivatives. Comparative transcriptome analysis identified 22,303 differential expressed genes (DEGs) from the four cultivars, and 2589 DEGs were commonly regulated in three comparison groups (colored vs. white cultivar), including anthocyanins biosynthesis-related genes and regulatory transcription factors. Two basic helix-loop-helix (bHLH) transcription factors, TgbHLH42-1 and TgbHLH42-2, with differential expression levels among cultivars and petal developmental stages, have high homology to TRANSPARENT TESTA 8 (AtTT8) of Arabidopsis. The anthocyanins accumulation in TgbHLH42-1 overexpressing (OE) seedlings was markedly greater than that in wild-type seedlings in the presence of methyl jasmonate (MeJA), but not for TgbHLH42-2 OE seedlings. Both TgbHLH42-1 and TgbHLH42-2 restored pigmentation defects in tt8 mutant seeds after complementation assay. TgbHLH42-1 could interact with MYB protein AtPAP1 to synergistically activate the transcription of AtDFR, whereas TgbHLH42-2 failed to. Silencing TgbHLH42-1 or TgbHLH42-2 individually could not, but simultaneously silencing both TgbHLH42 could reduce the anthocyanin in tulip petals. These results indicate that TgbHLH42-1 and TgbHLH42-2 function partially redundantly to positively regulate anthocyanin biosynthesis during tulip petal coloration.

Different LED light spectra’s and nano-chelated potassium affect the quality traits of Dolce Vita cut roses in soilless culture condition

Roses are classified as neutral day plants, but high light and cool temperatures produce high quality flowers in roses. As light quantity, the light quality and its special spectra can affect the flower yield and quality. This research aimed to study of the effect of LED light (control (sunlight), blue and red spectra’s) and nano-chelated potassium at three levels (0, 1.5 and 3 g/l) on some morphophysiological and biochemical traits of Rosa hybrida cv. Dolce Vita. Light and nano-chelated potassium treatments have a significant effect on most traits measured in the present study. According to the results, the use of red light and nano-chelated potassium in rose cultivation improved the quality characteristics and increased vase life. The highest fresh and dry weight of flowering branch and plant height was observed in red light treatment and the concentration of 3 g/l nano-chelated potassium. Biochemical parameters such as phenolic compounds, leaf and petal flavonoids, petal anthocyanin content, antioxidant capacity and vase life were also significantly increased under red light and with the concentration of 3 g/l nano-chelated potassium compared to the control. In general, it can be said that the use of red light and a concentration of 3 g/l nano-chelated potassium, can be effective in improving the quality of rose flowers, especially in low light condition.

Analysis of Physiological and Biochemical Factors Affecting Flower Color of Herbaceous Peony in Different Flowering Periods

Herbaceous peony (Paeonia lactiflora Pall.) is a famous ornamental plant, and the study of its flower color is of great significance for cultivating new flower varieties. To explore the factors driving the formation and change of herbaceous peony flower color, we selected five herbaceous peony varieties at four flowering stages to determine the change in flower color, petal area, and microstructure. We also examined the composition and content of petal pigments, soluble sugar and soluble protein content, pH value of cell fluid, and water content. Finally, we analyzed the correlations between each factor. We found that Pn3G5G, Pg3G5G, and Cy3G5G were the main anthocyanin components in red and purple petals. Qu3G, Qu7G, Is3G, and lutein play important roles in yellow petal formation. The change in herbaceous peony flower color during the flowering process is directly caused by changes in the anthocyanin and carotenoid content in petals. In addition, changes in other physiological indices also influence the change in flower color. This study explored the physiological and biochemical factors affecting the color of herbaceous peony petals, which has an important practical significance for studying the physiological mechanism of herbaceous peony flower color formation and color breeding of new flowers.

Flower transcriptional response to long term hot and cold environments in Antirrhinum majus.

Short term experiments have identified heat shock and cold response elements in many biological systems. However, the effect of long-term low or high temperatures is not well documented. To address this gap, we grew Antirrhinum majus plants from two-weeks old until maturity under control (normal) (22/16°C), cold (15/5°C), and hot (30/23°C) conditions for a period of two years. Flower size, petal anthocyanin content and pollen viability obtained higher values in cold conditions, decreasing in middle and high temperatures. Leaf chlorophyll content was higher in cold conditions and stable in control and hot temperatures, while pedicel length increased under hot conditions. The control conditions were optimal for scent emission and seed production. Scent complexity was low in cold temperatures. The transcriptomic analysis of mature flowers, followed by gene enrichment analysis and CNET plot visualization, showed two groups of genes. One group comprised genes controlling the affected traits, and a second group appeared as long-term adaptation to non-optimal temperatures. These included hypoxia, unsaturated fatty acid metabolism, ribosomal proteins, carboxylic acid, sugar and organic ion transport, or protein folding. We found a differential expression of floral organ identity functions, supporting the flower size data. Pollinator-related traits such as scent and color followed opposite trends, indicating an equilibrium for rendering the organs for pollination attractive under changing climate conditions. Prolonged heat or cold cause structural adaptations in protein synthesis and folding, membrane composition, and transport. Thus, adaptations to cope with non-optimal temperatures occur in basic cellular processes.

Relationship between Anthocyanin Composition and Floral Color of Hibiscus syriacus

Hibiscus syriacus is a highly ornamental flowering shrub widely grown in East Asia. Its abundant flower colors mainly reflect the accumulation of anthocyanins. Classifying H. syriacus petals and identifying the relationship between flower color and anthocyanins can provide references for flower color breeding. With eight cultivars of H. syriacus as experimental materials, the floral color was described using the Royal Horticultural Society Color Chart and the CIEL*a*b* coordinate. The anthocyanin in petals was qualitatively and quantitatively analyzed by using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), and the relationships between flower color and anthocyanin were analyzed by using stepwise regression analysis. We divided eight cultivars of H. syriacus into five color lines: red-purple, white, violet, purple, and blue-purple, and then into two groups: purple and red-purple. The results showed that the L* had a significant negative correlation with a* and C*. A total of 52 anthocyanin components were detected in the petals of H. syriacus, including cyanidin, delphinidin, malvidin, petunidin, peonidin, and pelargonidin derivatives. Cyanidin derivatives accounted for the highest proportion, and pelargonidin derivatives accounted for the lowest proportion of the total anthocyanins. Petals of ‘Pink Giant’ contained the largest number of types of anthocyanin components and the highest total anthocyanin content, while the petals of ‘Albus Single’ contained the smallest. Petunidin-3-O-glucoside showed a significant negative correlation with L* in the red-purple group and in all cultivars, whereas it showed a significant negative correlation with b* in the purple group. Delphinidin-3-O-(6-O-Malonyl-β-D-glucoside) exhibited a significant positive correlation with a* in the red-purple group, and delphinidin-3-O-glucoside showed a significant negative correlation with L* in the purple group. Therefore, our results suggest that changing the content of these three anthocyanin components may have the potential to alter the flower color. This research provides scientific guidance and a foundation for the molecular breeding of H. syriacus cultivars with new floral colors.

Drought-induced CsMYB6 interacts with CsbHLH111 to regulate anthocyanin biosynthesis in Chaenomeles speciosa.

Chaenomeles speciosa is a plant with high ornamental value, and the color of its petals deepens obviously under drought stress. To understand the mechanism of drought-induced reddening of C. speciosa petal color, the metabolites and transcriptomics of petals from 4% PEG-8000-treated and control cuttings were analyzed. In this study, the analysis of metabolites revealed the accumulation of anthocyanins in petals of PEG-treated cuttings, indicating anthocyanins might be the reason for the deepening of petal color. By using transcriptomics, we identified CsMYB6 as an overexpressed transcription factor in PEG-treated samples. Transient overexpression and suppression of CsMYB6 revealed that it is a key transcription factor for anthocyanin synthesis. We identified genes related to anthocyanin biosynthesis and constructed a network of drought- and anthocyanin-related genes (such as CsMYB6, CsbHLH111, CsANS, CsDFR, and CsUFGT). Further experiments indicated that CsMYB6 directly interacted with CsbHLH111, and this interaction increased the binding ability of CsMYB6 to the promoter regions of three structural genes of anthocyanin biosynthesis: CsANS, CsDFR, and CsUFGT. Our findings provide a molecular basis and new insight into drought-induced anthocyanin biosynthesis in C. speciosa.

A glutathione S-transferase GhTT19 determines flower petal pigmentation via regulating anthocyanin accumulation in cotton.

Anthocyanin accumulations in the flowers can improve seed production of hybrid lines, and produce higher commodity value in cotton fibre. However, the genetic mechanism underlying the anthocyanin pigmentation in cotton petals is poorly understood. Here, we showed that the red petal phenotype was introgressed from Gossypium bickii through recombination with the segment containing the R3 bic region in the A07 chromosome of Gossypium hirsutum variety LR compared with the near-isogenic line of LW with white flower petals. The cyanidin-3-O-glucoside (Cy3G) was the major anthocyanin in red petals of cotton. A GhTT19 encoding a TT19-like GST was mapped to the R3 bic site associated with red petals via map-based cloning, but GhTT19 homologue gene from the D genome was not expressed in G. hirsutum. Intriguingly, allelic variations in the promoters between GhTT19LW and GhTT19LR , rather than genic regions, were found as genetic causal of petal colour variations. GhTT19-GFP was found localized in both the endoplasmic reticulum and tonoplast for facilitating anthocyanin transport. An additional MYB binding element found only in the promoter of GhTT19LR , but not in that of GhTT19LW , enhanced its transactivation by the MYB activator GhPAP1. The transgenic analysis confirmed the function of GhTT19 in regulating the red flower phenotype in cotton. The essential light signalling component GhHY5 bonded to and activated the promoter of GhPAP1, and the GhHY5-GhPAP1 module together regulated GhTT19 expression to mediate the light-activation of petal anthocyanin pigmentation in cotton. This study provides new insights into the molecular mechanisms for anthocyanin accumulation and may lay a foundation for faster genetic improvement of cotton.