Cumulative effects of repeated drought stress on berry composition, and phenolic profile: Field experiment insights
Drought stress has a profound impact on grapevine productivity and significantly alters key quality-related traits of berries. Although research has been conducted on the effects of individual drought events, there is still a knowledge gap regarding the cumulative consequences of repeated exposure to water scarcity and the influence of the timing of stress imposition. To address this gap, a field experiment was conducted to investigate the impacts of repeated drought stress on yield, berry composition, and the phenolic profile of grape berries. The results indicate that yield is primarily influenced by pre-veraison water deficit. Although the number of clusters was only slightly reduced, a substantial decrease in berry size was observed, resulting in a notable reduction in overall yield.
Chemical activation of ABA signaling in grapevine through ABA receptor agonists
Grapevine (Vitis vinifera) and its derived products, in terms of cultivated area and economic volume, constitute the most relevant fruit crop in the world (7.5 million cultivated hectares). In the current context of climate change, the wine sector faces unprecedented challenges to satisfy a growing demand for wines of greater quality through sustainable viticulture. Global warming threatens quality wine production in Mediterranean wine regions in particular. The increase in heatwaves and drought episodes accelerate the vine phenology and alter the ripening and composition of grapes and wine. Extreme abiotic stress episodes compromise grape production and plant survival, intensifying the pressure on the use of limited resources like water. Abscisic acid (ABA) is an important hormone in the ripening of certain fruits and in plant response to abiotic stress.
Radiation-associated effects on regulated deficit irrigation management in grapevine cv. Cabernet Sauvignon
The main challenge of regulated deficit irrigation (RDI) research is to isolate the factors that come with RDI, the direct effect of plant water status from the indirect ones like increased radiation and temperature changes on the cluster zone. This study aims to isolate the effects of vine water status from the effects of increased radiation on the phenolic composition of grapes subjected to RDI.
A three-year study on an RDI experiment where radiation was controlled was implemented in a commercial vineyard of Cabernet Sauvignon in Chile. Four RDI treatments based on partial evapotranspiration (ET) irrigation were established. Irrigation treatments were 100% ET, 70% ET, 50-100% ET (50% ET before veraison and 100% ET afterward), and 35-100% ET (35% ET before veraison and 100% ET afterward).
Merging two genomes: a holistic approach to disentangle rootstock-mediated drought and recovery responses
Viticulture is facing many challenges due to climate change effects with increasingly attention to save resources, such as water, considering that drought events have been predicted to dramatically increase over the next future. Thanks to the -omics techniques, research pushed forward knowledge to deepen facets of drought response in diverse grapevine-rootstock combinations. However, the regulatory mechanisms orchestrating adaptation strategies during drought and recovery in grafted grapevines need further exploration. Herein, we combined ecophysiological, biochemical and molecular approaches to unravel drought and recovery-induced changes in potted Nebbiolo (NE) plants grafted onto three different rootstocks (3309, Kober5BB, Gravesac), by analysing root and leaf tissues.
Freeze-thaw temperature oscillations promote increased differential gene expression during grapevine bud dormancy
In northern cold climate conditions, chilling requirement fulfillment in dormant grapevine buds is slowed or stopped by subzero temperatures impacting the transcriptional processes needed to complete chilling requirement. Cabernet Franc and Reisling in Geneva, NY were used to determine the impact of natural oscillating temperatures on grapevine bud transcriptional activity during light and dark periods of a two-week period in January with fluctuating diurnal winter temperatures. Cabernet Franc and Reisling bud samples were collected at 32 time points during the natural vineyard temperature cycle at 6:00 (dark), 14:00 (light) and 18:00 (dark) hours) to monitor gene expression in consecutive freezing and non-freezing temperature oscillations. Genotype, light and dark, and temperature oscillations conditions were explored.
Identifying physiological and genetic bases of grapevine adaptation to climate change with maintained quality: Genome diversity as a driver for phenotypic plasticity (‘PlastiVigne’ project)
In the face of climate change, new grapevine varieties will have to show an adaptive phenotypic plasticity to maintain production with erratic water resources, and still ensure the quality of the final product. Their selection requires a better knowledge of the genetic basis of those traits and of the elementary processes involved in their variability. ‘PlastiVigne’, an emblematic project of the Vinid’Occ key challenge, funded by the Occitanie Region (France), tackles this issue with innovative genomic and physiological tools implemented on a unique panel of grape genetic resources representing the genetic diversity of Vitis vinifera. A graph-pangenome is developed from a representative set of high-quality genomes to study the extent and impact of structural genome variations and chromosomal rearrangements in the rapid adaptation capacity of grapevine.
REDWINE project: use of Chlorella vulgaris to prevent biotic and abiotic stress in Palmela’s region, Portugal, vineyards
The new EU Green Deal aims to achieve GHG emissions reduction by at least 55% by 2030 and a climate neutral EU economy by 2050.
REDWine concept will be realized through the establishment of an integrated Living Lab demonstrating the viability of the system at TRL 7. The Living Lab will be able to utilize 2 ton of fermentation off-gas/year (90% of total CO2 produced in the fermenter) and 80 m3 of liquid effluent (100% of the liquid effluent generated during fermenter washing) to produce 1 ton (dry weight) of Chlorella biomass/year. This biomass will be processed under a downstream extraction process to obtain added-value extracts and applied in food, cosmetic and agricultural end-products and to generate a new EcoWine. REDWine will focus on the recovery of off-gas from a 20.000L fermenter of red wine production existing in Adega Cooperativa de Palmela (ACP, located in Palmela, Portugal).
Postharvest ozone treatment in grapevine white cultivars: Effects on grape volatile composition
During postharvest management, the metabolism of fruits remains active and continuous physico-chemical changes occur. Ozone treatment has an elicitor effect on secondary metabolites and the treatment conditions can influence the grape response to the stress (Bellincontro et al., 2017; Botondi et al., 2015). Regarding volatile organic compounds (VOCs), previous studies showed that ozone treatment during postharvest dehydration induces the biosynthesis of terpenes in Moscato bianco grapes (Río Segade et al., 2017). It is well known that grape VOCs greatly influence the organoleptic properties of wines, particularly terpenes in aromatic varieties.
Leaf necrosis induced by the insecticide carbaryl in Vitis rupestris ‘B38’
Carbaryl is an acetylcholine esterase inhibitor-type insecticide used for pest control on grapevine. We repeatedly observed the occurrence of interveinal leaf necrosis following carbaryl spray application in a Vitis rupestris x Vitis riparia F1 hybrid progeny vineyard. Spray applications induced necrosis in this progeny under both Missouri and New York field conditions an approximate one-to-one sensitive-to-insensitive segregation ratio and with 42% concordance. Results of subsequent in vitro experiments established causality between carbaryl treatment and leaf necrosis and confirmed the pattern of segregation observed in the field. We consistently map this phenotype to a major QTL on chromosome 16 of the female parent V. rupestris ‘B38’ regardless of whether we used field or in vitro-generated phenotype data.
Effect of different canopy managements on microclimate and carbon allocation in Vitis vinifera cv Chardonnay
Climate change strongly affects the wine-growing sector which increasingly requires in situ adaptation strategies aimed at preserving the sustainability of production. Investigating microclimate becomes crucial in comprehending environmental pressures on plants. The microclimatic investigation conducted in the Orvieto PDO (central Italy) allowed us to highlight the climatic dynamics occurring in the last 25 years and the frequency and intensity of abiotic stresses. Two management strategies for the canopy were identified: early defoliation (ELR) and foliar application of Basalt Flour ® (FB) compared to the ordinary management (C) of the company (bud selection and topping). The effects on plant vigour indices (LAI), resource allocation in terms of carbon stored in the above-ground organs of the vine, and the microclimate of the canopy and the berry were evaluated. In particular, microclimate was evaluated through a network of sensors connected wirelessly (Wireless Sensor Network), dedicated to collecting information on temperature and humidity in the canopy and clusters.
From soil to canopy, the diversity of adaptation strategies to abiotic constraints in grapevine
Climate change is here. One of the main consequences is an increase in the frequency and severity of abiotic stresses which mostly occur in a combined manner. Grapevine, which grows in a large diversity of pedo-climatic conditions, has presumably evolved different mechanisms to allow this widespread adaptation. Harnessing the genetic diversity in these mechanisms will be central to the future of viticulture in many traditional wine growing areas. The interactions between the scion and the rootstock through grafting add an additional level of diversity and adaptive potential to explore.
At the physiological level, these mechanisms are related to processes such as root system development and functioning (water and nutrient uptake), interactions with the soil microbiome, gas exchange regulation, hydraulic properties along the soil-plant-atmosphere continuum, reserve storage, short and long distance signaling mechanisms and plasticity for some of these traits.
Effects of stress memory on grapevine resilience in response to recurrent drought and recovery events
Plants have evolved different strategies to cope with environmental stresses and, although still debated, it was observed that they can remember past stress occurrence.
Anatomical and physiological adjustments have been observed in different grapevine cultivars after repeated drought exposure, however epigenetic, transcriptional and biochemical changes associated with drought-primed ecological memory have been poorly studied.
This work was conceived to test whether exposure to recurring events of mild drought could prime vines to endure severe drought stress. Particularly, we investigated whether the expected improved stress tolerance of Vitis vinifera cv Nebbiolo plants subjected over years to moderate and long-lasting water stress events (WS-primed) depended on molecular memory phenomena or on resetting of stress-induced signals.
Integrated approaches for the functional characterization of miRNAs in grapevine
Micro(mi)RNAs are small non-coding RNAs that regulate several pathways and are widely recognised as key players in plant development, tissue differentiation, and many other important physiological processes, including plant adaptation to biotic and abiotic stresses. The release of plant genomes and the application of high throughput sequencing have considerably extended miRNA discovery across many species, including grapevine (Vitis spp.). Despite their relevance in plant development, functional studies in grapevine to clarify the function of miRNAs are not yet available. Through the grapevine genetic improvement platform IMPROVIT at CNR-IPSP (http://www.ipsp.cnr.it/en/thematics/turin-headquarter-thematics/improvit/), we developed integrated approaches to discover miRNA function in grapevine.
Diversity of leaf functioning under water deficit in a large grapevine panel: high throughput phenotyping and genetic analyses
Water resource is a major limiting factor impacted by climate change that threatens grapevine production and quality. Understanding the ecophysiological mechanisms involved in the response to water deficit is crucial to select new varieties more drought tolerant. A major bottleneck that hampers such advances is the lack of methods for measuring fine functioning traits on thousands of plants as required for genetic analyses. This study aimed at investigating how water deficit affects the trade-off between carbon gains and water losses in a large panel representative of the Vitis vinifera genetic diversity. 250 genotypes were grown under 3 watering scenarios (well-watered, moderate and severe water deficit) in a high-throughput phenotyping platform.
Rootstock influence on xylem embolized vulnerability and scion behavior under severe water deficit
Severe water stress events can induce cavitation damage by xylem embolism in grapevine, diminishing plant hydraulic conductance. This work aimed to determine the rootstock effects on 1) xylem embolism vulnerability to understand its function failure under severe drought, including segmentation processes from leaf to root; and 2) hydraulic conductance across water deficit and its recovery. For this purpose, two complementary experiments were performed in one-year-old Vitis vinifera cv. Tempranillo grafted onto two different rootstocks (110-Richter and SO4) under well-watered 12L pot conditions. In experiment 1, the water-stress induced xylem embolism was monitored in leaves and stems, above and below grafting-point, by using “Cavicam” for determining the percentage of embolized vessels (at P12, P50 and P88).
Winter physiology in a warmer world: Cold hardiness and deacclimation sensitivity drive variation in spring phenology
As the climate warms, the focus of concern in viticulture often turns to how higher temperatures may shift growing regions, change the character of AVAs, and alter fruit quality. However, climate warming is increasing most quickly during the winter dormancy cycle, a critical and often underappreciated portion of the grapevine life cycle. In response to decreasing temperatures and decreasing daylength, grapes initiate a series of physiological changes to enter dormancy, acquire freeze resistance, and time spring phenology such that the growing season begins after threat of frost.
Water status response of Vitis vinifera L. cv Cabernet Sauvignon during the first years within the long-term VineyardFACE (Free Air Carbon dioxide Enrichment) study
Understanding grapevine responses to increasing atmospheric CO2 (aCO2) concentrations is crucial for assessing the impact of climate change on viticulture. Previously, at the VineyardFACE (Free Air Carbon dioxide Enrichment) experiment in Geisenheim, leaf gas exchange measurements were made as Vitis vinifera cv. Cabernet Sauvignon established from planting (2014 to 2016) under aCO2 or elevated CO2 (eCO2, aCO2 + 20%) concentrations. Contrary to many preceding observations with grapevines and other perennial plant species the young vines showed an increased intrinsic water use efficiency (WUEi) that was mainly associated with an increase in net assimilation (A) rather than a decrease in stomatal conductance (gs) under eCO2.
Long-Term impact of elevated CO2 exposure on grapevine physiology (Vitis vinifera L. cvs. Riesling & Cabernet Sauvignon)
Over the next 25 years, the Intergovernmental Panel on Climate Change (IPCC 2013) predicts a ~20% increase in atmospheric carbon dioxide (CO2) concentration compared to the current level. Concurrently, temperatures are steadily rising. Grapevines, known for their climate sensitivity, will show changes in phenology, physiological processes and grape compositions in response. Investigating eco-physiological processes provides insights into the response of field-grown grapevines to elevated CO2 conditions. A Free Air Carbon Dioxide Enrichment (FACE) facility was established in the Rheingau region of Germany. Two grapevine varieties (Vitis vinifera L., cvs. Riesling and Cabernet Sauvignon) were planted, with the VineyardFACE comprising three rings with ambient atmospheric CO2 (approx. 400 – 420 ppm from 2014 to 2023, aCO2) and three rings with elevated CO2 concentration (+20% to ambient; eCO2).
Apoplastic pH influences Vitis vinifera Barbera recovery responses to short and prolonged drought
Alteration of sap pH is one of the first chemical changes that occurs within the xylem vessels of plants exposed to drought. Xylem sap acidification accompanied by the accumulation of soluble sugars has been recently documented in several species (Sharp and Davis, 2009; Secchi and Zwieniecki, 2016). Here, Vitis vinifera plants of the anysohydric cultivar Barbera were exposed to either short (no irrigation; SD) or to prolonged drought (continual reduction of 10% water; PD). When comparable severe stress was reached, the potted grapes were re-watered. SD was characterized by fast (2–3 days) stomatal closure and high abscisic acid (ABA) accumulation in xylem sap (>400 μg L−1) and in leaf. In PD plants, the rise in ABA levels was considerably diminished.
Rootstock-scion contributions to seasonal water and light use diversity under field conditions
Cultivar and rootstock selection are two well-known strategies for adapting vine production in challenging environments. Despite the vast diversity of rootstocks and cultivars, their effective contribution to grapevine sustainable development and acclimation to changing growing conditions remains an open question. The use of robust and prompt monitoring tools can allow a powerful screening of the water status of the vineyard before considering a further detailed characterization. This study leveraged new tools to monitor the stomatal conductance (gs), transpiration rate (E), and quantum efficiency of photosystem II (ᶲPSII) throughout a season, from pre-veraison to after-harvest.