Coordination between water relations strategy and carbon investment in leaf and stem in six fruit tree species.

The water relation strategy is a key issue in climate change. Given the difficulty of determining water relations strategy, there is a need for simple traits with a solid theoretical basis to estimate it. Traits associated with resource allocation patterns along a 'fast-slow' plant economics spectrum are particularly compelling, reflecting trade-offs between growth rate and carbon allocation. Avocado (Persea americana ), fig tree (Ficus carica ), mandarin (Citrus reticulata ), olive (Olea europaea ), pomegranate (Punica granatum ), and grapevine (Vitis vinifera ) were characterised in terms of iso-anisohydric strategy through stomatal behaviour, water potential at the turgor loss point (TLP), and hydroscape area. Additionally, the association of these metrics with leaf mass per area (LMA) and wood density (WDen) was explored. We observed high coordination between LMA and WDen, and both traits were related to metrics of water relation strategy. More anisohydric species tended to invest more carbon per unit leaf area or unit stem volume, which has implications for hydraulic efficiency and water stress tolerance. WDen and TLP were the most powerful traits in estimating the water relation strategy for six fruit species. These traits are easy to measure, time-cost efficient, and appear central to coordinating multiple traits and behaviours along the water relations strategies.

Unique root hydraulic and mechanical properties support the resilience of grapevines adapted to the Atacama Desert.

Cortical lacunae caused by drought, especially observed in hybrids originating from Vitis rupestris, disrupt the connection between roots and soil. Yet, the physiological processes behind lacuna formation during drought and its consistency across Vitis species remain unclear. Here, we used a root pressure probe to investigate fine root hydraulic and mechanical properties, in the arid-adapted R-65 and drought-susceptible 101-14Mgt cultivars. We then performed P-V curves, root sap osmolality, and electrolyte leakage (EL) and used fluorescent light microscopy techniques. Only 101-14Mgt showed lacunae formation during drought due to its stiffer cortical tissue, unlike R-65. Lacunae resulted in a notable decline in root hydraulic conductivity during severe drought, with increased EL and root sap osmolality, indicating potential cellular damage. R-65 displayed different and xerophyte-like characteristics featuring a higher turgor loss point and decreased root capacitance, essential for maintaining root structural integrity in arid conditions. Our findings highlight lacuna formation is impacted by root tissue elasticity possibly linked to specific Vitis species favoring deeper rooting. In arid-adapted grapevines, hydraulic regulators such as reduced turgor loss point, and root capacitance could contribute to enhanced drought tolerance.

Alterations induced by Colomerus vitis on the structural and physiological leaf features of two grape cultivars.

Vitis vinifera is cultivated worldwide for its high nutritional and commercial value. More than 60 grape cultivars are cultivated in Chile. Two of these, the país and the corinto cultivars, are the oldest known and widely used for the preparation of traditional homemade drinks and consumption as table grapes. These two grape cultivars are affected by Colomerus vitis, an eriophyid mite which establishes on their leaves and forms erinea, where the mite and its offspring obtain shelter and food. Although C. vitis has a cosmopolitan distribution, few studies of its impact on the structure and physiology of affected plants have been reported. Herein we aimed to evaluate the impact of C. vitis infection on the structural and physiological leaf performance of the two grape cultivars. The results showed tissue hyperplasia and cell hypertrophy in the epidermis, with an overproduction of trichomes and emergences in the abaxial epidermis in both cultivars. The anatomical changes were similar between the país and corinto cultivars, but they were proportionally greater in the país, where the area affected by the erinea were greater. No significant changes were detected in the photosynthetic pigment content; however, there was an increase in the total soluble sugars content in the erineum leaves of the país cultivar. Higher contents of anthocyanins and total phenols, as well as the presence of the pinocembrin in the corinto cultivar, which was less affected by C. vitis, could also indicate some resistance to mites' attack, which should be investigated in future studies.

Impacto de diferentes métodos de poda da videira 'Niágara Branca' cultivada na região do Planalto Norte Catarinense / Impact of different pruning methods of the 'Niágara Branca' vine cultivated in the region of the Planalto Norte Catarinense

O objetivo deste trabalho foi avaliar o efeito de dois métodos de poda invernal nos índices produtivos e na qualidade da uva 'Niágara Branca' cultivada na região do Planalto Norte Catarinense. O experimento foi realizado nas safras 2019 e 2020, em vinhedo da variedade Niágara Branca, situado em Canoinhas,SC. Os tratamentos consistiram em dois diferentes sistemas de poda: poda curta, deixando-se esporões com duas gemas, e poda mista, deixando-se varas com quatro gemas e esporões contendo duas gemas para renovação no ano seguinte. Avaliou-se índices vegetativos, produtivos, arquitetura de cachos e maturação tecnológica. O método de poda apresenta influência nas características produtivas e qualitativas da videira 'Niágara Branca', sendo que a adoção da poda mista resulta em maior número de ramos planta-¹, maior número de cachos planta-1, maior massa de cacho-1, maior número de bagas cacho-1, o que consequentemente propicia incremento dos índices produtivos. Plantas submetidas a poda mista, produção média de 5,5 e 11,2 kg planta-1, nas safras 2018 e 2019, respectivamente, enquanto plantas submetidas à poda curta obtiveram produção média de 1,9 e 7,2 kg planta-1. Desta forma a poda mista é recomendada para a videira 'Niágara Branca' cultivada na região do Planalto Norte Catarinense, sem que ocorra comprometimento da qualidade da uva.(AU)

The objective of this work was to evaluate the effect of two winter pruning methods on yield rates and quality of the 'Niágara Branca' grape grown in the Planalto Norte region of Santa Catarina. The experiment was carried out in the 2019 and 2020 harvests, in a vineyard on the Niágara Branca variety, located in Canoinhas. The treatments consisted of two different pruning systems: short pruning, leaving spurs with two buds, and mixed pruning, leaving canes with four buds and spurs containing two buds for renewal in the following year. Vegetative and productive indices, cluster architecture and technological maturation were evaluated. The pruning method has an influence on the productive and qualitative characteristics of the Niagara Branca vine, and the adoption of mixed pruning results in a greater number of plant-1branches, a greater number of plant-1bunches, a greater mass of bunch-1,a greater number of berries cluster-1, and consequently provides an increase in production rates.Plants produced mixed pruning, an average of 5.5 and 11.2 kg plant-1, in the 2018 and 2019 harvests, respectively, while plants supplied to short pruning obtained an average production of 1.9 and 7.2 kg plant-1. which is recommended for the 'Niágara Branca' vine grown in the Planalto Norte region of Santa Catarina, without compromising the quality of the grape.(AU)

Influence of foliar-applied glycinebetaine on growth, yield and some key physiological and biochemical attributes of grape (Vitis vinifera L) / Influência da glicinabetaína aplicada via foliar no crescimento, rendimento e alguns atributos fisiológicos e bioquímicos essenciais da uva (Vitis vinifera L)

Glycinebetaine (GB) plays an imperative role to mitigate the opposing impact of several environmental stresses in various crops. The objective of this investigation was to scrutinize the response of grape (Vitis vinifera L.) to the foliar application of GB. Diverse levels of GB (0, 10, 20 and 30 mM) were applied three times with fifteen days interval to grape cv. King's Ruby. All levels of GB improved the physiological, biochemical and growth attributes of the grape. As compared to control treatment, foliar spray of GB applied at 30 mM increased the number of leaves/vine, leaf area and number of newly emerged branches/plant by 20.55%, 12.28% and 48.13%, respectively. The pH of grape juice was decreased by increasing GB levels. However, total soluble solids, total chlorophyll contents, grape yield and photosynthesis rate was recorded maximum with foliar spray of GB applied at 30 mM. The regression model predicted that each increment in GB level enhanced the number of leaves/plant and the number of newly emerged branches/plant by 1.8 and 0.7, respectively. Thus, it is concluded that exogenous application GB applied at 30 mM might be more useful to obtain the optimum growth and quality of grapes.

A glicina betaína (GB) desempenha um papel fundamental para mitigar o impacto oposto de vários estresses ambientais em várias culturas agrícolas. O objetivo desta pesquisa foi examinar a resposta da uva (Vitis vinifera L.) à aplicação foliar de GB. Diversos níveis de GB (0, 10, 20 e 30 mM) foram aplicados três vezes com intervalo de 15 dias à videira cv. King's Ruby. Todos os níveis de GB melhoraram os atributos fisiológicos, bioquímicos e de crescimento da uva. Em comparação ao tratamento controle, a pulverização foliar de GB aplicada à 30 mM aumentou o número de folhas / videira, área foliar e número de ramos / planta recém-emergidos em 20,55%, 12,28% e 48,13%, respectivamente. O pH do suco de uva diminuiu com o aumento dos níveis de GB. No entanto, sólidos solúveis totais, conteúdo de clorofila total, rendimento de uva e taxa de fotossíntese foram registrados no máximo com pulverização foliar de GB aplicada a 30 mM. O modelo de regressão previu que cada incremento no nível de GB aumentava o número de folhas/planta e o número de ramos/planta recém-emergidos em 1,8 e 0,7, respectivamente. Assim, conclui-se que a aplicação exógena GB aplicada à 30 mM pode ser mais útil para obter o crescimento e a qualidade ideais das uvas.

Influence of foliar-applied glycinebetaine on growth, yield and some key physiological and biochemical attributes of grape (Vitis vinifera L) / Influência da glicinabetaína aplicada via foliar no crescimento, rendimento e alguns atributos fisiológicos e bioquímicos essenciais da uva (Vitis vinifera L)

Glycinebetaine (GB) plays an imperative role to mitigate the opposing impact of several environmental stresses in various crops. The objective of this investigation was to scrutinize the response of grape (Vitis vinifera L.) to the foliar application of GB. Diverse levels of GB (0, 10, 20 and 30 mM) were applied three times with fifteen days interval to grape cv. King's Ruby. All levels of GB improved the physiological, biochemical and growth attributes of the grape. As compared to control treatment, foliar spray of GB applied at 30 mM increased the number of leaves/vine, leaf area and number of newly emerged branches/plant by 20.55%, 12.28% and 48.13%, respectively. The pH of grape juice was decreased by increasing GB levels. However, total soluble solids, total chlorophyll contents, grape yield and photosynthesis rate was recorded maximum with foliar spray of GB applied at 30 mM. The regression model predicted that each increment in GB level enhanced the number of leaves/plant and the number of newly emerged branches/plant by 1.8 and 0.7, respectively. Thus, it is concluded that exogenous application GB applied at 30 mM might be more useful to obtain the optimum growth and quality of grapes.(AU)

A glicina betaína (GB) desempenha um papel fundamental para mitigar o impacto oposto de vários estresses ambientais em várias culturas agrícolas. O objetivo desta pesquisa foi examinar a resposta da uva (Vitis vinifera L.) à aplicação foliar de GB. Diversos níveis de GB (0, 10, 20 e 30 mM) foram aplicados três vezes com intervalo de 15 dias à videira cv. King's Ruby. Todos os níveis de GB melhoraram os atributos fisiológicos, bioquímicos e de crescimento da uva. Em comparação ao tratamento controle, a pulverização foliar de GB aplicada à 30 mM aumentou o número de folhas / videira, área foliar e número de ramos / planta recém-emergidos em 20,55%, 12,28% e 48,13%, respectivamente. O pH do suco de uva diminuiu com o aumento dos níveis de GB. No entanto, sólidos solúveis totais, conteúdo de clorofila total, rendimento de uva e taxa de fotossíntese foram registrados no máximo com pulverização foliar de GB aplicada a 30 mM. O modelo de regressão previu que cada incremento no nível de GB aumentava o número de folhas/planta e o número de ramos/planta recém-emergidos em 1,8 e 0,7, respectivamente. Assim, conclui-se que a aplicação exógena GB aplicada à 30 mM pode ser mais útil para obter o crescimento e a qualidade ideais das uvas.(AU)

Comprehensive Genome-Wide Exploration of C2H2 Zinc Finger Family in Grapevine (Vitis vinifera L.): Insights into the Roles in the Pollen Development Regulation.

Some C2H2 zinc-finger proteins (ZFP) transcription factors are involved in the development of pollen in plants. In grapevine (Vitis vinifera L.), it has been suggested that abnormalities in pollen development lead to the phenomenon called parthenocarpy that occurs in some varieties of this cultivar. At present, a network involving several transcription factors types has been revealed and key roles have been assigned to members of the C2H2 zinc-finger proteins (ZFP) family in model plants. However, particularities of the regulatory mechanisms controlling pollen formation in grapevine remain unknown. In order to gain insight into the participation of ZFPs in grapevine gametophyte development, we performed a genome-wide identification and characterization of genes encoding ZFP (VviZFP family). A total of 98 genes were identified and renamed based on the gene distribution into grapevine genome. The analysis performed indicate significant changes throughout VviZFP genes evolution explained by high heterogeneity in sequence, length, number of ZF and presence of another conserved domains. Moreover, segmental duplication participated in the gene family expansion in grapevine. The VviZFPs were classified based on domain and phylogenetic analysis into three sets and different groups. Heat-map demonstrated differential and tissue-specific expression patterns of these genes and k-means clustering allowed to identify a group of putative orthologs to some ZFPs related to pollen development. In transgenic plants carrying the promVviZFP13::GUS and promVviZFP68::GUS constructs, GUS signals were detectable in the anther and mature pollen grains. Expression profiling of selected VviZFP genes showed differential expression pattern during flower development and provides a basis for deepening in the understanding of VviZFPs role on grapevine reproductive development.

Vineyard environments influence Malbec grapevine phenotypic traits and DNA methylation patterns in a clone-dependent way.

KEY MESSAGE: By studying three cv. Malbec clones cultivated in two vineyards with contrasting environmental conditions, we demonstrated that DNA methylation has an important role in the phenotypic plasticity and that epigenetic modulation is clone-dependent. Clonal selection and vegetative propagation determine low genetic variability in grapevine cultivars, although it is common to observe diverse phenotypes. Environmental signals may induce epigenetic changes altering gene expression and phenotype. The range of phenotypes that a genotype expresses in different environments is known as phenotypic plasticity. DNA methylation is the most studied epigenetic mechanism, but only few works evaluated this novel source of variability in grapevines. In the present study, we analyzed the effects on phenotypic traits and epigenome of three Vitis vinifera cv. Malbec clones cultivated in two contrasting vineyards of Mendoza, Argentina. Anonymous genome regions were analyzed using methylation-sensitive amplified polymorphism (MSAP) markers. Clone-dependent phenotypic and epigenetic variability between vineyards were found. The clone that presented the clearer MSAP differentiation between vineyards was selected and analyzed through reduced representation bisulfite sequencing. Twenty-nine differentially methylated regions between vineyards were identified and associated to genes and/or promoters. We discuss about a group of genes related to hormones homeostasis and sensing that could provide a hint of the epigenetic role in the determination of the different phenotypes observed between vineyards and conclude that DNA methylation has an important role in the phenotypic plasticity and that epigenetic modulation is clone-dependent.

Induction and overcoming of dormancy of grapevine buds in response to thermal variations in the winter period / Indução e superação da dormência de gemas de videiras em resposta a variações térmicas no período hibernal

This study quantified the chilling requirements for the induction and overcoming of endodormancy (chilling-controlled physiological dormancy) of grapevines buds. Cuttings of the cultivars Chardonnay, Merlot and Cabernet Sauvignon were collected in vineyards in Veranópolis-RS in the winter period of 2019 and 2020. The cuttings were kept at a constant temperature of 7.2 °C or daily cycles of 7.2/18 °C for 6/18 h, 12/12 h or 18/6 h, up to 600 chilling hours (CH). Every 50 CH, part of the cuttings from each treatment was transferred to a temperature of 25 °C for daily assessment of the budburst in the green tip stage. The cultivars had different chilling requirements for inducing and overcoming endodormancy, reaching a total of 150 CH for ‘Chardonnay’, 300 CH for ‘Merlot’ and 400 CH for ‘Cabernet Sauvignon’. Of these, 50 CH were required to induce endodormancy in cultivars Chardonnay and Merlot and 100 CH for cultivar Cabernet Sauvignon. Dormancy evolution did not differ between cultivars in response to thermal regimes, with a temperature of 18 °C inert to the accumulation of CH. Precocity and uniformity of budburst were higher after chilling requirements were met during endodormancy for each genotype.

Este estudo visou quantificar as necessidades de frio para a indução e superação da endodormência (dormência fisiológica controlada por frio) de gemas de videiras. Estacas de das cultivares Chardonnay, Merlot e Cabernet Sauvignon foram coletadas em vinhedos em Veranópolis-RS, no período hibernal de 2019 e 2020. As estacas foram submetidas a temperatura de 7,2 ºC constante ou a ciclos diários de 7,2/18 °C por 6/18 h, 12/12 h ou 18/6 h, até 600 horas de frio (HF). A cada 50 HF, parte das estacas de cada tratamento foi transferida para a temperatura de 25°C, para avaliação diária da brotação das gemas, em estádio de ponta verde. As cultivares tiveram necessidades distintas de frio para indução e superação da endodormência, atingindo um total de 150 HF para ‘Chardonnay’, 300 HF para ‘Merlot’ e 400 HF para ‘Cabernet Sauvignon’. Destes totais, 50 HF foram necessárias para indução da endodormência nas cultivares Chardonnay e Merlot e 100 HF na cultivar Cabernet Sauvignon. A evolução da dormência não diferiu entre cultivares em resposta aos regimes térmicos, sendo a temperatura de 18 °C inerte ao acúmulo de HF. A precocidade e uniformidade de brotação das gemas foram maiores após suprido o frio na dormência para cada genótipo.

Induction and overcoming of dormancy of grapevine buds in response to thermal variations in the winter period / Indução e superação da dormência de gemas de videiras em resposta a variações térmicas no período hibernal

This study quantified the chilling requirements for the induction and overcoming of endodormancy (chilling-controlled physiological dormancy) of grapevines buds. Cuttings of the cultivars Chardonnay, Merlot and Cabernet Sauvignon were collected in vineyards in Veranópolis-RS in the winter period of 2019 and 2020. The cuttings were kept at a constant temperature of 7.2 °C or daily cycles of 7.2/18 °C for 6/18 h, 12/12 h or 18/6 h, up to 600 chilling hours (CH). Every 50 CH, part of the cuttings from each treatment was transferred to a temperature of 25 °C for daily assessment of the budburst in the green tip stage. The cultivars had different chilling requirements for inducing and overcoming endodormancy, reaching a total of 150 CH for ‘Chardonnay, 300 CH for ‘Merlot and 400 CH for ‘Cabernet Sauvignon. Of these, 50 CH were required to induce endodormancy in cultivars Chardonnay and Merlot and 100 CH for cultivar Cabernet Sauvignon. Dormancy evolution did not differ between cultivars in response to thermal regimes, with a temperature of 18 °C inert to the accumulation of CH. Precocity and uniformity of budburst were higher after chilling requirements were met during endodormancy for each genotype.(AU)

Este estudo visou quantificar as necessidades de frio para a indução e superação da endodormência (dormência fisiológica controlada por frio) de gemas de videiras. Estacas de das cultivares Chardonnay, Merlot e Cabernet Sauvignon foram coletadas em vinhedos em Veranópolis-RS, no período hibernal de 2019 e 2020. As estacas foram submetidas a temperatura de 7,2 ºC constante ou a ciclos diários de 7,2/18 °C por 6/18 h, 12/12 h ou 18/6 h, até 600 horas de frio (HF). A cada 50 HF, parte das estacas de cada tratamento foi transferida para a temperatura de 25°C, para avaliação diária da brotação das gemas, em estádio de ponta verde. As cultivares tiveram necessidades distintas de frio para indução e superação da endodormência, atingindo um total de 150 HF para ‘Chardonnay, 300 HF para ‘Merlot e 400 HF para ‘Cabernet Sauvignon. Destes totais, 50 HF foram necessárias para indução da endodormência nas cultivares Chardonnay e Merlot e 100 HF na cultivar Cabernet Sauvignon. A evolução da dormência não diferiu entre cultivares em resposta aos regimes térmicos, sendo a temperatura de 18 °C inerte ao acúmulo de HF. A precocidade e uniformidade de brotação das gemas foram maiores após suprido o frio na dormência para cada genótipo.(AU)

Transcriptomic study of pedicels from GA3-treated table grape genotypes with different susceptibility to berry drop reveals responses elicited in cell wall yield, primary growth and phenylpropanoids synthesis.

BACKGROUND: Gibberellins (GA3) are the most sprayed growth regulator for table grape production worldwide, increasing berry size of seedless varieties through pericarp cell expansion. However, these treatments also exacerbate berry drop, which has a detrimental effect on the postharvest quality of commercialized clusters. Several studies have suggested that pedicel stiffening caused by GA3 would have a role in this disorder. Nevertheless, transcriptional and phenotypic information regarding pedicel responses to GA3 is minimal. RESULTS: Characterization of responses to GA3 treatments using the lines L23 and Thompson Seedless showed that the former was up to six times more susceptible to berry drop than the latter. GA3 also increased the diameter and dry matter percentage of the pedicel on both genotypes. Induction of lignin biosynthesis-related genes by GA3 has been reported, so the quantity of this polymer was measured. The acetyl bromide method detected a decreased concentration of lignin 7 days after GA3 treatment, due to a higher cell wall yield of the isolated fractions of GA3-treated pedicel samples which caused a dilution effect. Thus, an initial enrichment of primary cell wall components in response to GA3 was suggested, particularly in the L23 background. A transcriptomic profiling was performed to identify which genes were associated with these phenotypic changes. This analysis identified 1281 and 1787 genes differentially upregulated by GA3 in L23 and cv. Thompson Seedless, respectively. Concomitantly, 1202 and 1317 downregulated genes were detected in L23 and cv. Thompson Seedless (FDR < 0.05). Gene ontology analysis of upregulated genes showed enrichment in pathways including phenylpropanoids, cell wall metabolism, xylem development, photosynthesis and the cell cycle at 7 days post GA3 application. Twelve genes were characterized by qPCR and striking differences were observed between genotypes, mainly in genes related to cell wall synthesis. CONCLUSIONS: High levels of berry drop are related to an early strong response of primary cell wall synthesis in the pedicel promoted by GA3 treatment. Genetic backgrounds can produce similar phenotypic responses to GA3, although there is considerable variation in the regulation of genes in terms of which are expressed, and the extent of transcript levels achieved within the same time frame.

Vineyards in transition: A global assessment of the adaptation needs of grape producing regions under climate change.

This paper suggests how climate change may transform vineyards. We consider changes in agro-climatic indicators derived from climatic variables as drivers for adaptation needs. We use two climate scenarios, GCM GFL-ESM2M and HadGEM2-ES, with 0.5° spatial resolution and daily time step forced by two emission scenarios, RCP2.6 and 6.0, to estimate the transition of potential vineyards in the major grape production world areas by the late 21st century. We present and discuss changes in three impact indicators - one drought indicator and two temperature ones - aimed at exploring the benefits of transition-based policies. The drought indicator provides insights to prepare adaptation for extreme events in probabilistic terms. The temperature indicators offer information on the transition towards suitable zones of production. Future projections suggest a lack of water to maintain current levels of production in all regions of the world. Furthermore, thermal suitability of grapevine may be greatly affected in China and the Mediterranean region. Nevertheless, the possibility of quality wines is not altered within the regions with adequate suitability. Lastly, a portfolio of strategies to adapt to the future climate is presented.

Changes in grapevine DNA methylation and polyphenols content induced by solar ultraviolet-B radiation, water deficit and abscisic acid spray treatments.

Environment and crop management shape plant's phenotype. Argentinean high-altitude vineyards are characterized by elevated solar ultraviolet-B radiation (UVB) and water deficit (D) that enhance enological quality for red winemaking. These signals promote phenolics accumulation in leaves and berries, being the responses mediated by abscisic acid (ABA). DNA methylation is an epigenetic mechanism that regulates gene expression and may affect grapevine growth, development and acclimation, since methylation patterns are mitotically heritable. Berry skins low molecular weight polyphenols (LMWP) were characterized in field grown Vitis vinifera L. cv. Malbec plants exposed to contrasting UV-B, D, and ABA treatments during one season. The next season early fruit shoots were epigenetically (methylation-sensitive amplification polymorphism; MSAP) and biochemically (LMWP) characterized. Unstable epigenetic patterns and/or stochastic stress-induced methylation changes were observed. UV-B and D were the treatments that induced greater number of DNA methylation changes respect to Control; and UV-B promoted global hypermethylation of MSAP epiloci. Sequenced MSAP fragments associated with UV-B and ABA showed similarities with transcriptional regulators and ubiquitin ligases proteins activated by light. UV-B was associated with flavonols accumulation in berries and with hydroxycinnamic acids in the next season fruit shoots, suggesting that DNA methylation could regulate the LMWP accumulation and participate in acclimation mechanisms.

Abscisic acid (ABA) and low temperatures synergistically increase the expression of CBF/DREB1 transcription factors and cold-hardiness in grapevine dormant buds.

BACKGROUND AND AIMS: It has been reported that low temperatures (LTs) and the plant hormone abscisic acid (ABA) induce the expression of CBF/DREB1 transcription factors in vegetative tissues and seedlings of Vitis vinifera and Vitis riparia and that foliar applications of ABA to V. vinifera increase the freezing tolerance or cold-hardiness of dormant buds. However, the combined effect of ABA and LTs on the expression of CBF/DREB1 transcription factors and on the acquisition of freezing tolerance in dormant grapevine buds has not been investigated. The objective of this study was to analyse the combined effect of ABA and LT treatments on the expression of CBF/DREB transcription factors and the acquisition of freezing tolerance. METHODS: In vitro experiments with single-bud cuttings of grapevines were used to analyse the effect of ABA, ABA + LT and LT on the expression of CBF/DREB transcription factors, dehydrin and antioxidant genes, the acquisition of freezing tolerance and the endogenous content of ABA. Gene expression analysis was performed by quantitative real-time PCR and freezing tolerance was determined by measuring the low-temperature exotherm by differential thermal analysis. ABA levels were determined by gas chromatography coupled to an electron capture detector. KEY RESULTS: The LT treatment and exogenous application of ABA to grapevine dormant buds increased the expression of the CBF/DREB1 transcription factors VvCBF2, VvCBF3, VvCBF4 and VvCBF6. The joint application of LT and ABA produced a huge increase in the expression of these transcription factors, which was greater than the sum of the increases produced by them individually, which indicates the existence of a synergistic effect between ABA and LT on the activation of these transcription factors. This synergic effect was also observed on the increase in bud cold-hardiness and on the expression of antioxidant and dehydrin genes. CONCLUSIONS: The synergy between ABA and LT on the expression of CBF/DREB1 transcription factors VvCBF2, VvCBF3, VvCBF4 and VvCBF6 plays a key role in cold acclimatization of grapevine buds. The results highlight the importance of the combination of stimuli in the improvement of genetic and physiological responses and help us to understand the adaption of plants to complex environments.

Water uptake can occur through woody portions of roots and facilitates localized embolism repair in grapevine.

Water acquisition is thought to be limited to the unsuberized surface located close to root tips. However, there are recurring periods when the unsuberized surfaces are limited in woody root systems, and radial water uptake across the bark of woody roots might play an important physiological role in hydraulic functioning. Using X-ray microcomputed tomography (microCT) and hydraulic conductivity measurements (Lpr ), we examined water uptake capacity of suberized woody roots in vivo and in excised samples. Bark hydration in grapevine woody roots occurred quickly upon exposure to water (c. 4 h). Lpr measurements through the bark of woody roots showed that it is permeable to water and becomes more so upon wetting. After bark hydration, microCT analysis showed that absorbed water was utilized to remove embolism locally, where c. 20% of root xylem vessels refilled completely within 15 h. Embolism removal did not occur in control roots without water. Water uptake through the bark of woody roots probably plays an important role when unsuberized tissue is scarce/absent, and would be particularly relevant following large irrigation events or in late winter when soils are saturated, re-establishing hydraulic functionality before bud break.

Macro- and microclimate conditions may alter grapevine deacclimation: variation in thermal amplitude in two contrasting wine regions from North and South America.

Low temperature is a limiting factor that affects vineyard distribution globally. The level of cold hardiness acquired during the dormant season by Vitis sp. is crucial for winter survival. Most research published on this topic has been generated beyond 40° N latitude, where daily mean temperatures may attain injurious levels during the dormant season resulting in significant damage to vines and buds. Symptoms of cold injury have been identified in Mendoza (32-35° S latitude), a Southern Hemisphere wine region characterized by a high thermal amplitude, and warm winds during the dormant season. These symptoms have usually been attributed to drought and/or pathogens, but not to rapid deacclimation followed by injurious low temperatures. Because local information on meteorological events as probable causes is scarce, this research was designed to test and study this assumption by comparing macro-, meso-, and microclimatic data from Mendoza, Argentina, and eastern Washington, USA. The goal was to unveil why freezing damage has occurred in both regions, despite the existence of large climatic differences. Because environmental parameters under field conditions may not correspond to data recorded by conventional weather stations, sensors were installed in vineyards for comparison. Microclimatic conditions on grapevines were also evaluated to assess the most vulnerable portions of field-grown grapevines. In order to better understand if it may be possible to modify cold hardiness status in a short period with high thermal amplitude conditions, deacclimation was induced using a thermal treatment. Hence, despite the fact that Mendoza is warmer, and temperatures are not as extreme as in Washington, high daily thermal amplitude might be partially involved in plant deacclimation, leading to a differential cold hardiness response.

Cell cycle genes are activated earlier than respiratory genes during release of grapevine buds from endodormancy.

Single-bud cuttings of Vitis vinifera L exposed to forced growing conditions were used to investigate the involvement of phytohormones, abscisic acid (ABA), auxin (Aux) and cytokinin (CK) in the release of buds from the ED and in bud-sprouting. This artificial system imitates and hastens the natural sprouting that occurs in spring. Temporal expression analysis of genes related to phytohormones synthesis, showed an early drop in the expression of ABA biosynthesis gene that preceded an increase in Aux and CK biosynthesis genes. Bud-break is headed by the activation of all structures of the latent bud, especially the differentiation of the inflorescence and the development of the early stages of floral organs. Therefore, resumption of cell division and increases in respiration are essential for the activation of the bud. Temporal expression analysis of the cell cycle and respiration genes indicate that an increase in cell division go before the increase in respiration. These results, together with results indicating that the cell cycle genes are upregulated by Aux and CK, suggest that the events before the bud-break, start with a reduction in ABA content, followed by an increase in the content of Aux and CK, which activates the machinery of the cell cycle, which eventually would cause an increase in respiration.

Inclusion of grape pomace in the diet of pigs on pork quality and oxidative stability of omega-3 enriched fat / Inclusão do bagaço de uva na dieta de suínos sobre a qualidade da carne e a estabilidade oxidativa da gordura enriquecida com ômega-3

The objective of this study was to assess the effects of including grape pomace in the diet of pigs on pork quality and oxidative stability of body fat enriched with omega-3 fatty acids. Four treatments were compared: T1) Control diet based on corn and soybean meal; T2) Diet with inclusion of 3% of a canola (50%) and flaxseed (50%) oil blend; T3) Diet with inclusion of 3% of the oil blend and sequential levels of 3 and 5% of grape pomace; T4) Diet with inclusion of 3% of the oil blend and sequential levels of 6 and 10% of grape pomace. Inclusion of grape pomace in the diet led to an increase (P 0.10) of a* value and color saturation index of meat. The omega-3 and polyunsaturated fatty acids (PUFA) content of backfat were increased (P>0.10) with dietary inclusion of oils blend. Neither the inclusion of the oil blend, nor the grape pomace had any effect (P>0.10) on the production of thiobarbituric acid reactive substances (TBARS) in the loin samples, despite the higher PUFA content in the fat of pigs fed the oil blend. Antioxidant effect of grape pomace was not possible to prove when measured by TBARS, but the increased redness of the pork from pigs fed with this ingredient suggested a possible antioxidant effect of grape pomace.

Este trabalho teve como objetivo avaliar a inclusão do bagaço de uva na dieta de suínos sobre a qualidade da carne e, a estabilidade oxidativa da gordura corporal enriquecida com ácidos graxos ômega-3. Foram comparados quatro tratamentos: T1 - Dieta controle baseada em milho e farelo de soja; T2 - Dieta com inclusão de 3% de uma mistura de óleos de canola (50%) e de semente de linho (50%); T3 - Dieta com inclusão de 3% da mistura de óleos e níveis sequenciais de 3 e 5% de bagaço de uva e; T4 - Dieta com inclusão de 3% da mistura de óleos e níveis sequenciais de 6 e 10% de bagaço de uva. A inclusão do bagaço de uva na dieta resultou no aumento (P 0,10) do valor de a* e índice de saturação da cor da carne. O conteúdo de ômega-3 e ácidos graxos poli-insaturados (PUFA) do toucinho aumentaram (P 0,10) em função da inclusão da mistura de óleos na dieta. A mistura de óleos e o bagaço de uva não afetaram a produção de substâncias reativas ao ácido tiobarbitúrico (TBARS) nas amostras de lombo, apesar do maior conteúdo de PUFA na gordura dos suínos que receberam a mistura de óleos na dieta. Não foi possível provar efeito antioxidante do bagaço de uva na carne através da determinação dos valores de TBARS. Porém, a cor vermelha mais intensa na carne dos suínos alimentados com este ingrediente sugere um possível efeito antioxidante do bagaço de uva.

Inclusion of grape pomace in the diet of pigs on pork quality and oxidative stability of omega-3 enriched fat / Inclusão do bagaço de uva na dieta de suínos sobre a qualidade da carne e a estabilidade oxidativa da gordura enriquecida com ômega-3

The objective of this study was to assess the effects of including grape pomace in the diet of pigs on pork quality and oxidative stability of body fat enriched with omega-3 fatty acids. Four treatments were compared: T1) Control diet based on corn and soybean meal; T2) Diet with inclusion of 3% of a canola (50%) and flaxseed (50%) oil blend; T3) Diet with inclusion of 3% of the oil blend and sequential levels of 3 and 5% of grape pomace; T4) Diet with inclusion of 3% of the oil blend and sequential levels of 6 and 10% of grape pomace. Inclusion of grape pomace in the diet led to an increase (P 0.10) of a* value and color saturation index of meat. The omega-3 and polyunsaturated fatty acids (PUFA) content of backfat were increased (P>0.10) with dietary inclusion of oils blend. Neither the inclusion of the oil blend, nor the grape pomace had any effect (P>0.10) on the production of thiobarbituric acid reactive substances (TBARS) in the loin samples, despite the higher PUFA content in the fat of pigs fed the oil blend. Antioxidant effect of grape pomace was not possible to prove when measured by TBARS, but the increased redness of the pork from pigs fed with this ingredient suggested a possible antioxidant effect of grape pomace.(AU)

Este trabalho teve como objetivo avaliar a inclusão do bagaço de uva na dieta de suínos sobre a qualidade da carne e, a estabilidade oxidativa da gordura corporal enriquecida com ácidos graxos ômega-3. Foram comparados quatro tratamentos: T1 - Dieta controle baseada em milho e farelo de soja; T2 - Dieta com inclusão de 3% de uma mistura de óleos de canola (50%) e de semente de linho (50%); T3 - Dieta com inclusão de 3% da mistura de óleos e níveis sequenciais de 3 e 5% de bagaço de uva e; T4 - Dieta com inclusão de 3% da mistura de óleos e níveis sequenciais de 6 e 10% de bagaço de uva. A inclusão do bagaço de uva na dieta resultou no aumento (P 0,10) do valor de a* e índice de saturação da cor da carne. O conteúdo de ômega-3 e ácidos graxos poli-insaturados (PUFA) do toucinho aumentaram (P 0,10) em função da inclusão da mistura de óleos na dieta. A mistura de óleos e o bagaço de uva não afetaram a produção de substâncias reativas ao ácido tiobarbitúrico (TBARS) nas amostras de lombo, apesar do maior conteúdo de PUFA na gordura dos suínos que receberam a mistura de óleos na dieta. Não foi possível provar efeito antioxidante do bagaço de uva na carne através da determinação dos valores de TBARS. Porém, a cor vermelha mais intensa na carne dos suínos alimentados com este ingrediente sugere um possível efeito antioxidante do bagaço de uva.(AU)