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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. [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]

• 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]

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]