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The evaluation of bioclimatic viticulture indices (BVIs) zones, similar to any other crop, necessitates a comprehensive understanding of the spatial variability of climate data. This study focuses on assessing the suitability of BVIs in the Jabal Al Arab region, a significant viticulture area in the Eastern Mediterranean. The aim is to analyze four temperature-based bioclimatic indices and the hydrothermal coefficient (HTC) to map their patterns and spatial variation across the region under climate change scenarios. Daily temperature data from 15 meteorological stations and 57 rain gauges spanning 1984–2014 were utilized, along with downscaled future scenarios (the Representative Concentration Pathways (RCPs) based on the second generation Canadian Earth System Model (CanESM2)) for 2016–2100. Additionally, statistical analysis and hybrid interpolation (regression-kriging) were employed to accurately map the BVIs throughout the region. The results reveal substantial spatial variability in Jabal Al Arab's climate, with heat accumulation and the hydrothermal index during the growing season significantly influenced by elevation and distance to the seacoast. Additionally, the viticulture zones vary based on the specific index used and the projected future climate scenarios compared to the current climate. Climate change projections indicate a trend toward warmer conditions in the future. Under the RCP scenarios, the region can be categorized into up to three bioclimatic classes for certain indices, in contrast to the current climate with six classes. These findings offer valuable insights into viticulture suitability within each climatic region and facilitate the identification of homogeneous zones. By employing consistent bioclimatic indices and advanced hybrid interpolation techniques, this study enables meaningful comparisons of Jabal Al Arab with other viticulture regions worldwide. Such information is crucial for selecting suitable grapevine varieties and assessing the potential for grape production in the future. [ABSTRACT FROM AUTHOR]

BACKGROUND: Powdery mildew affects grapevine growth and development and reduces grapevine fruit yield and quality. Plant U-box (PUB) E3 ubiquitin ligases play important roles in ubiquitin/proteasome-mediated protein degradation during plant development and in the plant defense response. OBJECTIVE: We cloned the VvPUB17 gene from Vitis vinifera and analyzed that VvPUB17 enhanced the resistance of grapevine to powdery mildew through the SA signal pathway. METHODS: Pathogen inoculation of Arabidopsis thaliana and grapevine plants was carried out by the tableting method. Gene expression was analyzed by quantitative real-time PCR. Sequence analysis and in vitro ubiquitination experiments show the structure and characteristics of VvPUB17. Exogenous salicylic acid, methyl jasmonate, ethylene and powdery mildew induced the expression of VvPUB17 in Arabidopsis leaves to verify the resistance of VvPUB17 to powdery mildew. RESULTS: Sequence analysis and in vitro ubiquitination experiments show that VvPUB17 contains U-box and Armadillo repeats (ARM repeat) and has E3 ubiquitin ligase activity dependent on the conserved U-box motif. Transgenic plants showed elevated levels of key genes related to the SA defense response pathway and high concentrations of salicylic acid. CONCLUSIONS: VvPUB17 functions as an E3 ubiquitin ligase that enhances the resistance of grapes to powdery mildew through the SA signal pathway. [ABSTRACT FROM AUTHOR]

Tempranillo is a grapevine (Vitis vinifera L.) variety extensively used for world wine production which is expected to be affected by environmental parameters modified by ongoing global climate changes, i.e., increases in average air temperature and rise of atmospheric CO2 levels. Apart from determining their effects on grape development and biochemical characteristics, this paper considers the intravarietal diversity of the cultivar Tempranillo as a tool to develop future adaptive strategies to face the impact of climate change on grapevine. Fruit-bearing cuttings of five clones (RJ43, CL306, T3, VN31, and 1084) were grown in temperature gradient greenhouses (TGGs), from fruit set to maturity, under two temperature regimes (ambient temperature vs. ambient temperature plus 4°C) and two CO2 levels (ambient, ca. 400 ppm, vs. elevated, 700 ppm). Treatments were applied separately or in combination. The analyses carried out included berry phenological development, the evolution in the concentration of must compounds (organic acids, sugars, and amino acids), and total skin anthocyanins. Elevated temperature hastened berry ripening, sugar accumulation, and malic acid breakdown, especially when combined with high CO2. Climate change conditions reduced the amino acid content 2 weeks after mid-veraison and seemed to delay amino acidic maturity. Elevated CO2 reduced the decoupling effect of temperature on the anthocyanin to sugar ratio. The impact of these factors, taken individually or combined, was dependent on the clone analyzed, thus indicating certain intravarietal variability in the response of Tempranillo to these climate change-related factors.

Tempranillo is a grapevine (Vitis vinifera L.) variety extensively used for world wine production which is expected to be affected by environmental parameters modified by ongoing global climate changes, i.e., increases in average air temperature and rise of atmospheric CO2 levels. Apart from determining their effects on grape development and biochemical characteristics, this paper considers the intravarietal diversity of the cultivar Tempranillo as a tool to develop future adaptive strategies to face the impact of climate change on grapevine. Fruit-bearing cuttings of five clones (RJ43, CL306, T3, VN31, and 1084) were grown in temperature gradient greenhouses (TGGs), from fruit set to maturity, under two temperature regimes (ambient temperature vs. ambient temperature plus 4°C) and two CO2 levels (ambient, ca. 400 ppm, vs. elevated, 700 ppm). Treatments were applied separately or in combination. The analyses carried out included berry phenological development, the evolution in the concentration of must compounds (organic acids, sugars, and amino acids), and total skin anthocyanins. Elevated temperature hastened berry ripening, sugar accumulation, and malic acid breakdown, especially when combined with high CO2. Climate change conditions reduced the amino acid content 2 weeks after mid-veraison and seemed to delay amino acidic maturity. Elevated CO2 reduced the decoupling effect of temperature on the anthocyanin to sugar ratio. The impact of these factors, taken individually or combined, was dependent on the clone analyzed, thus indicating certain intravarietal variability in the response of Tempranillo to these climate change-related factors. [ABSTRACT FROM AUTHOR]

Fatty acid hydroperoxides can generate short-chained volatile aldehydes that may participate in plant defence. A grapevine hydroperoxide lyase (VvHPL1) clustering to the CYP74B class was functionally characterized with respect to a role in defence. In grapevine leaves, transcripts of this gene accumulated rapidly to high abundance in response to wounding. Cellular functions of VvHPL1 were investigated upon heterologous expression in tobacco BY-2 cells. A C-terminal green fluorescent protein (GFP) fusion of VvHPL1 was located in plastids. The overexpression lines were found to respond to salinity stress or the bacterial elicitor harpin by increasing cell death. This signal-dependent mortality response was mitigated either by addition of exogenous jasmonic acid or by treatment with diphenyleneiodonium (DPI), an inhibitor of NADPH oxidases. By feeding different substrates to recombinantly expressed enzyme, VvHPL1 could also be functionally classified as true 13-HPL. The cognate products generated by this 13-HPL were cis-3-hexenal and trans-2-hexenal. Using a GFP-tagged actin marker line, one of these isomeric products, cis-3-hexenal, was found specifically to elicit a rapid disintegration of actin filaments. This response was not only observed in the heterologous system (tobacco BY-2), but also in a grapevine cell strain expressing this marker, as well as in leaf discs from an actin marker grape used as a homologous system. These results are discussed in the context of a role for VvHPL1 in a lipoxygenase-dependent signalling pathway triggering cell death-related defence that bifurcates from jasmonate-dependent basal immunity. [ABSTRACT FROM AUTHOR]

Grapevine is a world-wide cultivated economically relevant crop. The process of berry ripening is non-climacteric and does not rely on the sole ethylene signal. Abscisic acid (ABA) is recognized as an important hormone of ripening inception and color development in ripening berries. In order to elucidate the effect of this signal at the molecular level, pre-véraison berries were treated ex vivo for 20 h with 0.2 mM ABA and berry skin transcriptional modulation was studied by RNA-seq after the treatment and 24 h later, in the absence of exogenous ABA. This study highlighted that a small amount of ABA triggered its own biosynthesis and had a transcriptome-wide effect (1893 modulated genes) characterized by the amplification of the transcriptional response over time. By comparing this dataset with the many studies on ripening collected within the grapevine transcriptomic compendium Vespucci, an extended overlap between ABA- and ripening modulated gene sets was observed (71% of the genes), underpinning the role of this hormone in the regulation of berry ripening. The signaling network of ABA, encompassing ABA metabolism, transport and signaling cascade, has been analyzed in detail and expanded based on knowledge from other species in order to provide an integrated molecular description of this pathway at berry ripening onset. Expression data analysis was combined with in silico promoter analysis to identify candidate target genes of ABA responsive element binding protein 2 (VvABF2), a key upstream transcription factor of the ABA signaling cascade which is up-regulated at véraison and also by ABA treatments. Two transcription factors, VvMYB143 and VvNAC17, and two genes involved in protein degradation, Armadillo-like and Xerico-like genes, were selected for in vivo validation by VvABF2-mediated promoter trans-activation in tobacco. VvNAC17 and Armadillo-like promoters were induced by ABA via VvABF2, while VvMYB143 responded to ABA in a VvABF2-independent manner. This knowledge of the ABA cascade in berry skin contributes not only to the understanding of berry ripening regulation but might be useful to other areas of viticultural interest, such as bud dormancy regulation and drought stress tolerance.

Grapevine is a world-wide cultivated economically relevant crop. The process of berry ripening is non-climacteric and does not rely on the sole ethylene signal. Abscisic acid (ABA) is recognized as an important hormone of ripening inception and color development in ripening berries. In order to elucidate the effect of this signal at the molecular level, pre-véraison berries were treated ex vivo for 20 h with 0.2 mM ABA and berry skin transcriptional modulation was studied by RNA-seq after the treatment and 24 h later, in the absence of exogenous ABA. This study highlighted that a small amount of ABA triggered its own biosynthesis and had a transcriptome-wide effect (1893 modulated genes) characterized by the amplification of the transcriptional response over time. By comparing this dataset with the many studies on ripening collected within the grapevine transcriptomic compendium Vespucci, an extended overlap between ABA- and ripening modulated gene sets was observed (71% of the genes), underpinning the role of this hormone in the regulation of berry ripening. The signaling network of ABA, encompassing ABA metabolism, transport and signaling cascade, has been analyzed in detail and expanded based on knowledge from other species in order to provide an integrated molecular description of this pathway at berry ripening onset. Expression data analysis was combined with in silico promoter analysis to identify candidate target genes of ABA responsive element binding protein 2 (VvABF2), a key upstream transcription factor of the ABA signaling cascade which is up-regulated at véraison and also by ABA treatments. Two transcription factors, VvMYB143 and VvNAC17, and two genes involved in protein degradation, Armadillo-like and Xerico-like genes, were selected for in vivo validation by VvABF2-mediated promoter trans-activation in tobacco. VvNAC17 and Armadillo-like promoters were induced by ABA via VvABF2, while VvMYB143 responded to ABA in a VvABF2-independent manner. This knowledge of the ABA cascade in berry skin contributes not only to the understanding of berry ripening regulation but might be useful to other areas of viticultural interest, such as bud dormancy regulation and drought stress tolerance. [ABSTRACT FROM AUTHOR]

Characterization of grape GA signalling components and GA quantitation unveil the berry-size regulating DELLA, and show that differential organ responses stem from both VvDELLAs and endogenous GA levels.Gibberellins (GAs) regulate numerous developmental processes in grapevine (Vitis vinifera) such as rachis elongation, fruit set, and fruitlet abscission. The ability of GA to promote berry enlargement has led to its indispensable use in the sternospermocarpic (‘seedless’) table grape industry worldwide. However, apart from VvGAI1 (VvDELLA1), which regulates internode elongation and fruitfulness, but not berry size of seeded cultivars, little was known about GA signalling in grapevine. We have identified and characterized two additional DELLAs (VvDELLA2 and VvDELLA3), two GA receptors (VvGID1a and VvGID1b), and two GA-specific F-box proteins (VvSLY1a and VvSLY1b), in cv. Thompson seedless. With the exception of VvDELLA3-VvGID1b, all VvDELLAs interacted with the VvGID1s in a GA-dependent manner in yeast two-hybrid assays. Additionally, expression of these grape genes in corresponding Arabidopsis mutants confirmed their functions in planta. Spatiotemporal analysis of VvDELLAs showed that both VvDELLA1 and VvDELLA2 are abundant in most tissues, except in developing fruit where VvDELLA2 is uniquely expressed at high levels, suggesting a key role in fruit development. Our results further suggest that differential organ responses to exogenous GA depend on the levels of VvDELLA proteins and endogenous bioactive GAs. Understanding this interaction will allow better manipulation of GA signalling in grapevine. [ABSTRACT FROM PUBLISHER]

Abstract: Successful grafting in plants requires the development of a functional vascular system between the scion and the rootstock. Understanding the spatial organization of the graft interface is important to the evaluation of new rootstock genotypes and to the development of new grafting technologies. Until now the graft interface has only been studied using 2D classical histology and low resolution 3D magnetic resonance imaging. Here we investigate the ability of X-ray tomography to examine the graft interface of Vitis vinifera in high resolution and in 3D. Data were collected using a Skyscan 1076, scanning parameters, such as, X-ray energy, filter selection, pixel size and rotation angles, were optimized to study the particularities of the graft interface. The X-ray tomography technique was then used to evaluate graft quality. Two young vines were compared; one graft was classified as of ‘good’ quality, whereas the other was classified as of ‘bad’ quality. We were able to distinguish the “omega cut”, the pith, the phloem and the xylem vessels in the images. The analysis shows several differences between the two vines. In the good graft, tissues appear well-connected in the wood and phloem, and had a regular structure; the wood appears homogenous with a lot of vessels that form a compact mass. By contrast, in the bad graft, the structures appear disorganized and not completely connected. Numerous new vessels, continuous between the scion and the rootstock, are visible in the “good graft” whereas only few ones are visible in the “bad one”. It is the first time, to our knowledge, that 3D imaging of the graft interface and the vascular connections across it have been reported, opening new avenues for graft quality assessment in woody plants. [Copyright &y& Elsevier]

• Ethephon treatment strongly stimulated anthocyanin accumulation in the grape. • Ethephon inhibited auxin synthesis and induced its own and ABA synthesis. • Ethephon accelerated glucose and fructose accumulation and sweet taste sensation. • Overexpression VvACO4 and VvEIL3 fruit accelerated fruit ripening and ethylene production. Although grapevine (Vitis vinifera L.) is generally classified as a non-climacteric fruit, the regulatory mechanisms of ethylene in the ripening of non-climacteric fruit are still poorly understood. In this study, exogenous ethephon (ETH) strongly stimulated fruit color and anthocyanin accumulation, which was consistent with the increased expression of anthocyanin structural, regulatory, and transport genes. ETH application increased ABA content and decreased IAA content by coordinating ABA and auxin biosynthesis regulatory network. ETH treatment also accelerated sugar (glucose and fructose) accumulation by enhancing the gene expression involved in sugar transport and sucrose cleavage. ETH treatment blocked the synthesis of cellulose and accelerated the degradation of pectin, which was strongly associated with berry softening. To further confirm the function of ethylene biosynthesis and signaling genes, transient overexpression of VvACO4 and VvEIL3 were performed in both in tomato and strawberry fruits. These findings of the ethylene cascade add to our understanding of ethylene in non-climacteric berry ripening regulation and revealed a complex involvement of ethylene and its interplay with phytohormones during grapevine berry ripening. [ABSTRACT FROM AUTHOR]

• In grapevine, the penetration and sporulation of Plasmopara viticola occur via stomata, suggesting functional relationships between guard cells and the pathogen. This assumption was supported by our first observation that grapevine ( Vitis vinifera cv. Marselan) cuttings infected by P. viticola wilted more rapidly than healthy ones when submitted to water starvation. • Here, complementary approaches measuring stomatal conductance and infrared thermographic and microscopic observations were used to investigate stomatal opening/closure in response to infection. • In infected leaves, stomata remained open in darkness and during water stress, leading to increased transpiration. This deregulation was restricted to the colonized area, was not systemic and occurred before the appearance of symptoms. Cytological observations indicated that stomatal lock-open was not related to mechanical forces resulting from the presence of the pathogen in the substomatal cavity. In contrast to healthy leaves, stomatal closure in excised infected leaves could not be induced by a water deficit or abscisic acid (ABA) treatment. However, ABA induced stomatal closure in epidermal peels from infected leaves, indicating that guard cells remained functional. • These data indicate that the oomycete deregulates guard cell functioning, causing significant water losses. This effect could be attributed to a nonsystemic compound, produced by the oomycete or by the infected plant, which inhibits stomatal closure or induces stomatal opening; or a reduction of the back-pressure exerted by surrounding epidermal cells. Both hypotheses are under investigation. [ABSTRACT FROM AUTHOR]

The author discusses the important enzymes on the black pepper aroma in wines. The author mentions that one of the characteristics in wine is its spicy-peppery note that can be found only in grapes and wines produced through the use of selective cultivars. He cites several studies on the mentioned characteristic of wine including that of Takase and colleagues on the origin of rotundone in grapes.

Atmospheric CO 2 levels and global temperatures are expected to rise in the next decades, and viticulture must face these changes. Within this context, exploiting the intra-varietal diversity of grapevine (Vitis vinifera L.) can be a useful tool for the adaptation of this crop to climate change. The aim of the present work was to study the effect of elevated temperature and elevated levels of atmospheric CO 2 , both individually and combined, on the growth, phenology and carbon partitioning of five clones of the cultivar Tempranillo (RJ43, CL306, T3, VN31 and 1084). The hypothesis that clones within the same variety that differ in their phenological development may respond in a different manner to the above mentioned environmental factors from a physiological point of view was tested. Grapevine fruit-bearing cuttings were grown from fruit set to maturity under two temperature regimes: ambient (T) vs elevated (ambient + 4°C, T + 4), combined with two CO 2 levels: ambient (ca. 400 ppm, ACO 2) vs elevated (700 ppm, ECO 2), in temperature-gradient greenhouses (TGGs). Considering all the clones, elevated temperature hastened grape development and increased vegetative growth, but reduced grape production, the later most likely associated with the heat waves recorded during the experiment. Plants in the elevated CO 2 treatments showed a higher photosynthetic activity at veraison and an increased vegetative growth, but they showed signs of photosynthetic acclimation to ECO 2 at maturity according to the C:N ratio, especially when combined with high temperature. The combination of ECO 2 and T + 4, mimicking climate change environmental conditions, showed additive effects in some of the parameters analyzed. The clones showed differences in their phenological development, which conditioned some responses to elevated CO 2 and temperature in terms of vegetative production and C partitioning into different organs. The work adds new knowledge on the use of different grapevine clones, that can be useful to improve the viticultural efficiency in future climate change scenarios. [ABSTRACT FROM AUTHOR]

Powdery mildew is the most economically important disease of cultivated grapevines worldwide. Here, we report that the Arabidopsis broad-spectrum disease resistance gene RPW8.2 could improve resistance to powdery mildew in Vitis vinifera cv. Thompson Seedless. The RPW8.2-YFP fusion gene was stably expressed in grapevines from either the constitutive 35S promoter or the native promoter (NP) of RPW8.2. The grapevine shoots and plantlets transgenic for 35S::RPW8.2-YFP showed reduced rooting and reduced growth at later development stages in the absence of any pathogens. Infection tests with an adapted grapevine powdery mildew isolate En NAFU1 showed that hyphal growth and sporulation were significantly restricted in transgenic grapevines expressing either of the two constructs. The resistance appeared to be attributable to the ectopic expression of RPW8.2, and associated with the enhanced encasement of the haustorial complex (EHC) and onsite accumulation of H 2 O 2 . In addition, the RPW8.2-YFP fusion protein showed focal accumulation around the fungal penetration sites. Transcriptome analysis revealed that ectopic expression of RPW8.2 in grapevines not only significantly enhanced salicylic acid-dependent defense signaling, but also altered expression of other phytohormone-associated genes. Taken together, our results indicate that RPW8.2 could be utilized as a transgene for improving resistance against powdery mildew in grapevines., (Copyright © 2017 Elsevier B.V. All rights reserved.)