Effects of UV-B Radiation Exposure on Transgenerational Plasticity in Grain Morphology and Proanthocyanidin Content in Yuanyang Red Rice.

The effect of UV-B radiation exposure on transgenerational plasticity, the phenomenon whereby the parental environment influences both the parent's and the offspring's phenotype, is poorly understood. To investigate the impact of exposing successive generations of rice plants to UV-B radiation on seed morphology and proanthocyanidin content, the local traditional rice variety 'Baijiaolaojing' was planted on terraces in Yuanyang county and subjected to enhanced UV-B radiation treatments. The radiation intensity that caused the maximum phenotypic plasticity (7.5 kJ·m-2) was selected for further study, and the rice crops were cultivated for four successive generations. The results show that in the same generation, enhanced UV-B radiation resulted in significant decreases in grain length, grain width, spike weight, and thousand-grain weight, as well as significant increases in empty grain percentage and proanthocyanidin content, compared with crops grown under natural light conditions. Proanthocyanidin content increased as the number of generations of rice exposed to radiation increased, but in generation G3, it decreased, along with the empty grain ratio. At the same time, biomass, tiller number, and thousand-grain weight increased, and rice growth returned to control levels. When the offspring's radiation memory and growth environment did not match, rice growth was negatively affected, and seed proanthocyanidin content was increased to maintain seed activity. The correlation analysis results show that phenylalanine ammonialyase (PAL), cinnamate-4-hydroxylase (C4H), dihydroflavonol 4-reductase (DFR), and 4-coumarate:CoA ligase (4CL) enzyme activity positively influenced proanthocyanidin content. Overall, UV-B radiation affected transgenerational plasticity in seed morphology and proanthocyanidin content, showing that rice was able to adapt to this stressor if previous generations had been continuously exposed to treatment.

Transcriptome analysis reveals important regulatory factors for condensed tannins synthesis in acorn.

Condensed tannins are widely present in the fruits and seeds of plants and effectively prevent them from being eaten by animals before maturity due to their astringent taste. In addition, condensed tannins are a natural compound with strong antioxidant properties and significant antibacterial effects. Four samples of mature and near-mature Quercus fabri acorns, with the highest and lowest condensed tannin content, were used for genome-based transcriptome sequencing. The KEGG enrichment analysis revealed that the differentially expressed genes (DEGs) were highly enriched in phenylpropanoid biosynthesis and starch and sucrose metabolism. Given that the phenylpropanoid biosynthesis pathway is a crucial step in the synthesis of condensed tannins, we screened for significantly differentially expressed transcription factors and structural genes from the transcriptome data of this pathway and found that the expression levels of four MADS-box, PAL, and 4CL genes were significantly increased in acorns with high condensed tannin content. The quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) experiment further validated this result. In addition, yeast one-hybrid assay confirmed that three MADS-box transcription factors could bind the promoter of the 4CL gene, thereby regulating gene expression levels. This study utilized transcriptome sequencing to discover new important regulatory factors that can regulate the synthesis of acorn condensed tannins, providing new evidence for MADS-box transcription factors to regulate the synthesis of secondary metabolites in fruits.

Senolytic and senomorphic agent procyanidin C1 alleviates structural and functional decline in the aged retina.

Increased cellular senescence burden contributes in part to age-related organ dysfunction and pathologies. In our study, using mouse models of natural aging, we observed structural and functional decline in the aged retina, which was accompanied by the accumulation of senescent cells and senescence-associated secretory phenotype factors. We further validated the senolytic and senomorphic properties of procyanidin C1 (PCC1) both in vitro and in vivo, the long-term treatment of which ameliorated age-related retinal impairment. Through high-throughput single-cell RNA sequencing (scRNA-seq), we comprehensively characterized the retinal landscape after PCC1 administration and deciphered the molecular basis underlying the senescence burden increment and elimination. By exploring the scRNA-seq database of age-related retinal disorders, we revealed the role of cellular senescence and the therapeutic potential of PCC1 in these pathologies. Overall, these results indicate the therapeutic effects of PCC1 on the aged retina and its potential use for treating age-related retinal disorders.

Proanthocyanidins Ameliorate LPS-Inhibited Osteogenesis of PDLSCs by Restoring Lysine Lactylation.

Periodontitis is a bacteria-induced inflammatory disease characterized by the progressive destruction of periodontal supporting tissues. Periodontal ligament stem cells (PDLSCs) are capable of differentiating into osteoblasts, which is an important stem cell source for endogenous periodontal tissue regeneration. Lysine lactylation (Kla) is a novel post-translational modification of proteins that is recently thought to be associated with osteogenic differentiation. Here, we found that lactylation levels are reduced both in the periodontal tissue of rats with periodontitis and lipopolysaccharide (LPS)-stimulated human PDLSCs. Proanthocyanidins were able to promote the osteogenesis of inflamed PDLSCs by restoring lactylation levels. Mechanistically, proanthocyanidins increased lactate production and restored the lactylation levels of PDLSCs, which recovered osteogenesis of inflamed PDLSCs via the Wnt/ß-catenin pathway. These results provide evidence on how epigenetic regulation by pharmacological agents influence the osteogenic phenotype of stem cells and the process of periodontal tissue repair. Our current study highlights the valuable potential of natural product proanthocyanidins in the regenerative engineering of periodontal tissues.

Evaluation of biological activity and prebiotic properties of proanthocyanidins with different degrees of polymerization through simulated digestion and in vitro fermentation by human fecal microbiota.

The bioactive activity of proanthocyanidins (PAs) is closely associated with their degree of polymerization (DP), however, the effects of PAs with different DP on digestion and gut microbiota have remained unclear. To investigate this, we conducted in vitro simulated digestion and colonic fermentation studies on samples of PAs with different DP. The results showed that PAs was influenced by both protein precipitation and enzymolysis, resulting in a decrease in functional activity. PAs with a high DP were more sensitive to the gastrointestinal environment. The significant clustering trend in colonic fermentation verified the reliability of multivariate statistical techniques for screening samples with distinct functional differences. The gut microbiota analysis showed that oligomeric PAs had a stronger promoting effect on beneficial bacteria, while high polymeric PAs had a greater inhibitory effect on harmful bacteria. This study offers new insights into the biological activity and microbiological mechanisms of PAs with different DP.

Integrated Transcriptomic and Proteomic Analysis Identifies Novel Regulatory Genes Associated with Plant Growth Regulator-Induced Astringency in Grape Berries.

Astringency influences the sensory characteristics and flavor quality of table grapes. We tested the astringency sensory attributes of berries and investigated the concentration of flavan-3-ols/proanthocyanidins (PAs) in skins after the application of the plant growth regulators CPPU and GA3 to the flowers and young berries of the "Summer Black" grape. Our results showed that CPPU and GA3 applications increase sensory astringency perception scores and flavan-3-ol/proanthocyanidin concentrations. Using integrated transcriptomic and proteomic analysis, differentially expressed transcripts and proteins associated with growth regulator treatment were identified, including those for flavonoid biosynthesis that contribute to the changes in sensory astringency levels. Transient overexpression of candidate astringency-related regulatory genes in grape leaves revealed that VvWRKY71, in combination with VvMYBPA1 and VvMYC1, could promote the biosynthesis of proanthocyanidins, while overexpression of VvNAC83 reduced the accumulation of proanthocyanidins. However, in transient promoter studies in Nicotiana benthamiana, VvWRKY71 repressed the promoter of VvMYBPA2, while VvNAC83 had no significant effect on the promoter activity of four PA-related genes, and VvMYBPA1 was shown to activate its own promoter. This study provides new insights into the molecular mechanisms of sensory astringency formation induced by plant growth regulators in grape berries.

Cacao Procyanidins-Induced Lifespan Extension in Caenorhabditis elegans in a Nervous System and CaMKII-Dependent Manner.

Procyanidins are gaining attention due to their potential health benefits. We found that cacao liquor procyanidin (CLPr) from Theobroma cacao seeds increased the lifespan of Caenorhabditis elegans, a representative model organism for aging studies. The genetic dependence of the lifespan-extending effect of CLPr was consistent with that of blueberry procyanidin, which is dependent on unc-43, osr-1, sek-1, and mev-1, but not on daf-16, sir-2.1, or skn-1. The lifespan-extending effect of CLPr was inhibited by neuron-specific RNA interference (RNAi) targeting unc-43 and pmk-1, and in worms with loss-of-function mutations in the odr-3, odr-1, or tax-4 genes, which are essential in sensory neurons, including AWC neurons. It was also inhibited in worms in which AWC neurons or AIB interneurons had been eliminated, and in worms with loss-of-function mutations in eat-4 or glr-1, which are responsible for glutamatergic synaptic transmission. These results suggest that the lifespan-extending effect of CLPr is dependent on the nervous system. In addition, it also requires unc-43 and pmk-1 expression in nonneuronal cells, as demonstrated by the experiments with RNAi in wild-type worms, the neuronal cells of which are not affected by systemic RNAi. The osr-1 gene is expressed in hypodermal and intestinal cells and regulates the response to osmotic stress along with unc-43/calcium/calmodulin-dependent protein kinase II and the p38 mitogen-activated protein kinase pathway. Consistent with this, CLPr improved osmotic stress tolerance in an unc-43- and pmk-1-dependent manner, and it was also dependent on AWC neurons. The lifespan-extending and osmotic-tolerance-improving activities were attributed to procyanidins with a tetrameric or higher-order oligomeric structure.

Prebiotic proanthocyanidins inhibit bile reflux-induced esophageal adenocarcinoma through reshaping the gut microbiome and esophageal metabolome.

The gut and local esophageal microbiome progressively shift from healthy commensal bacteria to inflammation-linked pathogenic bacteria in patients with gastroesophageal reflux disease, Barrett's esophagus, and esophageal adenocarcinoma (EAC). However, mechanisms by which microbial communities and metabolites contribute to reflux-driven EAC remain incompletely understood and challenging to target. Herein, we utilized a rat reflux-induced EAC model to investigate targeting the gut microbiome-esophageal metabolome axis with cranberry proanthocyanidins (C-PAC) to inhibit EAC progression. Sprague-Dawley rats, with or without reflux induction, received water or C-PAC ad libitum (700 µg/rat/day) for 25 or 40 weeks. C-PAC exerted prebiotic activity abrogating reflux-induced dysbiosis and mitigating bile acid metabolism and transport, culminating in significant inhibition of EAC through TLR/NF-κB/TP53 signaling cascades. At the species level, C-PAC mitigated reflux-induced pathogenic bacteria (Streptococcus parasanguinis, Escherichia coli, and Proteus mirabilis). C-PAC specifically reversed reflux-induced bacterial, inflammatory, and immune-implicated proteins and genes, including Ccl4, Cd14, Crp, Cxcl1, Il6, Il1b, Lbp, Lcn2, Myd88, Nfkb1, Tlr2, and Tlr4, aligning with changes in human EAC progression, as confirmed through public databases. C-PAC is a safe, promising dietary constituent that may be utilized alone or potentially as an adjuvant to current therapies to prevent EAC progression through ameliorating reflux-induced dysbiosis, inflammation, and cellular damage.

Non-Mature miRNA-Encoded Micropeptide miPEP166c Stimulates Anthocyanin and Proanthocyanidin Synthesis in Grape Berry Cells.

The phenylpropanoid and flavonoid pathways exhibit intricate regulation, not only influenced by environmental factors and a complex network of transcription factors but also by post-transcriptional regulation, such as silencing by microRNAs and miRNA-encoded micropeptides (miPEPs). VviMYBC2-L1 serves as a transcriptional repressor for flavonoids, playing a crucial role in coordinating the synthesis of anthocyanin and proanthocyanidin. It works in tandem with their respective transcriptional activators, VviMYBA1/2 and VviMYBPA1, to maintain an equilibrium of flavonoids. We have discovered a miPEP encoded by miR166c that appears to target VviMYBC2-L1. We conducted experiments to test the hypothesis that silencing this transcriptional repressor through miPEP166c would stimulate the synthesis of anthocyanins and proanthocyanidins. Our transcriptional analyses by qPCR revealed that the application of exogenous miPEP166c to Gamay Fréaux grape berry cells resulted in a significant upregulation in flavonoid transcriptional activators (VviMYBA1/2 and VviMYBPA1) and structural flavonoid genes (VviLDOX and VviDFR), as well as genes involved in the synthesis of proanthocyanidins (VviLAR1 and VviANR) and anthocyanins (VviUFGT1). These findings were supported by the increased enzyme activities of the key enzymes UFGT, LAR, and ANR, which were 2-fold, 14-fold, and 3-fold higher, respectively, in the miPEP166c-treated cells. Ultimately, these changes led to an elevated total content of anthocyanins and proanthocyanidins.

AP3 promotes the synthesis of condensed tannin in fruit by positively regulating ANR expression.

Condensed tannins are often found in fruits and nuts and have an astringent flavor. The synthesis pathway of condensed tannins is already clear, but few related regulatory factors have been explored. Previous studies about MADS-box transcription factors have mainly focused on the regulation of floral organ development. Recent studies have shown that MADS-box are also involved in fruit development, maturation, and quality. The fruit of Quercus fabri is rich in starch and nutrients in its kernel but is difficult to eat directly because of its high condensed tannin content. This study identified and functionally characterized the MADS-box transcription factor QfAP3 in Q. fabri. Functional analysis based on overexpression in Micro-Tom showed that QfAP3 promoted condensed tannin synthesis. By analyzing the expression trend of key genes in the condensed tannin synthesis pathway in Micro-Tom plants, we found that the expression trend of ANR was consistent with that of QfAP3, and QfAP3 could bind to the promoter of ANR and positively regulate it. This study has discovered new functions of MADS-box transcription factors in fruit quality formation, developed new regulatory factors for the synthesis pathway of condensed tannin, and provided a biotechnological method that can effectively reduce astringency in fruit.

Effects of grape variety and roasting on the proanthocyanidin oligomers distribution, cyclic proanthocyanidins, and total polyphenol content in grape seed powders.

Grape seeds are a valuable source of natural phenolic compounds, particularly flavan-3-ol derivatives such as condensed tannins. Recent studies have shown that grape seed powder can be applied to reduce the undesirable effects of protein instability in wine. One pretreatment method applied to grape seeds is roasting. Roasting causes the heavier proanthocyanidins (PAC) oligomers to break down, thereby increasing the concentration of smaller oligomers available for interaction with proteins. In addition, roasting can prolong grape seed storage. Among the subclasses of proanthocyanidins, oligomeric macrocyclic proanthocyanidins have also shown potential effects in terms of wine stabilization, particularly by presenting selective interactions with metal cations such as potassium and calcium. However, their composition in grape seed extracts has never been studied. Here, the characterization of condensed tannins according to the degree of polymerization in grape seeds, the profile of cyclic proanthocyanidins and the total polyphenol content were characterized in relation to different grape varieties and the application of roasting. Roasting greatly influenced the distribution of PAC according to the degree of polymerization, increasing the abundance of almost all classes of PAC. However, the overall effect of roasting was highly dependent on grape variety. PAC were analyzed according to the degree of polymerization. Grape seed roasting of red varieties (Croatina and Sangiovese) showed an increase in all classes of PAC except trimers. The white variety (Ortrugo) and the mix of Nebbiolo and Barbera varieties (80% and 20% w/w, respectively) showed no clear effect on the profile of PAC upon roasting. Notably, cyclic procyanidins were identified for the first time in grape seeds: a cyclic tetrameric procyanidin (ESI + m/z 1153) and cyclic pentameric procyanidin (ESI + m/z 1441) were found. The abundances of these cyclic PAC were found to be completely stable upon roasting, also in agreement with the already known stability of these compounds against depolymerizing conditions. Interestingly, the cyclic pentameric procyanidin was significantly more abundant in Ortrugo (white variety), than in Sangiovese and Croatina (red varieties). Besides, no effect of roasting occurred on the profile of cyclic procyanidins in grape seed powder. Finally, the total polyphenol content was evaluated, showing that roasting caused an increase of polyphenolic molecular species potentially available for protein stabilization, but only in GSP of red varieties. Overall, the grape variety was found to be a significant factor in determining how much the roasting would change the PAC profile, providing valuable information for future applications of GSP in enology.

Rumen fermentation and microbiota in Shami goats fed on condensed tannins or herbal mixture.

BACKGROUND: Phytochemical compounds can modify the rumen microbiome and improve rumen fermentation. This study evaluated the impact of supplementation with tannin and an herbal mixture containing ginger (Zingiber officinale), garlic (Allium sativum), Artemisia (Artemisia vulgaris), and turmeric (Curcuma longa) on the rumen fermentation and microbiota, and histology of rumen tissue of goats. Eighteen Shami male goats were divided into three groups (n = 6): non-supplemented animals fed the basal diet (C, control); animals fed basal diet and supplemented with condensed tannin (T); and animals fed basal diet and supplemented with herbal mixture (HM). Each animal received a basal diet composed of Alfalfa hay and a concentrate feed mixture. RESULTS: Group HM revealed higher (P < 0.05) rumen pH, total volatile fatty acids (VFA), acetic, propionic, isobutyric, butyric, isovaleric, and valeric. Principal Co-ordinate analysis (PCoA) showed that rumen microbial communities in the control group and supplemented groups were distinct. The supplementation increased (P < 0.05) the relative abundances of phylum Bacteroidota and Proteobacteria and declined (P < 0.05) Firmicutes and Fibrobacterota. Additionally, the dominant genus Prevotella and Rikenellaceae RC9 gut group were increased (P < 0.05) and the family Ruminococcaceae was declined (P < 0.05) due to the supplementation. The supplementation decreased (P < 0.05) the archaeal genus Methanobrevibacter and increased (P < 0.05) Candidatus Methanomethylophilus. Tannin supplementation in T group shortened the rumen papillae. CONCLUSIONS: The results revealed that the herbal mixture might be used to alter the rumen microbiota to improve rumen fermentation.

The APETALA2-MYBL2 module represses proanthocyanidin biosynthesis by affecting formation of the MBW complex in seeds of Arabidopsis thaliana.

Proanthocyanidins (PAs) are the second most abundant plant phenolic natural products. PA biosynthesis is regulated by the well-documented MYB/bHLH/WD40 (MBW) complex, but how this complex itself is regulated remains ill defined. Here, in situ hybridization and ß-glucuronidase staining show that APETALA2 (AP2), a well-defined regulator of flower and seed development, is strongly expressed in the seed coat endothelium, where PAs accumulate. AP2 negatively regulates PA content and expression levels of key PA pathway genes. AP2 activates MYBL2 transcription and interacts with MYBL2, a key suppressor of the PA pathway. AP2 exerts its function by directly binding to the AT-rich motifs near the promoter region of MYBL2. Molecular and biochemical analyses revealed that AP2 forms AP2-MYBL2-TT8/EGL3 complexes, disrupting the MBW complex and thereby repressing expression of ANR, TT12, TT19, and AHA10. Genetic analyses revealed that AP2 functions upstream of MYBL2, TT2, and TT8 in PA regulation. Our work reveals a new role of AP2 as a key regulator of PA biosynthesis in Arabidopsis. Overall, this study sheds new light on the comprehensive regulation network of PA biosynthesis as well as the dual regulatory roles of AP2 in seed development and accumulation of major secondary metabolites in Arabidopsis.

Investigation of peanut allergen-procyanidin non-covalent interactions: Impact on protein structure and in vitro allergenicity.

Interactions between plant polyphenols and food allergens may be a new way to alleviate food allergies. The non-covalent interactions between the major allergen from peanut (Ara h 2) with procyanidin dimer (PA2) were therefore characterized using spectroscopic, thermodynamic, and molecular simulation analyses. The main interaction between the Ara h 2 and PA2 was hydrogen bonding. PA2 statically quenched the intrinsic fluorescence intensity and altered the conformation of the Ara h 2, leading to a more disordered polypeptide structure with a lower surface hydrophobicity. In addition, the in vitro allergenicity of the Ara h 2-PA2 complex was investigated using enzyme-linked immunosorbent assay (ELISA) kits. The immunoglobulin E (IgE) binding capacity of Ara h 2, as well as the release of allergenic cytokines, decreased after interacting with PA2. When the ratio of Ara h 2-to-PA2 was 1:50, the IgE binding capacity was reduced by around 43 %. This study provides valuable insights into the non-covalent interactions between Ara h 2 and PA2, as well as the potential mechanism of action of the anti-allergic reaction caused by binding of the polyphenols to the allergens.

Abrupt Photoperiod Changes Differentially Modulate Hepatic Antioxidant Response in Healthy and Obese Rats: Effects of Grape Seed Proanthocyanidin Extract (GSPE).

Disruptions of the light/dark cycle and unhealthy diets can promote misalignment of biological rhythms and metabolic alterations, ultimately leading to an oxidative stress condition. Grape seed proanthocyanidin extract (GSPE), which possesses antioxidant properties, has demonstrated its beneficial effects in metabolic-associated diseases and its potential role in modulating circadian disruptions. Therefore, this study aimed to assess the impact of GSPE administration on the liver oxidant system of healthy and diet-induced obese rats undergoing a sudden photoperiod shift. To this end, forty-eight photoperiod-sensitive Fischer 344/IcoCrl rats were fed either a standard (STD) or a cafeteria diet (CAF) for 6 weeks. A week before euthanizing, rats were abruptly transferred from a standard photoperiod of 12 h of light/day (L12) to either a short (6 h light/day, L6) or a long photoperiod (18 h light/day, L18) while receiving a daily oral dose of vehicle (VH) or GSPE (25 mg/kg). Alterations in body weight gain, serum and liver biochemical parameters, antioxidant gene and protein expression, and antioxidant metabolites were observed. Interestingly, GSPE partially ameliorated these effects by reducing the oxidative stress status in L6 through an increase in GPx1 expression and in hepatic antioxidant metabolites and in L18 by increasing the NRF2/KEAP1/ARE pathway, thereby showing potential in the treatment of circadian-related disorders by increasing the hepatic antioxidant response in a photoperiod-dependent manner.

The effects of proanthocyanidin on testicular toxicity in rats exposed to a glyphosate-based herbicide.

The purpose of this study is to determine the effects of proanthocyanidin (PA) on spermatological parameters and testicular toxicity in male rats exposed to glyphosate (GLP). In our study, four groups were formed out of 24 male rats, each group would include 6 rats. The rats in the PA group were given a dose of 400 mg/kg/day dissolved in DMSO via gastric gavage. The rats in the GLP+PA groups were first given GLP at the LD50/10 dose of 787.85 mg/kg/day, followed by administering PA at a dose of 400 mg/kg/day dissolved in DMSO via gastric gavage. The rats in the GLP group were given GLP at the LD50/10 dose of 787.85 mg/kg/day dissolved in DMSO via gastric gavage. It was determined that in terms of motility, in comparison to the control group, the decreases in the GLP group and the increases in the PA and GLP+PA groups were statistically significant (p<0.001). The administration of GLP increased DNA damage compared to the control group, but the GLP+PA and PA applications reduced DNA damage (p<0.001). The analysis of testosterone levels indicated a statistically significant reduction in the GLP group compared to the other groups. Consequently, it was determined that PA effectively prevented the decreases in the spermatological parameters lowered as a result of GLP exposure and the oxidative stress and toxicity in testicular tissue.

Tartary Buckwheat (Fagopyrum tataricum) FtTT8 Inhibits Anthocyanin Biosynthesis and Promotes Proanthocyanidin Biosynthesis.

Tartary buckwheat (Fagopyrum tataricum) is an important plant, utilized for both medicine and food. It has become a current research hotspot due to its rich content of flavonoids, which are beneficial for human health. Anthocyanins (ATs) and proanthocyanidins (PAs) are the two main kinds of flavonoid compounds in Tartary buckwheat, which participate in the pigmentation of some tissue as well as rendering resistance to many biotic and abiotic stresses. Additionally, Tartary buckwheat anthocyanins and PAs have many health benefits for humans and the plant itself. However, little is known about the regulation mechanism of the biosynthesis of anthocyanin and PA in Tartary buckwheat. In the present study, a bHLH transcription factor (TF) FtTT8 was characterized to be homologous with AtTT8 and phylogenetically close to bHLH proteins from other plant species. Subcellular location and yeast two-hybrid assays suggested that FtTT8 locates in the nucleus and plays a role as a transcription factor. Complementation analysis in Arabidopsis tt8 mutant showed that FtTT8 could not recover anthocyanin deficiency but could promote PAs accumulation. Overexpression of FtTT8 in red-flowering tobacco showed that FtTT8 inhibits anthocyanin biosynthesis and accelerates proanthocyanidin biosynthesis. QRT-PCR and yeast one-hybrid assay revealed that FtTT8 might bind to the promoter of NtUFGT and suppress its expression, while binding to the promoter of NtLAR and upregulating its expression in K326 tobacco. This displayed the bidirectional regulating function of FtTT8 that negatively regulates anthocyanin biosynthesis and positively regulates proanthocyanidin biosynthesis. The results provide new insights on TT8 in Tartary buckwheat, which is inconsistent with TT8 from other plant species, and FtTT8 might be a high-quality gene resource for Tartary buckwheat breeding.

The regulatory role of MdNAC14-Like in anthocyanin synthesis and proanthocyanidin accumulation in red-fleshed apples.

Flavonoids, such as anthocyanins and proanthocyanidins (PAs), play essential roles in plant growth, development, and stress response. Red-fleshed apples represent a valuable germplasm resource with high flavonoid content. Understanding and enriching the regulatory network controlling flavonoid synthesis in red-fleshed apples holds significant importance for cultivating high-quality fruits. In this study, we successfully isolated an NAC transcription factor, MdNAC14-Like, which exhibited a significant negative correlation with the content of anthocyanin. Transient injection of apple fruit and stable expression of callus confirmed that MdNAC14-Like acts as an inhibitor of anthocyanin synthesis. Through yeast monohybrid, electrophoretic mobility shift, and luciferase reporter assays, we demonstrated the ability of MdNAC14-Like to bind to the promoters of MdMYB9, MdMYB10, and MdUFGT, thus inhibiting their transcriptional activity and subsequently suppressing anthocyanin synthesis. Furthermore, our investigation revealed that MdNAC14-Like interacts with MdMYB12, enhancing the transcriptional activation of MdMYB12 on the downstream structural gene MdLAR, thereby promoting PA synthesis. This comprehensive functional characterization of MdNAC14-Like provides valuable insights into the intricate regulatory network governing anthocyanin and PA synthesis in apple.

Peanut skin procyanidins reduce intestinal glucose transport protein expression, regulate serum metabolites and ameliorate hyperglycemia in diabetic mice.

One of diabetic characteristics is the postprandial hyperglycemia. Inhibiting glucose uptake may be beneficial for controlling postprandial blood glucose levels and regulating the glucose metabolism Peanut skin procyanidins (PSP) have shown a potential for lowering blood glucose; however, the underlying mechanism through which PSP regulate glucose metabolism remains unknown. In the current study, we investigated the effect of PSP on intestinal glucose transporters and serum metabolites using a mouse model of diabetic mice. Results showed that PSP improved glucose tolerance and systemic insulin sensitivity, which coincided with decreased expression of sodium-glucose cotransporter 1 and glucose transporter 2 in the intestinal epithelium induced by an activation of the phospholipase C ß2/protein kinase C signaling pathway. Moreover, untargeted metabolomic analysis of serum samples revealed that PSP altered arachidonic acid, sphingolipid, glycerophospholipid, bile acids, and arginine metabolic pathways. The study provides new insight into the anti-diabetic mechanism of PSP and a basis for further research.

GhmiR858 Inhibits the Accumulation of Proanthocyanidins by Targeting GhTT2L in Cotton (Gossypium hirsutum).

Proanthocyanidins (PAs) are predominantly regulated at the transcriptional level by sophisticated regulatory networks. In cotton, the role of miRNAs as key regulatory factors at the post-transcriptional level is still unclear. Here, we demonstrated that GhmiR858 negatively regulates PA accumulation in cotton leaves and calli by targeting GhTT2L. Excessive expression of GhmiR858 restrained the expression of GhTT2L, resulting in a significant decrease in PA abundance. Conversely, a reduction in GhmiR858 activity upregulated GhTT2L, which increased PA accumulation. Additionally, GhTT2L was found to positively regulate PA accumulation in both cotton and Arabidopsis. Further analyses showed that GhTT2L interacted with transcription factor GhTTG1, which directly binds to the GhANR promoter, to facilitate its transcription. This study provides new information to guide future studies of the PA regulatory mechanisms affected by miRNAs as well as the breeding of novel varieties of colored cotton with rich PAs.