Light and electron microscopical studies of the infection of Vitis spp. by Plasmopara viticola, the downy mildew pathogen

The infection of the susceptible grapevine species, Vitis vinifera L., and the resistant species, V. riparia MICHX., by the downy mildew pathogen, Plasmopara viticola, has been studied by light and electron microscopy. The infection cycle and ultrastructural features of the disease are described in detail and compared with those of other hast-pathogen interactions. Licht- und elektronenmikroskopische Untersuchungen über die Infektion von Vitis spp. durch Plasmopara viticola, den Erreger des Falschen Rebenmehltaues Die Infektion der anfälligen Europäerrebe (Vitis vinifera L.) und einer resistenten Wildart (V. riparia MICHX.) durch den Erreger des Falschen Mehltaus (Plasmopara viticola) wurde mittels Licht- und Elektronenmikroskopie untersucht. Der Infektionsablauf und die ultrastrukturellen Besonderheiten der Krankheit werden eingehend beschrieben und mit dem Erscheinungsbild anderer Wirt-Parasit-Beziehungen verglichen

The relationship of resveratrol production to infection of grapevine leaves by Botrytis cinerea

The stilbene resveratrol is one of the stress metabolites produced by grapevine (7, 8). The distribution of resveratrol in spreading lesions caused by Botrytis cinerea on detached grapevine leaves has been examined. Both the highest absolute amounts and the highest concentrations of resveratrol were found in the apparently healthy zone of tissue up to 5 mm in advance of the visibly rotted area. The distribution of resveratrol corresponded with the distribution of blue fluorescence observable macroscopically under long wavelength (366 nm) UV irradiation. The relationship between the concentration of resveratrol around B. cinerea lesions on grapevine leaves and susceptibility of those leaves to infection was investigated. Susceptibility decreased with age of the leaf and varied between the varieties of grapevine studied. In both cases, there was an inverse relationship between the concentration of resveratrol around the lesion and susceptibility. The probable role of resveratrol as the precursor of antifungal stress metabolites, the viniferins, in the disease resistance of grapevine is discussed. Die Beziehungen zwischen der Bildung von Resveratrol und dem Befall von Rebenblättern durch Botrytis cinerea Das Stilben Resveratrol gehört zu den Stoffwechselprodukten, die von der Rebe unter Streßbedingungen gebildet werden. An isolierten Blättern von Vitis vinifera wurde die Verteilung von Resveratrol in den sich ausbreitenden Läsionen, die durch Botrytis cinerea verursacht werden, geprüft. In einer bis zu 5 mm breiten scheinbar gesunden Gewebezone, die den visuell geschädigten Blattbezirk umgibt, wurden sowohl die höchsten Absolutmengen als auch die höchsten Konzentrationen von Resveratrol gefunden. Die Verteilung von Resveratrol entsprach dem Auftreten einer Blaufluoreszenz, die bei langwelliger UV-Bestrahlung (366 nm) makroskopisch beobachtet werden kann. Die Beziehung zwischen der Resveratrolkonzentration, die im Umkreis der Botrytis-Läsionen an Rebenblättern vorliegt, und der Anfälligkeit dieser Blätter für die Pilzinfektion wurde untersucht. Die Pilzanfälligkeit nahm mit dem Alter der Blätter ab und variierte zwischen den untersuchten Rebsorten. In beiden Fällen stand die Resveratrolkonzentration im Umkreis der Läsion im umgekehrten Verhältnis zum Anfälligkeitsgrad. Die Rolle, die Resveratrol als Präcursor pilzfeindlicher Streßmetabolite, der Viniferine, bei der Krankheitsresistenz der Rebe spielen dürfte, wird diskutiert

Transcriptome profiling of grapevine seedless segregants during berry development reveals candidate genes associated with berry weight

Indexación: Web of Science; PubMedBackground Berry size is considered as one of the main selection criteria in table grape breeding programs. However, this is a quantitative and polygenic trait, and its genetic determination is still poorly understood. Considering its economic importance, it is relevant to determine its genetic architecture and elucidate the mechanisms involved in its expression. To approach this issue, an RNA-Seq experiment based on Illumina platform was performed (14 libraries), including seedless segregants with contrasting phenotypes for berry weight at fruit setting (FST) and 6–8 mm berries (B68) phenological stages. Results A group of 526 differentially expressed (DE) genes were identified, by comparing seedless segregants with contrasting phenotypes for berry weight: 101 genes from the FST stage and 463 from the B68 stage. Also, we integrated differential expression, principal components analysis (PCA), correlations and network co-expression analyses to characterize the transcriptome profiling observed in segregants with contrasting phenotypes for berry weight. After this, 68 DE genes were selected as candidate genes, and seven candidate genes were validated by real time-PCR, confirming their expression profiles. Conclusions We have carried out the first transcriptome analysis focused on table grape seedless segregants with contrasting phenotypes for berry weight. Our findings contributed to the understanding of the mechanisms involved in berry weight determination. Also, this comparative transcriptome profiling revealed candidate genes for berry weight which could be evaluated as selection tools in table grape breeding programs.http://bmcplantbiol.biomedcentral.com/articles/10.1186/s12870-016-0789-

Identification of molecular pathways affected by pterostilbene, a natural dimethylether analog of resveratrol

<p>Abstract</p> <p>Background</p> <p>Pterostilbene, a naturally occurring phenolic compound produced by agronomically important plant genera such as <it>Vitis </it>and <it>Vacciunium</it>, is a phytoalexin exhibiting potent antifungal activity. Additionally, recent studies have demonstrated several important pharmacological properties associated with pterostilbene. Despite this, a systematic study of the effects of pterostilbene on eukaryotic cells at the molecular level has not been previously reported. Thus, the aim of the present study was to identify the cellular pathways affected by pterostilbene by performing transcript profiling studies, employing the model yeast <it>Saccharomyces cerevisiae</it>.</p> <p>Methods</p> <p><it>S. cerevisiae </it>strain S288C was exposed to pterostilbene at the IC₅₀concentration (70 μM) for one generation (3 h). Transcript profiling experiments were performed on three biological replicate samples using the Affymetrix GeneChip Yeast Genome S98 Array. The data were analyzed using the statistical methods available in the GeneSifter microarray data analysis system. To validate the results, eleven differentially expressed genes were further examined by quantitative real-time RT-PCR, and <it>S. cerevisiae </it>mutant strains with deletions in these genes were analyzed for altered sensitivity to pterostilbene.</p> <p>Results</p> <p>Transcript profiling studies revealed that pterostilbene exposure significantly down-regulated the expression of genes involved in methionine metabolism, while the expression of genes involved in mitochondrial functions, drug detoxification, and transcription factor activity were significantly up-regulated. Additional analyses revealed that a large number of genes involved in lipid metabolism were also affected by pterostilbene treatment.</p> <p>Conclusion</p> <p>Using transcript profiling, we have identified the cellular pathways targeted by pterostilbene, an analog of resveratrol. The observed response in lipid metabolism genes is consistent with its known hypolipidemic properties, and the induction of mitochondrial genes is consistent with its demonstrated role in apoptosis in human cancer cell lines. Furthermore, our data show that pterostilbene has a significant effect on methionine metabolism, a previously unreported effect for this compound.</p

Metabolic constituents of grapevine and grape-derived products

The numerous uses of the grapevine fruit, especially for wine and beverages, have made it one of the most important plants worldwide. The phytochemistry of grapevine is rich in a wide range of compounds. Many of them are renowned for their numerous medicinal uses. The production of grapevine metabolites is highly conditioned by many factors like environment or pathogen attack. Some grapevine phytoalexins have gained a great deal of attention due to their antimicrobial activities, being also involved in the induction of resistance in grapevine against those pathogens. Meanwhile grapevine biotechnology is still evolving, thanks to the technological advance of modern science, and biotechnologists are making huge efforts to produce grapevine cultivars of desired characteristics. In this paper, important metabolites from grapevine and grape derived products like wine will be reviewed with their health promoting effects and their role against certain stress factors in grapevine physiology

Resveratrol Increases Glucose Induced GLP-1 Secretion in Mice: A Mechanism which Contributes to the Glycemic Control

Resveratrol (RSV) is a potent anti-diabetic agent when used at high doses. However, the direct targets primarily responsible for the beneficial actions of RSV remain unclear. We used a formulation that increases oral bioavailability to assess the mechanisms involved in the glucoregulatory action of RSV in high-fat diet (HFD)-fed diabetic wild type mice. Administration of RSV for 5 weeks reduced the development of glucose intolerance, and increased portal vein concentrations of both Glucagon-like peptid-1 (GLP-1) and insulin, and intestinal content of active GLP-1. This was associated with increased levels of colonic proglucagon mRNA transcripts. RSV-mediated glucoregulation required a functional GLP-1 receptor (Glp1r) as neither glucose nor insulin levels were modulated in Glp1r-/- mice. Conversely, levels of active GLP-1 and control of glycemia were further improved when the Dipeptidyl peptidase-4 (DPP-4) inhibitor sitagliptin was co-administered with RSV. In addition, RSV treatment modified gut microbiota and decreased the inflammatory status of mice. Our data suggest that RSV exerts its actions in part through modulation of the enteroendocrine axis in vivo