Open Access
Quantifying the effects of water status on grapevine vegetative growth, yield, and grape composition through a collaborative analysis
(Wiley, 2025-05-14) Contreras Uriarte, David; Santesteban García, Gonzaga; Mirás-Ávalos, José M.; Buesa, Ignacio; Cancela, Javier José; Chacón, Juan Luis; Escalona, José M.; Intrigliolo, Diego S.; Lampreave, Miriam; Montoro, Amelia; Rivacoba Gómez, Luis; Visconti, Fernando; Yuste, Jesús; Miranda Jiménez, Carlos; Agronomía, Biotecnología y Alimentación; Agronomia, Bioteknologia eta Elikadura
The consolidation of scientific knowledge is based on the accumulation and understanding of previous findings. Nowadays, reviews of the scientific literature have become more effective through the use of meta-analyses, which are systematic evaluations of the results from multiple studies. Similarly, mega-analyses, which combine raw data from many studies into a single sample for processing and statistical analysis, are a very powerful tool for analyzing results of heterogeneous origin but require a high level of collaboration between the researchers contributing data. In the framework of a collaborative methodology between different Spanish viticultural research groups, this work uses a mega-analytical approach to quantify the effects of changes in vine water status on vine vegetative growth, yield, and grape composition, integrating a wide range of growing conditions to obtain robust general trends of vine performance under water deficit. The mean seasonal stem water potential data from the different studies allowed a classification into five levels of water status (no deficit ⟶ mild ⟶ moderate ⟶ high ⟶ severe). A progressive decrease in vegetative growth with increasing deficit was observed, while yield decreased more markedly as water deficit progressed from moderate to high. On the other hand, titratable acidity was more sensitive to variation in water status than sugar concentration, with a greater decrease in titratable acidity when changing from no to moderate deficit. Conversely, increasing water deficit from moderate to high resulted in the greatest increases in grape anthocyanin in the red varieties explored. The results obtained in this work provide solid information on general trends in grapevine response to water deficit that can be used in simulation models or incorporated by grape growers in their decision-making processes in relation not only to irrigation management but also on other agronomic tools to impact grapevine water status.
Open Access
Four-year field study reveals variable effects of phytohormone- and natural-based elicitors on anthocyanin metabolism in Tempranillo grapes
(Wiley, 2025-08-08) Crespo Martínez, Sara; Torres Molina, Nazareth; Loidi Erviti, Maite; Miranda Jiménez, Carlos; Astráin, Jesús; Santesteban García, Gonzaga; Urrestarazu Vidart, Jorge; Institute for Multidisciplinary Research in Applied Biology - IMAB; Agronomía, Biotecnología y Alimentación; Agronomia, Bioteknologia eta Elikadura; Gobierno de Navarra / Nafarroako Gobernua; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, OTRI 001-1365-2022-000273
OBJECTIVES/BACKGROUND: Climate change has raised concerns about the imbalance between anthocyanin and sugar levels in grapevines. High temperatures tend to reduce anthocyanin content by inhibiting its synthesis and increasing degradation, while simultaneously enhancing sugar accumulation. The application of elicitors, which promote the anthocyanin biosynthetic pathway, may help alleviate this imbalance. METHODS: To investigate this, a four-year field trial was conducted on Vitis vinifera cv. Tempranillo to assess the effects of four commercial products: two natural-based (an antioxidant-mannitol and an alginic acid-mannitol products) and two phytohormone-based (an abscisic acid and an ethephon-based products). The study evaluated the effect of these treatments on the phenyl propanoid pathway gene expression, various yield parameters, and the content of primary and secondary metabolites. RESULTS: Although none of the treatments consistently increased anthocyanin levels across seasons, the results varied depending on the year. Two products influenced some parameters in specific seasons: the ethephon-based product, which influenced the anthocyanin-to-sugar ratio through the reduction of TSS and induced the expression of key anthocyanin genes, and the natural-based antioxidant-mannitol product, which transiently increased the expression of some phenylpropanoid genes. CONCLUSIONS: None of the treatments increased anthocyanin levels across seasons. Ethephon (Fruitel) showed greater effectiveness under temperature stress and reduced sugar accumulation, which may be advantageous in a warming climate. Natural elicitors like antioxidant-mannitol elicitor (Vitalfit) had short-term effects on gene expression but no lasting impact on anthocyanins. Further research is needed to assess their influence on other polyphenols and their potential for commercial use.
Open Access
Phenotyping xylem connections in grafted plants using X-ray micro-computed tomography
(Wiley, 2024) Camboué, Marilou; Janoueix, Anne; Tandonnet, Jean‐Pascal; Spilmont, Anne‐Sophie; Moisy, Cédric; Mathieu, Guillaume; Cordelières, Fabrice; Teillon, Jérémie; Santesteban García, Gonzaga; Ollat, Nathalie; Cookson, Sarah Jane; Agronomía, Biotecnología y Alimentación; Agronomia, Bioteknologia eta Elikadura
Plants are able to naturally graft or inosculate their trunks, branches and roots together, this mechanism is used by humans to graft together different genotypes for a range of purposes. Grafts are considered successful if functional vascular connections between the two genotypes occur. Various techniques can evaluate xylem connections across the graft interface. However, these methods are generally unable to assess the heterogeneity and three-dimensional (3D) structure of xylem vessel connections. Here we present the use of X-ray micro-computed tomography to characterize the 3D morphology of grafts of grapevine. We show that xylem vessels form between the two plants of natural root and human-made stem grafts. The main novelty of this methodology is that we were able to visualize the 3D network of functional xylem vessels connecting the scion and rootstock in human-made stem grafts thanks to the addition of a contrast agent to the roots and improved image analysis pipelines. In addition, we reveal the presence of extensive diagonal xylem connections between the main axial xylem vessels in 2-year old grapevine stems. In conclusion, we present a method that has the potential to provide new insights into the structure and function of xylem vessels in large tissue samples.
Open Access
Does omega-type graft compromise vine performance?: evaluation of five bench grafting methods across nursery, vineyard establishment, and first productive years
(Elsevier, 2025-08-13) Villa Llop, Ana; Torres Molina, Nazareth; Loidi Erviti, Maite; Velaz Barbarin, Maider; Galar Martínez, Mónica; Crespo Martínez, Sara; Santesteban García, Gonzaga; Agronomía, Biotecnología y Alimentación; Agronomia, Bioteknologia eta Elikadura; Institute for Multidisciplinary Research in Applied Biology - IMAB; Gobierno de Navarra / Nafarroako Gobernua
Grafting Vitis vinifera L. scions onto Vitis sp. rootstocks became essential in viticulture following the phylloxera crisis in the late 19th century. Among the various bench grafting methods, omega grafting became predominant due to high efficiency and compatibility with mechanization. However, concerns have been raised about its potential impact in vine performance. This study compares five bench grafting methods, omega (OM), full cleft (FC), V-shape (V), mechanical (WTm), and hand-made (WTh) whip and tongue, to evaluate implications during the nursery stage, vineyard establishment and vine performance over the first seven seasons after planting. Results suggest a three-phase trajectory in vine development following grafting: (1) a short-term nursery phase the grafting method clearly impacts performance, (2) a mid-term phase post vineyard establishment where growth and yield converge regardless of method; and (3) a long-term phase, in which structural weaknesses at the graft union may lead to delayed decline. During the nursery stage, OM consistently outperformed others in grafting success and vegetative development. In early vineyard years, OM and WTh showed a tendency to promote better vine development, although this trend faded after the third year. In contrast, differences in vine survival and training compliance emerged later. At the end of the seventh season, vine mortality reached 18 % in WTm and 7.5 % in V, whereas OM and FC maintained low losses (< 3 %). These findings contradict previous concerns about OM grafting limitations and support its continued use as a reliable method in commercial nurseries. In any case, longer-term monitoring is necessary to understand vineyard productive lifespan implications.
Open Access
Mycorrhizae and grapevines: the known unknowns of their interaction for wine growers' challenges
(Oxford University Press, 2025-03-11) Velaz Barbarin, Maider; Santesteban García, Gonzaga; Torres Molina, Nazareth; Agronomía, Biotecnología y Alimentación; Agronomia, Bioteknologia eta Elikadura; Institute for Multidisciplinary Research in Applied Biology - IMAB; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Arbuscular mycorrhizal fungi (AMF) play an important role in grapevine production systems. However, little is known about how this relationship is achieved in the nursery and how soil management might modify it and its derived benefits. Here, we review the current knowledge on the establishment of grapevine-AMF relationships from the nursery to the field, the main factors that affect the effectiveness of the symbiosis, the potential role of AMF as biostimulants in grapevine production systems, and the future perspectives of their use in the current context of climate change. The process of establishing mycorrhizal symbiosis is complex, and the molecular dialogue between the plant roots and the fungus is still not yet fully understood. During vine plant production, rooting occurs in nurseries, where spontaneous symbiosis can be generated. The effectiveness of mycorrhizal symbiosis appears to depend not only on the identity of the fungus but also on the diversity of the vine material and soil management. Finally, the use of AMF as biostimulants might be an effective strategy with which to face the new climatic scenario, but further research dealing with the application of AMF inocula and the protection of native cohorts should be conducted.