Studies on volatile composition consistently show that native and minority grape varieties often exhibit unique volatile profiles, supporting their use for wine differentiation, market diversification, and the valorisation of typicity. To advance knowledge of Portugal’s native grapevines, this study provides a comprehensive assessment of the volatile composition of three white (Encruzado, Malvasia Fina, and Terrantez) and red (Coração de Galo, Jaen, and Touriga Nacional) grape varieties over two consecutive years. This work helps us understand the aromatic potential of the varieties studied and the potential influence of annual climatic conditions on volatile composition. Results for the white varieties showed that the varietal aroma potential index (IPAv) was significantly modulated by year, depending on the variety, indicating differential accumulation of glycosylated aroma precursors. In contrast, for the red varieties studied, IPAv was unaffected by year, variety, or their interaction, suggesting a more stable precursor pool. Regarding individual volatile compounds, obtained by GC×GC-TOFMS, white varieties were mainly driven by varietal identity, particularly for terpenes and C13norisoprenoids, while year effects were stronger for C6 compounds and especially benzenoids. For the red varieties studied, volatile composition reflected combined genetic and year effects, with strong year × variety interactions for terpenes and C13 norisoprenoids, while C6 compounds were largely influenced by variety. Finally, benzenoids were mainly influenced by year. Overall, both variety and year influenced the volatile compounds and aromatic potential of the traditional Portuguese grape varieties studied. This work allowed for a first approach to the study of the aromatic potential of some traditional Portuguese grape varieties grown in northern Portugal, also contributing to a first approach to how the year, and particularly climatic conditions, may influence the main groups of volatile compounds.
Sensory evaluation studies of light-struck flavour reported in the literature mostly concentrate on the onset of typical off-aromas related to sulfur-containing products However, some recent chromatographic studies have also confirmed the change in varietal aroma compounds during light exposure before attaining the sensory threshold for wine faults. In this study, we have looked for aroma changes by sensory evaluation prior to the onset of typical light-struck notes in sparkling wines of different composition, technology and duration of lees contact. Evaluations were done in two different settings: i) completely randomised blind tasting, and ii) a tasting of a series of samples of known identity without the knowledge of the randomised order of light exposure durations. Thus, we aimed to simulate the real-life experience of consumers who do not have information about the actual shelf life of sparkling wines they buy. The main results are that, after moderate light doses – prior to the onset of light-struck off-flavours – tasters cannot distinguish significant differences depending on the length of exposure. In some cases, they rated moderately illuminated samples even higher than the control, reporting pleasant mellow, honey-like notes. HS–SPME–GC–MS studies supported a non-monotonic change in the aroma profile, similarly to a few recent findings reported in the literature. We also found marked differences in these temporal evolution patterns depending on the composition, technology, and vintage of the sparkling wine samples. We conclude that a proper consumer protection protocol would entail the monitoring of the light exposure of the bottles and consequently not selling wines when the critical light dose has been absorbed, which ultimately triggers a perceptible light-struck flavour.
Esca is one of the most damaging grapevine trunk diseases worldwide, and it is closely associated with wood decay processes. While fungi involved in esca have been extensively studied, the role of wood-inhabiting yeasts remains largely unknown. In this study, we investigated the diversity and potential functional role of endophytic yeasts isolated from asymptomatic, necrotic, and white rot tissues of Vitis vinifera cv. Cabernet-Sauvignon and Sauvignon blanc. A total of 31 yeast strains belonging to four species (Aureobasidium pullulans, Papiliotrema terrestris, Rhodotorula glutinis, and Hanseniaspora uvarum) were identified, with white rot representing the main source of isolation. In vitro assays were used to evaluate their antagonistic activity against Fomitiporia mediterranea by dual culture, volatile and non-volatile metabolite tests and enzymatic activity modulation. Results showed a strong strain-dependent inhibition of pathogen growth. Rhodotorula glutinis and P. terrestris were the most effective yeasts, with volatile compounds causing up to 83 % mycelial pathogen growth reduction. Non-volatile metabolites also significantly inhibited fungal growth, while co-cultivation altered ligninolytic enzyme activity in F. mediterranea. Overall, our findings highlight white rot as a selective niche for antagonistic yeasts and suggest that yeast-derived volatile compounds and metabolites may limit pathogen development, with potential applications in sustainable management of grapevine trunk diseases.
Carménère is a widely cultivated and internationally recognised grapevine cultivar in Chile. Early studies based on SSR and AFLP markers detected limited polymorphism among clones in Chile, but these approaches interrogate only a small fraction of the genome, leaving the extent of clonal diversity unresolved. Here, we generated a near-complete chromosome-scale diploid genome assembly of Carménère FPS 02 and characterised clonal genomic diversity by sequencing 36 biological replicates representing 12 clones maintained in Chile, including heritage selections rescued from old producer vineyards by Viña Santa Carolina as part of its Bloque Herencia conservation program, and commercial nursery-derived clones. Focusing on low-frequency variants and using replicate-aware consensus calling, we identified more than 9000 candidate private single nucleotide variants (SNVs) and small indels per clone. A subsampling simulation showed that as few as 83 ± 2 candidate private SNVs per clone were sufficient to correctly discriminate all clones by kinship-based clustering, a level of resolution undetectable by earlier SSR and AFLP-based approaches. Most variants occurred in repetitive or intergenic regions, but a subset affected coding sequences, collectively impacting an average of 7292 genes per haplotype when variants of all predicted impact classes are considered, with genes involved in plant–pathogen interactions, transport, and secondary metabolism most frequently affected. Overall, this study provides a genome-wide characterisation of extant clonal diversity in Carménère, with implications for clonal selection and genetic resource conservation.
The ample diversity in grapevine genotypes and their contrasting physiological responses to drought can be used by winegrowers to adapt to the increasingly drier conditions imposed by climate change. Still, the exposure to drought is more strongly associated with the rootstock genotype onto which grape scions are grafted. Indeed, certain rootstocks help maintain higher yields in drought conditions. Although some morphological, developmental, and physiological rootstock traits have been associated with greater drought resistance, information on how grapevine rootstocks access and use belowground water sources in field conditions is scarce. Besides, the rootstock-scion interaction could modulate the root growth that may dictate the root depth and root water uptake. Deciphering the grapevine belowground activity is critical to decide which rootstock is more suitable for each agronomic situation. Isotopic tracers (δ18O and δ2H) are a promising tool to study grapevine water sources, but they have been seldom used for phenotyping. Here we aimed to test whether different rootstocks influence the grapevine’s access to water, impacting whole-plant water status, plant growth, and yield, and if the interaction rootstock-scion has a role in the magnitude of this impact. For that, we combined isotopic-based determination of grapevine water sources with the monitoring of physiological and agronomical performance in an experimental vineyard with 9 rootstock-scion combinations (3 rootstocks x 3 scions). We found that the above-ground plant water use was mainly governed by the scion (e.g. midday water potential), whereas the rootstock has significant effects on the exposure to drought (e.g. predawn water potential). Surprisingly, isotopic tracers revealed that all rootstocks were accessing a similar belowground water pool, despite different predawn water potentials. This suggests that the lower exposure to drought offered by one of the studied rootstocks (110-R) is not caused by a deeper root system, but by a more efficient water uptake provided by non-explored morphological, anatomical, or physiological traits. In addition, we observed that plants rapidly took water up after the first substantial rain events following the summer drought, around harvest. Overall, we show that isotopic techniques can provide information on grapevine’s access to water that can guide vineyard management and rootstock phenotyping.
In Uruguayan wines elaborated from Vitis vinifera cv Tannat are the most known, being representative of the country wines between international consumers. Nevertheless, work is being carried out to improve quality to obtain premium wines, through blends using less frequent grape varieties being introduced and employed in wine production looking for sensory particularities. The aim of this study was to determine, by means of HPLC-DAD and HPLC-MS (Orbitrap), the polyphenolic profiles of four red Vitis vinifera L. grape varieties cultivated in small vineyards in southern Uruguay (Montevideo and Canelones Provinces) in the 2022–2023 vintages. The selected varieties were: Ancellotta, Aspiran Bouschet (Aramon × Teinturier du Cher × Aspiran, in Uruguay syn. Lacryma Christi), Egiodola (Abouriou × Tinta Negra Mole), and Caladoc (Malbec × Grenache). To our knowledge, only few previous studies have been focused on the volatile and polyphenolic profiles for these new varieties planted, even when they are cultivated by their color contribution to wines. While the study of free volatile compounds offers valuable insights, directing attention towards glycosylated compounds is imperative for a comprehensive grasp of how aromas evolve in wine and for refining the ultimate sensory characteristics of the product.
Viticulture currently faces major challenges, being among the land uses most prone to erosion and one of the most reliant on pesticide applications. One of the answers to these challenges is to establish service crops, which are non-commercial crops grown to provide ecosystem services. However, service crops are also prone to compete with grapevines for water and nitrogen, and need to be managed in order to find trade-offs between ecosystem services. In the present study, we conducted a three-year on-farm experiment between 2022 and 2024 on 7 commercial farms in the French departments of Hérault, Aude, and Pyrénées Orientales. During three years, we evaluated different service crop termination strategies for cover crop mixtures, combining two service crops termination periods (around budburst and one month after budburst) and two termination methods (mower + superficial tillage, roller-crimper), compared with a tilled control treatment. We monitored the service crop biomass, the surface temperature and water potential of the soil in the inter-row, and a variety of indicators on the grapevine (yield components, pruning weight, apex growth indicator, δ13C, yeast assimilable nitrogen (YAN), sugar and pH in musts). The results showed that the early termination using tillage (E-T) caused no vine water stress or production loss compared to other termination strategies. In contrast, late terminations and roller-crimping led to yield reductions, fewer bunches, lower berries weight, and reduced vigour. Overall, our findings demonstrate that, in a Mediterranean context, service crop termination by tillage at grapevine budburst limits vine water stress and preserves vine yield and vigour, and is therefore a preferable strategy in case of dry year.
The growing global demand for high-quality wines with distinctive territorial identities has sparked interest in biotechnological innovations, such as the use of non-Saccharomyces yeasts. This study evaluated the impact of a newly isolated strain of Torulaspora delbrueckii (LC 2-1) in combination with a commercial Saccharomyces cerevisiae strain (BW333) on the oenological and sensory profiles of wines from two iconic Apulian cultivars: Verdeca white wines and Nero di Troia rosé wines. Using pilot-scale vinification, three strategies were compared: pure S. cerevisiae fermentation (BW333), co-inoculation (TOR-COI), and sequential inoculation (TOR-SEQ). Fermentation kinetics revealed that TOR-SEQ led to a more gradual sugar consumption, particularly in Verdeca, while maintaining low volatile acidity. Comprehensive GC×GC-MS analysis identified significant shifts in the wine volatilome; the TOR-SEQ strategy nearly doubled total ethyl esters and quadrupled acetate esters in Verdeca wines. In Nero di Troia rosé wines, sequential fermentation triggered a steep increase in grape-derived terpenes and norisoprenoids, such as citronellol and damascenone. Rate-All-That-Apply (RATA) sensory analysis corroborated these chemical findings, with TOR-SEQ wines receiving significantly higher scores for fruity (orange, cherry) descriptors. Hierarchical clustered correlation heatmaps revealed that fermentation-derived esters collectively drove the aromatic profile of Verdeca wines, while a synergistic matrix of aliphatic esters and free monoterpenes dictated the red-berry character of Nero di Troia rosé wines, corroborating the chemical basis of the sensory differences observed. These results suggest that the metabolic impact of T. delbrueckii is highly cultivar-dependent but consistently enhances aromatic complexity. Consequently, the use of T. delbrueckii LC 2-1 via sequential inoculation represents a powerful technological tool to differentiate Apulian wines and meet modern market preferences for sophisticated, fruit-forward profiles.
For centuries, grapevine improvement relied primarily on massal selection, a practice whereby growers identified and vegetatively propagated individuals with targeted phenotypic characteristics within vineyard populations of a given variety. Through repeated cycles of observation and multiplication, this empirical process generated populations according to production objectives that formed the foundation of early directed selection for wine production. In the 20th century, clonal and sanitary selection emerged as a decisive advance, delivering uniformity, health status, in particular with regard to virus diseases, and greater consistency in propagation material. Nevertheless, the widespread adoption of a narrow set of certified clones has led to significant genetic erosion, reducing the capacity of vineyards to buffer environmental fluctuations, adapt to climate change and resist to existing or emerging diseases and pests. Despite this evidence, a persistent perception persists that massal selections may offer complementary advantages over clonal material. This review synthesizes the historical trajectory of grapevine domestication and the emergence of modern varieties, the mechanisms underlying intra-varietal variation, including somatic mutations, epigenetic modifications and virome composition, and the consequences of clonal standardization on genetic diversity. Drawing on palaeogenomic, phenotypic and molecular evidence, it suggests that massal populations can serve as dynamic genetic reservoirs, preserving rare alleles, structural variants and adaptive trait combinations that are may be lost in clonal systems. Recent studies reveal that even within certified clonal collections, substantial exploitable variation persists, with moderate to high heritability and strong genotype-by-environment interactions enabling resilience under present and projected conditions. The strategic revalorization of massal selection, supported by high-throughput genotyping, metagenomics and precision tools, emerges as a powerful strategy to enhance viticultural competitiveness. By maintaining diverse populations that distribute risk across genotypes, epigenotypes and viromes, massal approaches may contribute to more stable yields, improved stress tolerance and sustained terroir expression without altering varietal identity. This review argues that the strategic co-existence of clonal and massal selection represents the ultimate expression of precision viticulture, allowing diverse populations to be matched to specific terroirs for enhanced long-term adaptability in a changing climate.
Rotundone is the main aroma compound responsible for peppery notes in wines. Its biosynthesis is negatively affected by heat and drought, whereas the impact of light, particularly ultraviolet (UV) radiation, remains unestablished. This study aimed to investigate, under field conditions, the effects of grape exposure and UV treatments on rotundone in Vitis vinifera L. cv. Tardif. During the warm 2022 season, four treatments were compared to a control using a randomised complete block design with three replicates per treatment: early defoliation at Eichhorn & Lorenz stage 32 (ED), late defoliation at stage 34 (LD), exclusion of UV-A and UV-B radiations on late-defoliated vines using radiation screens (LD-UV), and four UV-C modulated light applications during daytime between mid-veraison and harvest on late-defoliated vines (LD+UV). No differences were observed between the control and ED, likely due to leaf regrowth limiting the initial increase in cluster exposure. In contrast, the LD treatment resulted in a significant 33 % increase in rotundone. LD-UV did not affect bunch zone air temperature but caused a significant reduction in rotundone, highlighting the key role of UV in its biosynthesis. UV-C treatments applied during daytime had no effect, whereas preliminary results on a limited number of fruiting cuttings suggest a substantial increase when treatments were applied at night. Overall, these results indicate that winegrowers cultivating Tardif can use late defoliation to enhance rotundone biosynthesis even during warm vintages. The effects of UV-C treatments warrant further validation on a larger number of vines under field conditions.
Climate change is disrupting grapevine phenology and threatening terroir-driven wine typicity, challenging the definition of optimal harvest timing. This study develops and validates an on-the-go dual-range hyperspectral imaging workflow for non-destructive, real-time monitoring of grape maturity in Vitis vinifera L. cv. Tempranillo. The system integrates two pushbroom cameras – visible to near-infrared (400–1000 nm) and short-wave infrared (900–1700 nm) – mounted on a mobile platform operating under field conditions. Over seven sampling dates from veraison to harvest (August – September 2025), hyperspectral images were collected in a commercial vineyard in Logroño (La Rioja, Spain). Corresponding reference analyses included total soluble solids, pH, titratable acidity, tartaric acid, malic acid, yeast-assimilable nitrogen, anthocyanins, total phenolic index, colour intensity, and chromatic coordinates L*, a* and b*. Partial least squares regression models were developed to predict grape composition parameters from processed hyperspectral data. Model performance was assessed through independent prediction, exhibiting very good to excellent predictive performance for key technological maturity traits: titratable acidity (R2p = 0.98), malic acid (R2p = 0.95), total soluble solids (R2p = 0.94), and pH (R2p = 0.93). Chromatic attributes also showed reliable estimations, particularly colour intensity (R2p = 0.88), b* (R2p = 0.89), and a* (R2p = 0.88), with L* reaching an R2p of 0.81. Tartaric acid (R2p = 0.79) and total phenolic index (R2p = 0.76) achieved good quantitative accuracy, while anthocyanins (R2p = 0.58) and yeast-assimilable nitrogen (R2p = 0.56) provided satisfactory discrimination for vineyard screening purposes. The high performance for malic acid highlights the relevance of including the short-wave infrared spectral range, where absorption features of organic acids are more pronounced. This work represents, to the best of our knowledge, the first field-based demonstration of yeast-assimilable nitrogen prediction from hyperspectral data, expanding the analytical scope of proximal sensing for viticulture. The proposed on-the-go hyperspectral imaging framework offers a practical, scalable tool for adaptive harvest decision-making under increasing climate variability. It supports the maintenance of varietal typicity and wine style consistency by facilitating timely, data-driven harvest scheduling. Future work will extend model validation across seasons and sites and explore advanced modelling approaches to support operational deployment.
Advancements in low-cost, connected temperature sensors have made local-scale climate zoning within vineyards more accessible for both the research community and the wine industry. However, the optimal sensor density and interpolation methods for capturing high-resolution thermal variability remain poorly defined. The following study evaluates the impact of network density on interpolation accuracy within an 800-ha wine-growing area in Burgundy (France), using 112 temperature sensors positioned at the grape-cluster level (60 cm) which were deployed from March 2023 to September 2024. To ensure methodological consistency within the high-density (1m x 1m) planting system, sensors were specifically installed in missing-vine spots. Seven interpolation techniques – spanning linear regressions, machine-learning ensembles (Random Forest) and hybrid geostatistical methods (Regression-Kriging) – were compared to determine their accuracy in mapping daily Tmin and Tmax. This evaluation followed a two-step sensitivity analysis: an initial baseline was established using the total sensor population, followed by a reduction in sensor density generated through terrain-informed stratified sampling. Results reveal a critical density threshold: below 5 sensors/km2 (N < 40), modelling efficiency (EFF) drops below 0.4 for over 50% of the study period, rendering the zoning unreliable. While Random Forest shows relative robustness at lower densities (5 -10 sensors/km2), Regression-Kriging (LMK) significantly outperforms all methods at high densities (14 sensors/km2), achieving a mean RMSE of 0.4°C for Tmin and 0.56°C for Tmax. Notably, Tmax interpolation was consistently less efficient (EFF = 0.264) than Tmin (EFF = 0.660). This disparity suggests that in high-density viticultural systems, maximum temperatures at the cluster level are driven by micro-scale energy fluxes and aerodynamic decoupling that override topographical signals. These findings provide a practical framework for optimizing sensor networks, suggesting that while 40 – 60 sensors (5 – 7.5 sensors/km2) are sufficient for mapping indices related to minimum temperatures (e.g. number of frost days), higher densities or additional surface-level covariates might be required to accurately map indices sensitive to maximum temperatures and thermal accumulation (e.g. average temperature during the growing season and heat stress indices). By quantifying how interpolation errors propagate into these agroclimatic indicators, this study provides essential guidance for the implementation of high-resolution climate zoning in viticultural terroirs.
Regional-scale vineyard monitoring is crucial for addressing climate change adaptation, notably water stress. While crowdsourcing offers a promising solution for collecting data at this large spatial scale, its true effectiveness, including participant mobilisation and robustness against sampling biases, remains under-documented. This paper provides a critical analysis of the potential and limitations of crowdsourcing for regional vineyard monitoring, using the seven-year Apex-Vigne project as a case study. Apex-Vigne monitors vine water status via a simple, calculated indicator, iG-Apex, derived from weekly vine shoot growth observations contributed by industry stakeholders (winegrowers and advisors) through a mobile application. The analysis focused on the spatio-temporal distribution of data collected in Metropolitan France and specifically within a 49,500 km2 study area in the South of France (2019–2025). The project’s capacity to generate regional-scale information was assessed by mapping iG-Apex values, and key scientific challenges were identified. Over seven seasons, Apex-Vigne successfully gathered 34,233 observations in Metropolitan France from over 771 contributors on 11,481 fields. Observations were collected following five different contribution patterns resulting from the specific interests of contributors. The Apex-Vigne mobile application was used for on-farm experimentation at the within-field level, field monitoring at the farm level, and reference field monitoring at the regional level. The data volume proved sufficient to spatialise vine water status and illustrate temporal dynamics at the regional level. These results demonstrate the potential of crowdsourcing as a new source of information for regional decision support in viticulture. The study also highlights scientific challenges raised by crowdsourcing projects in viticulture. Social sciences are needed to understand contributors' motivations and new data science approaches should be explored to automatically identify observations with atypical behaviour.
The P.D.O. Campo de Borja faces a challenge regarding its viticultural heritage, where the total Grenache surface area, over 2.000 ha are estimated to be between 30 and 50 years old, while 144 ha exceed 50 years old. The dating of these vineyards could be important for their preservation and commercial valorisation. However, official records occasionally lack sufficient detailed information about the planting dates. For this reason, this study aims to provide a tool for the certification and management of ‘old vineyards’ by combining historical aerial photographs, morphological characterisation, and plant material analysis. The aerial photography methodology integrated a time series of aerial photographs, from the American flight (1956–1957) to current PNOA flights (2024), providing insights into possible planting years as well as the spatial pattern and training systems of the plots. The results show that traditional free gobelet systems consistently exceeded mean ages of 45–50 years, with the tresbolillo pattern reaching the highest age ranges. In contrast, modern trellised systems and wider inter-row spacing (3–3.5 m) were 17 years-old in average. Furthermore, morphological analysis was useful in refining age ranges obtained through aerial photography. Finally, the identification of plant material, allowed for the classification of vineyards into three age groups based on the specific rootstocks identified. Overall, this study shows that combining multidisciplinary methodologies can refine the estimation of planting years, providing a basis for the official certification of historical plots and the long-term management of the viticultural landscape.
Agroforestry in vineyards has been proposed as a strategy to buffer climatic stress, potentially moderating microclimate and enhancing water availability for the vines. However, the net effects of tree proximity on grapevine water status remain unclear due to potential competition for water and nutrients. This study aimed to investigate the effects of tree proximity on grapevine growth and physiology. To do so, measurements were conducted on three vineyard sites in Geisenheim, Germany, where grapevines were grown in close proximity to tree rows. Predawn water potential and stomatal conductance, grape composition, and single berry weight were assessed on these sites as a function of distance to the tree row. In one site, where Vitis vinifera L. ‘Riesling’ was grown north of a row of field maples (Acer campestre), root systems of six vines were excavated and 3D-digitised in situ, soil was sampled for organic carbon and nitrogen, and fresh and dry biomass were determined. Results showed that vines closer to the trees exhibited lower stomatal conductance and more negative pre-dawn leaf water potentials, and lower berry weight. Root architecture analysis revealed a pronounced tendency for roots to grow away from the trees, with limited root proliferation toward the tree row, indicating growth limitation due to competition for water. These findings suggest that the nature of vine × tree interactions under the conditions of our study is competitive rather than facilitative, especially with regard to the acquisition of water. This study provides a foundation for further research on such interactions in vineyard agroforestry, offering insights into root spatial dynamics and water competition under varying environmental conditions.
Facing the challenges posed by climate change, quantifying the resilience of wine terroirs is imperative. Total Transpirable Soil Water (TTSW) represents the maximum water volume that vines can extract from soil, a critical parameter for water balance models. Current TTSW estimation methods often require expensive protocols, limiting their use in commercial vineyards and over large regions. This research aimed to evaluate a low-cost TTSW estimation method that combines Inverse Modelling (IM) with crowdsourced data. The chosen IM method, which has been validated locally, relies on observations of vine shoot growth (iG-Apex), weather data and satellite images. More precisely, the IM relies on a process-based relationship linking the decline in plant water status expressed as a slope coefficient, primarily inferred from plant growth and weather data, to the transpiration rate under bare soil and dry conditions, that is based on the basal crop coefficient (Kcb). By integrating a crowdsourced database, the IM method estimates TTSW at numerous locations where data were collected. A case study was carried out in a Southern French wine appellation (“Côtes du Rhône”), and a TTSW map defined by local experts was used for qualitative evaluation. The method produced TTSW estimates between 60 and 190 mm. High-confidence areas, where expert opinions converged and at least four field-level TTSW estimates existed, demonstrated coherent TTSW rankings. Two distinct geographical regions were identified: one characterised by low-to-medium TTSW and another by medium-to-high levels. This spatial differentiation suggests that crowdsourced data, when combined with inverse modelling, can effectively reveal broad-scale TTSW patterns. However, inaccurate estimates persisted in some areas. A large proportion of crowdsourced observations were excluded from the inversion due to insufficient time series length. This work demonstrates the capacity of farmer-generated plant observations to quantify the spatial patterns of a critical agronomic variable at the regional scale. The case study illustrates how farmers and viticulture professionals can contribute, through crowdsourcing, to the collective quantification of TTSW, a key variable for developing coordinated adaptation strategies in Mediterranean viticulture under climate change.
The ripening of fleshy fruits is characterised by extensive metabolic reprogramming, with substantial alterations in sugar and acid metabolism, hormonal signalling, and cell wall remodelling. Such intensified metabolic activities enhance respiratory and redox reactions, from which reactive oxygen species (ROS) are generated as by-products of aerobic metabolism. While excessive ROS can disrupt proteins, lipids, and nucleic acids, ROS signalling appears to function as a central regulator of developmental transitions during fruit ripening. In this study, we integrated quantitative proteomics and enzymatic profiling to investigate redox metabolism during key developmental stages of berry ripening in the table grape cultivar Vitis labrusca × Vitis vinifera cv. Niagara Rosada. We hypothesised that dynamic regulation of ROS-scavenging enzymes and NADPH-generating pathways limits oxidative injury and supports mesocarp functionality despite the enhanced metabolic activity associated with ripening. Among 1,434 identified proteins, 956 (67 %) were differentially accumulated. Functional enrichment revealed that antioxidant processes were predominant, but the dataset also encompassed proteins from energy metabolism, hormone metabolism, protein turnover, secondary metabolism, and stress-response categories. Distinct accumulation patterns were observed: photosynthetic and energy-related proteins predominated at early stages, whereas antioxidant and stress-related proteins accumulated later, suggesting stage-dependent reprogramming of the proteome. Integration with enzymatic assays reinforced this dynamic, as catalase followed a biphasic profile, superoxide dismutase peaked at late ripening, and peroxidase activity declined progressively. Glutathione reductase and glutathione peroxidase displayed stage-dependent regulation, underscoring the importance of NADPH-dependent detoxification pathways. Despite enhanced ROS-associated activity, Pi leakage and lipid peroxidation suggested moderate membrane-associated oxidative changes rather than extensive cellular deterioration. Together, these findings suggest that grape berries deploy a coordinated antioxidant network that adjusts proteome composition and enzymatic defences to balance ROS generation and detoxification. Stage-dependent redox regulation emerges as a central feature of berry development, supporting mesocarp functionality and fruit quality. By integrating proteomic and enzymatic evidence, this study establishes a comprehensive framework of redox metabolism during grape berry ripening.
The increased intensity and frequency of heatwaves, coupled with prolonged periods of drought, poses a significant threat to viticulture worldwide. Under these conditions, greater damage may occur when the leaf is also exposed to high radiation intensity. To better understand the impact of drought and high radiation exposure during heatwaves on grapevine physiology, we established a factorial experiment using well-watered or water-deficit Shiraz grapevines with different radiation exposure due to the row orientation. Given the East-West row orientation, the two sides faced directly north or south, receiving different radiation intensities. To monitor the impact of irrigation and radiation exposure on PSII functionality, leaf chlorophyll fluorescence was continuously monitored over a 20-day period on leaves on the north side and on the south side of the canopy of each plant, while leaf gas exchange measurements were performed on adjacent leaves. Water-deficit vines were maintained at a midday stem water potential (SWP) of –1.4 MPa, while well-watered plants had SWP of –0.8 MPa during the experiment. High radiation exposure was the dominant factor impairing PSII performance rather than heat or water stress alone. The north side leaves (N) showed lower maximum efficiency of PSII than the south side leaves (S) on hot days, especially when plants were water-stressed. S leaves had higher photochemical (Y(II)) and lower non-photochemical yields (Y(NPQ)) than N leaves, predominantly at midday. Water stress further decreased Y(II) and increased Y(NPQ) in N leaves, but not in S leaves. Leaf net assimilation, stomatal conductance, and transpiration were higher in N leaves compared to S leaves, notably pronounced in the well-watered plants than in the water-deficit ones. The coupling between stomatal conductance and assimilation showed similar pattern in water-deficit and well-watered vines in N leaves, while in S leaves, water-deficit plants showed lower changes in stomatal conductance compared to well-watered ones for the same increase in assimilation. These findings suggest that despite the positive impact of irrigation to sustain the canopy during heatwaves, additional management strategies (such as shade netting) may be required to reduce radiation exposure and to maintain leaf function during and following heatwaves.
Understanding the microbial diversity associated with grape berries is essential for improving vineyard management and wine production, particularly in extreme environments such as the Atacama Desert. This study examined the intra-vineyard heterogeneity of bacterial and fungal communities colonising Vitis vinifera cv. Ahmeur bou Ahmeur grapes cultivated under a hyper-arid environment. Grape samples were collected from individual vines, and microbial assemblages were characterised using high-throughput sequencing of the 16S rRNA and ITS regions. Results revealed marked heterogeneity among vines within the same vineyard, with fungal communities showing greater variability than bacterial ones. Fungal assemblages were dominated by Starmerella, Hanseniaspora, Malassezia, and Cladosporium, whereas bacterial communities were mainly composed of Gluconobacter, Tatumella, and Asaia. Alpha and beta diversity analyses demonstrated significant differences in microbial composition among vines, indicating strong plant-specific signatures. These results provide new insights into the fine-scale heterogeneity of grape-associated microbiota in desert viticulture and highlight the importance of considering individual plants as ecological units shaping the microbial dimension of terroir.
Oak wood has a significant impact on the chemical composition of wine, influencing its organoleptic properties such as aroma, structure, astringency, bitterness, and colour. Among the key extractable non-volatile polyphenols are ellagitannins, which can undergo oxidation and condensation reactions due to their multiple ortho-hydroxyl groups. Although these compounds are extracted from oak into wine, their high reactivity often results in lower concentrations in the final product. To investigate the compounds transferred from oak to wine, a model wine solution was aged for one year in two barrels with different toasting levels: a light-plus toasting barrel (LT+AAS) and a medium-plus toasting barrel (MT+AAS). Samples were collected monthly and analysed by liquid chromatography coupled with mass spectrometry (HPLC-QQQ-MS and HPLC-TOF-MS). Results showed significant compositional changes overtime, including the formation of oxidation and hydrolysis products. Monomeric ellagitannins, such as castalagin, increased sharply within the first eight months-from 29.83 mg/L to 115.98 mg/L in the LT+AAS barrel-while dimer concentrations rose more gradually and stabilised around the sixth month, with roburin D reaching about 15.25 mg/L. Several derivative products of C-glucosidic ellagitannins, including whiskey tannins and brandy tannins, were also identified and progressively accumulated during ageing. Differences between barrels suggest that wood toasting level influences the formation of these ellagitannin-derived products. These results provide new insights into the transformation pathways of C-glucosidic ellagitannins and the formation of whiskey and brandy tannins during barrel ageing.
