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Stimulation de la voie des phénylpropanoïdes par application de phénylalanine chez la fraise et la tomate pour le contrôle de Botrytis cinerea
No full textInternational audienceLa fraise (Fragaria × ananassa) et la tomate (Solanum lycopersicum) sont deux cultures économiquement importantes sensibles au champignon Botrytis cinerea, responsable de la pourriture grise au champ et sur les fruits lors du stockage post-récolte. Face aux enjeux environnementaux et sanitaires liés à l’usage des fongicides de synthèse, stimuler les défenses des plantes via la voie des phénylpropanoïdes apparaît comme une alternative prometteuse (Ramaroson et al., 2022). Cette voie métabolique débute par la conversion de la phénylalanine (Phe) en acide trans-cinnamique via l’enzyme phénylalanine ammonia-lyase (PAL). Les composés phénoliques produits, notamment les flavonoïdes, stilbènes ou acides phénoliques, contribuent à la résistance aux pathogènes via des fonctions antioxydantes, structurelles et de signalisation (Saini et al., 2024). Des travaux récents montrent que l’application exogène de Phe peut induire une résistance accrue des plantes à des infections fongiques. L’application préventive d’une solution de 4,1 mM de Phe confère une résistance à B. cinerea sur feuilles détachées de tomate (Oliva et al., 2020). Sur fraise, des pulvérisations de 10 mM en pré- ou post-récolte diminuent la sensibilité des fruits sans affecter leur qualité (Pons et al., 2025). L’effet de la Phe semble indirect, via l’induction de métabolites de défense par la plante (Oliva et al., 2020), et son efficacité accrue proche de la récolte pourrait s’expliquer par une métabolisation rapide de la Phe en composés actifs (Kumar Patel et al., 2020). L’étude vise à (1) explorer l’effet de différents paramètres sur l’efficacité de la protection induite par la pulvérisation de Phe contre B. cinerea (dose, moment d’application, génotype de la plante, souches de l’agent pathogène) sur fraise et tomate, (2) développer une compréhension fine de la métabolisation de la Phe dans ces conditions, et (3) évaluer l’impact de ce traitement sur la qualité et la conservation des fruits
Biopesticide Production from Trichoderma harzianum by Solid-State Fermentation: Impact of Drying Process on Spore Viability
No full textInternational audienceAmong the sustainable agricultural approaches, biological control agents are a promising new alternative to agrochemicals. However, expensive production methods, formulation, poor storage stability and short shelf life are limiting their adoption. One of the promising options for biopesticide production is solid-state fermentation (SSF). This study was conducted to evaluate spore production by two Trichoderma harzianum, Rey 3 and TF2, under forced air drying in SSF. A mixture of agroindustrial byproducts (sugarcane bagasse, vine shoots, wheat bran, potato flour and chitin) were used as substrates. CO 2 generated during fungi growth was recorded by respirometry. We also investigated the effect of hydric stress conditions on the decreasing phase of Trichoderma metabolism as an inducer of sporulation. In parallel, we analyzed the viability of T. harzianum TF2 and spores under different storage conditions (lyophilized, frozen and dried). Under the present culture conditions, the highest production of spores was 10.1 ± 0.3 × 10 9 spores/g DM (Dry Material) at 52 h for T. harzianum Rey 3 and 8.9 ± 0.6 × 10 9 spores/g DM at 72 h for T. harzianum TF2. The forced dry air during the fermentation process had no notable effect on spore production, but it did increase the spore viability (29% viability for T. harzianum Rey 3 and 33% viability for T. harzianum TF2). In parallel, the chitinase, cellulase, xylanase and lipase activities were evaluated, obtaining interesting results regarding enzymatic activities.</div
Contrasting emissions of biogenic volatile organic compounds from soil in a Mediterranean evergreen forest under natural and amplified long-term rain scarcity
No full textInternational audienceBackground and aimsBiogenic volatile organic compounds (BVOCs) play numerous ecological functions as they account for organism defenses and are drivers of organic matter decomposition, organism development and trophic interactions. BVOCs also act as precursors of secondary organic pollutants. Thus, studying their variability according to climate change is of crucial importance. This research aimed to assess the variability of BVOC emissions from natural forest soil under both natural drought (ND) and amplified drought (AD, ~ 30% rainfall exclusion over 9 years), as projected for the Mediterranean region by the end of the century.MethodsThe experiment took place in a representative and homogenous Mediterranean mixed forest (Pinus halepensis Mill. and Quercus ilex L.) using five different soil surfaces covered by litter under ND and AD conditions in July 2018. BVOCs were collected using a push–pull system, trapped within adsorbent cartridges and analyzed (quantitatively and qualitatively) by GC–MS.ResultsForest soil emissions released 184 µgC m−2 h−1 under ND but diminished by 84% under AD. Most monoterpenoids and oxygenated compounds were correlated with P. halepensis litter dry mass. Interestingly, sesquiterpenoids were positively corelated to Q. ilex litter while this litter does not possess terpene storage structures.ConclusionsThe future limited precipitation in the Mediterranean basin will result in the decline of forest soil BVOCs certainly implying a loss of both forest functionality and interaction with the atmosphere.Although litter biomass appeared as a driver of forest soil BVOCs, microorganisms and roots need to be further characterized to better understand their contribution to BVOC fluxes in natural forest soi
Kinetics of Lactic Acid, Acetic Acid and Ethanol Production During Submerged Cultivation of a Forest Litter-Based Biofertilizer
No full textInternational audienceFermented forest litter (FFL) is a biofertilizer obtained by anaerobic fermentation of forest litter combined with agricultural by-products. Its production involves an initial one-month solid-state fermentation of oak litter mixed with whey, molasses and wheat bran, followed by a one-week submerged fermentation-called the "activation" phase-during which the solid FFL is fermented with sugarcane molasses diluted in water. This study aimed to evaluate the effects storage duration (6, 18 and 30 months), and temperature (ambient and 29 • C) on the activation phase. For this purpose, pH, sugar consumption and metabolite production dynamics were monitored. Under all experimental conditions, the pH dropped to values close to 3.5, sucrose was rapidly hydrolyzed, and glucose was preferentially consumed over fructose. Fructose was metabolized only after glucose was depleted, suggesting the involvement of fructophilic microorganisms. The time-course evolution of lactic acid (LA) concentration was adequately fitted by the Gompertz model (R 2 > 0.970). The highest LA max concentration (6.30 g/L) and production rate (2.16 g/L•d) were obtained with FFL stored for 6 months. Acetic acid (AA) and ethanol were also detected reaching maxima values of 1.19 g/L and 0.96 g/L, respectively. Their profiles varied depending on the experimental conditions. Notably, the AA/LA ratio increased with the age of the FFL. Overall, sugar consumption and metabolite production were significantly slower at ambient temperature, than at 29 • C. These results contribute to a better understanding of the metabolic dynamics during FFL activation and highlight key parameters that should be considered to optimize future biofertilizer production processes
Classe flexible et formation initiale en master FLE :Effets sur les pratiques professionnelles et représentations des futurs enseignants
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Machine Learning for the Prediction of Size and Encapsulation Efficiency of mRNA-Loaded Lipid Nanoparticles Following a Postencapsulation Approach
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Growth and phosphorus uptake of micropropagated southern highbush blueberry plants inoculated with ericoid endophytic and mycorrhizal fungi in varied growth substrates
No full textInternational audiencePhosphorus (P) acquisition and use by southern highbush blueberry Vaccinium corymbosum L. plants is critical during early stages of development and impair root development, especially for growth substrates with poor nutrient contents. However, inoculation of blueberry plants with ericoid mycorrhizal fungi (ErMF) or dark septate endophytes (DSE) can improve P during the plants acclimation stages and reduce plant mortality, especially in dry northern Mediterranean climate conditions. Herein, we grew southern highbush blueberry micro-cuttings in conditions without inoculation (control) or in inoculated with four strains: two Ericoid mycorrhizal sp. (D01), and (C01), E. endophyte (C31), and Phialocephala fortinii Wang & Wilcox in sandy (S), fresh field (FF), and FF+S soil mix substrates for 10 months before harvest. At harvest, root colonization levels, plant height, leaf area, the fresh matter of roots and shoots, root-to-shoot ratio, P content, and P utilization efficiency (PUE) were measured. We found that the root colonization levels were inhibited in the S for the different inoculated F treatments, owing to the elevated carbonate and salt concentrations present. The average P uptake responses from the different F inoculated strains were 52.2 %, 29.6 %, and 22.4 % in the S, FF, and FF+S substrates. Inoculation of blueberry plants with C31 strain exhibited the highest (59.1 %) P uptake average response, inoculation with P. fortinii strain showed the lowest (15.8 %) response. The root growth responses were inhibited in the FF+S (-0.2 %), increased in the S (8.4 %), and FF (6.2 %) substrates. Our findings therefore describe responses under controlled nursery conditions with single-strain inoculation and three substrate types. Because blueberry roots in the field are commonly co-colonized by multiple ericoid and endophytic fungi, interactions among partners may amplify or dampen the effects observed here; future work should test coinoculation consortia and validate performance under field conditions.</div
Autonomic cardiac regulation to slow-paced respiration in seated and supine positions
No full textInternational audiencePurpose: Respiratory modulation and positional control are the main two regulators of cardiac autonomic activity. Although both slow-paced breathing and supine position promote parasympathetic regulation, their interaction remains poorly documented. Here, the objective of this work is to study the interaction between these two autonomic controls. Methods: Twenty healthy volunteers (12 males, 8 females), age of 25.9 ± 3.9 years were included in this study. They were randomly subjected to 6 different slow and controlled breathing at 4.5, 5, 5.5, 6, 6.5, and 7 min/cycles for 3 min in supine or seated position after a 3 min baseline recording in spontaneous breathing. ECG was continuously monitored and RR intervals (RRI), total power (Ptot), the standard deviation of normal R-R intervals (SDNN), high frequency power (HF), the root mean square of successive R-R interval differences (RMSSD), and low frequency power (LF) were calculated to study autonomic regulation. Results: We observed (1) a similar increase in parasympathetic (RMSSD and LF) and overall autonomic (RRI, Ptot, and SDNN) activities in slow-paced breathing conditions, whatever the respiratory rate in comparison with control spontaneous breathing; (2) these autonomic parameters increased in sitting position, but in parasympathetic (RMSSD and LF) and overall autonomic (Ptot, and SDNN) activities interacted with respiratory control and were higher in seated slow-paced breathing. Conclusion: These results showed that (1) whatever the slow-paced breathing frequency, slow breathing favours parasympathetic control and slow heart rhythm; and (2) seated position favors autonomic cardiovascular interaction between respiratory modulation and positional control
Decoding Tocopherol-Polyphenol interactions in oil-in-water emulsions through combined WIM-CAT and CV assays
No full textSource Agritrop Cirad (https://agritrop.cirad.fr/616786/) * Autres projets (id;sigle;titre): 101158035;PassIon;(EU) High Performance and Large-Scale Electrodes for Selective Ion Recovery//International audienceThe antioxidant interactions of α- and γ-tocopherol with curcumin and quercetin were assessed in an oil-in-water emulsion using the WIM-CAT assay, a method integrating Weibull interaction modeling with the conjugated autoxidizable triene technique. Synergistic effects were strongest for γ-tocopherol with curcumin and for α-tocopherol with quercetin, particularly at low tocopherol concentrations (0.2 μM in emulsion, 380 ppm in oil) and high molar ratios (3:1). Increasing tocopherol concentration to 0.6 μM in emulsion (1140 ppm in oil) reduced synergy, likely reflecting pro-oxidant activity. The presence of ferrous ions accelerated oxidation but did not influence synergistic interactions, while acidic conditions reduced tocopherol pro-oxidation and modified the effects of curcumin and quercetin. Weibull modeling revealed isoform-dependent differences during the propagation phase of oxidation. Cyclic voltammetry further suggested that the synergy of α-tocopherol may involve antioxidant regeneration mechanisms, whereas γ-tocopherol appears to act through alternative redox processes. Together, kinetic and electrochemical analyses provide complementary insights into the conditions governing antioxidant interactions
Conservacionismo, protesta ambiental y emergencia del ecologismo político en España, del Franquismo a la Democracia (Galicia, Aragón y Andalucía)
No full textInternational audienceThe aim of this article is to provide an approach to the history of environmentalism and to bring new perspectives to the study of Francoism and the Spanish transition by analyzing environmental conflicts on a regional scale. In response to the industrial, energy and urban planning policies of the regime, the main environmental conflicts of the period between 1960 and 1986 have proved to be a perfect historical laboratory for understanding in all their complexity the profound social and political transformations of the period. The methodology employed consists of consulting municipal, regional and national archives, press analyses and subsequently comparing our case studies (Galicia, Aragon and Andalusia). Through in-depth case studies of Aragon, Galicia and Andalusia, we observe the path from popular protest against environmental injustice to the subsequent formalization of an environmentalist political ideology in the 1980s. The article aims to highlight the links between popular environmentalism, social memory and processes of politicisation of the territory during the late Franco era and the TransitionEl objetivo de este artículo es dar un enfoque a la historia del ecologismo y aportar nuevas perspectivas al estudio del franquismo y la transición española, analizando los conflictos ambientales a escala regional. En respuesta a las políticas industriales, energéticas y urbanísticas del régimen, los principales conflictos ambientales del periodo compren-dido entre 1960 y 1986 se han revelado como un laboratorio histórico ideal para comprender en toda su complejidad las profundas transformaciones sociales y políticas del periodo. La metodología empleada consiste en la consulta de archivosmunicipales, regionales y nacionales, análisis de prensa y una posterior comparación en nuestros casos de estudio (Galicia, Aragón y Andalucía). A través de los estudios en profundidad de estos casos de Aragón, Galicia y Andalucía, analizamos el camino desde la protesta popular contra la injusticia ambiental hasta la posterior formalización de una ideología política ecologista en los años ochenta. El artículo pretende poner de relieve los vínculos entre ecologismo popular, memoria social y procesos de politización del territorio durante el tardofranquismo y la Transición