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Grape production worldwide is increasingly threatened by grapevine trunk diseases (GTDs). No grapevine cultivar is known to be entirely resistant to GTDs, but susceptibility varies greatly. To quantify these differences, four Hungarian grape germplasm collections containing 305 different cultivars were surveyed to determine the ratios of GTDs based on symptom expression and the proportion of plant loss within all GTD symptoms. The cultivars of monophyletic Vitis vinifera L. origin were amongst the most sensitive ones, and their sensitivity was significantly (p < 0.01) higher than that of the interspecific (hybrid) cultivars assessed, which are defined by the presence of Vitis species other than V. vinifera (e.g., V. labrusca L., V. rupestris Scheele, and V. amurensis Rupr.) in their pedigree. We conclude that the ancestral diversity of grapes confers a higher degree of resilience against GTDs. [ABSTRACT FROM AUTHOR]

The red-fleshed grape cultivars, called teinturier or dyer grapes, contain anthocyanins in both the skin and flesh. These phenolic compounds exhibit excellent coloring ability, and as antioxidants, they are important bioactive compounds in food crops. In this work, anthocyanin patterns of grape berries of fifteen teinturier varieties collected from the gene bank located at Pécs in the southwest of Hungary were compared. Anthocyanin profiles of numerous varieties originating from Hungary such as 'Bíborkadarka', 'Kármin', 'Kurucvér', and 'Turán' are reported for the first time. Anthocyanins extracted separately from the skin and juice were analyzed using high-performance liquid chromatography coupled with a photodiode array detector. For the identification of compounds, high-resolution orbitrap mass spectrometry was used. All in all, twenty-one anthocyanins were identified and quantified. We found that anthocyanin patterns differed significantly in the skin and juice for all investigated cultivars. For Vitis vinifera varieties, the predominant anthocyanin in the skin was malvidin-3-O-glucoside, while the main pigment in the juice was peonidin-3-O-glucoside. For the first time, a significant amount of diglucosides was detected in two Vitis Vinifera cultivars with a direct relationship. In general, the pigment composition of the skin was much more complex than that of the juice. The comparative study with presented patterns gives valuable and beneficial information from a chemotaxonomical point of view. Our results also help to choose the appropriate teinturier varieties with the desired anthocyanins for food coloring or winemaking purposes. [ABSTRACT FROM AUTHOR]

Grape production worldwide is increasingly threatened by grapevine trunk diseases (GTDs). No grapevine cultivar is known to be entirely resistant to GTDs, but susceptibility varies greatly. To quantify these differences, four Hungarian grape germplasm collections containing 305 different cultivars were surveyed to determine the ratios of GTDs based on symptom expression and the proportion of plant loss within all GTD symptoms. The cultivars of monophyletic Vitis vinifera L. origin were amongst the most sensitive ones, and their sensitivity was significantly (p < 0.01) higher than that of the interspecific (hybrid) cultivars assessed, which are defined by the presence of Vitis species other than V. vinifera (e.g., V. labrusca L., V. rupestris Scheele, and V. amurensis Rupr.) in their pedigree. We conclude that the ancestral diversity of grapes confers a higher degree of resilience against GTDs.

Grapevine varieties showing putative resistance to pathogens are a promising alternative to reduce the impact of disease management. Despite research efforts in understanding pathogen susceptibility/resistance to pathogens, the mechanisms that regulate these processes remain unclear. To identify the molecular and metabolic mechanisms associated with putative different susceptibility to pathogens and/or constitutive resistance, comparative transcriptomics and metabolomics were carried out in cultured cells of V. vinifera 'Malvasia' and V. rupestris 'Du Lot'. Transcriptomic analysis revealed a higher enrichment of genes involved in biosynthesis of cell wall proteins, PR protein, ROS activation, phenylpropanoid pathway, TIR-NBS-LRR proteins and WRKY transcription factors in V. rupestris compared to V. vinifera. 1H-NMR based metabolomic analysis highlighted that leucine, isoleucine, valine, threonine, alanine, γ-aminobutyric acid (GABA), glutamine, phenylalanine and pyruvate significantly increased in V. rupestris compared to V. vinifera. Conversely, glucose, sucrose, and fumarate significantly decreased in V. rupestris compared to V. vinifera. Our findings reveal distinct pre-constitutive defense systems in two species consisting in an up-regulation of genes and primary metabolites involved in plant defense responses. These responses could be constitutively activated in V. rupestris opening new insights for sustainable viticulture through improved breeding programs. [ABSTRACT FROM AUTHOR]

Background and aims: In most viticultural areas of the world, Vitis vinifera grapevines require grafting onto phylloxera-tolerant rootstocks of American origin. The species most commonly used in rootstock creation are Vitis berlandieri, V. riparia and V. rupestris. Rootstocks not only provide tolerance to phylloxera but also ensure the supply of water and mineral nutrients to the scion. The aim of the study was to investigate the extent to which rootstocks with different genetic backgrounds modify the mineral composition of the petioles of the scion. Methods and results: Vitis vinifera cv. Cabernet-Sauvignon grapevines were grafted onto rootstocks of 13 different genotypes and planted in a vineyard in three blocks. Petiolar concentrations of 13 mineral elements at veraison (berry softening) were determined. The genetic background of the rootstock had significant effects on the mineral composition of the petioles. Use of rootstocks with a genetic background including at least one Vitis riparia parent decreased the concentration of phosphorus and magnesium and increased the concentration of sulphur in the petioles of Cabernet-Sauvignon. Conclusion: Rootstocks with a Vitis riparia genetic background confer low petiolar concentrations of phosphorus and magnesium, and conversely, high petiolar concentration of sulphur. Significance of the study: The kind of rootstock onto which a grapevine has been grafted is known to influence the nutrient content of the scion. The results of the study show a significant relation between the genetic background of a rootstock and its ability to modify concentrations of phosphorus, magnesium and sulphur in the petioles of the scion under field conditions.

Background: Scion physiology and grape quality are impacted by rootstock choice. There is little available information about the effects of rootstock on wine volatile composition, particularly when comparing grafted with own‐rooted grapevines. This field trial was aimed at studying the influence of rootstock choice on volatile composition of Merlot wines. Results: Wines made from grapes harvested from own‐rooted grapevines had the lowest content of (E)‐3‐hexenol, diethyl succinate and total ethyl esters and the highest content of 1‐pentanol, 1‐hexanol, (Z)‐3‐hexenol, diethyl malate and acetovanillone. Rootstocks such as 99R and 140Ru led to a higher content of total ethyl esters in wines followed by 110R, 1103P and Gravesac. According to odor activity values, Merlot wines were characterized by roses, sweat, cheese and banana aromas. Conclusions: This work provides valuable information about the potential impact of rootstocks on wine volatile composition for Merlot wines. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Metacaspase, as hypersensitive response (HR) executors, has been identified in many plant species. Previously, the entire gene family of metacaspase has been uncovered, but there are still questions that remain unclear regarding HR-regulating gene members. In this study, based on metacaspase expression during different grapevine genotypes interacting with Plasmopara viticola, we identified MC2 and MC5 as candidates involved in HR. We overexpressed both metacaspases as GFP fusions in tobacco BY-2 cells to address subcellular localization and cellular functions. We found MC2 located at the ER, while MC5 was nucleocytoplasmic. In these overexpressor lines, cell death elicited by the bacterial protein harpin, is significantly enhanced, indicating MC2 and MC5 mediated defence-related programmed cell death (PCD). This effect was mitigated, when the membrane-located NADPH oxidase was inhibited by the specific inhibitor diphenylene iodonium, or when cells were complemented with methyl jasmonate, a crucial signal of basal immunity. Both findings are consistent with a role of MC2 and MC5 in cell death-related immunity. Using a dual-luciferase reporter system in grapevine cells we demonstrated both MC2 and MC5 promoter alleles from V. rupestris were more responsive to harpin than those from V. vinifera cv 'Müller-Thurgau', while they were not induced by MeJA as signal linked with basal immunity. These findings support a model, where MC2 and MC5 act specifically as executors of the HR. [ABSTRACT FROM AUTHOR]

Programmed cell death (PCD) is considered as a hallmark of strain-specific immunity. In contrast, generic basal immunity is thought to act without PCD. This classical bifurcation has been questioned during recent years. Likewise, the role of jasmonate signalling for these two modes of innate immunity has remained ambiguous. We have addressed both questions using two closely related grapevine cell lines (V. rupestris , V. vinifera cv. 'Pinot Noir') that contrast in their cell-death response to the bacterial elicitor harpin and the hormonal trigger methyl jasmonate (MeJA). We follow different cellular (loss of membrane integrity, mortality), molecular (induction of transcripts for phytoalexin synthesis and for metacaspases), as well as metabolic (sphingolipid profiles) responses to the two triggers in the two cell lines. The role of NADPH oxidases and induction of transcripts for the class-II metacaspases MC5 differ qualitatively between the two cell lines. We tested a possible role of sphingolipid metabolism but can rule this out. We propose a model, where V. rupestris , originating from co-evolution with several biotrophic pathogens, readily activates a hypersensitive cell death in response to harpin, while the context of MeJA-induced cell death in 'Pinot Noir' might not be related to immunity at all. We propose that the underlying signalling is modular, recruiting metacaspases differently depending on upstream signalling. • 1st time to report the elicitors harpin and MeJA induce mortality in an inverted pattern in grapevine. • Based on the above two induced death modes, histochemistry fluorescence assay and relative quantitative study further revealed harpin and MeJA induce a different mode of cell death. • V. rupestris originating from co-evolution with several biotrophic pathogens, readily activates a hypersensitive cell death in response to harpin. [ABSTRACT FROM AUTHOR]

In mid-autumn 2013, a disease of Vitis rupestris affecting 30 to 50% of the plants was observed in an orchard of the Kırıkhan district of Hatay province in the east Mediterranean region of Turkey. Symptoms included presence of initially tiny and angular chlorotic halos but latterly large black spots. On the spots, cercosporoid structures were present. Based on cultural and morphological characteristics of the consistently isolated fungus and pathogenicity tests, the causal agent of this leaf spot or blight was identified as Pseudocercospora vitis. This appears to be the first report of P. vitis on V. rupestris in Turkey. Since Isariopsis leaf spot caused by P. vitis can also affect grapevines (V. vinifera), it might negatively impact orchards and vineyards in the future and might be considered a potential threat to Turkish grapevine production. [ABSTRACT FROM AUTHOR]

Plant microtubules (MTs), in addition to their role in cell division and cell expansion, respond to various stress signals. To understand the biological function of this early response requires non-destructive strategies for visualization in cellular models that are highly responsive to stress signals. We have therefore generated a transgenic tubulin marker line for a cell line from the grapevine Vitis rupestris that readily responds to stress factors of defense-related and abiotic stresses based on a fusion of the green fluorescent protein with Arabidopsis β-tubulin 6. By a combination of spinning-disk confocal microscopy with quantitative image analysis, we could detect early and specific responses of MTs to defense-related and abiotic stress factors in vivo . We observed that Harpin Z (HrpZ), a bacterial elicitor that can trigger programmed cell death, rapidly eliminated radial MTs, followed by a slower depletion of the cortical array. Jasmonic acid (JA), in contrast, induced bundling of cortical MTs. Auxin reduced the thickness of cortical MTs. This effect followed a characteristic bell-shaped dose-dependency and could revert JA-induced bundling. Impeded cell expansion as a consequence of stress treatment or superoptimal auxin was linked with the appearance of intranuclear tubulin speckles. The early and stimulus-specific responses of MTs are discussed with respect to a function in processing or decoding of stress signals. [ABSTRACT FROM AUTHOR]

En réponse à une période de sécheresse, certaines espèces américaines du genre Vitis et V. vinifera (cv. Sauvignon blanc), mettent en jeu des ajustements osmotiques de l'ordre de 0,08 - 0,20 MPa Alors que V. riparia réagit à la carence hydrique par un ajustement osmotique, causé principalement par une nette accumulation de glucose et de fructose, V. rupestris est capable de modifier rapidement et fortement sa propre élasticité cellulaire. V. berlandieri, espèce résistante à la sécheresse, manifeste un ajustement osmotique beaucoup plus bas mais possède un tissu foliaire qui lui permet de perdre une grande quantité d'eau avant la fermeture des stomates. Cette caractéristique et aussi conférée au greffon par un porte-greffe résistant à la sécheresse (775 Paulsen). +++ Osmotic adjustements, ranging from 0,08 MPa to 0,20 MPa have been observed in some American Vitis species and in V. vinifera (cv. Sauvignon blanc), as response to drought. ln V. rupestris a quick and wide modification of leaf tissue elasticity occurs, while in V. riparia the response to drought is related to a osmotic adjustement, due to a net storage of glucose and fructose. V. berlandieri, a drought resistant specie, seems to have a very low osmotic adjustement, but also a leaf tissue able to allow a water loss before to close stomata. This behaviour has also been observed in a scion grafted on a dought resitant rootstock (775 P).

The influence of genotype on leaf gas exchange was investigated for Vitis riparia and Vitis rupestris plants cultured in vivo and in vitro. Gas exchange was measured at constant temperature and photosynthetic photon flux density and at varying relative humidity from 75 p. cent to 65 p. cent. Differences of transpiration and CO2 assimilation rates between genotypes were observed that did not depend upon conditions. Water use efficiency was strongly controlled by the genotype. Linear correlations between assimilation, transpiration and relative humidity were used to estimate extra stomatal (cuticular) and stomatal transpiration of in vitro plants. Cuticular transpiration of in vitro plants was also measured directly during the darkness. Our results confirmed the indirect estimates of cuticular transpiration elaborated with a linear regression model. Results also show that cuticular transpiration of in vitro grown plants may be relevant and is strongly influenced by the genotype. Similarly, the sensitivity of plantlets to transplantation from in vitro to in vivo conditions may be strongly related by the genotype.

The effect of a hypoxic pre-treatment (HPT) on improving tolerance to prolonged anoxia conditions in two contrasting Vitis species (V. riparia, anoxia tolerant; V. rupestris, anoxia sensitive) was evaluated. The energy economy of root cells was studied by measuring heat production, the activity of pyruvate decarboxylase (PDC) and alcohol dehdrogenase (ADH), ethanol and ATP production, and K+ fluxes. The results showed that HPT is an effective tool in order to maintain a sustainable metabolic performance in both the species under anoxia conditions, especially in sensitive species such as V. rupestris. Our results showed that the improved tolerance was mainly driven by: (i) an enhanced activity of key enzymes in alcohol fermentation (ADC and PDC); (ii) the capability to maintain a higher level of respiration, evidenced by a lesser decrease in heat development and ATP production; and (iii) the maintenance of a better ion homeostasis (highlighted by measurement of K+ fluxes) and K+ channel functionality. [ABSTRACT FROM PUBLISHER]

The incidence of Rupestris stem-pitting-associated virus (RSPaV) in two vineyards in South Australia was studied by comparing symptoms with the results obtained from biological indexing and from virus detection by reverse-transcription-polymerase chain reaction (RT-PCR). Vineyard 1 was an experimental block comprising a number of varieties grafted onto Vitis rupestris cv. St George rootstocks for the detection of Rupestris stem pitting disease. No swelling at graft union or decline was observed at 3 years, but some vines showed pitting on the rootstock trunk. Vineyard 2 contained Vitis vinifera cv. Shiraz (Syn. Syrah) vines on Paulsen 1103 rootstock, showing a range of symptoms including swelling of the graft union, pitting on the rootstock, leaf reddening and vine decline, resembling those in Syrah Decline, a disorder known to occur in this variety. RT-PCR using the coat-protein-specific primers detected RSPaV in all samples from either vineyard including symptomless V. rupestris cv. St George, which is used as the biological indicator for the virus. In contrast, a pair of primers designed from the replicase gene detected the virus only in symptomatic vines, whereas the symptomless St George control and nonsymptomatic vines in both vineyards tested negative. An assay for 12 other major grapevine viruses showed that none were associated with either type of symptom. Comparison of a 628-bp amplicon on the replicase gene in 13 RSPaV isolates showed that while they had 96–99% nucleotide sequence identity to each other, their identity to the American isolates from California and New York was around 65%. This low homology may indicate that a different virus species is present. The variability was more pronounced between the two vineyards than among the virus isolates in the Shiraz vines within the same vineyard. However, even the vines of the same vineyard did not contain viruses with exactly the same sequence homology. We found no association between the type of symptom expressed and the sequence variation in the amplicons in either vineyard. The sequence variants in Vineyard 1 showed a closer cluster than in Vineyard 2. [ABSTRACT FROM AUTHOR]

Previously, there has not been any in situ conservation sites for crop germplasm within the United States Department of Agriculture (USDA), Agricultural Research Service (ARS), National Plant Germplasm System (NPGS). Using morphologic and molecular (SSR markers) techniques, we assessed the genetic variation present in populations of rock grape ( Vitis rupestris Scheele), a native American grape species, throughout its range. We identified seven in situ conservation sites for rock grape using a strategy based on morphologic and molecular data, taxonomic information, population size and integrity, and landholder commitment. In collaboration with federal and state landholding agencies, we have established the first NPGS in situ conservation sites for American wild relatives of a crop. [ABSTRACT FROM AUTHOR]

The effects of viral diseases on the photosynthetic activity of grapevine ( Vitis rupestrisvar. Rupestris du Lot) leaves were investigated. The third and sixth leaves used for measurements were obtained from in vitrogrown healthy plants and plants affected by grapevine fanleaf and rupestris stem pitting viruses. The induction curves of prompt and delayed chlorophyll fluorescence, as well as the temperature characteristics of steady-state, prompt, and delayed emissions, were investigated. Age-dependent changes were found, which were related, on the one hand, to the acceleration of electron transport and the enhancement of thylakoid energization and, on the other hand, to a smaller extent of transmembrane ΔμH+in the younger sixth leaf compared to that in the third leaf. The infected plants characteristically showed faster electron transport, an elevated energetic efficiency of photosynthesis, and the suppression of CO2fixation owing to a presumable activation of the adenylate metabolism. An analysis of the thermograms of prompt and delayed fluorescence revealed the shifts in the position of the M1peak and a half-inhibition temperature T50towards a higher temperature in infected plants, which indicates a certain increase in the thermal tolerance of thylakoid membranes. The data suggest that the viral metabolism affects the functional activity and stability of thylakoid membranes. [ABSTRACT FROM AUTHOR]

Isolated somatic embryos from petiole-derived callus cultures of Vitis rupestris Scheele have been employed in experiments on genetic transformation. Co-cultivation of somatic embryos during embryogenesis induction with Agrobacterium tumefaciens strain LBA4404, which contains the plasmid pBI121 carrying the neomycin phosphotranspherase and the β-glucuronidase genes, produced transformed cellular lines capable of recurrent somatic embryogenesis. Precocious selection for high levels of kanamycin (100 mgl) was an important part of our transformation protocol. Transformed lines still have strong β-glucuronidase expression as well as stable insertion of the marker genes after 3 years of in-vitro culture, during which they have maintained their capacity to organize secondary embryos and to regenerate transgenic plants with an agreeable efficiency (13%). [ABSTRACT FROM AUTHOR]

Diplodia seriata, one of the major causal agents of Botryosphaeria dieback, spreads worldwide, causing cankers, leaf spots and fruit black rot in grapevine. Vitis rupestris is an American wild grapevine widely used for resistance and rootstock breeding and was found to be highly resistant to Botryosphaeria dieback. The defense responses of V. rupestris to D. seriata 98.1 were analyzed by RNA-seq in this study. There were 1365 differentially expressed genes (DEGs) annotated with Gene Ontology (GO) and enriched by the Kyoto Encyclopedia of Genes and Genomes (KEGG) database. The DEGs could be allocated to the flavonoid biosynthesis pathway and the plant–pathogen interaction pathway. Among them, 53 DEGs were transcription factors (TFs). The expression levels of 12 genes were further verified by real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR). The aggregation of proteins on the plasma membrane, formation variations in the cytoskeleton and plasmodesmata and hormone regulations revealed a declined physiological status in V. rupestris suspension cells after incubation with the culture filtrates of D. seriata 98.1. This study provides insights into the molecular mechanisms in grapevine cells' response to D. seriata 98.1, which will be valuable for the control of Botryosphaeria dieback. [ABSTRACT FROM AUTHOR]

La multiplication végétative de la vigne cultivée in vitro à partir de boutures à un œil ayant 1 cm de longueur ne présente aucune difficulté technique. Par contre la propagation d'implants de plus petite taille s'avère délicate et aléatoire. Or l'élimination durable de virus thermorésistants nécessite le prélèvement (à la fin du thermotraitement) de très petites parties terminales de tiges. Des « boutures apicales » de 2 à 5 mm de longueur de Vitis Vinifera variété Grenache N, et de Vitis Rupestris, variété Lot ont été mises en culture sur un milieu de base additionné de diverses substances de croissance. L'AIA à la concentration 10-7M s'est révélé le régulateur favorisant le mieux la rhizogénèse des « boutures apicales ». Le transfert des « boutures apicales » enracinées sur le milieu de référence facilite leur croissance. +++ Vegetative multiplication of vine grown in vitro from one-eyed-cuttings one centimeter long, does not present any technical difficulty. On the other hand, propagation of smaller implants is difficult and (random). The trouble is durable elimination of thermoresistant virus needs picking up (at the end of heat treatment) very small shoot tips. Apical cuttings of Vitis Vinifera, var. Grenache N. and of Vitis Rupestris, var. Lot two or five millimeters long are grown on a standard medium in which different growing substances are added. AIA at the concentration of 10-7M increases the best rhizogenesis of apical cuttings. The transfer of rooted cuttings upon the standard medium makes their growth easier.