Anthocyanins Research Articles

A single nucleotide polymorphism affects protein translation and leads to post-anthesis color change variation in closely related Lotus species.

Flower color change, a common phenomenon that is important in pollination ecology, has intrigued scientists for decades. While previous flower color studies have mainly focused on color diversity among different plant species, our focus is on unraveling the mechanism of post-anthesis color change (PACC) and the molecular basis for its presence and absence, respectively, in two closely related species of Lotus, Lotus filicaulis and Lotus japonicus MG20. Metabolomic analysis reveals anthocyanins as the key metabolites responsible for the observed PACC. Differential expression of anthocyanin biosynthetic and transport genes causes the variation in PACC between the two Lotus species. Crucially, the significant upregulation of a functionally characterized MYB regulator, LfPAP1, is linked to the accumulation of anthocyanins and visible color alterations in L. filicaulis flowers. Notably, we uncover a nucleotide polymorphism in the initiation codon of LjPAP1. Although this mutation does not affect transcription, we show that it has a major effect in attenuating protein translation, reducing its capacity to activate anthocyanin biosynthesis, and leading to a failure of PACC in L. japonicus MG20. Our study sheds light on mechanisms of PACC phenomenon and highlights the potential for mutations in initiation sequences to generate phenotypic differences between species in evolution.

ArMYB89 and ArCOP1 interaction modulates anthocyanin biosynthesis in Acer rubrum leaves under low-temperature conditions.

Acer rubrum, a famous ornamental tree, produces bright red-coloured leaves because of the temperature decline from summer to autumn. This process's molecular mechanism is elusive, so we have investigated how anthocyanin biosynthesis is induced in A. rubrum leaves under low temperatures. The results of low-temperature treatment under light and dark conditions showed that the low-temperature promoted anthocyanin accumulation in A. rubrum is light-dependent. The transcriptome analysis showed that ArMYB89 was significantly highly expressed in leaves of A. rubrum growing under low temperatures with light conditions. The findings from the Dap-seq analysis, yeast one hybridisation, electrophoretic mobility shift assay and luciferase reporter assay indicated that the ArMYB89 transcription factor binds directly to the promoter of ArUGT52 and stimulates its transcription. The co-expression of ArUGT52 with ArMYB89 significantly induced anthocyanin levels under low temperatures with light conditions. Enzyme activity analysis showed that ArUGT52 could convert Cyanidins and Pelargonidins into Cyanidin-3-O-glucoside and Pelargonidin 3-glucoside, which are considered the main anthocyanins in red colour leaves of A. rubrum. The results of yeast two hybridisation, pulldown assay and bimolecular fluorescence complementation experiment showed an interaction between COP1 and ArMYB89, while in vivo and in vitro protein ubiquitination assay demonstrated that ArCOP1 ubiquitinates ArMYB89. Notably, co-expression of ArCOP1 with ArMYB89 significantly reduced anthocyanin levels, while the virus-induced gene silencing of ArCOP1 significantly induced anthocyanin levels under low temperatures with light conditions. In conclusion, this work revealed the molecular mechanism regulating anthocyanin accumulation in the A. rubrum leaves under low temperatures.

Identification of ANS gene regulating fruit color in jujube (Ziziphus jujuba Mill. cv. Lingwuchangzao) and analysis of its expression under elevated temperature and drought stress

BackgroundThe anthocyanin synthase (ANS) gene is pivotal in plant anthocyanin biosynthesis, significantly influencing fruit coloration. Despite extensive on various studies, there remains a notable absence of research on the regulatory functions of the ANS gene in the ‘Lingwuchangzao’ variety under elevated temperature and drought stress.ResultsIn this study, 107 ZjANS genes were identified. Analyses of their physicochemical properties and gene structures revealed that most are localized in the cytosol and nucleus, with only seven ZjANS genes exhibiting basic characteristics. All genes contained the conserved domains 2OG-FeII_Oxy and DIOX-N. Chromosomal localization and Ka/Ks analysis indicated that these genes are distributed across 12 chromosomes, with 22 tandem gene pairs, suggesting purifying selection. Phylogenetic and synteny analysis demonstrated that ZjANS genes are evolutionarily conserved, forming collinear gene pairs with four species. Cis-acting element analysis identified elements related to anthocyanin synthesis and environmental stress, such as LTR and MBS. Predictions of protein interaction indicated that certain ZjANS proteins interact with MYB, CHI, and GA proteins, potentially involved in the anthocyanin synthesis pathway. Transcriptome and qRT-PCR analysis revealed that thirteen ZjANS genes positively respond to coloring in jujube under elevated temperature and drought stress, with ZjANS17 identified as particularly significant.ConclusionThis study identified 107 ZjANS genes and systematically analyzed their evolutionary conservation. Thirteen ZjANS genes were found to positively influence fruit coloring in ‘Lingwuchangzao’ under elevated temperature and drought stress. These findings provide a foundation for further investigations into ZjANS genes and the breeding new jujube varieties.

The evaluation of transcription factor binding site prediction tools in human and Arabidopsis genomes

BackgroundThe precise prediction of transcription factor binding sites (TFBSs) is pivotal for unraveling the gene regulatory networks underlying biological processes. While numerous tools have emerged for in silico TFBS prediction in recent years, the evolving landscape of computational biology necessitates thorough assessments of tool performance to ensure accuracy and reliability. Only a limited number of studies have been conducted to evaluate the performance of TFBS prediction tools comprehensively. Thus, the present study focused on assessing twelve widely used TFBS prediction tools and four de novo motif discovery tools using a benchmark dataset comprising real, generic, Markov, and negative sequences. TFBSs of Arabidopsis thaliana and Homo sapiens genomes downloaded from the JASPAR database were implanted in these sequences and the performance of tools was evaluated using several statistical parameters at different overlap percentages between the lengths of known and predicted binding sites.ResultsOverall, the Multiple Cluster Alignment and Search Tool (MCAST) emerged as the best TFBS prediction tool, followed by Find Individual Motif Occurrences (FIMO) and MOtif Occurrence Detection Suite (MOODS). In addition, MotEvo and Dinucleotide Weight Tensor Toolbox (DWT-toolbox) demonstrated the highest sensitivity in identifying TFBSs at 90% and 80% overlap. Further, MCAST and DWT-toolbox managed to demonstrate the highest sensitivity across all three data types real, generic, and Markov. Among the de novo motif discovery tools, the Multiple Em for Motif Elicitation (MEME) emerged as the best performer. An analysis of the promoter regions of genes involved in the anthocyanin biosynthesis pathway in plants and the pentose phosphate pathway in humans, using the three best-performing tools, revealed considerable variation among the top 20 motifs identified by these tools.ConclusionThe findings of this study lay a robust groundwork for selecting optimal TFBS prediction tools for future research. Given the variability observed in tool performance, employing multiple tools for identifying TFBSs in a set of sequences is highly recommended. In addition, further studies are recommended to develop an integrated toolbox that incorporates TFBS prediction or motif discovery tools, aiming to streamline result precision and accuracy.

Whole-pathway stimulation of anthocyanin biosynthesis by UDP-glycose: flavonoid glycosyltransferase gene (UFGT) providing new insights into natural product development based on plant cell factory

Anthocyanins are a type of plant natural products (PNPs) that play a crucial role in various fields, including food, medicine, cosmetics, and dyes. However, their primary source is plant extraction, leading to significant ecological damage and resource wastage issues. To address the challenge of achieving ecologically sustainable high-throughput anthocyanin production, this study proposes a plant cell factory (PCF) strategy based on suspension cell culture (SCC). In this study, the key gene VdUFGT involved in anthocyanin biosynthesis was cloned from Vitis davidii, and gene overexpression was conducted using Agrobacterium-mediated methods. Notably, the vgt3 transgenic cell line exhibited 4.4-fold increase in anthocyanin content, reaching 286.9 μg/g (FW) in solid medium, along with enhanced levels of flavonoids and proanthocyanidins. Integrative analysis of transcriptomics and metabolomics demonstrated that VdUFGT significantly promoted the expression of genes involved in anthocyanin biosynthesis, leading to the enhanced accumulation of various flavonoids, including anthocyanins. A small-scale plant cell factory was established, achieving an impressive production of 4.11 mg/g (DW) of anthocyanin within just 12 days, which is 8.5 times higher than that of the WT cell line, with the yield of purified freeze-dried anthocyanin powder reaching 3.17%. The plant cell factory, employing genetic engineering and suspension cell culture, offers a safe, ecological, economical, and efficient approach for the high-throughput production of plant natural products such as anthocyanins.

Polysaccharide-potato protein coacervates for enhanced anthocyanin bioavailability and stability

Anthocyanins (ACNs) possess strong antioxidants, anti-cancer, anti-obesity, anti-diabetic, and anti-inflammatory properties but are limited use by their susceptibility to environmental factors. This study aims to overcome these limitations by developing and assessing a novel coacervate system, consisting of potato protein isolate (PPI) combined with various polysaccharides, to stabilize and encapsulate anthocyanins from black carrot concentrate The polysaccharides included in this system include inulin, gum Arabic, guar gum, pectin, and soluble fiber. The coacervate system's effectiveness in maintaining stability and increasing the bioavailability of anthocyanins was evaluated compared to conventional soybean protein-based systems. The results show that pH considerably influences potato protein solubility, with maximum solubility at strongly acidic (pH 2) conditions. Hygroscopicity and moisture content analysis of the coacervates showed significant variations, with potato protein-guar gum (PPIGG) microcapsules having the lowest moisture content and potato protein gum Arabic (PPIGA) microcapsules having the highest moisture content. SEM imaging illustrated distinct microcapsule morphologies, while FT-IR measurement verified the successful integration of proteins and polysaccharides. The significance of the research reflects its proof that potato protein isolate (PPI) based coacervate systems consists of potato protein with polysaccharides, particularly those containing gum Arabic and pectin, have significant potential for improving anthocyanin stability and bioavailability. These findings guide future studies to investigate other polysaccharides, improve coacervation processes, and explore applications in the food and nutraceutical sectors. It also offers valuable insights for creating efficient encapsulation techniques for bioactive substances.

MYB-1 regulates anthocyanin biosynthesis in Magnolia wufengensis

Anthocyanin is an essential pigment in all major horticultural crops especially in ornamental trees. Magnolia wufengensis (new species of Magnolia) with red color flower was recently found as a popular species for ornamental use, but anthocyanin synthesis and regulation in M. wufengensis are poorly understood. Herein, transcriptome analysis was used to decipher the gene network associated with anthocyanin biosynthesis. An R2R3-like MwMYB-1 transcription factor was found. MwMYB-1 overexpression resulted in anthocyanin accumulation in tobacco and Arabidopsis. MwMYB-1 worked independently rather than forming a protein complex with bHLH or WD40 protein. According to MwMYB-1 DAP-seq analysis in Arabidopsis, the MwMYB-1 transcription factor preferred to bind the “AAGAGAG” motif (DREME-5) in the third exon of the AtMYB75 gene. The yeast one hybrid assay and transcription activity assay further confirmed this. Thus, MwMYB-1 activated AtMYB75 gene expression and conducted cascade amplification of anthocyanin biosynthesis. Taken together, our findings provide a novel understanding of anthocyanin biosynthesis regulation in M. wufengensis and can be used to promote agronomic trait improvement in tree species.

Functional Profiling of Abundant Glycosyltransferases in the Rhizospheric Bacteriome of Abutilon fruticosum

In this study, we undertook an extensive exploration of the rhizospheric bacteriome of Abutilon fruticosum, focusing on the activities of Carbohydrate-Active Enzymes (CAZymes) of class glycosyltransferases (GTs), and their potential impact on plant growth and fortification against environmental adversities and soil-borne pathogens. Investigation revealed a predominance of families GT1, GT31, GT35, GT39, and GT51, mainly ascribed to bacterial genera Microvirga, Arthrobacter, Blastococcus, Bacillus, Nocardioides, and Kocuria. Our findings unveiled the pivotal role of phenylalanine, mostly exuded by plant roots, serving as the primary substrate for the catalytic activities of the identified CAZymes. With glucosylation emerging as the predominant enzymatic function, we propose UDP-D-glucose as the central core intermediate metabolite, orchestrating a multifaceted network of interrelated metabolic pathways. Subsequent profiling delineated a diverse array of metabolites synthesized by 10 CAZymes actively participating in 10 crosstalking pathways. Functional analyses of these metabolites underscore their significance in the biosynthesis of flavonoids, anthocyanins, and related derivatives, crucial for the reproductive success of plants by serving as visual cues for insect pollinators and conferring protection against deleterious effects of radiation. Certain other metabolites play vital roles in reinforcing the structural integrity of plant cell walls, thus enhancing resistance against enzymatic degradation while augmenting cytokinin activity. In conclusion, our study elucidates a novel paradigm of plant-bacteria mutualistic interaction, offering insights into the intricate mechanisms underlying plant-microbe symbiosis. We posit that the integration of high-throughput technologies with metabolic engineering strategies presents a promising approach for applying cost-effective and environmentally benign alternatives to conventional agricultural practices. (249 words)

Analysis of Transcriptional and Metabolic Differences in the Petal Color Change Response to High-Temperature Stress in Various Chrysanthemum Genotypes

Flower color is one of the most important ornamental traits of chrysanthemums. Previous studies have shown that high temperatures can cause the petals of some chrysanthemum varieties to fade; however, the molecular mechanisms behind this phenomenon remain poorly understood. This study examines the mechanisms of color change in purple chrysanthemums under high-temperature stress using combined metabolomic and transcriptomic analyses. Four chrysanthemum varieties—two heat-stable (‘Zi Feng Che’ and ‘Chrystal Regal’) and two heat-sensitive (‘Zi Hong Tuo Gui’ and ‘Zi Lian’)—were analyzed. High-temperature conditions (35 °C) significantly downregulated key anthocyanins in heat-sensitive varieties, particularly cyanidin-3-O-(3″,6″-O-dimalonyl)glucoside and pelargonidin-3-O-(3″,6″-O-dimalonyl)glucoside. Transcriptome analysis revealed differential gene expression involved in anthocyanin biosynthesis and degradation, with significant enrichment in the MAPK signaling, phenylpropanoid biosynthesis, flavonoid biosynthesis, and anthocyanin biosynthesis pathways. The study highlighted the differential expression of CHS, DFR, ANS, GT1, 3AT, and UGT75C1 genes in anthocyanin synthesis between heat-sensitive and heat-tolerant varieties. Compared to heat-stable varieties, the petals of heat-sensitive varieties exhibited greater differential expression of heat-responsive transcription factors, including HSFs, ERFs, MYBs, and WRKYs. Genes that show a significant negative correlation with the downregulated anthocyanins, including Cse_sc012959.1_g030.1 (βG), Cse_sc001798.1_g020.1 (MYB), Cse_sc006944.1_g010.1 (MYB), and Cse_sc000572.1_g090.1 (HSF), might regulate anthocyanin accumulation in chrysanthemums in response to high-temperature stress. These results provide guidance for the cultivation management and variety selection of chrysanthemums under high-temperature conditions. Additionally, they lay the foundation for elucidating the molecular mechanisms of flower color stability under heat stress and for breeding new heat-tolerant varieties.

Combined Metabolome and Transcriptome Analyses Reveals Anthocyanin Biosynthesis Profiles Between Purple and White Potatoes

Colored potatoes with red and purple skin or flesh possess significant nutritional value and health benefits due to their rich anthocyanin content. To investigate the genetic mechanisms underlying color formation, the high-anthocyanin-content purple-skinned and purple-fleshed potato line 15-12-16, and the white-skinned and white-fleshed Xiazhai 65 variety were used for ultra-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI-MS/MS) analysis, which was conducted to identify and quantify anthocyanins. RNA sequencing was performed to analyze the transcriptome. The results indicated a significant upregulation of genes within the anthocyanidin biosynthesis pathway in the purple potato, while these genes were either downregulated or absent in the white potato. The bHLH, MYB, and WRKY gene families exhibited a greater number of regulatory members, suggesting their pivotal role in color formation. Integrated analysis of the transcriptional and metabolic revealed that 12 differentially expressed genes (DEGs) related to the anthocyanidin biosynthetic had a significant correlation with 18 anthocyanin metabolites. Notably, the key gene St5GT in the anthocyanidin biosynthesis pathway was markedly upregulated in the purple skin and flesh. Furthermore, the overexpression of St5GT (PGSC0003DMG400004573) in tobacco contributed to anthocyanin accumulation. The expression of 10 DEGs was validated through quantitative real-time PCR. In conclusion, these findings provide new insights into anthocyanin biosynthesis and accumulation in purple potatoes, offering valuable candidate genes for the future breeding of colored potatoes.

Metabolomic and transcriptomic analyses provide insights into temperature and light regulated anthocyanin accumulation in flesh of ‘Furongli’ plum (Prunus salicina Lindl.)

Anthocyanins are health-promoting pigments that contribute to the quality of fruits. Anthocyanin biosynthesis is affected by light and temperature. However, there is no information available on the effects of light and temperature on anthocyanin accumulation in plum flesh. In this study, we investigated the effects of temperature and light on anthocyanin accumulation in postharvest ‘Furongli’ plum (Prunus salicina Lindl.) flesh and found that 20◦C promoted anthocyanin accumulation with or without light. However, no significant anthocyanin accumulation was detected in the flesh of plums treated with 30 ◦C/light. RNA-Seq analysis showed that the transcript levels of anthocyanin accumulation-related genes in the flesh were upregulated by 20◦C/light and 20◦C/dark treatments. Moreover, several genes involved in sucrose metabolism as well as plant hormone biosynthesis and signal transduction were transcriptionally correlated with anthocyanin accumulation. NAA treatment confirmed that auxin promoted anthocyanin accumulation in plum flesh. Transcription factors differentially regulated by temperature and light were identified. The anthocyanin MYB activator, PsMYB10.2, was only upregulated in the flesh of 20◦C/light and 20◦C/dark treated fruits, wheras the anthocyanin repressor, PsMYB18, was upregulated in flesh of fruits under all treatment conditions. The PsMYB10.2 promoter was responsive to light, but not to temperature. Transient overexpression assays showed that PsMYB18 inhibited PsMYB10.2 and PsbHLH3 induced anthocyanin accumlation in tobacco leaves. Dual luciferase assays further showed that PsMYB18 repressed the activation activity of PsMYB10.2 on the promoters of PsANS, PsUFGT and PsGST. Yeast one-hybrid and dual luciferase assays showed PsMYB10.2 could bind to and activated the PsMYB18 promoter. These results suggest that temperature and light modulate anthocyanin accumulation in the flesh of ‘Furongli’ plum by regulating the expression of structural genes involved in anthocyanin accumulation via the cooperation of anthocyanin regulators PsMYB10.2 and PsMYB18.

Improved uptake of anthocyanins-loaded nanoparticles based on phenolic acid-grafted zein and lecithin

Anthocyanins (ACNs) exhibit various physiological activities but have low bioavailability. This study aimed to improve cellular uptake and permeability of ACNs by utilizing phenolic acids grafted zein and lecithin (ZLAs) as the carrier. With the highest grafting rate achieved in rosmarinic acid (RA)-zein at 39.79 ± 0.40 % using alkali treatment, the grafted zein samples were characterized through spectroscopy, NMR, and analysis of physicochemical properties. Ferulic acid (FA)-ZLAs exhibited the smallest particle size (69.72 ± 0.50 nm) and PDI value of 0.206 ± 0.012. Multi-spectroscopy indicated hydrogen bonding and hydrophobic forces were the major forces to stabilize ACNs. Moreover, carrier binding including electrostatic interaction effectively enhanced processing, thermal degradation, color, and gastrointestinal stability. In Caco-2 monolayers, FA-ZLAs significantly improved cellular transport efficiency, resulting in up to a 1.9-fold enhancement. RA-ZLAs exhibited the strongest antioxidant activity. This work proposes a feasible strategy for stabilizing ACNs and propelling their use in dietary supplements.

Accumulation of Anthocyanin in the Aleurone of Barley Grains by Targeted Restoration of the MYC2 Gene

Blue barley grain pigmentation results from anthocyanin accumulation in the aleurone layer. Anthocyanins are known for their beneficial effects on human health. The gene encoding the MYELOCYTOMATOSIS 2 (MYC2) transcription factor is potentially responsible for the blue coloration of the aleurone. In non-pigmented barley, a single nucleotide insertion in this gene causes a frameshift mutation with a premature stop codon. It was hypothesized that restoring the MYC2 reading frame could activate anthocyanin accumulation in the aleurone. Using a targeted mutagenesis approach in the present study, the reading frame of MYC2 was restored in the non-pigmented cultivar Golden Promise. Genetic constructs harboring cas9 and gRNA expression units were developed, pre-validated in protoplasts, and then functional MYC2 alleles were generated at the plant level via Agrobacterium-mediated transformation. Anthocyanin accumulation in the aleurone layer of grains from these mutants was confirmed through microscopy and chemical analysis. The expression of anthocyanin biosynthesis genes was analyzed, revealing that the restoration of MYC2 led to increased transcript levels of F3H and ANS genes. These results confirm the critical role of the MYC2 transcription factor in the blue aleurone trait and provide a biotechnological solution for enriching barley grain with anthocyanins.

Molecular Functional and Transcriptome Analysis of Arabidopsis thaliana Overexpression BrBBX21 from Zicaitai (Brassica rapa var. purpuraria)

B-box transcription factors (TFs) in plants are essential for circadian rhythm regulation, abiotic stress responses, hormonal signaling pathways, secondary metabolism, photomorphogenesis, and anthocyanin formation. Here, by blasting the AtBBX21 gene sequence, we identified a total of 18 BBX21 genes from five distinct Brassica species (Arabidopsis thaliana, Brassica rapa, Brassica oleracea, Brassica napus, and Brassica juncea). The BrBBX21-1 gene is most closely linked to the AtBBX21 gene based on phylogeny and protein sequence similarities. The BrBBX21-1 gene, which encodes a polypeptide of 319 amino acids, was identified from Zicaitai (Brassica rapa ssp. purpuraria) and functionally characterized. BrBBX21-1 was localized within the nucleus, and its overexpression in Arabidopsis augmented anthocyanin accumulation in both leaves and seeds. We further performed an RNA-seq analysis between the BrBBX21-OE and WT A. thaliana to identify the key regulators involved in anthocyanin accumulation. In detail, a total of 7583 genes demonstrated differential expression, comprising 4351 that were upregulated and 3232 that were downregulated. Out of 7583 DEGs, 81 F-box protein genes and 9 B-box protein genes were either up- or downregulated. Additionally, 7583 differentially expressed genes (DEGs) were associated with 109 KEGG pathways, notably including plant hormone signal transduction, the biosynthesis of secondary metabolites, metabolic pathways, glutathione metabolism, and starch and sucrose metabolism, which were considerably enriched. A transcriptome analysis led us to identify several structural genes, including DFRA, GSTF12, UGT75C1, FLS1, CHI1, 4CL3, and PAL1, and transcription factors, MYB90, TT8, and HY5, that are regulated by the overexpression of the BrBBX21-1 gene and involved in anthocyanin biosynthesis. Altogether, these findings demonstrate the beneficial regulatory function of BrBBX21-1 in anthocyanin accumulation and offer valuable information about the basis for breeding superior Brassica crops.

Chemically modified filter paper with Jaman fruit extract for visual sensing of milk freshness

Developing a non-toxic, cost-effective, and user-friendly indicator for detecting milk freshness and spoilage, with potential applications in smart packaging, presents a significant challenge. In this study, we extracted natural anthocyanins (ACNs) from Jaman (Syzgium cumini) and incorporated it in to filter paper. The presence of ACNs in the extract was confirmed through UPLC-MS/MS analysis. To enhance stability and prevent leaching, the ACNs-loaded filter paper was coated with 1 % chitosan (CH). The sensor strips were thoroughly characterized using FTIR, contact angle measurements, XRD, and FE-SEM. These strips displayed a distinct and quantifiable color change from red to colorless to yellow across different pH levels. Additionally, in real-time milk spoilage detection, the sensor transitioned from light purple to colorless. The strips demonstrated reproducibility and stability, even under high temperatures and extreme pH conditions. These findings suggest that the ACNs-loaded sensor strips hold promise for use as smart packaging materials.

Integrated Transcriptome and Metabolome Analysis Revealed Mechanism Underlying Anthocyanin Biosynthesis During Flower Color Formation in Lagerstroemia indica

Lagerstroemia indica is a widely used ornamental woody plant known for its summer flowering and significant ornamental and economic value. While L. indica boasts a variety of rich flower colors, the molecular mechanisms underlying this color formation remain unclear. In this study, we selected three different flower colors of L. indica—white (W), red (R), and purple (P)—for transcriptome and metabolome analysis. The metabolome analysis identified 538 flavonoids, with 22 anthocyanins highly accumulated in the red and purple flowers. RNA-seq analysis annotated a total of 35,505 genes. Furthermore, we identified 42 differentially expressed genes (DEGs) involved in anthocyanin biosynthesis, with their expression levels aligning with anthocyanin content. Correlation analysis revealed that 19 MYB and 11 bHLH transcription factors are likely involved in anthocyanin biosynthesis. Additionally, we identified 59 auxin biosynthesis and signaling-related genes that are positively correlated with anthocyanin-related genes and metabolites, suggesting that auxin may play a role in regulating anthocyanin biosynthesis in L. indica. This study provides valuable insights into the regulatory mechanisms underlying anthocyanin accumulation and color formation in L. indica petals and identifies several potential genes, laying the groundwork for further research on regulatory mechanisms and genetic improvement of L. indica.

Anthocyanin-Rich Extract Mitigates the Contribution of the Pathobiont Genus Haemophilus in Mild-to-Moderate Ulcerative Colitis Patients.

Anthocyanins (ACs) have been shown to elicit anti-inflammatory and antioxidant effects in animal models of ulcerative colitis (UC). Furthermore, we previously observed in a double-blind randomized trial in UC patients that biochemical disease activity tended to be lower in patients that were exposed to AC. Here, we report on the changes in the fecal microbiome composition in these patients upon AC exposure. UC patients received a 3 g daily dose of an AC-rich bilberry extract (ACRE) for eight weeks. We determined the microbiome composition in longitudinal stool samples from 24 patients and quantified the degree of change over time. We also correlated the relative abundances of individual microbial taxa at different timepoints to fecal concentrations of calprotectin, a proxy for inflammation. Microbiome composition did not change over time as a result of the intervention, in terms of both alpha and beta diversity. However, before the intervention, the abundance of Haemophilus parainfluenzae was positively correlated with fecal calprotectin concentrations, and this correlation persisted in placebo-treated subjects throughout the study. In contrast, the correlation between H. parainfluenzae and calprotectin vanished in ACRE-treated subjects, while the relative abundance of H. parainfluenzae did not change. Our results suggest that ACRE treatment mitigates the contribution of H. parainfluenzae to inflammation. Further research is warranted to better comprehend the role of microbial composition in response to medical therapy including AC-rich extract in UC patients.

Transcriptome-based analysis reveals a role for PpCDF5 in the promotion of anthocyanin accumulation at a low nighttime temperature

For red pear, the anthocyanin content is a crucial factor determining the fruit skin color, which affects consumer preferences. Low overnight temperatures promote anthocyanin accumulation, but the molecular mechanism responsible is unclear. In this study, ‘Hongzaosu’ pear (Pyrus pyrifolia × Pyrus communis) fruit were treated with a low nighttime temperature (LNT, 16 °C) or a warm nighttime temperature (WNT, 26 °C), with sampling conducted within two diurnal cycles. The results showed that LNT promoted anthocyanin accumulation in the fruit skin. The structural anthocyanin biosynthetic genes PpCHS, PpF3H, and PpUFGT exhibited a rhythmic increase in expression at night under LNT. To examine the underlying mechanism, RNA sequencing was conducted using pear calli exposed to LNT and WNT for different durations (24, 48, 72, or 96 h). Transcriptome analysis revealed 285 differentially expressed genes (DEGs) common to all pairwise comparisons of LNT- and WNT-treated calli of ‘Clapp's Favorite’ (P. communis) at the sampling time points. KEGG pathway and gene ontology enrichment analyses indicated that the common DEGs were enriched in secondary metabolic processes and phenylpropanoid metabolic processes, which are associated with anthocyanin biosynthesis. The transcription factor PpCDF5, which was responsive to LNT, was selected for further study. Dual-luciferase assays showed that PpCDF5 activated the transcription of anthocyanin biosynthetic genes PpMYB10, PpCHS, PpF3H, PpDFR, PpANS, and PpUFGT. The yeast one-hybrid and EMSA assays demonstrated that PpCDF5 directly binds to the PpF3H promoter, which contains an AAAG motif. Overexpression of PpCDF5 in pear calli and transient overexpression in pear fruit both increased anthocyanin accumulation. The results indicate that PpCDF5 is involved in LNT-induced anthocyanin biosynthesis in pear fruit and provide insights into the molecular regulation of commercial fruit coloration.

Muti-omics analysis reveals the anthocyanin biosynthesis and accumulation mechanism in the hawk tea tree (Litsea coreana var. lanuginose)

Hawk tea, an herbal tea with unique flavors and health benefits that manufactured from the tender shoots of Litsea coreana var. lanuginose (hawk tea tree), has been consumed for a long time in Southern China. Anthocyanin compounds are a class of water-soluble pigments in plants and have important healthcare benefits. However, the anthocyanin biosynthesis and accumulation in hawk tea are largely unknown. In this study, the hawk tea trees with green (G), green-purple (GP), and purple (P) colored tender shoots were selected for investigation. Their anthocyanin and metabolomic profiling were identified and compared. Results showed that hawk tea trees contained a high abundance of proanthocyanidins and quercetin-3-O-glucoside, and the anthocyanin compounds accumulations in P and GP shoots are higher than in G. The transcriptional network of anthocyanin-mediated purple coloration in hawk tea trees was elucidated by single-molecule real-time (SMRT) sequencing RNA sequencing (RNA-seq) analyses. Moreover, the importance of structural genes and transcription factor genes (TFs), including DFRs, ANS/LODXs, and MYBs, in anthocyanin biosynthesis was revealed. Our study provided a comprehensive understanding of anthocyanin biosynthesis and accumulation in hawk tea trees and a fundamental basis for further development and application of hawk tea products.

Overexpression of MYB transcription factor LrAN2 from Lycium ruthenicum activated the anthocyanin biosynthesis in the leaf and fruit of Lycium barbarum

AN2 was thought to be the key gene inducing the fruit color differentiation of Lycium barbarum and Lycium ruthenicum, but there was no direct evidence. In this study, AN2 from L. ruhtenicum was overexpressed in L. barbarum to conform its function in regulating anthocyanin biosynthesis. The results showed that the stems, leaves, and fruits of transgenic plants were purple and contained significantly higher anthocyanin levels compared to the wild-type plants. Transcriptome analysis of leaf and fruit identified 5,832 differentially expressed genes (DEGs) in leaves and 2,029 DEGs in fruits, with 910 genes common to both tissues. GO and KEGG pathway enrichment analyses indicated a significant impact of LrAN2 on flavonoid biosynthesis and anthocyanin biosynthesis. The structural genes involved in the anthocyanin pathway, such as 4CL, CHS, F3H, F3’5’H, DFR, ANS, and UFGT, were up-regulated in transgenic lines, while the expression of transcription factors bHLH and WD40 were remained unchanged. These findings confirm the role of LrAN2 in the color differentiation of L. barbarum and L. ruthenicum and highlight its potential for the genetic enhancement of anthocyanin content in L. barbarum and other Solanaceae species.