Ubiquitin ligase VvPUB26 in grapevine promotes proanthocyanidin synthesis and resistance to powdery mildew.

Proanthocyanidins (PAs) are an important group of flavonoids that contribute to astringency, color, and flavor in grape (Vitis vinifera) and wines. They also play a crucial role in enhancing plant resistance to various stresses. However, the underlying regulatory mechanism governing PAs biosynthesis, particularly in relation to conferring resistance to powdery mildew, has not been extensively explored. This study focused on identifying a key player in PAs biosynthesis, namely the plant U-box (PUB) E3 ubiquitin ligase VvPUB26. We discovered that overexpression of VvPUB26 in grape leads to a significant increase in PAs content, whereas interfering with VvPUB26 has the opposite effect. Additionally, our findings demonstrated that overexpression of VvPUB26 in transgenic grapevines enhances defense against powdery mildew, while interfering with VvPUB26 results in increased susceptibility to the pathogen. Interestingly, we observed that VvPUB26 interacts with the WRKY transcription factor VvWRKY24, thereby facilitating ubiquitination and degradation processes. Through RNA-Seq analysis, we found that VvWRKY24 primarily participates in secondary metabolites biosynthesis, metabolic pathways, and plant-pathogen interaction. Notably, VvWRKY24 directly interacts with the promoters of dihydroflavonol-4-reductase (DFR) and leucoanthocyanidin reductase (LAR) to inhibit PAs biosynthesis. Meanwhile, VvWRKY24 also influences the expression of MYB transcription factor genes related to PAs synthesis. In conclusion, our results unveil a regulatory module involving VvPUB26-VvWRKY24-VvDFR/VvLAR that plays a fundamental role in governing PAs biosynthesis in grapevines. These findings enhance our understanding of the relationship between PAs biosynthesis and defense mechanisms against powdery mildew.

VqMAPK3/VqMAPK6, VqWRKY33, and VqNSTS3 constitute a regulatory node in enhancing resistance to powdery mildew in grapevine.

Grapevine powdery mildew is caused by Erysiphe necator, which seriously harms grape production in the world. Stilbene synthase makes phytoalexins that contribute to the resistance of grapevine against powdery mildew. A novel VqNSTS3 was identified and cloned from Chinese wild Vitis quinquangularis accession Danfeng-2. The novel VqNSTS3 was transferred into susceptible 'Thompson Seedless' by Agrobacterium-mediated transformation. The transgenic plants showed resistance to the disease and activated other resistance-related genes. VqNSTS3 expression in grapevine is regulated by VqWRKY33, and which binds to TTGACC in the VqNSTS3 promoter. Furthermore, VqWRKY33 was phosphorylated by VqMAPK3/VqMAPK6 and thus led to enhanced signal transduction and increased VqNSTS3 expression. ProVqNSTS3::VqNSTS3-GFP of transgenic VqNSTS3 in Arabidopsis thaliana was observed to move to and wrap the pathogen's haustoria and block invasion by Golovinomyces cichoracearum. These results demonstrate that stilbene accumulation of novel VqNSTS3 of the Chinese wild Vitis quinquangularis accession Danfeng-2 prevented pathogen invasion and enhanced resistance to powdery mildew. Therefore, VqNSTS3 can be used in generating powdery mildew-resistant grapevines.

Fisetin alleviates chronic urticaria by inhibiting mast cell activation via MRGPRX2.

OBJECTIVES: The activation of mast cell (MC) plays an important part in the pathogenesis of chronic urticaria (CU), and the expression of MRGPRX2 (Mas-related G-protein coupled receptor X2) and the circulating levels of SP (substance P) in skin MC of CU patients increased. Fisetin is a natural flavonoid with anti-inflammatory and antiallergic pharmacological effects. This study aimed to investigate the inhibitory effect of fisetin on CU via MRGPRX2 and its possible molecular mechanisms. METHODS: OVA/SP co-stimulated and SP-stimulated CU like murine models were used to evaluate the effect of fisetin on CU. MRGPRX2/HEK293 cells and LAD2 cells were used to perform the antagonism effect of fisetin on MC via MRGPRX2. KEY FINDINGS: The results indicated that fisetin prevented urticaria-like symptoms in murine CU models, and inhibited MCs activation by suppressing calcium mobilization and degranulation of cytokines and chemokines via binding to MRGPRX2. The bioinformatics analysis showed that fisetin might have an interaction relationship with Akt in CU. The western blotting experiments showed that fisetin downregulated the phosphorylation levels of Akt, P38, NF-κB, and PLCγ in C48/80 activated LAD2 cells. CONCLUSIONS: Fisetin alleviates CU progression by inhibiting mast cell activation via MRGPRX2, which may be a novel therapeutic candidate for CU.

Anti-inflammatory effect of dictamnine on allergic rhinitis via suppression of the LYN kinase-mediated molecular signaling pathway during mast cell activation.

Mast cells (MCs) are important therapeutic targets for allergic diseases. High-affinity immunoglobulin E (IgE) Fc receptors (FcεRI) trigger abnormal activation of MCs. Allergic rhinitis (AR) is an IgE-mediated antigen inhalation reaction that occurs in the nasal mucosa. MC aggravation and dysfunction were observed during the early stages of AR pathogenesis. Herb-derived dictamnine exhibits anti-inflammatory effects. Here, we investigated the pharmacological effects of herb-derived dictamnine on IgE-induced activation of MCs and an ovalbumin (OVA)-induced murine AR model. The results indicated that dictamnine attenuated OVA-induced local allergic reactions and reduced body temperature in OVA-challenged mice with active systemic anaphylaxis. Additionally, dictamnine decreased the frequency of nasal rubbing and sneezing in an OVA-induced murine AR model. Moreover, dictamnine inhibited FcεRI-activated MC activation in a dose-dependent manner without causing cytotoxicity, reduced the activation of the tyrosine kinase LYN in LAD2 cells, and downregulated the phosphorylation of PLCγ1, IP3R, PKC, Erk1/2, and Akt, which are downstream of LYN. In conclusion, dictamnine suppressed the OVA-stimulated murine model of AR and activated IgE-induced MCs via the LYN kinase-mediated molecular signaling pathway, suggesting that dictamnine may be a promising treatment for AR.

Paeonol attenuates Substance P-induced urticaria by inhibiting Src kinase phosphorylation in mast cells.

BACKGROUND: Treatment of chronic urticaria is challenging, the discovery of effective therapeutic drugs is urgently in demand. PURPOSE: To study the effect and mechanism of Paeonol targeting mast cells and its therapeutic effect on chronic urticaria. STUDY DESIGN: We developed a chronic urticaria model in vivo and mast cell model in vitro examined the effect of Paeonol in the treatment of chronic urticaria and its mechanism of action in mast cells. METHOD: The anti-anaphylactoid effect of Paeonol was evaluated in PCA and systemic anaphylaxis models. The treatment role of Paeonol was studied in urticaria model. The release of cytokines and chemokines was measured using enzyme immunoassay kits. Western blot analysis was conducted to investigate phosphorylation of Src, PI3K, and PLC. In vitro kinase assays were conducted to investigate the kinase activity of Lyn, PLC, PI3K and Src. RESULTS: In our study, Paeonol was able to attenuate evans blue leakage, serum histamine and chemokine release in a passive skin allergic reaction model. Simultaneously, Paeonol inhibited vasodilation and mast cell degranulation in C57BL/6 mice. Further research found that Paeonol alleviated symptoms such as erythema and rash in the Substance P-induced urticaria model, this is accompanied by inhibiting the release of related inflammatory factors. Validation experiments on mast cells in vitro found that Paeonol inhibited the activation of Src-PI3K/Lyn-PLC-NF-κB signaling pathway by crosslinking with Src kinase. Moreover, calcium influx, mast cell degranulation, cytokines generation and chemotaxis were reduced in LAD2 cells. Molecular docking experiments revealed that Paeonol is a specific antagonist targeting Src kinase in the treatment of skin diseases such as urticaria. CONCLUSION: Paeonol, a herb-derived phenolic compound, can provide drug candidate for developing new drug in treatment of skin disease such as urticaria. SIGNIFICANCE STATEMENT: In this study, we primarily examined the effect of Paeonol in the treatment of chronic urticaria and its mechanism of action in mast cells. Interestingly, Paeonol was found to regulate Src kinase activity downstream of MRGPRX2 triggered signaling cascade in mast cells. Therefore, this plant-derived phenolic compound may provide a therapeutic option for the treatment of chronic urticaria.

Harringtonine: A more effective antagonist for Omicron variant.

Fusion with host cell membrane is the main mechanism of infection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Here, we propose that a new strategy to screen small-molecule antagonists blocking SARS-CoV-2 membrane fusion. Using cell membrane chromatography (CMC), we found that harringtonine (HT) simultaneously targeted SARS-CoV-2 S protein and host cell surface TMPRSS2 expressed by the host cell, and subsequently confirmed that HT can inhibit membrane fusion. HT effectively blocked SARS-CoV-2 original strain entry with the IC50 of 0.217 µM, while the IC50 in delta variant decreased to 0.101 µM, the IC50 in Omicron BA.1 variant was 0.042 µM. Due to high transmissibility and immune escape, Omicron subvariant BA.5 has become the dominant strain of the SARS-CoV-2 virus and led to escalating COVID-19 cases, however, against BA.5, HT showed a surprising effectiveness. The IC50 in Omicron BA.5 was even lower than 0.0019 µM. The above results revealed the effect of HT on Omicron is very significant. In summary, we characterize HT as a small-molecule antagonist by direct targeting on the Spike protein and TMPRSS2.

Alpha-linolenic acid improves nasal mucosa epithelial barrier function in allergic rhinitis by arresting CD4+ T cell differentiation via IL-4Rα-JAK2-STAT3 pathway.

BACKGROUND: Allergic rhinitis (AR) defined as inflammation and tissue remodeling of the nasal mucosa in atopic individuals after allergen exposure. Alpha-linolenic acid [cis-9, cis-12, cis-15-octadecatrienoic acid (18:3)] (ALA) as dietary supplementation can reduce inflammation and allergic symptoms. OBJECTIVE: To evaluate the potential therapeutic effect and mechanism of ALA in AR mouse model. METHODS: Ovalbumin sensitized AR mouse model were challenged with oral ALA administration. Nasal symptoms, tissue pathology, immune cell infiltration and goblet cell hyperplasia were investigated. Levels of IgE, TNF-ß, IFN-γ, IL-2, IL-4, IL-5, IL-12, IL-13 and IL-25 were determined by ELISA in serum and nasal fluid. Quantitative RT-PCR and immunofluorescence were performed for occludin and zonula occludens-1 expression. CD3+CD4+ T-cells from peripheral blood and splenic lymphocytes were isolated and Th1/Th2 ratio were determined. Mouse naive CD4+ T cell were isolated and Th1/Th2 ratio, IL-4Rα expression, and IL5/IL13 secretion were determined. IL-4Rα-JAK2-STAT3 pathway change in AR mice were performed by western blot. RESULTS: Ovalbumin induced AR, nasal symptoms, pathological performance, IgE, and cytokine production. ALA treated mice showed reduced nasal symptoms, nasal inflammation, nasal septum thickening, goblet cell hyperplasia, and eosinophil infiltration. In serum and nasal fluid of ovalbumin challenged mice, ALA decreased IgE, IL-4 levels, and the increase of Th2-cells. ALA prevented the disruption of the epithelial cell barrier in ovalbumin-challenged AR mice. Simultaneously, ALA prevents IL-4 induced barrier disruption. ALA treatment of AR by affecting the differentiation stage of CD4+T cells and block IL-4Rα-JAK2-STAT3 pathway. CONCLUSION: This study suggests that ALA has the potential therapeutic effect to ovalbumin-induced AR. ALA can affect the differentiation stage of CD4+T cells and improve epithelial barrier functions through IL-4Rα-JAK2-STAT3 pathways. CLINICAL IMPLICATION: ALA might be considered as drug candidate for improving epithelial barrier function through Th1/Th2 ratio recovery in AR.

Silibinin attenuated pseudo-allergic reactions and mast cell degranulation via PLCγ and PI3K/Akt signaling pathway.

Anaphylaxis is a type of potentially fatal hypersensitivity reaction resulting from the activation of mast cells. Many endogenous or exogenous factors could cause this reaction. Silibinin is the main chemical component of silymarin and has been reported to have pharmacological activities. However, the anti-allergic reaction effect of silibinin has not yet been investigated. This study aimed to evaluate the effect of silibinin to attenuate pseudo-allergic reactions in vivo and to investigate the underlying mechanism in vitro. In this study, calcium imaging was used to assess Ca2+ mobilization. The levels of cytokines and chemokines, released by stimulated mast cells, were measured using enzyme immunoassay kits. The activity of silibinin was evaluated in a mouse model of passive cutaneous anaphylaxis (PCA). Western blotting was used to explore the related molecular signaling pathways. In results, silibinin markedly inhibited mast cell degranulation, calcium mobilization, and preventing the release of cytokines and chemokines in a dose-dependent manner via the PLCγ and PI3K/Akt signaling pathway. Silibinin also attenuated PCA in a dose-dependent manner. In summary, silibinin has an anti-pseudo-allergic pharmacological activity, which makes it a potential candidate for the development of a novel agent to arrest pseudo-allergic reactions.

The putative ABCG transporter VviABCG20 from grapevine (Vitis vinifera) is strongly expressed in the seed coat of developing seeds and may participate in suberin biosynthesis.

Half-size ATP binding cassette G (ABCG) transporters participate in many biological processes by transporting specific substrates. Our previous study showed that VviABCG20 was strongly expressed in the seeds of seeded grape and the silencing of VviABCG20 homolog gene in tomato led to a reduction in seed number. To reveal the molecular mechanism of VviABCG20 gene involved in grape seed development/abortion, the gene expression and functional analysis of VviABCG20 were further carried out in the grapevine. It was shown that the gene expression of VviABCG20 was higher in seeds of seeded grapes compared with seedless. Further the expression of VviABCG20 in the seed coat was significantly higher than in ovules (young seeds) and endosperm. VviABCG20 was also induced by exogenous hormones (especially MeJA) in grape leaves. Subcellular localization analysis showed that VviABCG20 is a membrane protein. In overexpressed VviABCG20 transgenic callus of Thompson seedless, expression of genes GPAT5, FAR1 and FAR5 was increased significantly. After treatment with suberin precursors, the transgenic callus reduced the sensitivity to three cinnamic acid derivatives (cis-ferulic acid, caffeic acid, coumaric acid), succinic acid, and glycerol. In suspension cells, expression of VviABCG20 was increased significantly after treatment with suberin precursors. Our research suggested that VviABCG20 may function in seed development in grapevine, at least in part by participating in suberin biosynthesis in the seed coat.

Alfin-like transcription factor VqAL4 regulates a stilbene synthase to enhance powdery mildew resistance in grapevine.

Resveratrol is a phytoalexin that is synthesized by stilbene synthase (STS). Resveratrol in the human diet is known to have beneficial effects on health. We previously identified six novel STS (VqNSTS) transcripts from the transcriptome data of Vitis quinquangularis accession Danfeng-2. However, the functions of and defensive mechanisms triggered by these VqNSTS transcripts remain unknown. In the present study, we demonstrate that the expression of five of these six novel members, VqNSTS2-VqNSTS6, can be induced by the powdery mildew-causing fungus Uncinula necator. Additionally, overexpression of VqNSTS4 in the V. vinifera susceptible cultivar Thompson Seedless promoted accumulation of stilbenes and enhanced resistance to U. necator by activating salicylic acid (SA) signalling. Furthermore, our results indicate that the Alfin-like (AL) transcription factor VqAL4 can directly bind to the G-rich element (CACCTC) in the VqNSTS4 promoter and activate gene expression. Moreover, overexpression of VqAL4 in Thompson Seedless enhanced resistance to U. necator by promoting stilbene accumulation and activating SA signalling. Conversely, RNA interference-mediated silencing of VqNSTS4 and VqAL4 resulted in increased susceptibility to U. necator. Collectively, our results reveal that VqNSTS4, regulated by VqAL4, enhances grapevine resistance to powdery mildew by activating SA signalling. Our findings may be useful to improve disease resistance in perennial fruit trees.

VqWRKY56 interacts with VqbZIPC22 in grapevine to promote proanthocyanidin biosynthesis and increase resistance to powdery mildew.

Powdery mildew (PM) is a severe fungal disease of cultivated grapevine world-wide. Proanthocyanidins (PAs) play an important role in resistance to fungal pathogens; however, little is known about PA-mediated PM resistance in grapevine. We identified a WRKY transcription factor, VqWRKY56, from Vitis quinquangularis, the expression of which was significantly induced by PM. Overexpression (OE) of VqWRKY56 in Vitis vinifera increased PA content and reduced susceptibility to PM. Furthermore, the transgenic plants showed more cell death and increased accumulation of salicylic acid and reactive oxygen species. Transient silencing of VqWRKY56 in V. quinquangularis and V. vinifera reduced PA accumulation and increased the susceptibility to PM. VqWRKY56 interacted with VqbZIPC22 in vitro and in planta. The protein VqWRKY56 can bind to VvCHS3, VvLAR1, and VvANR promoters, and VqbZIPC22 can bind to VvANR promoter. Co-expression of VqWRKY56 and VqbZIPC22 significantly increased the transcript level of VvCHS3, VvLAR1, and VvANR genes. Finally, transient OE of VqbZIPC22 in V. vinifera promoted PA accumulation and improved resistance to PM, while transient silencing in V. quinquangularis had the opposite effect. Our study provides new insights into the mechanism of PA regulation by VqWRKY56 in grapevine and provides a basis for further metabolic engineering of PA biosynthesis to improve PM resistance.

Artemisinic acid attenuated symptoms of substance P-induced chronic urticaria in a mice model and mast cell degranulation via Lyn/PLC-p38 signal pathway.

BACKGROUND: Chronic urticaria (CU) is a common skin disease that affects about 1% of the world's population of all ages and seriously affects patients' quality of life. Therefore, further safe and effective treatments are urgently needed. Therefore, artemisinic acid was investigated in the present study due to its pharmacologic effect on inhibiting mast cell degranulation and chronic urticaria in a mouse model. RESULTS: 4Artemisinic acid decreased the symptoms of substance P-induced chronic urticaria in the mouse model and alleviated secretagogue-induced local cutaneous and systemic anaphylaxis through the Lyn-PLC-p38-NF-κB signaling pathway. Artemisinic acid inhibited mast cell degranulation and pro-inflammatory cytokine production in vitro. Mechanism analysis demonstrated that it could arrest mast cell activation through the Lyn-PLC-p38/ERK1/2/AKT-NF-κB signaling pathway. Based on the results of in vitro kinase assay of Lyn and PLC, artemisinic acid was a potential small molecule inhibitor of Lyn. Artemisinic acid displayed good structural affinity (KD = 2.64 × 10-6) with Lyn SPR results. CONCLUSION: Artemisinic acid can attenuate substance P/MRGPRX2-mediated chronic urticaria and mast cell activation. Artemisinic acid is an antagonist of Lyn kinase and can be developed as a drug candidate to treat allergic diseases.

Understanding the paradox between tragedies of the commons and the anticommons: From a cognitive psychology perspective.

The tragedy of the commons refers to the overuse of resources which are rival in consumption but lack excludability and it also refers to rent dissipation. While the tragedy of the anticommons is a tragedy closely connected with underuse of resources that are rival in consumption and with too strong excludability. The prior studies proved that the tragedy of the commons and the tragedy of the anticommons are symmetric from the perspective of pure mathematics, especially the game theory, which was later refuted by behavioral economics experiments. According to them, the tragedy of the anticommons is severer than the tragedy of the commons. The asymmetry of the tragedy of the commons and the tragedy of the anticommons is a paradox by these different research methods. This paradox shows that there are imperfections in the completely rational economic man hypothesis set up by neoclassical economics. As a fundamental theory, the tragedy of the commons is quite influential in many disciplines, such as microeconomics, public sector economics, ecological economics, environmental economics, management, sociology, property law, and political science. And the tragedy of the anticommons theory has also opened its door of both theoretical research and practical implications since its acceptance by Nobel laureate Buchanan, the main founder of public choice school. Only when theoretical issues are thoroughly discussed and made clear enough, can people avoid misunderstanding or misusing the commons theory. Thus, it is necessary to elucidate the paradox between them. Based on Simon's bounded rationality, Kahneman and Tversky's prospect theory, value function, Thaler's mental accounting, endowment effect, and other cognitive psychological tools, this study clearly shows that agents' decision-making process is not just based on the long-believed marginal benefit and marginal cost analysis advocated by traditional neoclassical economists. Agents' decision-making is a process in which agents selectively absorb, code the objective marginal revenue and marginal cost, and feed relevant information to their brain. Therefore, what plays a directly decisive role is not the objective marginal revenue and marginal cost per se, but the mentally perceived subjective utility of marginal revenue and marginal cost by the human brain. Followed by this research clue, the paradox between the tragedy of the commons and the tragedy of the anticommons is elucidated from the perspective of cognitive psychology.

Grafting with rootstocks promotes phenolic compound accumulation in grape berry skin during development based on integrative multi-omics analysis.

In viticulture, grafting has been practiced widely and influences grape development as well as berry and wine quality. However, there is limited understanding of the effects of rootstocks on grape phenolic compounds, which are located primarily in the berry skin and contribute to certain sensory attributes of wine. In this study, scion-rootstock interactions were investigated at the green-berry stage and the veraison stage when grapevines were hetero-grafted with three commonly used rootstock genotypes (5BB, 101-14MG, and SO4). Physiological investigations showed that hetero-grafts, especially CS/5BB, contained higher concentrations of total proanthocyanidins (PAs) and various PA components in berry skins compared with the auto-grafted grapevines. Further metabolomics analysis identified 105 differentially accumulated flavonoid compounds, the majority of which, including anthocyanins, PAs, and flavonols, were significantly increased in the berry skins of hetero-grafted grapevines compared with auto-grafted controls. In addition, transcriptomic analysis of the same samples identified several thousand differentially expressed genes between hetero-grafted and auto-grafted vines. The three rootstocks not only increased the transcript levels of stilbene, anthocyanin, PA, and flavonol synthesis genes but also affected the expression of numerous transcription factor genes. Taken together, our results suggest that hetero-grafting can promote phenolic compound accumulation in grape berry skin during development. These findings provide new insights for improving the application value of grafting by enhancing the accumulation of nutritious phenolic components in grape.

Cloning and activity analysis of the highly expressed gene VviABCG20 promoter in seed and its activity is negatively regulated by the transcription factor VviDof14.

Half-size ATP binding cassette G (ABCG) transporters participate in the growth and development of plants by transporting substrates. The VviABCG20 gene is highly expressed in seed and plays an important role in seed development/abortion. However, little is known about the function of the VviABCG20 promoter (pVviABCG20) and its regulatory factors. In our study, we obtained pVviABCG20s from 15 seeded and seedless grape varieties and there were two types of 'a' and 'b' with 41 bp non-deletion or deletion, respectively. The pVviABCG20 activity was higher in seeds, siliques, flowers and roots of pVviABCG20-GUS Arabidopsis. The GUS activity analysis revealed that the activities of P4 (-586 bp) to P7 (-155 bp) were becoming increasingly weaker, and the P7 activity almost disappears compared with the pVviABCG20 (P0, -1604). Yeast one-hybrid and GUS activity analysis indicated that VviDof14 binds to the AAAG element in the P7' (-586 bp) fragment of the pVviABCG20 and regulated the activity negatively. The quantitative real-time PCR analysis suggested that the expression of VviDof14 in Thompson seedless seeds was higher than that in Pinot noir. Our study laid the foundation for further analysis of the functions of the pVviABCG20 and its regulator VviDof14 in grape seed development/abortion.

Alpha-linolenic acid inhibits IgE-mediated anaphylaxis by inhibiting Lyn kinase and suppressing mast cell activation.

Excessive reactions to allergens can induce systemic, life-threatening physiological dysfunction (anaphylaxis) in humans. The surface of mast cells expresses high-affinity IgE receptors that play a vital role during anaphylaxis. Alpha-linolenic acid (ALA) is an essential non-toxic fatty acid in humans. Since it has been reported having potential to regulate pro-inflammatory reactions, we postulated that ALA could inhibit anaphylaxis by down-regulating Lyn kinase phosphorylation. We found that local and systematic inflammation induced by albumin from chicken egg white (OVA) were attenuated by ALA in vivo. Furthermore, ALA inhibited IgE-mediated Ca2+ mobilization, degranulation, and cytokine release in Laboratory of Allergic Disease 2 (LAD2) cells. The western blot results showed that ALA down-regulate the FcεRI/Lyn/Syk signaling pathway by suppressing Lyn kinase activity. Therefore, ALA could serve as a therapeutic drug candidate for preventing IgE-mediated anaphylaxis.

Genome Sequence Resource for Colletotrichum viniferum, the Cause of Grapevine Ripe Rot in China.

Grape ripe rot is an important disease that has seriously damaged the yield and quality of grape worldwide. The disease is caused by Colletotrichum viniferum, a hemibiotrophic fungus that belongs to the Glomerellaceae family of Sordariomycetes class. Here, we present the genome of C. viniferum CvYL2a from grape, based on Illumina HiSeq 2500 and PacBio RS II. The high-quality genome consists of 70 contigs with a 73.41 Mb genome size and encodes 14,668 protein-coding genes. These genes were annotated using Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, EuKaryotic Orthologous Groups, Nonredundant Protein, and Swiss-Prot databases. In addition, we identified a series of genes involved in pathogenicity, including 909 carbohydrate-active enzymes, 67 secondary metabolite gene clusters, and 307 cytochrome P450 enzymes. This genome sequence provides a valuable reference for research on grape-C. viniferum interactions, the pathogenesis of C. viniferum, and comparative genome analyses.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Genome-wide identification, phylogenetic analysis, and expression profiling of glycine-rich RNA-binding protein (GRPs) genes in seeded and seedless grapes (Vitis vinifera).

Glycine-rich RNA-binding proteins (GRPs) are essential for many physiological and biochemical processes in plants, especially the response to environmental stresses. GRPs exist widely in angiosperms and gymnosperms plant species; however, their roles in Vitis vinifera are still poorly understood. To characterize VviGRP gene family, we performed a genomic survey, bioinformatics and expression analysis of VviGRPs in grape. We identified nineteen VviGRPs gene family members. The result of bioinformatics analysis showed their motif distribution, gene structure characteristics and chromosomal locations. Then we carried out synteny and phylogenetic analysis to study the origin and evolutionary relationship of GRPs. Tissue-specific expression analysis showed that VviGRPs have different expression patterns. Meanwhile, we studied expression profiles of seventeen ovule-expressed genes during seed development of stenospermocarpic seedless and seeded grapes, and the result showed that most of them have much higher relative expression levels in stenospermocarpic seedless grapes than that of seeded one before 25 days after full bloom (DAFB). It is suggested that VviGRPs may involve in the seed development process. Taken together, our research indicated that VviGRPs are related to seed development and will be beneficial for further investigations into the seed abortion mechanism under stenospermocarpic grapes. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12298-021-01082-3.

The co-expression of genes involved in seed coat and endosperm development promotes seed abortion in grapevine.

MAIN CONCLUSION: The seed coat gene VviAGL11 coordinates with endosperm development genes FIS2, PHERESE1 and IKU2 and functions as the key regulator in seed development and abortion processes in grapevine. Seed development is essential for the reproduction of flowering plants. Seed abortion is a specific characteristic that produces seedless berries and is often observed in cultivated grapevines. Although seedlessness is an important trait for table and dried grapevine production, the mechanism of seed abortion remains poorly understood. This research aimed to analyze the co-expression of the seed coat development gene VviAGL11 and the endosperm development genes FERTILIZATION INDEPENDENT SEED2 (FIS2), PHERESE1 and HAIKU2 (IKU2) that regulate seedless fruit development in grapevine. The transcript levels of VviAGL11, FIS2, PHERESE1 and IKU2 all decreased during seed abortion in the seedless grape 'Thompson Seedless' plants, compared to those of the seeded grape 'Pinot Noir'. The transcript levels of the salicylic acid (SA)-dependent defense response genes EDS1, NPR1, NDR1 and SID2 were higher in 'Thompson Seedless' than 'Pinot Noir' during seed development. Also, WRKY3, WRKY6 and WRKY52, which participate in the SA pathway, were higher expressed in 'Thompson Seedless' than in 'Pinot Noir', indicating that SA-dependent defense responses may regulate seed abortion. The genes related to synthesis and metabolism of gibberellic acid (GA) and abscisic acid (ABA) also showed differential expression between 'Thompson Seedless' and 'Pinot Noir'. Exogenous applications of plant growth regulators (PGRs) to inflorescences of three stenospermocarpy grapevines before flowering showed that GA3 was critical prominently in seed development. Therefore, the co-expression of seed coat and endosperm development-related genes, SA pathway genes, and genes for the synthesis and metabolism of GA3 together enhance seed abortion in seedless grapes.

VqMYB154 promotes polygene expression and enhances resistance to pathogens in Chinese wild grapevine.

Resveratrol plays a crucial phytoalexin role in the grapevine and is beneficial to human health. However, the molecular mechanism of resveratrol accumulation in the enhancement of disease resistance is unclear. Here, we report that the transcription factor VqMYB154 from Vitis quinquangularis accession Danfeng-2 is strongly expressed under artificial inoculation with Uncinula necator and regulates resveratrol accumulation. Unlike its homolog, VqMYB154 has a pathogen-induced promoter and responds to stimulation by U. necator, Pseudomonas syringae, and other treatments. Yeast one-hybrid and GUS activity assays confirmed that VqMYB154 can activate the stilbene synthase genes VqSTS9, VqSTS32, and VqSTS42 by directly binding to their promoters. Overexpression of VqMYB154 in grape leaves resulted in activation of the stilbene pathway, upregulation of STS genes, and accumulation of stilbenoids. In addition, heterologous overexpression of VqMYB154 in Arabidopsis activated resistance-related genes and resulted in greater programmed cell death and accumulation of reactive oxygen species, which led to resistance against P. syringae. These results suggest that the transcription factor VqMYB154 from V. quinquangularis accession Danfeng-2 participates in the regulatory mechanism that improves the biosynthesis and accumulation of stilbenes and enhances resistance to disease in grapevine.