Expérimentation de systèmes viticoles à faible usage d’intrants phytosanitaires en Val de Loire.

Ce numéro est constitué d’articles de synthèse des projets DEPHY EXPE publiés à l’occasion du colloque national DEPHY, qui s’est déroulé les 13 et 14 novembre 2018 à la Cité des Sciences et de l'Industrie (Paris). Nous vous invitons à découvrir le bilan et les enseignements des 21 projets conduits sur la période 2012-2017.The EcoViti Val de Loire project evaluated various viticulture systems during 6 years. One system wasbased on a combination of already assessed practices (at the time of design), a second one on theimpact of the pruning system on diseases susceptibility, and the last on the association of grapevineand roses. These systems led to significant TFI reductions, with sometimes some drawbacks in terms ofyield. They also allowed to show the importance of the transition period in system experimentations, andthe interest to lead these experimentations from the plantation for perennial crops. The time for thesystem to get back in balance is not to be underestimated, even a plant as plastic as grapevine takesseveral years ti adapt to a change in pruning or soil management.Le projet EcoViti Val de Loire a évalué trois systèmes de culture viticoles pendant 6 ans. Le premiersystème était basé sur la combinaison de pratiques déjà éprouvées au moment du lancement du projet,un second sur l’impact du mode de taille de la vigne sur la sensibilité aux maladies, et le dernier surl’association de vigne et rosiers. Ces divers systèmes ont permis des réductions significatives d’IFT,avec parfois des revers, en termes de rendement notamment. Ils ont également mis en évidence lanécessité de prendre en compte la phase de transition dans les essais systèmes, et l’intérêt de menerles essais systèmes en culture pérenne dès la plantation. En effet, le temps de rééquilibrage d’uneplante pérenne n’est pas à sous-estimer, et même une plante aussi plastique que la vigne met plusieursannées pour s’adapter à une modification de taille ou de mode d’entretien du sol

Field-Based Metabolomics of Vitis vinifera L. Stems Provides New Insights for Genotype Discrimination and Polyphenol Metabolism Structuring

Grape accumulates numerous polyphenols with abundant health benefit and organoleptic properties that in planta act as key components of the plant defense system against diseases. Considerable advances have been made in the chemical characterization of wine metabolites particularly volatile and polyphenolic compounds. However, the metabotyping (metabolite-phenotype characterization) of grape varieties, from polyphenolic-rich vineyard by-product is unprecedented. As this composition might result from the complex interaction between genotype, environment and viticultural practices, a field experiment was setting up with uniform pedo-climatic factors and viticultural practices of growing vines to favor the genetic determinism of polyphenol expression. As a result, UPLC-MS-based targeted metabolomic analyses of grape stems from 8 Vitis vinifera L. cultivars allowed the determination of 42 polyphenols related to phenolic acids, flavonoids, procyanidins, and stilbenoids as resveratrol oligomers (degree of oligomerization 1–4). Using a partial least-square discriminant analysis approach, grape stem chemical profiles were discriminated according to their genotypic origin showing that polyphenol profile express a varietal signature. Furthermore, hierarchical clustering highlights various degree of polyphenol similarity between grape varieties that were in agreement with the genetic distance using clustering analyses of 22 microsatellite DNA markers. Metabolite correlation network suggested that several polyphenol subclasses were differently controlled. The present polyphenol metabotyping approach coupled to multivariate statistical analyses might assist grape selection programs to improve metabolites with both health-benefit potential and plant defense traits

Projet EcoViti Val de Loire-Centre : expérimentation de systèmes viticoles à faible usage d’intrants phytosanitaires en Val de Loire.

Le projet EcoViti Val de Loire a évalué trois systèmes de culture viticoles pendant 6 ans. Le premier système était basé sur la combinaison de pratiques déjà éprouvées au moment du lancement du projet, un second sur l’impact du mode de taille de la vigne sur la sensibilité aux maladies, et le dernier sur l’association de vigne et rosiers. Ces divers systèmes ont permis des réductions significatives d’IFT, avec parfois des revers, en termes de rendement notamment. Ils ont également mis en évidence la nécessité de prendre en compte la phase de transition dans les essais systèmes, et l’intérêt de mener les essais systèmes en culture pérenne dès la plantation. En effet, le temps de rééquilibrage d’une plante pérenne n’est pas à sous-estimer, et même une plante aussi plastique que la vigne met plusieurs années pour s’adapter à une modification de taille ou de mode d’entretien du sol.The EcoViti Val de Loire project evaluated various viticulture systems during 6 years. One system was based on a combination of already assessed practices (at the time of design), a second one on the impact of the pruning system on diseases susceptibility, and the last on the association of grapevine and roses. These systems led to significant TFI reductions, with sometimes some drawbacks in terms of yield. They also allowed to show the importance of the transition period in system experimentations, and the interest to lead these experimentations from the plantation for perennial crops. The time for the system to get back in balance is not to be underestimated, even a plant as plastic as grapevine takes several years ti adapt to a change in pruning or soil management

Semi-Targeted Metabolomics to Validate Biomarkers of Grape Downy Mildew Infection Under Field Conditions

International audienc

Perception et prise en compte des demandes de la société envers l’élevage de porcs par des responsables de groupements de producteurs

Perception and taking into account of societal demands regarding pig production by leaders of producer groups In a context of social questioning of pig production methods, four AGROCAMPUS-Ouest students conducted interviews with leaders of seven producer groups representing 70% of national pig production, and who were invited to answer two questions: i) How do economic actors perceive the questioning of pig production by society? ii) What actions are they taking to address them? The environment was cited by 10 of the 11 leaders interviewed as being society’s primary concern, before animal welfare; the third concern of society was the reduction in antibiotic use. Social representation of associations that support these claims is disputed. Faced with these demands, the profession highlights its compliance with regulations, developing innovations to reduce the environmental impact or the use of antibiotics, or to improve animal welfare. Communication is considered to be strategic. The questioning of intensive production is not considered, nor the expansion of differentiated products. A proactive and collective strategy to respond to societal demands is not mentioned, although this route has been selected in some other countries

Vineyard evaluation of stilbenoid‐rich grape cane extracts against downy mildew: a large‐scale study

International audienceBACKGROUND:Plasmopara viticola control in organic viticulture requires copper-based fungicides with harmful effects on health and the environment. Plant extracts represent a biorational eco-friendly alternative to copper. The aim of this study was to evaluate the potential of stilbenoid-rich grape cane extract (GCE) against downy mildew on three cultivars over 3 years following natural downy mildew infection.RESULTS:Over all field trials, GCE treatments showed an average reduction in disease incidence of -35% and -38% on leaves and clusters, respectively. The average reduction in disease severity was -35% and -43% on leaves and clusters, respectively. Under artificial downy mildew infection, GCE efficacy corresponded to 1 g L-1 of copper. Neither phytotoxicity nor adverse effects on auxiliary fauna were observed after treatment with GCE.CONCLUSION:Because few or no biocontrol agents are active alone against P. viticola, GCE is a promising alternative to copper-based fungicides. Grape canes, an abundant by-product of viticulture, have great potential for valorization as a biocontrol agent for sustainable viticulture

Composition and Tissue-Specific Distribution of Stilbenoids in Grape Canes Are Affected by Downy Mildew Pressure in the Vineyard

Grape canes are byproducts of viticulture containing valuable bioactive stilbenoids including monomers and oligomers of E-resveratrol. Although effective contents in stilbenoids are known to be highly variable, the determining factors influencing this composition remain poorly understood. As stilbenoids are locally induced defense compounds in response to phytopathogens, this study assessed the impact of downy mildew infection during the growing season on the stilbenoid composition of winter-harvested grape canes. The spatial distribution between pith, conducting tissues, and cortex of E-piceatannol, E-resveratrol, E-ε-viniferin, ampelopsin A, E-miyabenol C, Z/E-vitisin B, hopeaphenol, and isohopeaphenol in grape canes from infected vineyards was strongly altered. In conducting tissues, representing the main site of stilbenoid accumulation, E-ε-viniferin content was higher and E-resveratrol content was lower. These findings suppose that the health status in vineyards could modify the composition of stilbenoids in winter-harvested grape canes and subsequently the potential biological properties of the valuable extracts

Biosynthetic Origin of <i>E</i>-Resveratrol Accumulation in Grape Canes during Postharvest Storage

Grape canes are vineyard waste products containing valuable phytochemicals of medicine and agriculture interest. Grape canes storage is critical for the accumulation of these bioactive compounds. In the present study, we investigated the changes in stilbenoid phytochemical composition during grape cane storage and the influence of the temperature on final concentrations. A strong increase in the concentration of the monomer E-resveratrol (approximately 40-fold) was observed during the first 6 weeks of storage at 20 °C in eight different grape varieties without any change in oligomer concentrations. The E-resveratrol accumulation was temperature-dependent with an optimal range at 15-20 °C. A 2 h heat-shock treatment aiming at protein denaturation inhibited E-resveratrol accumulation. The constitutive expression of key genes involved in the stilbene precursor biosynthesis along with an induction of stilbene synthase (STS) expression during the first weeks of storage contribute to a de novo biosynthesis of E-resveratrol in pruned wood grapes

Terroir Influence on Polyphenol Metabolism from Grape Canes: A Spatial Metabolomic Study at Parcel Scale

International audienceThe composition of bioactive polyphenols from grape canes, an important viticultural byproduct, was shown to be varietal-dependent; however, the influence of soil-related terroir factors remains unexplored. Using spatial metabolomics and correlation-based networks, we investigated how continuous changes in soil features and topography may impact the polyphenol composition in grape canes. Soil properties, topography, and grape cane extracts were analyzed at georeferenced points over 3 consecutive years, followed by UPLC-DAD-MS-based metabolomic analysis targeting 42 metabolites. Principal component analyses on intra-vintage metabolomic data presented a good reproducibility in relation to geographic coordinates. A correlation-driven approach was used to explore the combined influence of soil and topographic variables on metabolomic responses. As a result, a metabolic cluster including flavonoids was correlated with elevation and curvature. Spatial metabolomics driven by correlation-based networks represents a powerful approach to spatialize field-omics data and may serve as new field-phenotyping tool in precision agriculture