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

Proteomic analysis of β-1,3-glucanase in grape berry tissues

Grape berries are considered recalcitrant materials in proteomic analysis, because berry tissues contain large amounts of secondary metabolites, especially phenolic compounds, which severely interfere with protein extraction and electrophoresis separation. We report hereby a PVPP/TCA-based protein extraction protocol for grape berries. Phenolic compounds in berry extracts were removed with repeated PVPP cleanups, and proteins were recovered with TCA precipitation. Protein resolution in 2-D gels was gradually improved with the increase of PVPP cleanup steps. By the protocol, about 760 protein spots of berry tissues were clearly resolved in 2-D gels with CBB staining. This protocol was also used to analyze b-1,3-glucanase (EC 3.2.1.39) in berry tissues. An antisynthetic peptide antibody was prepared against 15 amino acid sequence residing on the surface of b-1,3-glucanase molecule. It detected two major spots in 2-D blots of berry extracts. The spots were identified by MALDI-TOF analysis as b-1,3-glucanase. The present study validates that b-1,3-glucanase is present in higher abundance in berry skins than in pulps, and in red berries than in white berries. Therefore, b-1,3-glucanase displays a tissue-specific expression. The preferential accumulation of b-1,3-glucanase in skins may be relevant to berry ripening

Characterization of a new, nonpathogenic mutant of Botrytis cinerea with impaired plant colonization capacity

International audienceBotrytis cinerea is a necrotrophic pathogen that attacks more than 200 plant species.Here, the nonpathogenic mutant A336, obtained via insertional mutagenesis, was characterized.Mutant A336 was nonpathogenic on leaves and fruits, on intact and wounded tissue, while still able to penetrate the host plant. It grew normally in vitro on rich media but its conidiation pattern was altered. The mutant did not produce oxalic acid and exhibited a modified regulation of the production of some secreted proteins (acid protease 1 and endopolygalacturonase 1). Culture filtrates of the mutant triggered an important oxidative burst in grapevine ( Vitis vinifera ) suspension cells, and the mutant–plant interaction resulted in the formation of hypersensitive response-like necrosis. Genetic segregation analyses revealed that the pathogenicity phenotype was linked to a single locus, but showed that the mutated gene was not tagged by the plasmid pAN7-1.Mutant A336 is the first oxalate-deficient mutant to be described in B. cinerea and it differs from all the nonpathogenic B. cinerea mutants described to date

Infection pathway of Botrytis cinerea in capsicum fruit (Capsicum annuum L.)

Botrytis cinerea, which causes grey mould, infects fruit of a number of horticultural crops during their development but then remains latent until the ripening process when the disease manifests. However, how B. cinerea grows in capsicum fruit after harvest has not been fully characterised. The present research has examined the growth of B. cinerea in fruit of two cultivars of capsicum (cv. Aries and cv. Papri Queen) that were inoculated either before or after harvest. Three concentrations of conidial suspensions (10⁴, 10⁵ and 10⁶ conidia mL⁻¹) were used to inoculate flowers at three preharvest stages – anthesis, 3 days after anthesis (DAA) and 6 DAA, and fruit at three postharvest ripening stages – deep green (DG), breaker red (BR) and red (R). Inoculation with water served as a control. Rot development was then monitored daily during postharvest storage at 10 °C by measuring the length and width of lesions. Cv. Aries was more susceptible to B. cinerea than cv. Papri Queen regardless of whether inoculation occurred preharvest or postharvest. Flowers often died when inoculated at anthesis. Regardless of cultivar, as inoculum concentration increased the number of flowers that died also increased. However, disease development on fruit was not affected by inoculum concentration or the timing of inoculation before harvest. When fruit were inoculated after harvest, grey mould developed most rapidly in BR fruit of cv. Papri Queen and in R fruit of cv. Aries. The understanding of infection of B. cinerea revealed by this research and its implications for disease management are discussed.Thong D. Le & Glenn McDonald & Eileen S. Scott & Amanda J. Abl

Water limitation and rootstock genotype interact to alter grape berry metabolism through transcriptome reprogramming

Grapevine is a perennial crop often cultivated by grafting a scion cultivar on a suitable rootstock. Rootstocks influence scions, particularly with regard to water uptake and vigor. Therefore, one of the possibilities to adapt viticulture to the extended drought stress periods is to select rootstocks conferring increased tolerance to drought. However, the molecular mechanisms associated with the ability of rootstock/scion combination to influence grape berry metabolism under drought stress are still poorly understood. The transcriptomic changes induced by drought stress in grape berries (cv. Pinot noir) from vines grafted on either 110R (drought-tolerant) or 125AA (drought-sensitive) rootstock were compared. The experiments were conducted in the vineyard for two years and two grape berry developmental stages (50% and 100% veraison). The genome-wide microarray approach showed that water stress strongly impacts gene expression in the berries, through ontology categories that cover cell wall metabolism, primary and secondary metabolism, signaling, stress, and hormones, and that some of these effects strongly depend on the rootstock genotype. Indeed, under drought stress, berries from vines grafted on 110R displayed a different transcriptional response compared to 125AA-concerning genes related to jasmonate (JA), phenylpropanoid metabolism, and pathogenesis-related proteins. The data also suggest a link between JA and secondary metabolism in water-stressed berries. Overall, genes related to secondary metabolism and JA are more induced and/or less repressed by drought stress in the berries grafted on the drought-sensitive rootstock 125AA. These rootstock-dependent gene expression changes are relevant for berry composition and sensory properties