Obtaining plants from crosses of seedless grapevine varieties by means of in vitro embryo culture

Die Gewinnung von Pflanzen aus Kreuzungen kernloser Rebsorten mit Hilfe der in-vitro-Kultur von EmbryonenZwischen den Neuzüchtungen Seedless hybrid VI-4 und Kishmish Moldavski wurden reziproke Kreuzungen durchgeführt. Aus den entstandenen Beeren wurden 52 bzw. 66 d nach der Vollblüte Samenanlagen isoliert. Mit Hilfe der in-vitro-Technik wurden auf einem festen Nährmedium (NITSCH und NITSCH 1969) mit optimal angepaßter Phytohormonkonzentration aus beiden Kreuzungskombinationen und zu beiden Kulturterminen vitale Embryonen herangezogen.Der frühere Kulturbeginn, etwa 50 d nach der Anthese, erwies sich als günstiger. Die Embryonen aus der Kombination Kishmish Moldavski x Seedless hybrid VI-4 zeigten eine erhöhte Variabilität. Dementsprechend wurden aus ihnen mehr normale Pflanzen gewonnen. Das Wachstum der Embryonen war nicht von Kallusbildung begleitet. Die jungen Sämlinge wurden in einem Erdgemisch unter Gewächshaus- und Freilandbedingungen weiterkultiviert.Die Technik der Embryokultur aus kernlosen Traubenbeeren könnte eine interessante Alternative zu den klassischen Methoden der Rebenzüchtung darstellen

Grape Seed Nutraceuticals for Disease Prevention: Current Status and Future Prospects

Grapes (Vitis spp.) are consumed as fresh table fruits, raisins, and processed into wine, juice, jelly and other value-added products. Grapes contain bioactive secondary metabolites (polyphenols), such as proanthocyanins (oliogemeric flavonoids), flavonoids (catechin, epicatechin, and quercetin), and anthocyanins. They have non-flavonoids such as hydroxycinnamic acids (p-coumaric, cinnamic, caffeic, gentisic, ferulic, and vanillic acids), and hydroxybenzoic acids: trihydroxy stilbenes (resveratrol and polydatin). These phytochemicals are of economic importance to pharmaceutical, food and cosmetic industries. Nutraceuticals from grape seeds have potential cardioprotective, anti-cancer, antioxidant, anti-inflammatory, antiviral, neuroprotective, hepatoprotective and antimicrobial properties. Grape seed nutraceuticals have been re-invented in the past few years as a new paradigm in human medicine. In particular, nutraceuticals from grape seeds have been used in stopping wound bleeding, anti-inflammatory agents, pain relief, and anti-diarrhea. In addition, they can be used for the treatment of various human health conditions such as cancer, cholera, smallpox, and nausea as well as eye infections, skin, kidney, liver diseases, etc. Nowadays, consumers are demanding for healthy supplements and personal care products with natural ingredients. Therefore, the present review highlights recent developments and future opportunities of grape seed nutraceuticals for the prevention of human diseases

Influence of Malolactic Fermentation on the Quality of Riesling Wine

Biotic and abiotic stress has a negative effect on both the quality and quantity of grape production. Like many woody crops, grape has been relatively recalcitrant to in vitro manipulations. The crucial point in the process of genetic transformation is to have cells that are able to both regenerate and be transformed. A regeneration system seems to be a major problem in the transformation process. Somatic embryogenesis is the favoured regenerative protocol in genetic transformations of grapes. Comparison of an embryogenic and organogenic system in grape demonstrated that organogenesis frequently leads to chemical transformation of tissues. In this respect we started to develop and apply procedures suitable for the genetic transformation of grapevine. Two sources of explants were used for embryo induction. In the first case, immature zygotic ovules of Vitis vinifera seedless genotypes were used. In the second case in vivo leaf tissues from rootstocks Vitis rupestris cv. Rupestris du Lot and 110 Richter (Vitis berlandieri x Vitis rupestris). Continual transfer to fresh medium maintained embryogenic cultures. Agrobacterium tumefaciens mediated transformation of enbryogenic cultures of seedless grapes (Vitis vinifera L.) with constructs containing the gene encoding the coat protein of Grape Fanleaf Virus (GFLV) and with four constructs containing genes encoding for an antifreeze protein. An embryogenic culture of rootstock Vitis rupestris cv. Rupestris du Lot was transformed with a construct carrying the bete-glucoronidase (GUS) gene. The first transformed plantlets have been regenerated from somatic embryos and the presence of the NPTII gene was verified by PCR and Southern blot analyses

Induction of polyembryony and secondary embryogenesis in culture for embryo rescue of stenospermocarpic genotypes of Vitis vinifera L.

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Recent Advances and Uses of Grape Flavonoids as Nutraceuticals

Grape is one of the oldest fruit crops domesticated by humans. The numerous uses of grape in making wine, beverages, jelly, and other products, has made it one of the most economically important plants worldwide. The complex phytochemistry of the berry is characterized by a wide variety of compounds, most of which have been demonstrated to have therapeutic or health promoting properties. Among them, flavonoids are the most abundant and widely studied, and have enjoyed greater attention among grape researchers in the last century. Recent studies have shown that the beneficial health effects promoted by consumption of grape and grape products are attributed to the unique mix of polyphenolic compounds. As the largest group of grape polyphenols, flavonoids are the main candidates considered to have biological properties, including but not limited to antioxidant, anti-inflammatory, anti-cancer, antimicrobial, antiviral, cardioprotective, neuroprotective, and hepatoprotective activities. Here, we discuss the recent scientific advances supporting the beneficial health qualities of grape and grape-derived products, mechanisms of their biological activity, bioavailability, and their uses as nutraceuticals. The advantages of modern plant cell based biotechnology as an alternative method for production of grape nutraceuticals and improvement of their health qualities are also discussed

Horizontal Transfer of LTR Retrotransposons Contributes to the Genome Diversity of Vitis

While horizontally transferred transposable elements (TEs) have been reported in several groups of plants, their importance for genome evolution remains poorly understood. To understand how horizontally transferred TEs contribute to plant genome evolution, we investigated the composition and activity of horizontally transferred TEs in the genomes of four Vitis species. A total of 35 horizontal transfer (HT) events were identified between the four Vitis species and 21 other plant species belonging to 14 different families. We determined the donor and recipient species for 28 of these HTs, with the Vitis species being recipients of 15 of them. As a result of HTs, 8–10 LTR retrotransposon clusters were newly formed in the genomes of the four Vitis species. The activities of the horizontally acquired LTR retrotransposons differed among Vitis species, showing that the consequences of HTs vary during the diversification of the recipient lineage. Our study provides the first evidence that the HT of TEs contributes to the diversification of plant genomes by generating additional TE subfamilies and causing their differential proliferation in host genomes

Anthocyanin Accumulation in Muscadine Berry Skins Is Influenced by the Expression of the MYB Transcription Factors, MybA1, and MYBCS1

The skin color of grape berry is very important in the wine industry. The red color results from the synthesis and accumulation of anthocyanins, which is regulated by transcription factors belonging to the MYB family. The transcription factors that activate the anthocyanin biosynthetic genes have been isolated in model plants. However, the genetic basis of color variation is species-specific and its understanding is relevant in many crop species. This study reports the isolation of MybA1, and MYBCS-1 genes from muscadine grapes for the first time. They are designated as VrMybA1 (GenBank Accession No. KJ513437), and VrMYBCS1 (VrMYB5a) (GenBank Accession No. KJ513438). The findings in this study indicate that, the deduced VrMybA1 and VrMYBCS1 protein structures share extensive sequence similarity with previously characterized plant MYBs, while phylogenetic analysis confirms that they are members of the plant MYB super-family. The expressions of MybA1, and MYBCS1 (VrMYB5a) gene sequences were investigated by quantitative real-time PCR using in vitro cell cultures, and berry skin samples at different developmental stages. Results showed that MybA1, and MYBCS1 genes were up-regulated in the veràison and physiologically mature red berry skins during fruit development, as well as in in vitro red cell cultures. This study also found that in ripening berries, the transcription of VrMybA1, and VrMYBCS1 in the berry skin was positively correlated with anthocyanin accumulation. Therefore, the upregulation of VrMybA1, and VrMYBCS1 results in the accumulation and regulation of anthocyanin biosynthesis in berry development of muscadine grapes. This work greatly enhances the understanding of anthocyanin biosynthesis in muscadine grapes and will facilitate future genetic modification of the antioxidants in V. rotundifolia

Chemical Composition, In Vitro Antioxidant Potential, and Antimicrobial Activities of Essential Oils and Hydrosols from Native American Muscadine Grapes

Essential oils and hydrosols of two cultivars of muscadine grapes (Muscadinia rotundifolia (Michx.) Small.) were obtained by hydro-distillation of flowers and berry skins. Twenty-three volatile compounds were identified in essential oils from the muscadine flowers, and twenty volatiles in their corresponding hydrosols. The composition of volatiles in berry skins differed significantly from that of the vine flowers. The antioxidant potential of investigated essential oils and hydrosols was evaluated using five in vitro assays: DPPH (2,2-diphenyl-1-picrylhydrazyl) method, TEAC (Trolox equivalent antioxidant capacity), FRAP (Ferric reducing antioxidant power), CUPRAC (cupric ion reducing antioxidant capacity), and NO (nitric oxide radical scavenging assay). The essential oils from the flowers of both cultivars showed the strongest antioxidant power, whereas the hydrosols were the significantly less active. All investigated essential oils showed very weak antibacterial activities against Bacillus cereus, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. However, the essential oils from the flowers of both cultivars showed moderate antifungal activities against Candida albicans, which were stronger for the oil from “Carlos” (white muscadine cultivar). To the best of our knowledge, this is the first report on obtaining and characterizing essential oils and hydrosols from muscadine grapes. This study demonstrated the variations in aromatic compounds accumulated in flowers and mature berry skins of muscadine grapes, and evaluated their possible antioxidant and antimicrobial activities. The presented results will be the base for future research, focused on a better understanding of the molecular and regulatory mechanisms involved in aromatic compound biosynthesis and accumulation in muscadine grapes