The Transcription Factor MiMYB8 Suppresses Peel Coloration in Postharvest 'Guifei' Mango in Response to High Concentration of Exogenous Ethylene by Negatively Modulating MiPAL1.

Anthocyanin accumulation is regulated by specific genes during fruit ripening. Currently, peel coloration of mango fruit in response to exogenous ethylene and the underlying molecular mechanism remain largely unknown. The role of MiMYB8 on suppressing peel coloration in postharvest 'Guifei' mango was investigated by physiology detection, RNA-seq, qRT-PCR, bioinformatics analysis, yeast one-hybrid, dual-luciferase reporter assay, and transient overexpression. Results showed that compared with the control, low concentration of exogenous ethylene (ETH, 500 mg·L-1) significantly promoted peel coloration of mango fruit (cv. Guifei). However, a higher concentration of ETH (1000 mg·L-1) suppressed color transformation, which is associated with higher chlorophyll content, lower a* value, anthocyanin content, and phenylalanine ammonia-lyase (PAL) activity of mango fruit. M. indica myeloblastosis8 MiMYB8 and MiPAL1 were differentially expressed during storage. MiMYB8 was highly similar to those found in other plant species related to anthocyanin biosynthesis and was located in the nucleus. MiMYB8 suppressed the transcription of MiPAL1 by binding directly to its promoter. Transient overexpression of MiMYB8 in tobacco leaves and mango fruit inhibited anthocyanin accumulation by decreasing PAL activity and down-regulating the gene expression. Our observations suggest that MiMYB8 may act as repressor of anthocyanin synthesis by negatively modulating the MiPAL gene during ripening of mango fruit, which provides us with a theoretical basis for the scientific use of exogenous ethylene in practice.

Effect of Light Conditions, Trichoderma Fungi and Food Polymers on Growth and Profile of Biologically Active Compounds in Thymus vulgaris and Thymus serpyllum.

The research investigates the influence of different lighting conditions and soil treatments, in particular the application of food polymers separately and in combination with spores of Trichoderma consortium, on the growth and development of herbs-Thymus vulgaris and Thymus serpyllum. The metabolic analysis focuses on detecting changes in the levels of biologically active compounds such as chlorophyll a and b, anthocyanins, carotenoids, phenolic compounds (including flavonoids), terpenoids, and volatile organic compounds with potential health-promoting properties. By investigating these factors, the study aims to provide insights into how environmental conditions affect the growth and chemical composition of selected plants and to shed light on potential strategies for optimising the cultivation of these herbs for the improved quality and production of bioactive compounds. Under the influence of additional lighting, the growth of T. vulgaris and T. serpyllum seedlings was greatly accelerated, resulting in an increase in shoot biomass and length, and in the case of T. vulgaris, an increase in carotenoid and anthocyanin contents. Regarding secondary metabolites, the most pronounced changes were observed in total antioxidant capacity and flavonoid content, which increased significantly under the influence of additional lighting. The simultaneous or separate application of Trichoderma and food polymers resulted in an increase in flavonoid content in the leaves of both Thymus species. The increase in terpenoid content under supplemental light appears to be related to the presence of Trichoderma spores as well as food polymers added to the soil. However, the nature of these changes depends on the thyme species. Volatile compounds were analysed using an electronic nose (E-nose). Eight volatile compounds (VOCs) were tentatively identified in the vapours of T. vulgaris and T. serpyllum: α-pinene, myrcene, α-terpinene, γ-terpinene; 1,8-cineole (eucalyptol), thymol, carvacrol, and eugenol. Tendencies to increase the percentage of thymol and γ-terpinene under supplemental lighting were observed. The results also demonstrate a positive effect of food polymers and, to a lesser extent, Trichoderma fungi on the synthesis of VOCs with health-promoting properties. The effect of Trichoderma and food polymers on individual VOCs was positive in some cases for thymol and γ-terpinene.

Stability of individual anthocyanins from black carrots stored in light and darkness - Impact of acylation.

Black carrot anthocyanins have gained increasing attention as natural coloring agent, owing to their higher stability than anthocyanins from berries. The stability has been attributed to their higher degree of acylation. This study investigated the impact of acylation on the stability of individual anthocyanins during storage in light and darkness. We hypothesized that the acylated anthocyanins would be more stable than the non-acylated ones. The major five anthocyanins were fractioned by semi-preparative HPLC and stored at pH 4.5 in light and darkness to investigate how acylation affected the stability. The stability was evaluated by absorption spectroscopy and mass spectrometry (MS). Two of the anthocyanins were non-acylated; 3-xylosyl(glucosyl)galactoside and cyanidin 3-xylosylgalactoside, and three were acylated; cyanidin 3-xylosyl(sinapolyglucosyl)galacto-side, cyanidin 3-xylosyl(feruloylglu-cosyl)galactoside, and cyanidin 3-xylosyl(coumaroyl-glucosyl)galactoside. Both methods (spectroscopy and MS) showed a clear effect of acylation when stored in light, but surprisingly the two non-acylated anthocyanins, showed higher stability than the three acylated ones.

Integrative analysis of transcriptome and target metabolites uncovering flavonoid biosynthesis regulation of changing petal colors in Nymphaea 'Feitian 2'.

BACKGROUND: Nymphaea (waterlily) is known for its rich colors and role as an important aquatic ornamental plant globally. Nymphaea atrans and some hybrids, including N. 'Feitian 2,' are more appealing due to the gradual color change of their petals at different flower developmental stages. The petals of N. 'Feitian 2' gradually change color from light blue-purple to deep rose-red throughout flowering. The mechanism of the phenomenon remains unclear. RESULTS: In this work, flavonoids in the petals of N. 'Feitian 2' at six flowering stages were examined to identify the influence of flavonoid components on flower color changes. Additionally, six cDNA libraries of N. 'Feitian 2' over two blooming stages were developed, and the transcriptome was sequenced to identify the molecular mechanism governing petal color changes. As a result, 18 flavonoid metabolites were identified, including five anthocyanins and 13 flavonols. Anthocyanin accumulation during flower development is the primary driver of petal color change. A total of 12 differentially expressed genes (DEGs) in the flavonoid biosynthesis pathway were uncovered, and these DEGs were significantly positively correlated with anthocyanin accumulation. Six structural genes were ultimately focused on, as their expression levels varied significantly across different flowering stages. Moreover, 104 differentially expressed transcription factors (TFs) were uncovered, and three MYBs associated with flavonoid biosynthesis were screened. The RT-qPCR results were generally aligned with high-throughput sequencing results. CONCLUSIONS: This research offers a foundation to clarify the mechanisms underlying changes in the petal color of waterlilies.

Comparative transcriptomic and metabolomic profiles reveal fruit peel color variation in two red pomegranate cultivars.

Pomegranate (Punica granatum L.) which belongs to family Lythraceae, is one of the most important fruit crops of many tropical and subtropical regions. A high variability in fruit color is observed among different pomegranate accessions, which arises from the qualitative and quantitative differences in anthocyanins. However, the mechanism of fruit color variation is still not fully elucidated. In the present study, we investigated the red color mutation between a red-skinned pomegranate 'Hongbaoshi' and a purple-red-skinned cultivar 'Moshiliu', by using transcriptomic and metabolomic approaches. A total of 51 anthocyanins were identified from fruit peels, among which 3-glucoside and 3,5-diglucoside of cyanidin (Cy), delphinidin (Dp), and pelargonidin (Pg) were dominant. High proportion of Pg in early stages of 'Hongbaoshi' but high Dp in late stages of 'Moshiliu' were characterized. The unique high levels of Cy and Dp anthocyanins accumulating from early developmental stages accounted for the purple-red phenotype of 'Moshiliu'. Transcriptomic analysis revealed an early down-regulated and late up-regulated of anthocyanin-related structure genes in 'Moshiliu' compared with 'Hongbaoshi'. Alao, ANR was specially expressed in 'Hongbaoshi', with extremely low expression levels in 'Moshiliu'. For transcription factors R2R3-MYB, the profiles demonstrated a much higher transcription levels of three subgroup (SG) 5 MYBs and a sharp decrease in expression of SG6 MYB LOC116202527 in high-anthocyanin 'Moshiliu'. SG4 MYBs exhibited two entirely different patterns, LOC116203744 and LOC116212505 were down-regulated whereas LOC116205515 and LOC116212778 were up-regulated in 'Moshiliu' pomegranate. The results indicate that specific SG members of the MYB family might promote the peel coloration in different manners and play important roles in color mutation in pomegranate.

Effect of common horsetail extract on growth characteristics, essential oil yield and chemical compositions of basil (Ocimum basilicum L.).

To investigate the effect of horsetail extract containing high silicon on morphological traits, growth, content, and compositions of essential oil of sweet basil (Ocimum basilicum L.) an experiment turned into carried out in the shape of a randomized complete block design with three replications. Foliar treatment of horsetail extract with zero, 0.5, 1, and 2% concentrations was applied on 6-8 leaf plants. The assessed traits include plant height, number of leaves per plant, number of sub-branches, leaf area index, plant fresh weight, plant dry weight, total anthocyanin, the content of total phenol and total flavonoid, antioxidant activity, essential oil content, and compounds were measured. The findings demonstrated that the increase of silicon-containing horsetail extract enhanced the improved increase in growth and phytochemical trait values. The use of horsetail extract in the 2% treatment increased plant height, the number of leaves per plant, the number of sub-branches, leaf area index, fresh weight, and dry weight of the plant by 49.79, 45.61, 91.09, 99.78, 52.78 and 109.25%, respectively, compared to the control. The highest content of total phenol (2.12 mg GAE/g DW), total flavonoid (1.73 mg RE/g DW), total anthocyanin (0.83 mg C3G/g DW), and antioxidant activity (184.3 µg/ml) was observed in the 2% extract treatment. The content of essential oil increased with increasing the concentration of horsetail extract, so the highest amount of essential oil was obtained at the concentration of 2%, which increased by 134.78% compared to the control. By using GC-MS, the essential oil was analyzed. The main components of the essential oil include methyl eugenol (12.93-25.93%), eugenol (17.63-27.51%), 1,8-cineole (15.63-20.84%), linalool (8.31-19.63%) and (Z)-caryophyllene (6.02-14.93%). Increasing the concentration of horsetail extract increased the compounds of eugenol, 1,8-cineole, and linalool in essential oil compared to the control, but decreased the compounds of methyl eugenol and (Z)-caryophyllene. Foliar spraying of horsetail extract, which contains high amounts of silicon, as a stimulant and biological fertilizer, can be a beneficial ingredient in increasing the yield and production of medicinal plants, especially in organic essential oil production.

Promoter replication of grape MYB transcription factor is associated with a new red flesh phenotype.

KEY MESSAGE: In our study, we discovered a fragment duplication autoregulation mechanism in 'ZS-HY', which may be the reason for the phenotype of red foliage and red flesh in grapes. In grapes, MYBA1 and MYBA2 are the main genetic factors responsible for skin coloration which are located at the color loci on chromosome 2, but the exact genes responsible for color have not been identified in the flesh. We used a new teinturier grape germplasm 'ZhongShan-HongYu' (ZS-HY) which accumulate anthocyanin both in skin and flesh as experimental materials. All tissues of 'ZS-HY' contained cyanidin 3-O-(6″-p-coumaroyl glucoside), and pelargonidins were detected in skin, flesh, and tendril. Through gene expression analysis at different stage of flesh, significant differences in the expression levels of VvMYBA1 were found. Gene amplification analysis showed that the VvMYBA1 promoter is composed of two alleles, VvMYBA1a and 'VvMYBA1c-like'. An insertion of a 408 bp repetitive fragment was detected in the allele 'VvMYBA1c-like'. In this process, we found the 408 bp repetitive fragment was co-segregated with red flesh and foliage phenotype. Our results revealed that the 408 bp fragment replication insertion in promoter of 'VvMYBA1c-like' was the target of its protein, and the number of repeat fragments was related to the increase of trans-activation of VvMYBA1 protein. The activation of promoter by VvMYBA1 was enhanced by the addition of VvMYC1. In addition, VvMYBA1 interacted with VvMYC1 to promote the expression of VvGT1 and VvGST4 genes in 'ZS-HY'. The discovery of this mutation event provides new insights into the regulation of VvMYBA1 on anthocyanin accumulation in red-fleshed grape, which is of great significance for molecular breeding of red-fleshed table grapes.

Identification of a candidate gene for the I locus determining the dominant white bulb color in onion (Allium cepa L.).

KEY MESSAGE: Through a map-based cloning approach, a gene coding for an R2R3-MYB transcription factor was identified as a causal gene for the I locus controlling the dominant white bulb color in onion. White bulb colors in onion (Allium cepa L.) are determined by either the C or I loci. The causal gene for the C locus was previously isolated, but the gene responsible for the I locus has not been identified yet. To identify candidate genes for the I locus, an approximately 7-Mb genomic DNA region harboring the I locus was obtained from onion and bunching onion (A. fistulosum) whole genome sequences using two tightly linked molecular markers. Within this interval, the AcMYB1 gene, known as a positive regulator of anthocyanin production, was identified. No polymorphic sequences were found between white and red AcMYB1 alleles in the 4,860-bp full-length genomic DNA sequences. However, a 4,838-bp LTR-retrotransposon was identified in the white allele, in the 79-bp upstream coding region from the stop codon. The insertion of this LTR-retrotransposon created a premature stop codon, resulting in the replacement of 26 amino acids with seven different residues. A molecular marker was developed based on the insertion of this LTR-retrotransposon to genotype the I locus. A perfect linkage between bulb color phenotypes and marker genotypes was observed among 5,303 individuals of segregating populations. The transcription of AcMYB1 appeared to be normal in both red and white onions, but the transcription of CHS-A, which encodes chalcone synthase and is involved in the first step of the anthocyanin biosynthesis pathway, was inactivated in the white onions. Taken together, an aberrant AcMYB1 protein produced from the mutant allele might be responsible for the dominant white bulb color in onions.

Do red and yellow autumn leaves make use of different photoprotective strategies during autumn senescence?

Our goal was to determine whether anthocyanin-producing species (red) use different photoprotective strategies to cope with excess light during fall senescence compared with non-anthocyanin-producing species (yellow). In a previous study, we found that a yellow species retained the photoprotective PsbS protein in late autumn, while a red species did not. Specifically, we tested the hypothesis that red species make less use of zeaxanthin and PsbS-mediated thermal dissipation, as they rely on anthocyanins for photoprotection. We monitored four red (Acer ginnala, Rhus typhnia, Parenthocissus quinquefolia, Viburnum dentatum) and four yellow species (Acer negundo, Ostrya virginiana, Vitis riparia, Zanthoxylum americanum) throughout autumn senescence and analyzed pigments, protein content, and chlorophyll fluorescence. We found yellow species retained the PsbS protein at higher levels, and had higher dark retention of zeaxanthin in late autumn relative to red species. All species retained lutein and the pool of xanthophyll cycle pigments in higher amounts than other carotenoids in late autumn. Our data support the hypothesis that red species use anthocyanins as a photoprotective strategy during autumn senescence, and therefore make less use of PsbS and zeaxanthin-mediated thermal dissipation. We also found species-specific variation in the particular combination of photoprotective strategies used.

Black Rice Anthocyanins as An Effective Antioxidant of Inhibition of Oil Oxidative Based on Molecular Modification.

This present work investigated the influence of black rice anthocyanins as antioxidants on the oxidation stability of oil. Malonic acid, succinic acid and succinic anhydride were grafted on black rice anthocyanins through acylation method to improve their antioxidant activity in oil. The results from fourier transform infrared spectroscopy (FTIR) showed new absorption peaks near 1744 cm -1 and 1514 cm -1 , which implied that malonic acid, succinic acid and succinic anhydride grafted on the -OH of glucoside and rutinoside through esterification reaction and resulted that the polarity of these were reduced. Total content of anthocyanin (TAC) decreased to 166. 3 mg/g, 163.7 mg/g and 150.2 mg/g, respectively after modification with succinic acid, malonic acid and succinic anhydride. Compared with native anthocyanins, the acylation of black rice anthocyanins partially reduced its antioxidant activity. In addition, DPPH clearance of molecular modified anthocyanins decreased to 62.6% (San-An). As revealed in the oil stability through the determination of primary oxidation products (PV) and secondary oxidation products (p-AV), Sa-An, Ma-An and San-An showed stronger antioxidant activity in Schaal oven accelerated oxidation test during 12 days than native black rice anthocyanin in both corn oil and flaxseed oil. Molecular modified black rice anthocyanins are expected to be used as colorants, antioxidants, etc. in oil-rich food.

Association between Flavonoid Intake and Cognitive Executive Function among African American and White Adults in the Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS) Study.

Healthy dietary patterns rich in flavonoids may benefit cognitive performance over time. Among socioeconomically disadvantaged groups, the association between flavonoid intake and measures of cognition is unclear. This study sought to identify associations between flavonoid intake and cognitive performance among Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS) study participants (n = 1947) across three study visits. Flavonoid intakes were assessed via two 24-h dietary recalls. Cognitive performance was assessed via the Trail Making Test (TMT)-A and TMT-B, which provide measures of attention and executive function, respectively. Mixed effects linear regression was used to model TMT scores over three study visits against visit 1 (v1) flavonoid intake, time (years from v1), and the interaction between v1 flavonoid intake and time, capturing both the cross-sectional association between flavonoid intake and time at v1 as well as the longitudinal association between v1 flavonoid intake and the change in TMT scores over time. Prior to adjustment, inverse cross-sectional associations at v1 were observed between (1) anthocyanidin intake and TMT-A scores for the overall sample and (2) total flavonoid, anthocyanidin, flavan-3-ol, flavone, and flavonol intake and TMT-B scores for the overall sample and among White adults. Only the association between anthocyanidin intake and TMT-B at v1 among White adults persisted after adjustment (for demographic characteristics such as age). One possible explanation for the few significant associations is universally low flavonoid intakes resulting from the consumption of an unhealthy dietary pattern.

Dietary anthocyanin is associated with a lower prevalence of hyperuricemia independently of metabolic syndrome among females: Results from NHANES 2007-2010 and 2017-2018.

OBJECTIVE: Known for anti-inflammatory and antioxidant properties, flavonoid has phytoestrogenic effects, but it is unclear whether its role in hyperuricemia and metabolic syndrome (MetS) differs by gender. Moreover, given the strong association between hyperuricemia and MetS, we aimed to explore whether flavonoid is a protective factor for hyperuricemia, independently of MetS, in different genders. METHODS: Data for 2007-2010 and 2017-2018 were obtained from the National Health and Nutrition Examination Survey (NHANES) and the Food and Nutrient Database for Dietary Studies (FNDDS). To assess the association among flavonoid, hyperuricemia, and MetS, multivariate logistic regression and subgroup analyses were conducted. Besides, to investigate whether the association between flavonoid and hyperuricemia was independent of MetS, multivariate logistic regression models were further conducted to explore the association between flavonoid and MetS among females with hyperuricemia and to investigate the association between flavonoid and hyperuricemia among females after excluding MetS. RESULT: Among 5356 females, anthocyanin intake was inversely associated with the prevalence of hyperuricemia (Q4 vs. Q1: OR 0.49, 95% CI 0.31 to 0.76), and MetS (Q4 vs. Q1: OR 0.68, 95% CI 0.50 to 0.93). Furthermore, subgroup analyses showed the beneficial association between anthocyanin and hyperuricemia among females aged 40 to 59 years and menopausal. However, among 5104 males, no significant association was observed after adjustment for covariates (Q4 vs. Q1: OR 0.81, 95% CI 0.56 to 1.18). While in 372 females with hyperuricemia, no significant association was found between MetS and anthocyanin (Q4 vs. Q1: OR 0.88, 95% CI 0.31 to 2.49). Meanwhile, among 3335 females after excluding MetS, there was still a significant association between anthocyanin and a lower prevalence of hyperuricemia (Q4 vs. Q1: OR 0.38, 95% CI 0.17 to 0.85). CONCLUSION: Dietary anthocyanin is associated with a lower prevalence of hyperuricemia independently of MetS among females. Foods rich in anthocyanin should be emphasized for females, especially those aged 40 to 59 years and menopausal, which may be of potential significance in the prevention of hyperuricemia.

Terroir Dynamics: Impact of Vineyard and Canopy Treatment with Chitosan on Anthocyanins, Phenolics, and Volatile and Sensory Profiles of Pinot Noir Wines from South Tyrol.

The effects of canopy treatment with chitosan and the effects of the vineyard location on the quality parameters, volatile and non-volatile profiles, and sensory profile of Pinot Noir wines from South Tyrol (Italy) were studied. Multivariate statistical analysis was applied to identify the most relevant compounds associated with the variability in phenolics and anthocyanins (analyzed by UHPLC-MS), volatile components (HS-SPME-GCxGC-ToF/MS), and basic enological parameters. A clear separation of low-altitude wines (350 m.a.s.l.), which had a high concentration of most of the identified volatile compounds, compared to high-altitude wines (800 and 1050-1150 m.a.s.l.) was pointed out. Low altitude minimized the concentration of the most significant anthocyanins in wines from a valley bottom, presumably due to reduced sun exposure. Wines obtained from chitosan-treated canopies, and, more particularly, those subjected to multiple treatments per year showed a higher amount of the main non-volatile phenolics and were sensorially described as having "unpleasant flavors" and "odors", which might suggest that grape metabolism is slightly altered compared to untreated grapevines. Thus, optimization of the treatment with chitosan should be further investigated.

Theoretical Study of Cyanidin-Resveratrol Copigmentation by the Functional Density Theory.

Anthocyanins are colored water-soluble plant pigments. Upon consumption, anthocyanins are quickly absorbed and can penetrate the blood-brain barrier (BBB). Research based on population studies suggests that including anthocyanin-rich sources in the diet lowers the risk of neurodegenerative diseases. The copigmentation caused by copigments is considered an effective way to stabilize anthocyanins against adverse environmental conditions. This is attributed to the covalent and noncovalent interactions between colored forms of anthocyanins (flavylium ions and quinoidal bases) and colorless or pale-yellow organic molecules (copigments). The present work carried out a theoretical study of the copigmentation process between cyanidin and resveratrol (CINRES). We used three levels of density functional theory: M06-2x/6-31g+(d,p) (d3bj); ωB97X-D/6-31+(d,p); APFD/6-31+(d,p), implemented in the Gaussian16W package. In a vacuum, the CINRES was found at a copigmentation distance of 3.54 Å between cyanidin and resveratrol. In water, a binding free energy ∆G was calculated, rendering -3.31, -1.68, and -6.91 kcal/mol, at M06-2x/6-31g+(d,p) (d3bj), ωB97X-D/6-31+(d,p), and APFD/6-31+(d,p) levels of theory, respectively. A time-dependent density functional theory (TD-DFT) was used to calculate the UV spectra of the complexes and then compared to its parent molecules, resulting in a lower energy gap at forming complexes. Excited states' properties were analyzed with the ωB97X-D functional. Finally, Shannon aromaticity indices were calculated and isosurfaces of non-covalent interactions were evaluated.

A Fruit-Expressed MYB Transcription Factor Regulates Anthocyanin Biosynthesis in Atropa belladonna.

Anthocyanins are water-soluble flavonoid pigments that play a crucial role in plant growth and metabolism. They serve as attractants for animals by providing plants with red, blue, and purple pigments, facilitating pollination and seed dispersal. The fruits of solanaceous plants, tomato (Solanum lycopersicum) and eggplant (Solanum melongena), primarily accumulate anthocyanins in the fruit peels, while the ripe fruits of Atropa belladonna (Ab) have a dark purple flesh due to anthocyanin accumulation. In this study, an R2R3-MYB transcription factor (TF), AbMYB1, was identified through association analysis of gene expression and anthocyanin accumulation in different tissues of A. belladonna. Its role in regulating anthocyanin biosynthesis was investigated through gene overexpression and RNA interference (RNAi). Overexpression of AbMYB1 significantly enhanced the expression of anthocyanin biosynthesis genes, such as AbF3H, AbF3'5'H, AbDFR, AbANS, and Ab3GT, leading to increased anthocyanin production. Conversely, RNAi-mediated suppression of AbMYB1 resulted in decreased expression of most anthocyanin biosynthesis genes, as well as reduced anthocyanin contents in A. belladonna. Overall, AbMYB1 was identified as a fruit-expressed R2R3-MYB TF that positively regulated anthocyanin biosynthesis in A. belladonna. This study provides valuable insights into the regulation of anthocyanin biosynthesis in Solanaceae plants, laying the foundation for understanding anthocyanin accumulation especially in the whole fruits of solanaceous plants.

Genome-Wide Identification of Glutathione S-Transferase Genes in Eggplant (Solanum melongena L.) Reveals Their Potential Role in Anthocyanin Accumulation on the Fruit Peel.

Anthocyanins are ubiquitous pigments derived from the phenylpropanoid compound conferring red, purple and blue pigmentations to various organs of horticultural crops. The metabolism of flavonoids in the cytoplasm leads to the biosynthesis of anthocyanin, which is then conveyed to the vacuoles for storage by plant glutathione S-transferases (GST). Although GST is important for transporting anthocyanin in plants, its identification and characterization in eggplant (Solanum melongena L.) remains obscure. In this study, a total of 40 GST genes were obtained in the eggplant genome and classified into seven distinct chief groups based on the evolutionary relationship with Arabidopsis thaliana GST genes. The seven subgroups of eggplant GST genes (SmGST) comprise: dehydroascorbate reductase (DHAR), elongation factor 1Bγ (EF1Bγ), Zeta (Z), Theta(T), Phi(F), Tau(U) and tetra-chlorohydroquinone dehalogenase TCHQD. The 40 GST genes were unevenly distributed throughout the 10 eggplant chromosomes and were predominantly located in the cytoplasm. Structural gene analysis showed similarity in exons and introns within a GST subgroup. Six pairs of both tandem and segmental duplications have been identified, making them the primary factors contributing to the evolution of the SmGST. Light-related cis-regulatory elements were dominant, followed by stress-related and hormone-responsive elements. The syntenic analysis of orthologous genes indicated that eggplant, Arabidopsis and tomato (Solanum lycopersicum L.) counterpart genes seemed to be derived from a common ancestry. RNA-seq data analyses showed high expression of 13 SmGST genes with SmGSTF1 being glaringly upregulated on the peel of purple eggplant but showed no or low expression on eggplant varieties with green or white peel. Subsequently, SmGSTF1 had a strong positive correlation with anthocyanin content and with anthocyanin structural genes like SmUFGT (r = 0.9), SmANS (r = 0.85), SmF3H (r = 0.82) and SmCHI2 (r = 0.7). The suppression of SmGSTF1 through virus-induced gene silencing (VIGs) resulted in a decrease in anthocyanin on the infiltrated fruit surface. In a nutshell, results from this study established that SmGSTF1 has the potential of anthocyanin accumulation in eggplant peel and offers viable candidate genes for the improvement of purple eggplant. The comprehensive studies of the SmGST family genes provide the foundation for deciphering molecular investigations into the functional analysis of SmGST genes in eggplant.

Effects of Anthocyanins on Components of Metabolic Syndrome-A Review.

Metabolic syndrome (MetS) is a significant health problem. The co-occurrence of obesity, carbohydrate metabolism disorders, hypertension and atherogenic dyslipidaemia is estimated to affect 20-30% of adults worldwide. Researchers are seeking solutions to prevent and treat the conditions related to MetS. Preventive medicine, which focuses on modifiable cardiovascular risk factors, including diet, plays a special role. A diet rich in fruits and vegetables has documented health benefits, mainly due to the polyphenolic compounds it contains. Anthocyanins represent a major group of polyphenols; they exhibit anti-atherosclerotic, antihypertensive, antithrombotic, anti-inflammatory and anticancer activities, as well as beneficial effects on endothelial function and oxidative stress. This review presents recent reports on the mechanisms involved in the protective effects of anthocyanins on the body, especially among people with MetS. It includes epidemiological data, in vivo and in vitro preclinical studies and clinical observational studies. Anthocyanins are effective, widely available compounds that can be used in both the prevention and treatment of MetS and its complications. Increased consumption of anthocyanin-rich foods may contribute to the maintenance of normal body weight and modulation of the lipid profile in adults. However, further investigation is needed to confirm the beneficial effects of anthocyanins on serum glucose levels, improvement in insulin sensitivity and reduction in systolic and diastolic blood pressure.

Genome-wide characterization of SmZHD gene family and the role of SmZHD12 in regulating anthocyanin biosynthesis in eggplant (Solanum melongena L.).

KEY MESSAGE: SmZHDs was highly expressed in anthocyanin-rich parts of eggplant. SmZHD12 can activate the expression of SmCHS, SmANS, SmDFR and SmF3H. Overexpression of SmZHD12 promotes anthocyanin biosynthesis in Arabidopsis. The Zinc finger-homeodomain (ZHD) proteins family genes are known to play a significant role in plant development and physiological processes. However, the evolutionary history and function of the ZHD gene family in eggplant remain largely unexplored. This study categorizes a total of 15 SmZHD genes into SmMIF and SmZHD subfamilies based on conserved domains. The phylogeny, gene structure, conserved motifs, promoter elements, and chromosomal locations of the SmZHD genes were comprehensively analyzed. Tissue expression profiles indicate that the majority of SmZHD genes are expressed in anthocyanin-rich areas. qRT-PCR assays revealed distinct expression patterns of SmZHD genes in response to various treatments, indicating their potential involvement in multiple signaling pathways. Analysis of transcriptomic data from light-treated eggplant peel identified SmZHD12 as the most light-responsive gene among the 15 SmZHD genes. Consequently, this study provides further evidence that SmZHD12 facilitates anthocyanin accumulation in Arabidopsis leaves by upregulating the expression of anthocyanin biosynthesis structural genes, as confirmed by dual-luciferase assays and Arabidopsis genetic transformation. Our study will lay a solid foundation for the in-depth study of the involvement of SmZHD genes in the regulation of anthocyanin biosynthesis.

Molecular mechanism of abscisic acid signaling response factor VcbZIP55 to promote anthocyanin biosynthesis in blueberry (Vaccinium corymbosum).

A high content of anthocyanin in blueberry (Vaccinium corymbosum) is an important indicator to evaluate fruit quality. Abscisic acid (ABA) can promote anthocyanin biosynthesis, but since the molecular mechanism is unclear, clarifying the mechanism will improve for blueberry breeding and cultivation regulation. VcbZIP55 regulating anthocyanin synthesis in blueberry were screened and mined using the published Isoform-sequencing, RNA-Seq and qRT-PCR at different fruit developmental stages. Blueberry genetic transformation and transgenic experiments confirmed that VcbZIP55 could promote anthocyanin biosynthesis in blueberry adventitious buds, tobacco leaves, blueberry leaves and blueberry fruit. VcbZIP55 responded to ABA signals and its expression was upregulated in blueberry fruit. In addition, using VcbZIP55 for Yeast one hybrid assay (Y1H) and transient expression in tobacco leaves demonstrated an interaction between VcbZIP55 and a G-Box motif on the VcMYB1 promoter to activate the expression of VcMYB1. This study will lay the theoretical foundation for the molecular mechanisms of phytohormone regulation responsible for anthocyanin synthesis and provide theoretical support for blueberry quality improvement.

Anthocyanins from blueberry ameliorated arsenic-induced memory impairment, oxidative stress, and mitochondrial-biosynthesis imbalance in rat hippocampal neurons.

In this study, blueberry anthocyanins extract (BAE) was used to investigate its protective effect on arsenic-induced rat hippocampal neurons damage. Arsenic exposure resulted in elevated levels of oxidative stress, decreased antioxidant capacity and increased apoptosis in rat hippocampal brain tissue and mitochondria. Immunohistochemical results showed that arsenic exposure also significantly decreased the expression of mitochondrial biosynthesis-related factors PGC-1α and TFAM. Treatment with BAE alleviated the decrease in antioxidant capacity, mitochondrial biogenesis related protein PGC-1α/NRF2/TFAM expression, and ATP production of arsenic induced hippocampal neurons in rats, and improved cognitive function in arsenic damaged rats. This study provides new insights into the detoxification effect of anthocyanins on the nervous system toxicity caused by metal exposure in the environment, indicating that anthocyanins may be a natural antioxidant against the nervous system toxicity caused by environmental metal exposure.