Search

Fruit ripening is a highly coordinated process involving molecular and biochemical changes that collectively determine fruit quality. The underlying metabolic programs and their transitions leading to fruit ripening remain largely under-characterized in blueberry (Vaccinium sp.), which exhibits atypical climacteric behavior. In this study, we focused on sugar, acid and anthocyanin metabolism in two rabbiteye blueberry cultivars, Premier and Powderblue, during fruit development and ripening. Concentrations of the three major sugars, sucrose (Suc), glucose (Glc), and fructose (Fru) increased steadily during fruit development leading up to ripening, and increased dramatically by around 2-fold in 'Premier' and 2- to 3-fold in 'Powderblue' during the final stage of fruit ripening. Starch concentration was very low throughout fruit development in both cultivars indicating that it does not serve the role of a major transitory carbon (C) storage form in blueberry fruit. Together, these patterns indicate continued import of C, likely in the form of Suc, throughout blueberry fruit development. Concentrations of the predominant acids, malate and quinate, decreased during ripening, and may contribute to increased shikimate biosynthesis which, in-turn, allows for downstream phenylpropanoid metabolism leading to anthocyanin synthesis. Consistently, anthocyanin concentrations were highest in fully ripened blue fruit. Weighted gene co-expression network analysis (WGCNA) was performed using a 'Powderblue' fruit ripening transcriptome and targeted fruit metabolite concentration data. A 'dark turquoise' module positively correlated with sugars and anthocyanins, and negatively correlated with acids (malate, quinate), was identified. Gene Ontology (GO) enrichment analysis of this module identified transcripts related to sugar, acid, and phenylpropanoid metabolism pathways. Among these, increased transcript abundance of a VACUOLAR INVERTASE during ripening was consistent with sugar storage in the vacuole. In general, transcript abundance of the glycolysis pathway genes was upregulated during ripening. The transcript abundance of PHOSPHOENOLPYRUVATE (PEP) CARBOXYKINASE increased during fruit ripening and was negatively correlated with malate concentration, suggesting increased malate conversion to PEP, which supports anthocyanin production during fruit ripening. This was further supported by the co-upregulation of several anthocyanin biosynthesis-related genes. Together, this study provides insights into important metabolic programs, and their underlying gene expression patterns during fruit development and ripening in blueberry., (© 2024. The Author(s).)

The species-rich cosmopolitan genus Rhododendron offers a good system for exploring the genomic mechanisms underlying adaptation to diverse habitats. Here, we report high-quality chromosomal-level genome assemblies of nine species, representing all five subgenera, different altitudinal distributions, and all flower color types of this genus. Further comprehensive genomic analyses indicate diverse adaptive strategies employed by Rhododendron, particularly adaptation to alpine and subalpine habitats by expansion/contraction of gene families involved in pathogen defense and oxidative phosphorylation, genomic convergent evolution, and gene copy-number variation. The convergent adaptation to high altitudes is further shown by population genomic analysis of R. nivale from the Himalaya-Hengduan Mountains. Moreover, we identify the genes involved in the biosynthesis of anthocyanins and carotenoids, which play a crucial role in shaping flower color diversity and environmental adaptation. Our study is significant for comprehending plant adaptive evolution and the uneven distribution of species diversity across different geographical regions., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Blueberries ( Vaccinium spp.) are extremely sensitive to drought stress. Flavonoids are crucial secondary metabolites that possess the ability to withstand drought stress. Therefore, improving the drought resistance of blueberries by increasing the flavonoid content is crucial for the development of the blueberry industry. To explore the underlying molecular mechanism of blueberry in adaptation to drought stress, we performed an integrated analysis of the metabolome and transcriptome of blueberry leaves under drought stress. We found that the most enriched drought-responsive genes are mainly involved in flavonoid biosynthesis and plant hormone signal transduction pathways based on transcriptome data and the main drought-responsive metabolites come from the flavonoid class based on metabolome data. The UDP-glucose flavonoid 3-O-glucosyl transferase ( UFGT ), flavonol synthase ( FLS ), and anthocyanidin reductase ( ANR-2 ) genes may be the key genes for the accumulation of anthocyanins, flavonols, and flavans in response to drought stress in blueberry leaves, respectively. Delphinidin 3-glucoside and delphinidin-3-O-glucoside chloride may be the most important drought-responsive flavonoid metabolites. VcMYB1 , VcMYBPA1 , MYBPA1.2 , and MYBPA2.1 might be responsible for drought-induced flavonoid biosynthesis and VcMYB14, MYB14, MYB102 , and MYB108 may be responsible for blueberry leaf drought tolerance. ABA responsive elements binding factor ( ABF ) genes, MYB genes, bHLH genes, and flavonoid biosynthetic genes might form a regulatory network to regulate drought-induced accumulation of flavonoid metabolites in blueberry leaves. Our study provides a useful reference for breeding drought-resistant blueberry varieties.

Background: Spine grape (Vitis davidii) is a promising source of high-quality anthocyanins, with vast potential for application in food, pharmaceutical, and cosmetic industries. However, their availability is limited by resource constraints. Plant cell culture has emerged as a valuable approach for anthocyanin production and serves as an ideal model to investigate the regulation of anthocyanin biosynthesis. Elicitors are employed to achieve targeted enhancement of anthocyanin biosynthesis. The present study investigated the impact of 5-aminolevulinic acid (ALA) as an elicitor on the accumulation of anthocyanins and flavonoids during spine grape callus growth. Specifically, we examined the effects of ALA on anthocyanin and its component accumulation in callus, and biosynthetic anthocyanin gene expression., Results: ALA at 25 µg/L increased the biomass of spine grape callus. ALA induction enhanced the levels of flavonoids, anthocyanins and proanthocyanidins in callus, with maximum values reaching 911.11 mg/100 g DW, 604.60 mg/100 g DW, and 5357.00 mg/100 g DW, respectively, after callus culture for 45 days. Notably, those levels were 1.47-, 1.93- and 1.83-fold higher than controls. ALA induction modulated the flavonoid profile, and among 97 differential flavonoid metabolites differing from controls, 77 were upregulated and 20 were downregulated. Six kinds of anthocyanins, namely cyanidin (8), delphinidin (6), peonidin (5), malvidin (4), petunidin (3) and pelargonidin (3), were detected in callus, with peonidin most abundant. Compared with controls, anthocyanin components were increased in ALA-treated callus. The key genes PAL1, PAL2, PAL4, CHI, CHS3, F3'H, F3H, FLS, DFR, UFGT, MYBA1, LDOX, OMT3, GT1 and ACT involved in anthocyanin biosynthesis were upregulated following ALA treatment, resulting in anthocyanin accumulation., Conclusion: This study revealed a novel mode of ALA-mediated promotion of plant anthocyanin biosynthesis and accumulation at the cellular level, and a strategy for enhancing anthocyanin content in spine grape callus. The findings advance commercial-scale production of anthocyanins via spine grape callus culture. we also explored the accumulation patterns of flavonoids and anthocyanins under ALA treatment. Augmentation of anthocyanins coincided with elevated expression levels of most genes involved in anthocyanin biosynthesis within spine grape callus following ALA treatment., (© 2024. The Author(s).)

The health-promoting properties of blueberries are widely recognized and are mainly attributed to anthocyanins. However, fruit's chemical composition includes also other components and strongly depends on varieties and climatic conditions. Here, 1 H NMR metabolite profiling and biological activity of four blueberry cultivars (Spartan, Jewels, Misty, Camelia) grown in Central Italy over two years were reported. Untargeted and targeted NMR analyses allowed the quantification of sugars, organic acids, amino acids, anthocyanins, lipids, and other compounds. Spectrophotometric assays evaluated total phenolic and flavonoid content, antioxidant activity, and enzyme inhibitory activity toward cholinesterase, α -amylase, α -glucosidase, and tyrosinase. Statistical analysis showed a correlation between chemical composition and biological activity, revealing markers specific to blueberry cultivars (quinic acid, quercitrin, myo -inositol, myrtillin, and petunidin-3- O -glucoside). Almost all antioxidant assays were correlated with the chlorogenic acid levels. A strong effect of harvesting on chemical composition and biological activities was observed, with Misty cultivar having the highest antioxidant activity.

Horticulture in controlled environments has been increasingly used to tackle limitations on crop production. As a crucial environmental factor, light regulate plant growth and metabolism. In the present study, basil plants were subjected to different light durations and intensities considering constant daily light integral (DLI). The lighting environment included 200, 300, and 400 µmol m - 2 s - 1 intensities for 18, 12, and 9 h, respectively. DLI amounted to 12.96 mol m - 2 d - 1 among all light treatments (LI200 for 18 h, LI300 for 12 h, and LI400 for 9 h). Half of the plants under each light treatment were exposed to 30 µmol m - 2 s - 1 of far-red light. The results indicated the general negative impact of LI400/9 on the growth of basils. Exposure to far-red light hurt the growth of the shoot, while it enhanced stem and petiole elongation. This effect was due to higher gibberellin accumulation, which resulted in shade avoidance responses. Exposure to far-red light also reduced anthocyanin and flavonoid contents, as two important nutritional components. Soluble carbohydrates increased, while storage carbohydrates decreased by increasing lighting duration/decreasing light intensity or by far-red light inclusion. The lowest antioxidant activity was detected in LI400/9. In the LI200/18, the highest level of auxin and the lowest level of cytokinin were detected, while the LI300/12 exhibited the highest level of gibberellin hormone. Low light intensity and long photoperiod enhanced plant biomass and phytochemical production and are recommended for basil production in controlled environments., (© 2024. The Author(s).)

The color of coffee fruits is influenced by several factors, including cultivar, ripening stage, and metabolite composition. However, the metabolic accumulation of pigments and the molecular mechanisms underlying peel coloration during the ripening process of Coffea arabica L. remain relatively understudied. In this study, UPLC-MS/MS-based metabolomics and RNA sequencing (RNA-seq)-based transcriptomics were integrated to investigate the accumulation of anthocyanins and carotenoids in the peel of Coffea arabica at different ripening stages: green peel (GP), green-yellow peel (GYRP), red peel (RP), and red-purple peel (RPP). This integration aimed at elucidating the molecular mechanisms associated with these changes. A total of ten anthocyanins, six carotenoids, and thirty-five xanthophylls were identified throughout the ripening process. The results demonstrated a gradual decrease in the total carotenoid content in the peel with fruit maturation, while anthocyanin content increased significantly. Notably, the accumulation of specific anthocyanins was closely associated with the transition of peel colors from green to red. Integrated metabolomics and transcriptomics analyses identified the GYRP stage as critical for this color transition. A weighted gene co-expression network analysis (WGCNA) revealed that enzyme-coding genes such as 3AT, BZ1, and lcyE, along with transcription factors including MYB, NAC, and bHLH, which interact with PHD and SET TR, may regulate the biosynthesis of anthocyanins and carotenoids, thereby influencing peel pigmentation. These findings provide valuable insights into the molecular mechanisms underlying the accumulation of anthocyanins and carotenoids in Coffea arabica peel during fruit maturation.

As one innate immune pattern recognition receptor, Toll-like receptor 4 (TLR4) recently has been considered as a critical player in glucolipid metabolism. Blueberries contain high level of anthocyanins, especially malvidin-3-glucoside (Mv-3-glc), which contribute the anti-inflammatory, hypoglycemic, and hypolipidemic effects. It is speculated that Mv-3-glc is able to possess these functions by binding to TLR4. Here, the noncovalent interactions of Mv-3-glc and TLR4 was explored through multi-techniques including fluorescence and ultraviolet-visible (UV-Vis) absorption spectroscopy, as well as molecular docking. The results demonstrated that Mv-3-glc was able to quench TLR4 intrinsic fluorescence effectively. A stable complex was formed spontaneously and the reaction was exothermic. The degree of binding of Mv-3-glc to TLR4 showed a strong dependence on the chemical concentration, temperature, and pH values. The negative signs for enthalpy (ΔH = -69.1 ± 10.8 kJ/mol) and entropy (ΔS = -105.0 ± 12.3 J/mol/K) from the interaction of the Mv-3-glc and TLR4 shows that the major driving forces are the hydrogen bonding and van der Waals' force, which is consistent with the molecular docking results. In addition, molecular docking predicted that the active center with specific amino acid residues, Phe126, Ser127, Leu54, Ile153, and Tyr131 was responsible for the site of Mv-3-glc binding to TLR4/myeloid differentiation protein-2 (MD-2). These findings confirmed that Mv-3-glc could bind to TLR4, which would be beneficial to understand the target therapeutic effects of blueberry anthocyanins on TLR4 in regulating glucolipid metabolism., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Although the strigolactone (SL) signaling pathway and SL-mediated anthocyanin biosynthesis have been reported, the molecular association between SL signaling and anthocyanin biosynthesis remains unclear. In this study, we identified the SL signal transduction pathway associated with anthocyanin biosynthesis and the crosstalk between gibberellin (GA) and SL signaling in apple (Malus × domestica). ELONGATED HYPOCOTYL5 (HY5) acts as a key node integrating SL signaling and anthocyanin biosynthesis, and the SL-response factor AGAMOUS-LIKE MADS-BOX9 (AGL9) promotes anthocyanin biosynthesis by activating HY5 transcription. The SL signaling repressor SUPPRESSOR OF MAX2 1-LIKE8 (SMXL8) interacts with AGL9 to form a complex that inhibits anthocyanin biosynthesis by downregulating HY5 expression. Moreover, the E3 ubiquitin ligase PROTEOLYSIS1 (PRT1) mediates the ubiquitination-mediated degradation of SMXL8, which is a key part of the SL signal transduction pathway associated with anthocyanin biosynthesis. In addition, the GA signaling repressor REPRESSOR-of-ga1-3-LIKE2a (RGL2a) mediates the crosstalk between GA and SL by disrupting the SMXL8-AGL9 interaction that represses HY5 transcription. Taken together, our study reveals the regulatory mechanism of SL-mediated anthocyanin biosynthesis and uncovers the role of SL-GA crosstalk in regulating anthocyanin biosynthesis in apple., Competing Interests: Conflict of interest statement. None declared., (© The Author(s) 2024. Published by Oxford University Press on behalf of American Society of Plant Biologists. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Many organisms have complex pigmentation patterns. However, how these patterns are formed remains largely unknown. In wild carrot (Daucus carota subsp. carota), which is also known as Queen Anne's lace, one or several purple central flowers occur in white umbels. Here, we investigated the unique central flower pigmentation pattern in wild carrot umbels. Using wild and cultivated carrot (D. carota subsp. sativus L.) accessions, transcriptome analysis, protein interaction, stable transformation, and CRISPR/Cas9-mediated knockout, an anthocyanin-activating R2R3-myeloblastosis (MYB) gene, Purple Central Flower (DcPCF), was identified as the causal gene that triggers only central flowers to possess the purple phenotype. The expression of DcPCF was only detected in tiny central flowers. We propose that the transition from purple to nonpurple flowers in the center of the umbel occurred after 3 separate adverse events: insertion of transposons in the promoter region, premature termination of the coding sequence (caused by a C-T substitution in the open reading frame), and the emergence of unknown anthocyanin suppressors. These 3 events could have occurred either consecutively or independently. The intriguing purple central flower pattern and its underlying mechanism may provide evidence that it is a remnant of ancient conditions of the species, reflecting the original appearance of Umbelliferae (also called Apiaceae) when a single flower was present., Competing Interests: Conflict of interest statement. None declared., (© The Author(s) 2024. Published by Oxford University Press on behalf of American Society of Plant Biologists. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Rehmannia piasezkii is a kind of medicinal plants, of the Orobanchaceae family, and well known for its large pink or purple corolla. However, no research on the molecular mechanism of flower color formation in R. piasezkii has been conducted so far. In this study, we investigated the transcriptome of root, stem, leaf and corollas of R. piasezkii using transcriptome sequencing technology and assembled 144,582 unigenes. A total of 58 anthocyanin biosynthetic genes were identified in the R. piasezkii transcriptome, fourteen of which were highly correlated with anthocyanin content, especially RpF3H2, RpDFR2, RpANS1, RpANS2 and RpUFGT. Totally, 35 MYB genes with FPKM values greater than 5 were identified in the R. piasezkii transcriptome, including an R2R3 MYB transcriptional factor RpMYB1, which belongs to subgroup 6 of the R2R3 MYB family. Agrobacterium-mediated transient expression of Nicotiana benthamiana revealed that overexpression of RpMYB1 could activate the expression of structural genes in anthocyanin synthesis pathway and promote the accumulation of anthocyanins in N. benthamiana leaves, indicating that RpMYB1 is a positive regulator of anthocyanin synthesis. Furthermore, combined transient overexpression of RpMYB1 with RpANS1, RpMYB1+RpANS1 with other structural genes all could further enhance the accumulation of anthocyanins in N. benthamiana leaves. Permanent overexpression of RpMYB1 in R. glutinosa promoted anthocyanin accumulation and expression levels of RgCHS, RgF3H, RgDFR and RgANS. Further evidence from dual-luciferase assay suggested that RpMYB1 could bind to the promoter of RpDFR2 and hence activating its expression. These findings provide insight into the molecular regulation in anthocyanin biosynthesis in R. piasezkii and provide valuable genetic resources for the genetic improvement of flower color., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Masson SAS.)

The Chinese gentian, Gentiana sino-ornata produces brilliant blue flowers. To investigate the biological function and transcriptional regulation mechanism of the anthocyanin 5-O-acyltransferase gene (Gs5AT ) in the corolla, it is beneficial to analyse the mechanism of blue flower colour presentation. In this investigation, we obtained the CDS and promoter sequences of the gene Gs5AT . Yeast one-hybrid experiments were used to identify the transcription factor GsbHLH7 that activates the gene Gs5AT . According to quantitive reverse transcription polymerase chain reaction analysis, the expression of the gene Gs5AT was significantly and positively correlated with the gene GsbHLH7 . The colour phenotype of the flowers was significantly altered by the virus-induced gene silencing transduction of Gs5AT and GsbHLH7 , with GsbHLH7 silencing producing more pronounced changes in the corolla colour than Gs5AT . The expression of GsF3'5'H , GsDFR , GsANS , Gs3GT , and Gs5GT all fell to varying degrees after GsbHLH7 silencing, indicating that GsbHLH7 may regulate transcription of these genes as well as Gs5AT . The results of this study indicate that Gs5AT was positively regulated by the GsbHLH7 , and thus affects the colour presentation of the blue corolla.

'Benihoppe' and 'Fenyu No.1' are representative varieties of red and pink strawberries in China, possess distinct hue and flavor profiles. This study analyzed the underlying biochemical and molecular differences of two varieties utilizing transcriptomics and high-performance liquid chromatography (HPLC). Ripening 'Benihoppe' fruits accumulated more sucrose and pelargonin-3-glucoside (P3G) with a little cyanidin and higher firmness. Whereas ripening 'Fenyu No.1' fruits contained more fructose, glucose, malic acid and ascorbic acid (AsA), but less P3G and citric acid. Moreover, genotype significantly influenced phenolic compounds contents in strawberries. Transcriptome analysis revealed that pectin degradation (PL, PG, PE), sucrose synthesis (CWINV, SUS, TPS) and citric acid metabolism (α-OGDH, ICDH, GAD, GS, GDH, PEPCK, AST) were weakened in 'Benihoppe' fruit. In contrast, the synthesis of sucrose (CWINH, SPS), citric acid (CS, PEPC), anthocyanin (F3H, F3'H, F3'5'H, DFR, UFGT and ANS), and citric acid transport (V-ATPase) was enhanced. In 'Fenyu No.1' fruit, the degradation of sucrose, citric acid, and pectin was enhanced, along with the synthesis of malic acid (ME) and ascorbic acid (PMM, MDHAR and GaLUR). However, anthocyanins synthesis, glucose metabolism (HK, G6PI, PFK, G6PDH, PGK, PGM, ENO, PK), fructose metabolism (FK), citric acid synthesis and transport, and AsA degradation (AO, APX) were relatively weak. RT-qPCR results corroborated the transcriptome data. In conclusion, this study revealed the distinctions and characteristics of strawberries with different fruit colors regarding texture, flavor and color formation processes. These findings offer valuable insights for regulating metabolic pathways and identifying key candidate genes to improve strawberry quality., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

Background: Understanding the molecular basis of sport mutations in fruit trees has the potential to accelerate generation of improved cultivars., Results: For this, we analyzed the genome of the apple tree that developed the RubyMac phenotype through a sport mutation that led to the characteristic fruit coloring of this variety. Overall, we found 46 somatic mutations that distinguished the mutant and wild-type branches of the tree. In addition, we found 54 somatic gene conversions (i.e., loss-of-heterozygosity mutations) that also distinguished the two parts of the tree. Approximately 20% of the mutations were specific to individual cell lineages, suggesting that they originated from the corresponding meristematic layers. Interestingly, the de novo mutations were enriched for GC =  > AT transitions while the gene conversions showed the opposite bias for AT =  > GC transitions, suggesting that GC-biased gene conversions have the potential to counteract the AT-bias of de novo mutations. By comparing the gene expression patterns in fruit skins from mutant and wild-type branches, we found 56 differentially expressed genes including 18 involved in anthocyanin biosynthesis. While none of the differently expressed genes harbored a somatic mutation, we found that some of them in regions of the genome that were recently associated with natural variation in fruit coloration., Conclusion: Our analysis revealed insights in the characteristics of somatic change, which not only included de novo mutations but also gene conversions. Some of these somatic changes displayed strong candidate mutations for the change in fruit coloration in RubyMac., (© 2024. The Author(s).)

Anthocyanins and proanthocyanidins (PAs) are important secondary metabolites in plants, high contents of which are an important goal for quality breeding of white clover (Trifolium repens). However, the involvement of glutathione S-transferase (GST) in the transport of anthocyanins and PAs remains unexplored in white clover. This study identified 153 different TrGSTs in white clover. At the transcriptional level, compared to other TrGSTFs, TrGSTF10 and TrGSTF15 are highly expressed in the 'Purple' white clover, and they may work with the anthocyanin biosynthesis structural genes CHS and CHI to contribute to pigment buildup in white clover. Subcellular localization confirmed that TrGSTF10 and TrGSTF15 are located in the cytoplasm. Additionally, molecular docking experiments showed that TrGSTF10 and TrGSTF15 have similar binding affinity with two flavonoid monomers. Overexpression of TrGSTF15 complemented the deficiency of anthocyanin coloring and PA accumulation in the Arabidopsis tt19 mutant. The initial findings of this research indicate that TrGSTF15 encodes an important transporter of anthocyanin and PA in white clover, thus providing a new perspective for the further exploration of related transport and regulatory mechanisms., Competing Interests: Declaration of competing interest We declare no conflict of interest of the manuscript “Functional characterization of TrGSTF15, a glutathione S-transferase (GST) gene family member, on the transport and accumulation of anthocyanins and proanthocyanidins in Trifolium repens”., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

Asparagus is a key global vegetable crop with significant economic importance. Purple asparagus, rich in anthocyanins, stands out for its nutritional value. Despite its prominence, the molecular mechanisms driving purple peel coloration in asparagus remain unclear. This study focuses on three asparagus varieties with distinct peel colors to analyze anthocyanins in both the metabolome and transcriptome, unraveling the regulatory mechanisms. Our findings identify 30 anthocyanins, categorized into five major anthocyanin aglycones across diverse asparagus peel colors. Notably, among the 30 differentially expressed metabolites (DEMs), 18 anthocyanins displayed significantly up-regulated expression in the 'Purple Passion' variety. Key contributors include Cyanidin-3-O-rutinoside-5-O-glucoside and Cyanidin-3-O-sophoroside. Cyanidin-3-O-glucoside is most abundant in 'Purple Passion', while Petunidin-glucoside-galactoside is the least. Analysis of differentially expressed genes (DEGs) displayed 21 structural genes in anthocyanin synthesis, with F3H, DFR, ANS, and one of three UFGTs showing significantly higher expression in the 'Purple Passion' compared to 'Grande' and 'Erasmus'. Additionally, transcription factors (TFs), including 38 MYB, 33 bHLH, and 13 bZIP, also display differential expression in this variety. Validation through real-time qPCR supports the idea that increased expression of anthocyanin structural genes contribute to anthocyanin accumulation. Transient overexpression of AoMYB17 in tobacco further showed that it had the vital function of increasing anthocyanin content. This study sheds light on the mechanisms behind anthocyanin coloration in three distinct asparagus peels. Therefore, it lays the foundation for potential genetic enhancements, aiming to develop new purple-fleshed asparagus germplasms with heightened anthocyanin content., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

Anthocyanins are high-value natural compounds, but to date, their production still mainly relies on extraction from plants. A five-step metabolic pathway was constructed in probiotic Lactococcus lactis NZ9000 for rapid, stable, and glycosylated anthocyanin biosynthesis using chalcone as a substrate. The genes were cloned from anthocyanin-rich blueberry: chalcone isomerase (CHI), flavanone 3-hydroxylase (F3H), dihydroflavonol 4-reductase (DFR), anthocyanin synthase (ANS), and UDPG-flavonoid 3-O-glycosyltransferase (3GT). Using HR, the polysaccharide pellicle (PSP) segment of the cell wall polysaccharide synthesis (cwps) gene cluster from L. lactis NZ9000 was cloned into vector p15A-Cm-repDE. Then, CHI and F3H were placed sequentially under the control of NZProm 3 of this gene cluster in the vector, which was transformed into L. lactis NZ9000 to obtain Strain A. Furthermore, Strain B was constructed by placing F3H-DFR-ANS and 3GT under NZProm 2 and 3, respectively. Using LC-MS/MS analysis, several types of anthocyanins, including callistephin chloride, oenin chloride, malvidin O-hexoside, malvidin 3,5-diglucoside, and pelargonidin 3-O-malonyl-malonylhexoside, increased in the supernatant of the co-culture of Strains A and B compared to that of L. lactis NZ9000. This is the first time that a five-step metabolic pathway has been developed for anthocyanin biosynthesis in probiotic L. lactis NZ9000. This work lays the groundwork for novel anthocyanin production by a process involving the placement of several biosynthesis genes under the control of a gene cluster., (© 2024 Wiley‐VCH GmbH.)

Light exposure significantly impacted the coloration and metabolism of Auricularia cornea, although the underlying mechanisms remain unclear. This study aimed to test the apparent color and pigment metabolic profiles of A. cornea in response to red (λp = 630 nm) and blue (λp = 463 nm) visible light exposure. Colorimeter analysis showed that fruiting bodies appeared bright-white under red-light and deeper-red under blue-light, both with a yellow tinge. On the 40th day of light-exposure, bodies were collected for metabolite detection. A total of 481 metabolites were targeted analysis, resulting in 18 carotenoids and 11 anthocyanins. Under red and blue light exposure, the total carotenoids levels were 1.1652 μg/g and 1.1576 μg/g, the total anthocyanins levels were 0.0799 μg/g and 0.1286 μg/g, respectively. Four differential metabolites and three putative gene linked to the visual coloration of A. cornea were identified. This pioneering study provides new insights into the role of light in regulating A. cornea pigmentation and metabolic profile., Competing Interests: Declaration of Competing Interest The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

In this study, we assessed the impact of varied water deficit irrigation frequencies (T1: 2.5 L/4 days; T2: 5 L/8 days; CK: 5 L/4 days) on Zitian Seedless grapes from veraison to post-ripening. Notably, total soluble solids increased during on-tree storage compared to at maturity, while total anthocyanin content decreased, particularly in CK (60.16%), T1 (62.35%), and less in T2 (50.54%). Glucose and fructose levels increased significantly in T1 and T2, more so in T2, but slightly declined in CK. Tartaric acid content increased by 41.42% in T2. Moreover, compared to regular irrigation, water deficit treatments enhanced phenolic metabolites and volatile compounds, including chlorogenic acid, various flavonoids, viniferin, hexanal, 2-nonenal, 2-hexen-1-ol, (E)-, 3-hydroxy-dodecanoic acid, and 1-hexanol, etc. Overall, the T2 treatment outperformed T1 and CK in maintaining grape quality. This study reveals that combining on-tree storage with water deficit irrigation not only improves grape quality but also water efficiency., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The garden strawberry (Fragaria x ananassa Duch.) is cultivated and consumed worldwide because of the pleasant flavor and health-promoting phytochemicals of its false fruits. Monocrop cultivars produce fully ripe strawberries in about one month post-anthesis throughout the spring, while everbearing cultivars undergo additional strawberry production in autumn. In this work, we evaluated the impact of different season-dependent environmental conditions on the ripening program of an everbearing field-gown strawberry variety from autumn 2015 to spring 2016. We combined ad hoc sampling and environmental data collection with LC-MS-based untargeted metabolomics to dissect the effects of cumulative temperature and solar irradiation on fruit quality parameters and secondary metabolism during ripening. Different dynamics in specific sub-groups of metabolites were observed in strawberries experiencing distinct amounts of cumulative temperature and solar irradiation during spring and autumn. The integration of statistical analyses on collected data revealed that solar irradiation mainly affected fruit fresh weight and organic acid levels, whereas temperature had a more selective effect on the accumulation of specific flavonols, anthocyanins, and soluble sugar. These findings are of suitable interest to design further approaches for the study of the complex interactions among environmental conditions and ripening in strawberries grown in a real-world scenario., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

Background: Polymorphisms are common in nature, but they are rarely shared among closely related species. Polymorphisms could originate through convergence, ancestral polymorphism, or introgression. Although shared neutral genomic variation across species is commonplace, few examples of shared functional traits exist. The blue-orange petal color polymorphisms in two closely related species, Lysimachia monelli and L. arvensis were investigated with UV-vis reflectance spectra, flavonoid biochemistry, and transcriptome comparisons followed by climate niche analysis., Results: Similar color morphs between species have nearly identical reflectance spectra, flavonoid biochemistry, and ABP gene expression patterns. Transcriptome comparisons reveal two orange-specific genes directly involved in both blue-orange color polymorphisms: DFR-2 specificity redirects flux from the malvidin to the pelargonidin while BZ1-2 stabilizes the pelargonidin with glucose, producing the orange pelargonidin 3-glucoside. Moreover, a reduction of F3'5'H expression in orange petals also favors pelargonidin production. The climate niches for each color morph are the same between the two species for three temperature characteristics but differ for four precipitation variables., Conclusions: The similarities in reflectance spectra, biochemistry, and ABP genes suggest that a single shift from blue-to-orange shared by both lineages is the most plausible explanation. Our evidence suggests that this persistent flower color polymorphism may represent an ancestrally polymorphic trait that has transcended speciation, yet future analyses are necessary to confidently reject the alternative hypotheses., (© 2024. The Author(s).)

Background: Oil palm (Elaeis guineensis Jacq.) is a very important tropical woody oil plant with high commercial and ornamental value. The exocarp of the oil palm fruit is rich in anthocyanosides and proanthocyanidins, which not only give it a bright colour, but also mark the maturity of the fruit. The study of the dynamic change pattern of anthocyanoside content and important anthocyanoside metabolism-related regulatory genes during oil palm ripening is conducive to the improvement of the ornamental value of oil palm and the determination of the optimal harvesting period of the fruits., Methods: We analyzed the virescens oil palm (AS) and nigrescens oil palm (AT) at 95 days (AS1, AT1), 125 days (AS2, AT2) and 185 days (AS3, AT3) after pollination were used as experimental materials for determining the changes in the total amount of anthocyanins as well as their metabolomics and transcriptomics studies by using the LC-MS/MS technique and RNA-Seq technique., Result: The results showed that the total anthocyanin content decreased significantly from AS1 (119 µg/g) to AS3 (23 µg/g), and from AT1 (1302 µg/g) to AT3 (170 µg/g), indicating a clear decreasing trend during fruit development. Among them, the higher flavonoids in AS and AT included anthocyanins such as peonidin-3-O-rutinoside (H35), pelargonidin-3-O-rutinoside (H21), and cyanidin-3-O-glucoside (H7), as well as condensed tannins such as procyanidin B2 (H47), procyanidin C1 (H49), and procyanidin B3 (H48). Notably, nine genes involved in the anthocyanin biosynthetic pathway exhibited up-regulated expression during the pre-development stage of oil palm fruits, particularly during the AS1 and AT1 periods. These genes include: Chalcone synthase (CHS; LOC105036364); Flavanone 3-hydroxylase (F3H; LOC105054663); Dihydroflavonol 4-reductase (DFR; LOC105040724, LOC105048473); Anthocyanidin synthase (ANS; LOC105035842), UDP-glucose: flavonoid 3-O-glucosyltransferase (UFGT; LOC105039612); Flavonoid 3',5'-hydroxylase (F3'5'H; LOC105036086, LOC105044124, LOC105045493). In contrast, five genes demonstrated up-regulated expression as the fruits developed, specifically during the AS3 and AT3 periods. These genes include: Chalcone synthase (CHS; LOC105036921, LOC105035716); Chalcone isomerase (CHI; LOC105045978); UDP-glucose: flavonoid 3-O-glucosyltransferase (UFGT; LOC105046326); Flavonoid 3'-hydroxylase (F3'H; LOC105036086)., Conclusion: Most of differentially expressed genes exhibited up-regulation during the early stages of fruit development, which may contribute to the elevated anthocyanin content observed in oil palm fruits of both types during the pre-developmental period. Furthermore, the expression levels of most genes were found to be higher in the AT fruit type compared to the AS fruit type, suggesting that the differential expression of these genes may be a key factor underlying the differences in anthocyanoside production in the exocarp of oil palm fruits from these two fruit types. The findings of this study provide a theoretical foundation for the identification and characterization of genes involved in anthocyanin synthesis in oil palm fruits, as well as the development of novel variations using molecular biology approaches., (© 2024. The Author(s).)

Microalgae like Chlamydomonas are beneficial organisms employed as biological stimulants to improve plants' growth, fruit quality, and stress tolerance. In the current study, the effects of Chlamydomonas sp. foliar spraying (0, 20, and 40 ml L -1 ) were assayed on Camarosa strawberry plants under salinity stress (0, 40, and 80 mM NaCl). The results showed that the foliar application of Chlamydomonas extract influenced strawberry's morphological, physiological, and biochemical characteristics under salinity stress. Foliar treatment of Chlamydomonas extract with and without salinity stress increased the leaf number and leaf area, the leaf relative water content, and photosynthetic pigments content. Moreover, the foliar application of Chlamydomonas extract decreased lipid peroxidation and hydrogen peroxide content and, on the other hand, enhanced the antioxidant enzymes activity (superoxide dismutase, guaiacol peroxidase, and peroxidase), phenolics, flavonoids, and anthocyanins content under salinity stress. For instance, the highest total antioxidant capacity was found in the plants foliar treated with 40 ml L -1  of Chlamydomonas algae extract under 80 mM salinity stress, which increased by 102.4% compared to the controls, as well as the highest total phenolic compounds and anthocyanin's content were 30.22, and 7.2% more than the control plants, respectively. Overall, the foliar application of Chlamydomonas algae extracts, especially at a concentration of 20 ml L -1  enhanced the strawberry's growth, yield, and physiological traits under saline conditions. The results with more detailed evaluations will be advisable for the pioneer farmers and extension section., (© 2024. The Author(s).)

Background: While water availability is important for quality at harvest, it also continues to influence the quality of pomegranates during storage. Reducing the amount of irrigation, in addition to water saving has different effects on bioactive compounds of pomegranate during storage time. This study was conducted to determine the influence of irrigation level on fruit quality changes during storage period of two commercial Iranian pomegranate cultivars ('Shishecap' and 'Malas-Yazdi'). Sustained deficit irrigation (SDI) was applied to plants that received 75% (moderate stress) or 50% (severe stress) of their normal water requirement. A control group received 100% of their water requirement., Results: At harvest time and during storage period, fruit weight loss and some biochemical traits such as fruit total soluble solids (TSS), titratable acidity (TA), pH, total phenolic compounds (TPC), total anthocyanins content (TAC), antioxidant activity and vitamin C were measured in pomegranate fruits. Also, the quantity of the produced product was also measured at the time of harvesting. Results indicated that control fruits exhibited more weight loss than those produced under water deficit during the storage period in both years. According to results, fruit TSS, TAC, and antioxidant activity significantly increased during storage period but fruit TA and vitamin C significantly decreased throughout storage period. Also, reduction in irrigation level resulted in a decline in the yield., Conclusions: This study revealed a crucial link between irrigation level and the quality of pomegranate fruits, despite a reduction in the yield. This included affecting weight loss and the content of bioactive compounds, both at harvest and during storage., (© 2024. The Author(s).)

Strawberry (Fragaria × ananassa) is a model plant for studying non-climacteric fruit ripening regulated by abscisic acid (ABA); however, the signaling of ABA in the regulation of fruit coloration is not fully understood. In this study, we identified the transcription factor BASIC HELIX-LOOP-HELIX 3 (bHLH3) as being key to fruit coloration via yeast two-hybrid library screening using the bait SUCROSE NONFERMENTING 1 (SNF1)-RELATED PROTEIN KINASE 2 (SnRK2.6), which is a core ABA signaling component that negatively regulates ripening. The interaction was also confirmed by firefly luciferase complementation assays and pull-down assays. RT-qPCR and western blot analysis confirmed that bHLH3 is expressed ubiquitously in strawberry tissues, and it is expressed stably during fruit development. Overexpression and RNAi of both bHLH3 and SnRK2.6 demonstrated that bHLH3 and SnRK2.6 promote and inhibit strawberry fruit coloration, respectively. Using EMSAs, we showed that bHLH3 promotes the expression of UDP-GLUCOSE: FLAVONOL-O-GLUCOSYLTRANSFERASE (UFGT), a key gene for anthocyanin biosynthesis, by directly binding to its promoter. We determined that SnRK2.6 can phosphorylate bHLH3 and that this inhibits its binding to the UFGT promoter, consequently suppressing expression. Altogether, we propose that increased ABA content during strawberry fruit ripening leads to decreased expression of SnRK2.6, which in turn releases the phosphorylation of bHLH3 and thereby enhances UFGT expression, ultimately promoting the coloration of the fruit., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Anthocyanins are bioactive compounds responsible for various physiological processes in plants and provide characteristic colors to fruits and flowers. Their biosynthetic pathway is well understood; however, the enzymatic degradation mechanism is less explored. Anthocyanase (β-glucosidase (BGL)), peroxidase (POD), and polyphenol oxidase (PPO) are enzymes involved in degrading anthocyanins in plants such as petunias, eggplants, and Sicilian oranges. The aim of this work was to investigate the physicochemical interactions between these enzymes and the identified anthocyanins (via UPLC-MS/MS) in cranberry ( Vaccinium macrocarpon ) through molecular docking to identify the residues likely involved in anthocyanin degradation. Three-dimensional models were constructed using the AlphaFold2 server based on consensus sequences specific to each enzyme. The models with the highest confidence scores (pLDDT) were selected, with BGL, POD, and PPO achieving scores of 87.6, 94.8, and 84.1, respectively. These models were then refined using molecular dynamics for 100 ns. Additionally, UPLC-MS/MS analysis identified various flavonoids in cranberries, including cyanidin, delphinidin, procyanidin B2 and B4, petunidin, pelargonidin, peonidin, and malvidin, providing important experimental data to support the study. Molecular docking simulations revealed the most stable interactions between anthocyanase and the anthocyanins cyanidin 3-arabinoside and cyanidin 3-glucoside, with a favorable ΔG of interaction between -9.3 and -9.2 kcal/mol. This study contributes to proposing a degradation mechanism and seeking inhibitors to prevent fruit discoloration.

Fruit color is a key feature of fruit quality, primarily influenced by anthocyanin or carotenoid accumulation or chlorophyll degradation. Adapting the pigment content is crucial to improve the fruit's nutritional and commercial value. Genetic factors along with other environmental components (i.e., light, temperature, nutrition, etc.) regulate fruit coloration. The fruit coloration process is influenced by plant hormones, which also play a vital role in various physiological and biochemical metabolic processes. Additionally, phytohormones play a role in the regulation of a highly conserved transcription factor complex, called MBW (MYB-bHLH-WD40). The MBW complex, which consists of myeloblastosis (MYB), basic helix-loop-helix (bHLH), and WD40 repeat (WDR) proteins, coordinates the expression of downstream structural genes associated with anthocyanin formation. In fruit production, the application of plant hormones may be important for promoting coloration. However, concerns such as improper concentration or application time must be addressed. This article explores the molecular processes underlying pigment formation and how they are influenced by various plant hormones. The ABA, jasmonate, and brassinosteroid increase anthocyanin and carotenoid formation, but ethylene, auxin, cytokinin, and gibberellin have positive as well as negative effects on anthocyanin formation. This article establishes the necessary groundwork for future studies into the molecular mechanisms of plant hormones regulating fruit color, ultimately aiding in their effective and scientific application towards fruit coloration., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

Basic leucine zipper (bZIP) transcription factors (TFs) play a crucial role in anthocyanin accumulation in plants. In addition to bZIP TFs, abscisic acid (ABA) increases anthocyanin biosynthesis. Therefore, this study aimed to investigate whether bZIP TFs are involved in ABA-induced anthocyanin accumulation in sweet cherry and elucidate the underlying molecular mechanisms. Specifically, the BLAST method was used to identify bZIP genes in sweet cherry. Additionally, we examined the expression of ABA- and anthocyanin-related genes in sweet cherry following the overexpression or knockdown of a bZIP candidate gene. In total, we identified 54 bZIP -encoding genes in the sweet cherry genome. Basic leucine zipper 6 ( bZIP6 ) showed significantly increased expression, along with increased anthocyanin accumulation in sweet cherry. Additionally, yeast one-hybrid and dual-luciferase assays indicated that PavbZIP6 enhanced the expression of anthocyanin biosynthetic genes ( PavDFR , PavANS , and PavUFGT ), thereby increasing anthocyanin accumulation. Moreover, PavbZIP6 interacted directly with the PavBBX6 promoter, thereby regulating PavNCED1 to promote abscisic acid (ABA) synthesis and enhance anthocyanin accumulation in sweet cherry fruit. Conclusively, this study reveals a novel mechanism by which PavbZIP6 mediates anthocyanin biosynthesis in response to ABA and contributes to our understanding of the mechanism of bZIP genes in the regulation of anthocyanin biosynthesis in sweet cherry.

This study investigated the effects of high hydrostatic pressure (HHP) on the binding interactions of cyanindin-3-O-glucoside (C3G) to bovine serum albumin, human serum albumin (HSA), bovine lactoferrin, and ovotransferrin. Fluorescence quenching revealed that HHP reduced C3G-binding affinity to HSA, while having a largely unaffected role for the other proteins. Notably, pretreating HSA at 500 MPa significantly increased its dissociation constant with C3G from 24.7 to 34.3 μM. Spectroscopic techniques suggested that HSA underwent relatively pronounced tertiary structural alterations after HHP treatments. The C3G-HSA binding mechanisms under pressure were further analyzed through molecular dynamics simulation. The localized structural changes in HSA under pressure might weaken its interaction with C3G, particularly polar interactions such as hydrogen bonds and electrostatic forces, consequently leading to a decreased binding affinity. Overall, the importance of pressure-induced structural alterations in proteins influencing their binding with anthocyanins was highlighted, contributing to optimizing HHP processing for anthocyanin-based products., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Dihydroflavonol 4-reductase (DFR) significantly influences the modification of flower color. To explore the role of DFR in the synthesis of strawberry anthocyanins, in this study, we downloaded the CDS sequences of the DFR gene family from the Arabidopsis genome database TAIR; the DFR family of forest strawberry was compared; then, a functional domain screen was performed using NCBI; the selected strawberry DFR genes were analyzed; and the expression characteristics of the family members were studied by qRT-PCR. The results showed that there are 57 members of the DFR gene family in strawberry, which are mainly expressed in the cytoplasm and chloroplast; most of them are hydrophilic proteins; and the secondary structure of the protein is mainly composed of α-helices and random coils. The analysis revealed that FvDFR genes mostly contain light, hormone, abiotic stress, and meristem response elements. From the results of the qRT-PCR analysis, the relative expression of each member of the FvDFR gene was significantly different, which was expressed throughout the process of fruit coloring. Most genes had the highest expression levels in the full coloring stage (S4). The expression of FvDFR30 , FvDFR54 , and FvDFR56 during the S4 period was 8, 2.4, and 2.4 times higher than during the S1 period, indicating that the DFR gene plays a key role in regulating the fruit coloration of strawberry. In the strawberry genome, 57 members of the strawberry DFR gene family were identified. The higher the DFR gene expression, the higher the anthocyanin content, and the DFR gene may be the key gene in anthocyanin synthesis. Collectively, the DFR gene is closely related to fruit coloring, which lays a foundation for further exploring the function of the DFR gene family.

Long non-coding RNAs (lncRNAs), a class of important regulatory factors for many biological processes in plants, have received much attention in recent years. To explore the molecular roles of lncRNAs in sweet cherry fruit ripening, we conducted widely targeted metabolome, transcriptome and lncRNA analyses of sweet cherry fruit at three ripening stages (yellow stage, pink stage, and dark red stage). The results show that the ripening of sweet cherry fruit involves substantial metabolic changes, and the rapid accumulation of anthocyanins (cyanidin 3-rutinoside, cyanidin 3-O-galactoside, and cyanidin 3-O-glucoside) is the main cause of fruit coloration. These ripening-related alterations in the metabolic profile are driven by specific enzyme genes related to the synthesis and decomposition of abscisic acid (ABA), cell wall disintegration, and anthocyanin biosynthesis, as well as transcription factor genes, such as MYBs , bHLHs , and WD40s . LncRNAs can target these ripening-related genes to form regulatory modules, incorporated into the sweet cherry fruit ripening regulatory network. Our study reveals that the lncRNA-mRNA module is an important component of the sweet cherry fruit ripening regulatory network. During sweet cherry fruit ripening, the differential expression of lncRNAs will meditate the spatio-temporal specific expression of ripening-related target genes (encoding enzymes and transcription factors related to ABA metabolism, cell wall metabolism and anthocyanin metabolism), thus driving fruit ripening.

Chlorophyll (Chl) catabolism and anthocyanin synthesis play pivotal roles in determining the final skin color of fruits during maturation. However, in peach ( Prunus persica ) fruit, the regulatory mechanism governing skin color, especially the Chl catabolism, remains largely elusive. In this study, we identified ten Chl catabolic genes (CCGs), with PpSGR emerging as a key regulator in Chl degradation in peaches. Furthermore, a NAC-like, activated by AP3/P1 (NAP) transcription factor (TF), PpNAP4, was identified as a positive modulator of Chl breakdown. PpNAP4 induced the expression of PpSGR and other CCGs, including PpPPH , PpPAO , and PpTIC55-2 , by directly binding to their promoters. Overexpression of PpNAP4 resulted in a heightened expression of these genes and accelerated Chl degradation. Notably, PpNAP4 also positively regulated the expression of PpANS and PpMYB10.1 , one key structural gene and a core transcriptional regulator of anthocyanin synthesis, thereby contributing to fruit coloration. In summary, our findings elucidate that PpNAP4 serves as a pivotal regulator in determining the final skin color of peach by orchestrating Chl degradation and anthocyanin accumulation through direct activation of multiple CCGs and anthocyanin related genes.

Plants are increasingly vulnerable to environmental stresses because of global warming and climate change. Stress-induced reactive oxygen species (ROS) accumulation results in plant cell damage, even cell death. Anthocyanins are important antioxidants that scavenge ROS to maintain ROS homeostasis. However, the mechanism underlying ROS-induced anthocyanin accumulation is unclear. In this study, we determined that the HD-Zip I family member transcription factor PuHB40 mediates ROS-dependent anthocyanin biosynthesis under high-light stress in pear (Pyrus ussuriensis). Specifically, PuHB40 induces the PuMYB123-like-PubHLH3 transcription factor complex for anthocyanin biosynthesis. The PuHB40-mediated transcriptional activation depends on its phosphorylation level, which is regulated by protein phosphatase PP2A. Elevated ROS content maintains high PuHB40 phosphorylation levels while also enhancing the PuHB40-induced PuMYB123-like transcription by decreasing the PuPP2AA2 expression, ultimately leading to increased anthocyanin biosynthesis. Our study reveals a pathway regulating the ROS-induced anthocyanin biosynthesis in pears, further clarifying the mechanism underlying the abiotic stress-induced anthocyanin biosynthesis, which may have implications for improving plant stress tolerance., Competing Interests: Conflict of interest statement. The authors declare that they have no competing interests., (© The Author(s) 2024. Published by Oxford University Press on behalf of American Society of Plant Biologists. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Anthocyanins play critical roles in protecting plant tissues against diverse stresses. The complicated regulatory networks induced by various environmental factors modulate the homeostatic level of anthocyanins. Here, we show that anthocyanin accumulation is induced by brassinosteroids (BRs) in Arabidopsis (Arabidopsis thaliana) shoots and shed light on the underlying regulatory mechanism. We observed that anthocyanin levels are altered considerably in BR-related mutants, and BRs induce anthocyanin accumulation by upregulating the expression of anthocyanin biosynthetic genes. Our genetic analysis indicated that BRASSINAZOLE RESISTANT 1 (BZR1) and PRODUCTION OF ANTHOCYANIN PIGMENT 1 (PAP1) are essential for BR-induced anthocyanin accumulation. The BR-responsive transcription factor BZR1 directly binds to the PAP1 promoter, regulating its expression. In addition, we found that intense anthocyanin accumulation caused by the pap1-D-dominant mutation is significantly reduced in BR mutants, implying that BR activity is required for PAP1 function after PAP1 transcription. Moreover, we demonstrated that BZR1 physically interacts with PAP1 to cooperatively regulate the expression of PAP1-target genes, such as TRANSPARENT TESTA 8, DIHYDROFLAVONOL 4-REDUCTASE, and LEUKOANTHOCYANIDIN DIOXYGENASE. Our findings indicate that BZR1 functions as an integral component of the PAP1-containing transcription factor complex, contributing to increased anthocyanin biosynthesis. Notably, we also show that functional interaction of BZR1 with PAP1 is required for anthocyanin accumulation induced by low nitrogen stress. Taken together, our results demonstrate that BR-regulated BZR1 promotes anthocyanin biosynthesis through cooperative interaction with PAP1 of the MBW complex., Competing Interests: Conflict of interest statement. The authors declare no confilct of interests., (© The Author(s) 2024. Published by Oxford University Press on behalf of American Society of Plant Biologists. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Background: The Flavonoid 3'-hydroxylase gene(F3'H) is an important structural gene in the anthocyanin synthesis pathway of plants, which has been proven to be involved in the color formation of organs such as leaves, flowers, and fruits in many plants. However, the mechanism and function in barley are still unclear., Results: In order to explore the molecular mechanism of the grain color formation of purple qingke, we used the cultivated qingke variety Nierumzha (purple grain) and the selected qingke variety Kunlun 10 (white grain) to conduct transcriptomic sequencing at the early milk, late milk and soft dough stage. Weighted Gene Co-expression Network Analysis (WGCNA) was used to construct weighted gene co-expression network related to grain color formation, and three key modules (brown, yellow, and turquoise modules) related to purple grain of qingke were selected. F3'H (HORVU1Hr1G094880) was selected from the hub gene of the module for the yeast library, yeast two-hybrid (Y2H), subcellular localization and other studies. It was found that in purple qingke, HvnF3'H mainly distributed in the cytoplasm and cell membrane and interacted with several stress proteins such as methyltransferase protein and zinc finger protein., Conclusions: The results of this study provide reference for the regulation mechanism of anthocyanin-related genes in purple grain qingke., (© 2024. The Author(s).)

Background: Grape peels, the main by-products of wine processing, are rich in bioactive ingredients of phenolics, including proanthocyanidins, flavonoids and anthocyanins. Phenolics have the function of regulating intestinal microbiota and promoting intestinal health. From the perspective of the dietary nutrition of grape peel phenolics (GPP), the present study aimed to investigate the influence of GPP on the composition and metabolism of human gut microbiota during in vitro fermentation., Results: The results indicated that GPP could decrease pH and promote the production of short-chain fatty acids. ACE and Chao1 indices in GPP group were lower than that of the Blank group. GPP enhanced the levels of Lachnospiraceae UCG-004, Bacteroidetes and Roseburia, but reduced the Firmicutes/Bacteroidetes ratio. Kyoto Encyclopedia of Proteins and Genome enrichment pathways related to phenolic acid metabolism mainly included flavonoid, anthocyanin, flavone and flavonol biosynthesis. Gut microbiota could accelerate the release and breakdown of phenolic compounds, resulting in a decrease in the content of hesperetin-7-O-glucoside, delphinidin-3-O-glucoside and cyanidin-3-rutinoside etc. In vitro antibacterial test found that GPP increased the diameters of the inhibition zones of Escherichia coli and Staphylococcus aureus in a dose-dependent manner., Conclusion: The results of the present study revealed that GPP might be a potential prebiotic-like to prevent diseases by improving gut health. The findings could provide a theoretical basis for the potential to exploit GPP as dietary nutrition to maintain intestinal function. © 2024 Society of Chemical Industry., (© 2024 Society of Chemical Industry.)

Receptor-like kinase (ERECTA, ER) is essential for mediating growth, development, and stress response signaling pathway in plants. In this study, we investigated the effect of VvER on anthocyanin synthesis as a regulatory factor in transgenic grape callus in response to chilling stress. Results showed that overexpression of VvER reduced the expression of transcription factors VvMYBA1, VvMYB5b, VvMYC2, and VvWDR1, as well as the structural genes VvCHS, VvCHI, VvDFR, VvLDOX, and VvUFGT, and inhibited the anthocyanins synthesis of grape callus at 25℃. VvER reduced proline content and antioxidant enzymes activities of superoxide dismutase (SOD) and peroxidase (POD), and inhibited the expression of anthocyanin synthesis genes to reduce the cold resistance of grape callus. In transgenic Arabidopsis, overexpression of VvER promoted the elongation of Arabidopsis rosettes and sprigs. Under strong light treatment, VvER inhibited the accumulation of anthocyanins in Arabidopsis; Transient expression in strawberry fruit showed that VvER inhibited the synthesis of anthocyanin in strawberry fruit by inhibiting the expression of FaCHI, FaCHS, FaDFR and FaUFGT under low temperature treatment at 10°C, but not under the normal temperature of 25℃. Using Yeast two-hybrid, we found that VvER interacted with transcription factor proteins including VvMYBA1, VvMYB5b and VvWDR1. Furthermore, VvER led to the repression of VvUFGT promoter activity and decreased the anthocyanin biosynthesis genes expression by downregulation MBW complex activity. Totally, VvER could inhibit anthocyanin biosynthesis and involve in the grape plant susceptible to cold stress for grape cultivation in northern China., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Global warming significantly threatens crop production, and adversely affects plant physiology due to rising temperatures. Oriental hybrid lily, an ornamental plant of economic importance, experiences flower color changes in response to elevated temperatures. Anthocyanins belong to a subgroup of flavonoids and are the primary pigments responsible for the coloration of oriental hybrid lily petals. However, the regulatory mechanisms governing flavonoid biosynthesis under high temperature conditions in lilies remain poorly understood. In this study, we revealed the altered metabolite profiles in flavonoid biosynthesis using quasi-targeted metabolomic and transcriptomic analyses. Isoflavonoids accumulate substantially under high temperature conditions, whereas the accumulation of anthocyanin decreases. The expression of the isoflavone reductase gene (LhIFR) and the transcription factor LhMYBC2 were upregulated in response to high temperatures. The LhMYBC2 protein, which belongs to Subgroup 4-AtMYB4, competes with the anthocyanin positive regulator LhMYBA1 for the LhTT8 partner, thereby repressing the formation of a positively regulated transcription complex. Heterologous overexpression of LhMYBC2 in tobacco led to reduced anthocyanin accumulation and increased isoflavonoid accumulation, corroborating its role in inhibiting anthocyanin biosynthesis. This study proposes a regulatory model wherein LhMYBC2 acts as a mediator of flavonoid biosynthesis, influencing the coloration of lily flowers under high-temperature stress. These findings deepen our understanding of the metabolic and transcriptional responses of lily to heat stress and underscore the potential role of LhMYBC2 in mitigating anthocyanin accumulation., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

Angelica sinensis, a traditional Chinese medicinal plant, has been primarily reported due to its nutritional value. Pigmentation in this plant is an important appearance trait that directly affects its commercial value. To understand the mechanism controlling purpleness in A. sinensis, hormonal and transcriptomic analyses were performed in three different tissues (leave, root and stem), using two cultivars with contrasting colors. The two-dimensional data set provides dynamic hormonal and gene expression networks underpinning purpleness in A. sinensis. We found abscisic acid as a crucial hormone modulating anthocyanin biosynthesis in A. sinensis. We further identified and validated 7 key genes involved in the anthocyanin biosynthesis pathway and found a specific module containing ANS as a hub gene in WGCNA. Overexpression of a candidate pigment regulatory gene, AsANS (AS08G02092), in transgenic calli of A. sinensis resulted in increased anthocyanin production and caused purpleness. Together, these analyses provide an important understanding of the molecular networks underlying A. sinensis anthocyanin production and its correlation with plant hormones, which can provide an important source for breeding., (© 2024 Scandinavian Plant Physiology Society.)

Anthocyanins are major flavonoid compounds with established health benefits. Although the molecular mechanisms of MYB transcription factors (TFs) within the MYB-basic helix-loop-helix (bHLH)-WD-repeat protein (MBW) complex in anthocyanin biosynthesis have been revealed, the functions of other MYB TFs that are unable to form the MBW complex in this process remain unclear. In this study, we uncovered and extensively characterized an R2R3-MYB TF in onion (Allium cepa L.), named AcMYB96, which was identified as a potential anthocyanin activator. AcMYB96 was classified into subgroup 1 of the R2R3-MYB TF family and lacked the conserved sequences required for interactions with bHLH IIIf TFs. Consistently, yeast two-hybrid assays showed that AcMYB96 did not interact with any bHLH IIIf TFs examined, including AcB2 and AtTT8. The transcription pattern of AcMYB96 correlated with the level of anthocyanin accumulation, and its role in activating anthocyanin biosynthesis was confirmed through overexpression in the epithelial cells of onion bulbs and Arabidopsis. Yeast one-hybrid, electrophoretic mobility shift, and promoter transactivation assays further demonstrated that AcMYB96 promoted anthocyanin biosynthesis by binding to the promoters of the chalcone synthase (AcCHS1), anthocyanidin synthase (AcANS), and UDP-glucose-flavonoid 3-O-glucosyltransferase (AcUFGT) genes, thereby activating their expression independent of bHLH IIIf TFs. These results demonstrate that AcMYB96 activates anthocyanin biosynthesis without forming the MBW complex, providing a theoretical foundation to further enrich the gene resources for promoting anthocyanin accumulation and breeding red onions with high anthocyanin content., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financialinterests or personal relationships that could have appeared to influencethe work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

Nitrogen (N) is a key factor for plant growth and affects anthocyanin synthesis. This study aimed to clarify the potential mechanisms of N levels (LN, 0 kg·ha -1 ; MN, 150 kg·ha -1 ; HN, 225 kg·ha -1 ) in anthocyanin synthesis and grain quality of colored grain wheat. HN increased the yield component traits and grain morphology traits in colored grain wheat while decreasing the processing and nutrient quality traits. Most quality traits were significantly negatively correlated with the yield composition and morphological traits. Anthocyanin was more accumulated under LN conditions, but other related yield and morphological traits of colored grain wheat declined. The anthocyanin content was the highest in blue wheat, followed by that in purple wheat. Cyanidin-3- O -(6- O -malonyl-β-d-glucoside) and cyanidin-3- O -rutinoside were the predominant anthocyanins in blue and purple wheat. The identified anthocyanin-related metabolites were associated with flavonoid biosynthesis, anthocyanin biosynthesis, and secondary metabolite biosynthesis. Therefore, the study provided information for optimizing nitrogen fertilizer management in producing high quality colored wheat and verified the close relationship between anthocyanin and low N condition.

Indoor farming systems enable plant production in precisely controlled environments. However, implementing stable growth conditions and the absence of stress stimulants can weaken plants' defense responses and limit the accumulation of bioactive, health-beneficial phytochemicals. A potential solution is the controlled application of stressors, such as supplemental ultraviolet (UV) light. To this end, we analyzed the efficiency of short-term pre-harvest supplementation of the red-green-blue (RGB, LED) spectrum with ultraviolet B (UV-B) or C (UV-C) light to boost phytochemical synthesis. Additionally, given the biological harm of UV radiation due to high-energy photons, we monitored plants' photosynthetic activity during treatment and their morphology as well as sensory attributes after the treatment. Our analyses showed that UV-B radiation did not negatively impact photosynthetic activity while significantly increasing the overall antioxidant potential of lettuce through enhanced levels of secondary metabolites (total phenolics, flavonoids, anthocyanins), carotenoids, and ascorbic acid. On the contrary, UV-C radiation-induced anthocyanin accumulation in the green leaf cultivar significantly harmed the photosynthetic apparatus and limited plant growth. Taken together, we showed that short-term UV-B light supplementation is an efficient method for lettuce biofortification with healthy phytochemicals, while UV-C treatment is not recommended due to the negative impact on the quality (morphology, sensory properties) of the obtained leafy products. These results are crucial for understanding the potential of UV light supplementation for producing functional plants.

As important secondary metabolites in plants, anthocyanins not only contribute to colored plants organs, but also provide protections against various biotic and abiotic stresses. In this study, a MYB transcription factor gene TdRCA1 from wild emmer wheat regulating anthocyanin biosynthesis in wheat coleoptile was identified on the short arm of chromosome 7A in common wheat genetic background. The TdRCA1 overexpression lines showed colored callus, coleoptile, auricle and stem nodes, as well as up regulation of six anthocyanin-related structural genes. The expression of TdRCA1 was activated by light in a temporal manner. While coleoptile color of 48 and 60 h dark-grown seedlings changed from green to red after 24 h light treatment, those grown in dark for 72 and 96 h failed to develop red coleoptiles after light restoration. Interestingly, the over expression of TdRCA1 resulted in increased resistance to Fusarium crown rot, a chronic and severe fungal disease in many cereal growing regions in the world. Our results offer a better understanding of the molecular basis of coleoptile color in bread wheat., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The present study attempted for the first time to investigate the metabolic fate of (poly)phenolic compounds provided by a hull-less and purple grain barley genotype biofortified in anthocyanins. Balb/c mice were supplemented either with standard purified diet (SD) or whole-grain barley supplemented diet (WGB) for six weeks. Subsequently, (poly)phenolic metabolites were determined in urine samples by UPLC-MS/MS, and the principal metabolic pathways were elucidated. Thirty-nine (poly)phenolics compounds were identified in WGB which were distributed between the free (58%) and bound (42%) fractions, encompassing anthocyanins, phenolic acids, flavan-3-ols and flavones. Upon WGB intake, forty-two (poly)phenolic metabolites were identified, predominantly comprising phase-II sulphate, glucuronide, and/or methylated conjugates, along with colonic catabolites. Noteworthy metabolites included peonidin-3- O -glucuronide, peonidin-3- O -6''- O -malonylglucoside, and peonidin-3- O -glucoside among anthocyanins; hydroxyphenylpropanoic acid- O -sulphate among phenolic acids; and 5-(3',4'-dihydroxyphenyl)-γ-valerolactone- O -sulphate among flavan-3-ols. Metabolites like phenylpropionic, phenylacetic, hydroxybenzoic, and hippuric acids were found in both WGB and SD groups, with higher levels after barley consumption, indicating both endogenous and polyphenolic metabolism origins. Overall, this study offers valuable insights into the metabolism of (poly)phenols in purple barley, setting the stage for future investigations into the health benefits linked to the consumption of purple grain barley.

Main Conclusion: Supplying monochromatic blue LED light during the day, but not at night, promotes early coloration and improves anthocyanin accumulation in the skin of grape berries. Specific light spectra, such as blue light, are known to promote the biosynthesis and accumulation of anthocyanins in fruit skins. However, research is scarce on whether supplement of blue light during different periods of one day can differ in their effect. Here, we compared the consequences of supplying blue light during the day and night on the accumulation of anthocyanins in pigmented grapevine (Vitis vinifera) berries. Two treatments of supplemented monochromatic blue light were tested, with light emitting diodes (LED) disposed close to the fruit zone, irradiating between 8:00 and 18:00 (Dayblue) or between 20:00 and 6:00 (Nightblue). Under the Dayblue treatment, berry coloration was accelerated and total anthocyanins in berry skins increased faster than the control (CK) and also when compared to the Nightblue condition. In fact, total anthocyanin content was similar between CK and Nightblue. qRT-PCR analysis indicated that Dayblue slightly improved the relative expression of the anthocyanin-structural gene UFGT and its regulator MYBA1. Instead, the expression of the light-reception and -signaling related genes CRY, HY5, HYH, and COP1 rapidly increased under Dayblue. This study provides insights into the effect of supplementing monochromatic LED blue light during the different periods of one day, on anthocyanins accumulation in the berry skin., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Flavonoids play an important role in forming wine grapes and wine quality characteristics. The flavonoids of three winter red wine grapes, Yeniang No. 2 (YN2), Marselan (Mar), and Guipu No. 6 (GP6), were analyzed by ultra-high-performance liquid chromatography-triple quadrupole mass spectrometry (UPLC-QQQ-MS). Furthermore, the flavonoids in GP6 grapevines using two types of training systems, namely, trellis (T) and espaliers (E), were also compared in this study. Overall, 196 flavonoid metabolites, including 96 flavones, 38 flavonols, 19 flavanones, 18 polyphenols, 15 anthocyanins, 7 isoflavones, and 3 proanthocyanidins, were identified. The flavonoid profiles were remarkably different among these three grape varieties, while they did not change much in the GP6 managed on trellis and espaliers. Grape varieties with different genetic backgrounds have their own unique flavonoid profiles. Compared with Mar-T, isoflavones and flavonols presented higher contents in GP6-T and YN2-T, which mainly contain glycitein, genistin, calycosin, kaempferide, isotrifoliin, and ayanin. The anthocyanin content was significantly higher in YN2-T than in the other two varieties. YN2 and GP6-T present a more stable color, with significantly more acetylated diglucosides and methylated anthocyanins in YN2-T and GP6-T than in Mar-T. Notably, GP6 had more varied flavonoids and the better characteristics to its flavonoid profile out of these three varieties, due to it containing a higher number of anthocyanins, flavone, and flavonols and the greatest number of different flavonoid metabolites (DFMs), with higher contents than YN2 and Mar. Compared with the trellis training system, the espaliers training system increased the content of flavonoids detected in GP6 grape berries; however, the composition of flavonoids strictly depends on the grape variety.

Rhododendron simsii Planchon is an important ornamental species in the northern hemisphere. Flower color is an important objective of Rhododendron breeding programs. However, information on anthocyanin synthesis in R. simsii is limited. In this research, the regulatory mechanism of anthocyanin biosynthesis in R. simsii was performed through the integrated analysis of metabolome and RNA-seq. A total of 805 and 513 metabolites were screened by positive and negative ionization modes, respectively, In total, 79 flavonoids contained seven anthocyanidins, 42 flavanones, 10 flavans, 13 flavones, and seven flavonols. Methylated and glycosylated derivatives took up the most. Differentially accumulated metabolites were mainly involved in "flavone and flavonol biosynthesis", "cyanoamino acid metabolism", "pyrimidine metabolism", and "phenylalanine metabolism" pathways. For flavonoid biosynthesis, different expression of shikimate O-hydroxycinnamoyltransferase , caffeoyl-CoA O-methyltransferase , flavonoid 3'-monooxygenase , flavonol synthase , dihydroflavonol 4-reductase/flavanone 4-reductase , F3'5'H , chalcone synthase , leucoanthocyanidin reductase , and 5-O-(4-coumaroyl)-D-quinate 3'-monooxygenase genes ultimately led to different accumulations of quercetin, myricetin, cyanidin, and eriodictyol. In flavone and flavonol biosynthesis pathway, differential expression of F3'5'H , flavonoid 3'-monooxygenase and flavonol-3-O-glucoside/galactoside glucosyltransferase genes led to the differential accumulation of quercetin, isovitexin, and laricitrin. This research will provide a biochemical basis for further modification of flower color and genetic breeding in R. simsii and related Rhododendron species.

The purple leaves of Brassica napus are abundant in anthocyanins, which are renowned for their role in conferring distinct colors, stress tolerance, and health benefits, however the genetic basis of this trait in B. napus remains largely unelucidated. Herein, the purple leaf B. napus (PL) exhibited purple pigments in the upper epidermis and a substantial increase in anthocyanin accumulation, particularly of cyanidin, compared to green leaf B. napus (GL). The genetic control of the purple leaf trait was attributed to a semi-dominant gene, pl, which was mapped to the end of chromosome A03. However, sequencing of the fragments amplified by the markers linked to pl indicated that they were all mapped to chromosome B05 from B. juncea. Within this B05 chromosomal segment, the BjMYB113 gene-specific marker showed perfect co-segregation with the purple leaf trait in the F 2 population, suggesting that the BjMYB113 introgression from B. juncea was the candidate gene for the purple leaf trait in B. napus. To further verify the function of candidate gene, CRISPR/Cas9 was performed to knock out the BjMYB113 gene in PL. The three myb113 mutants exhibited evident green leaf phenotype, absence of purple pigments in the adaxial epidermis, and a significantly reduced accumulation of anthocyanin compared to PL. Additionally, the genes involved in positive regulatory (TT8), late anthocyanin biosynthesis (DFR, ANS, UFGT), as well as transport genes (TT19) were significantly suppressed in the myb113 mutants, further confirming that BjMYB113 was response for the anthocyanin accumulation in purple leaf B. napus. This study contributes to an advanced understanding of the regulation mechanism of anthocyanin accumulation in B. napus., (© 2024. The Author(s).)

Purple carrot accumulates anthocyanins modified with galactose, xylose, glucose, and sinapic acid. Most of the genes associated with anthocyanin biosynthesis have been identified, except for the glucosyltransferase genes involved in the step before the acylation in purple carrot. Anthocyanins are commonly glycosylated in reactions catalyzed by UDP-sugar-dependent glycosyltransferases (UGTs). Although many studies have been conducted on UGTs, the glucosylation of carrot anthocyanins remains unknown. Acyl-glucose-dependent glucosyltransferase activity modifying cyanidin 3-xylosylgalactoside was detected in the crude protein extract prepared from purple carrot cultured cells. In addition, the corresponding enzyme was purified. The cDNA encoding this glucosyltransferase was isolated based on the partial amino acid sequence of the purified protein. The recombinant protein produced in Nicotiana benthamiana leaves via agroinfiltration exhibited anthocyanin glucosyltransferase activity. This glucosyltransferase belongs to the glycoside hydrolase family 3 (GH3). The expression pattern of the gene encoding this GH3-type anthocyanin glucosyltransferase was consistent with anthocyanin accumulation in carrot tissues and cultured cells., (© 2024 Society for Experimental Biology and John Wiley & Sons Ltd.)

Nonenzymatic glycosylation of proteins can generate advanced glycosylation end products, which are closely associated with the pathogenesis of certain chronic physiological diseases and aging. In this study, we characterized the covalent binding of cyanidin-3-glucoside (C3G) to bovine serum albumin (BSA) and investigated the mechanism by which this covalent binding inhibits the nonenzymatic glycosylation of BSA. The results indicated that the covalent interaction between C3G and BSA stabilized the protein's secondary structure. Through liquid chromatography-electrospray ionization tandem mass spectrometry analysis, we identified the covalent binding sites of C3G on BSA as lysine, arginine, asparagine, glutamine, and cysteine residues. This covalent interaction significantly suppressed the nonenzymatic glycosylation of BSA, consequently reducing the formation of nonenzymatic glycosylation products. C3G competitively binds to nonenzymatic glycosylation sites (e.g., lysine and arginine) on BSA, thereby impeding the glycosylation process and preventing the misfolding and structural alterations of BSA induced by fructose. Furthermore, the covalent attachment of C3G to BSA preserves the secondary structure of BSA and hinders subsequent nonenzymatic glycosylation events., (© 2024 Institute of Food Technologists.)