77 research outputs found
High-throughput gene-expression quantification of grapevine defense responses in the field using microfluidic dynamic arrays
Background The fight against grapevine diseases due to biotrophic pathogens usually requires the massive use of chemical fungicides with harmful environmental effects. An alternative strategy could be the use of compounds able to stimulate plant immune responses which significantly limit the development of pathogens in laboratory conditions. However, the efficiency of this strategy in natura is still insufficient to be included in pest management programs. To understand and to improve the mode of action of plant defense stimulators in the field, it is essential to develop reliable tools that describe the resistance status of the plant upon treatment.[br/][br/]
Results We have developed a pioneering tool (âNeoViGen96â chip) based on a microfluidic dynamic array platform allowing the expression profiling of 85 defense-related grapevine genes in 90 cDNA preparations in a 4 h single run. Two defense inducers, benzothiadiazole (BTH) and fosetyl-aluminum (FOS), have been tested in natura using the âNeoViGen96â chip as well as their efficacy against downy mildew.[br/]
BTH-induced grapevine resistance is accompanied by the induction of PR protein genes (PR1, PR2 and PR3), genes coding key enzymes in the phenylpropanoid pathway (PAL and STS), a GST gene coding an enzyme involved in the redox status and an ACC gene involved in the ethylene pathway.[br/]
FOS, a phosphonate known to possess a toxic activity against pathogens and an inducing effect on defense genes provided a better grapevine protection than BTH. Its mode of action was probably strictly due to its fungicide effect at high concentrations because treatment did not induce significant change in the expression level of selected defense-related genes.[br/]
[br/]
Conclusions The NeoViGen96â chip assesses the effectiveness of plant defense inducers on grapevine in vineyard with an excellent reproducibility. A single run with this system (4 h and 1,500 âŹ), corresponds to 180 qPCR plates with conventional Q-PCR assays (Stragene system, 270 h and 9,000 âŹ) thus a throughput 60â70 times higher and 6 times cheaper. Grapevine responses after BTH elicitation in the vineyard were similar to those obtained in laboratory conditions, whereas our results suggest that the protective effect of FOS against downy mildew in the vineyard was only due to its fungicide activity since no activity on plant defense genes was observed. This tool provides better understanding of how the grapevine replies to elicitation in its natural environment and how the elicitor potential can be used to reduce chemical fungicide inputs
Reconstruction des identités professionnelles autour de la multi-fonctionnalité de l'agriculture. L'exemple des Coteaux du Lyonnais.
La reconnaissance de la multifonctionnalité de l'agriculture implique une remise en question du métier d'agriculteur, car elle modifie les finalités de la production ainsi que la nature des liens entre les agriculteurs et la société. L'article propose une analyse sociologique de la multifonctionnalité, au travers des représentations du métier. L'hypothÚse est que la construction de la multifonctionnalité est liée à la capacité des groupes à transformer leur systÚme de normes. Les auteurs proposent une typologie des représentations professionnelles autour de trois logiques : la premiÚre fait référence à une culture de métier, la deuxiÚme est tournée vers la rationalisation de la production et de la gestion et la troisiÚme se fonde sur des pratiques innovantes en lien avec le territoire. Puis, l'évolution des représentations est expliquée par le rÎle des réseaux professionnels. L'appartenance à un réseau professionnel dominant ou l'insertion dans des réseaux professionnels et sociaux plus diversifiés jouent sur la perception de la multifonctionnalité. Le développement de la multifonctionnalité ne résulte pas d'une réponse de l'agriculture à une demande plus ou moins explicite de la société, mais s'inscrit dans un processus d'innovation en lien avec le territoire et les demandes perçues par chaque agriculteur.Reconstruction of Professional Identities around the Multifunctionality of Agriculture. The Example of the "Coteaux du Lyonnais" Area The multifunctionality of agriculture leads to the questioning of the profession of farmer, in the way it modifies the aims of production and the nature of the link between farmers and society. This paper is focused on a sociological approach, based on the study of professional representations and behaviours. The hypothesis is that the development of multifunctionality is linked to the ability of groups to convert their system of norms. The authors propose a typology of professional representations based on three logics: the first one refers to professional culture; the second one to production rationalization and economic management; and the third one is based on innovation linked with territorial logics. The evolution of representations is therefore explained by the role of networks. The perception of multifunctionality is influenced by the insertion of farmers within a diversified professional and social network, in comparison with membership of dominating professional networks. The change in question does not result from an agricultural answer to a society demand (more or less clearly explained), but fits into an innovation process linked with territorial logics and the perceptions of each farmer
Clonal and plasmidic dissemination of critical antimicrobial resistance genes through clinically relevant ExPEC and APEC-like lineages (ST) in the dairy cattle population of Québec, Canada
Antimicrobial resistance can be effectively limited by improving the judicious use of antimicrobials in food production. However, its effect on the spread of AMR genes in animal populations is not well described. In the province of QuĂ©bec, Canada, a new legislation implemented in 2019 has led to an unprecedented reduction in the use of critical antimicrobials in dairy production. We aimed to investigate the potential link between ESBL/AmpC E. coli isolated before and after legislation and to determine the presence of plasmids carrying genes responsible for critical AMR. We collected fecal samples from calves, cows, and manure pit from 87 QuĂ©bec dairy farms approximately 2 years before and 2 years after the legislation came into effect. The whole genomes of 183 presumptive ESBL/AmpC E. coli isolated after cefotaxime enrichment were sequenced. Their phylogenetic characteristics (MLST, serogroup, cgMLST) and the presence of virulence and resistance genes and replicons were examined. A maximum likelihood phylogenetic tree was constructed based on single nucleotide polymorphism (SNPs). We identified 10 clonal lineages (same cgMLST) and 7 clones (SNPs †52). Isolates belonging to these clones could be found on different farms before and after the legislation, strongly suggesting a clonal spread of AMR genes in the population during this 4-year period. All isolates were multidrug resistant (MDR), with clone 2 being notable for the presence of macrolide, fluoroquinolone, and third-generation cephalosporin resistance genes. We also identified clinically relevant ExPEC (ST10) and APEC-like lineages (ST117, ST58, ST88) associated with the presence of ExPEC and APEC virulence genes, respectively. Our data also suggests the presence of one epidemic plasmid belonging to the IncY incompatibility group and carrying qnrs1 and blaCTXâMâ15. We demonstrated that AMR genes spread through farms and can persist over a 4-year period in the dairy cattle population through both plasmids and E. coli clones, despite the restriction of critical antimicrobial use. MDR ExPEC and APEC-like STs are present in the normal microbiota of cattle (more frequently in calves). These data increase our knowledge on gene dissemination dynamics and highlight the fact that biosecurity measures should be enhanced in this industry to limit such dissemination
CD133, CD15/SSEA-1, CD34 or side populations do not resume tumor-initiating properties of long-term cultured cancer stem cells from human malignant glio-neuronal tumors
<p>Abstract</p> <p>Background</p> <p>Tumor initiating cells (TICs) provide a new paradigm for developing original therapeutic strategies.</p> <p>Methods</p> <p>We screened for TICs in 47 human adult brain malignant tumors. Cells forming floating spheres in culture, and endowed with all of the features expected from tumor cells with stem-like properties were obtained from glioblastomas, medulloblastoma but not oligodendrogliomas.</p> <p>Results</p> <p>A long-term self-renewal capacity was particularly observed for cells of malignant glio-neuronal tumors (MGNTs). Cell sorting, karyotyping and proteomic analysis demonstrated cell stability throughout prolonged passages. Xenografts of fewer than 500 cells in Nude mouse brains induced a progressively growing tumor. CD133, CD15/LeX/Ssea-1, CD34 expressions, or exclusion of Hoechst dye occurred in subsets of cells forming spheres, but was not predictive of their capacity to form secondary spheres or tumors, or to resist high doses of temozolomide.</p> <p>Conclusions</p> <p>Our results further highlight the specificity of a subset of high-grade gliomas, MGNT. TICs derived from these tumors represent a new tool to screen for innovative therapies.</p
Transcriptomic analysis of milk somatic cells in mastitis resistant and susceptible sheep upon challenge with Staphylococcus epidermidis and Staphylococcus aureus
<p>Abstract</p> <p>Background</p> <p>The existence of a genetic basis for host responses to bacterial intramammary infections has been widely documented, but the underlying mechanisms and the genes are still largely unknown. Previously, two divergent lines of sheep selected for high/low milk somatic cell scores have been shown to be respectively susceptible and resistant to intramammary infections by <it>Staphylococcus spp</it>. Transcriptional profiling with an 15K ovine-specific microarray of the milk somatic cells of susceptible and resistant sheep infected successively by <it>S. epidermidis </it>and <it>S. aureus </it>was performed in order to enhance our understanding of the molecular and cellular events associated with mastitis resistance.</p> <p>Results</p> <p>The bacteriological titre was lower in the resistant than in the susceptible animals in the 48 hours following inoculation, although milk somatic cell concentration was similar. Gene expression was analysed in milk somatic cells, mainly represented by neutrophils, collected 12 hours post-challenge. A high number of differentially expressed genes between the two challenges indicated that more T cells are recruited upon inoculation by <it>S. aureus </it>than <it>S. epidermidis</it>. A total of 52 genes were significantly differentially expressed between the resistant and susceptible animals. Further Gene Ontology analysis indicated that differentially expressed genes were associated with immune and inflammatory responses, leukocyte adhesion, cell migration, and signal transduction. Close biological relationships could be established between most genes using gene network analysis. Furthermore, gene expression suggests that the cell turn-over, as a consequence of apoptosis/granulopoiesis, may be enhanced in the resistant line when compared to the susceptible line.</p> <p>Conclusions</p> <p>Gene profiling in resistant and susceptible lines has provided good candidates for mapping the biological pathways and genes underlying genetically determined resistance and susceptibility towards <it>Staphylococcus </it>infections, and opens new fields for further investigation.</p
Pineoblastoma segregates into molecular sub-groups with distinct clinico-pathologic features: a Rare Brain Tumor Consortium registry study
Pineoblastomas (PBs) are rare, aggressive pediatric brain tumors of the pineal gland with modest overall survival despite intensive therapy. We sought to define the clinical and molecular spectra of PB to inform new treatment approaches for this orphan cancer. Tumor, blood, and clinical data from 91 patients with PB or supratentorial primitive neuroectodermal tumor (sPNETs/CNS-PNETs), and 2 pineal parenchymal tumors of intermediate differentiation (PPTIDs) were collected from 29 centres in the Rare Brain Tumor Consortium. We used global DNA methylation profiling to define a core group of PB from 72/93 cases, which were delineated into five molecular sub-groups. Copy number, whole exome and targeted sequencing, and miRNA expression analyses were used to evaluate the clinico-pathologic significance of each sub-group. Tumors designated as group 1 and 2 almost exclusively exhibited deleterious homozygous loss-of-function alterations in miRNA biogenesis genes (DICER1, DROSHA, and DGCR8) in 62 and 100% of group 1 and 2 tumors, respectively. Recurrent alterations of the oncogenic MYC-miR-17/92-RB1 pathway were observed in the RB and MYC sub-group, respectively, characterized by RB1 loss with gain of miR-17/92, and recurrent gain or amplification of MYC. PB sub-groups exhibited distinct clinical features: group 1â3 arose in older children (median ages 5.2â14.0 years) and had intermediate to excellent survival (5-year OS of 68.0â100%), while Group RB and MYC PB patients were much younger (median age 1.3â1.4 years) with dismal survival (5-year OS 37.5% and 28.6%, respectively). We identified age
Extracorporeal Membrane Oxygenation for Severe Acute Respiratory Distress Syndrome associated with COVID-19: An Emulated Target Trial Analysis.
RATIONALE: Whether COVID patients may benefit from extracorporeal membrane oxygenation (ECMO) compared with conventional invasive mechanical ventilation (IMV) remains unknown. OBJECTIVES: To estimate the effect of ECMO on 90-Day mortality vs IMV only Methods: Among 4,244 critically ill adult patients with COVID-19 included in a multicenter cohort study, we emulated a target trial comparing the treatment strategies of initiating ECMO vs. no ECMO within 7 days of IMV in patients with severe acute respiratory distress syndrome (PaO2/FiO2 <80 or PaCO2 â„60 mmHg). We controlled for confounding using a multivariable Cox model based on predefined variables. MAIN RESULTS: 1,235 patients met the full eligibility criteria for the emulated trial, among whom 164 patients initiated ECMO. The ECMO strategy had a higher survival probability at Day-7 from the onset of eligibility criteria (87% vs 83%, risk difference: 4%, 95% CI 0;9%) which decreased during follow-up (survival at Day-90: 63% vs 65%, risk difference: -2%, 95% CI -10;5%). However, ECMO was associated with higher survival when performed in high-volume ECMO centers or in regions where a specific ECMO network organization was set up to handle high demand, and when initiated within the first 4 days of MV and in profoundly hypoxemic patients. CONCLUSIONS: In an emulated trial based on a nationwide COVID-19 cohort, we found differential survival over time of an ECMO compared with a no-ECMO strategy. However, ECMO was consistently associated with better outcomes when performed in high-volume centers and in regions with ECMO capacities specifically organized to handle high demand. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/)
Study of the effectiveness of different genotypes of Vitis vinifera defenses induced by elicitation face to the genetic diversity of pathogens (Plasmopara viticola and Erysiphe necator) : from gene to the field
La vigne est soumise Ă la pression de nombreux bioagresseurs dont des parasites obligatoires tels que lâoĂŻdium et le mildiou. La lutte contre les maladies causĂ©es par les pathogĂšnes biotrophes nĂ©cessite une utilisation souvent intensive de fongicides. Le vignoble consomme Ă lui seul 16% des fongicides commercialisĂ©s chaque annĂ©e en France. Pour rĂ©duire leur impact environnemental qui conduit Ă lâacquisition de la rĂ©sistance aux pesticides des pathogĂšne et la prĂ©sence de rĂ©sidus dans les vins et dans lâatmosphĂšre, des efforts doivent ĂȘtre entrepris pour dĂ©velopper des stratĂ©gies de protection innovante de remplacement ou complĂ©mentaire permettant de rĂ©duire les intrants pesticides.Les stimulateurs des dĂ©fenses des plantes permettent de limiter le dĂ©veloppement des bioagresseurs en conditions contrĂŽlĂ©es. Toutefois, leurs efficacitĂ©s in natura sont variables et souvent dĂ©cevantes. Suite au grand nombre de produits potentiellement stimulateurs des dĂ©fenses des plantes, et Ă lâintĂ©rĂȘt que leur portent les viticulteurs, il est nĂ©cessaire de disposer de connaissances et dâoutils qui permettent dâĂ©valuer leus efficacitĂ©s et mieux connaitre leurs potentiels de protection du vignoble. Pour ce faire, une mĂ©thode dâĂ©valuation de lâefficacitĂ© de produits potentialisateurs ou Ă©liciteurs a Ă©tĂ© dĂ©veloppĂ©e au niveau biologique, molĂ©culaire (expression de gĂšnes impliquĂ©s dans les dĂ©fenses) et biochimique (analyses qualitatives et quantitatives des polyphĂ©nols), nommĂ©e "BioMolChem". Cette mĂ©thode a permis dâĂ©valuer lâefficacitĂ© de deux phosphonates et dâun analogue de lâacide salicylique, sur diffĂ©rents gĂ©notypes et phĂ©notypes de mildiou de la vigne et dâoĂŻdium. Cette approche mĂ©thodologique "BioMolChem" a permis dâĂ©tablir des corrĂ©lations entre lâexpression de gĂšnes de dĂ©fense, la prĂ©sence de certains stilbĂšnes et une efficacitĂ© des dĂ©fenses de Vitis vinifera cv. Cabernet-Sauvignon vis-Ă -vis de lâoĂŻdium et du mildiou. Les modifications des patrons dâexpression des 19 gĂšnes suivis dans les feuilles de vigne et les profils HPLC de polyphĂ©nols rĂ©vĂšlent des mĂ©canismes de dĂ©fense multigĂ©niques et complexes. Ainsi, les rĂ©actions de dĂ©fense de la plante sont-elles modulĂ©es, en fonction de lâĂ©liciteur considĂ©rĂ©, mais aussi en fonction de la diversitĂ© phĂ©notypique et gĂ©nĂ©tique des agents pathogĂšnes contre lesquels elle se dĂ©fend. Ces dĂ©fenses se caractĂ©risent par une sur-expression dâun ensemble de gĂšnes de dĂ©fense et une accumulation de composĂ©s phĂ©noliques spĂ©cifiques.Les marqueurs (gĂšnes et molĂ©cules) ainsi identifiĂ©s, la mĂ©thode "BioMolChem" a Ă©tĂ© appliquĂ©e in natura et a confortĂ©, pour partie, les rĂ©sultats obtenus au laboratoire. Dans des conditions de fortes pressions parasitaires, il est donc possible de protĂ©ger les feuilles et les grappes, Ă lâaide de SDP et des essais dâassociation ou dâalternance avec des fongicides conventionnels montrent lâintĂ©rĂȘt potentiel de lâemploi des SDP au vignoble. Chemin faisant, dans le cadre dâune viticulture innovante et durable, les SDP et la mĂ©thode "BioMolChem" ont Ă©tĂ© appliquĂ©s sur des gĂ©notypes hybrides (Vitis vinifera x Muscadinia rotundifolia). Nous rĂ©vĂ©lons que selon le niveau de rĂ©sistance intrinsĂšque des gĂ©notypes (plus ou moins rĂ©sistants Ă lâoĂŻdium et au mildiou), il est possible dâaugmenter le niveau de la rĂ©sistance exprimĂ©e par Ă©licitation. Ainsi, les SDP pourraient-ils sâavĂ©rer des alliĂ©s dâintĂ©rĂȘt pour lâutilisation de variĂ©tĂ©s partiellement rĂ©sistantes et limiter potentiellement le contournement des QTL de rĂ©sistance. Lâensemble de ce travail, Ă but appliquĂ©, a conduit Ă lâobtention de rĂ©sultats qui nous permettent de mieux comprendre comment la vigne rĂ©agit aux SDP dans son environnement agronomique. Leur exploitation et leur finalisation devraient nous permettre dâexploiter et de mettre en place une utilisation des Ă©liciteurs mieux adaptĂ©e, Ă des stratĂ©gies alternatives ou complĂ©mentaires de la gestion des bioagresseurs de la vigne.Powdery (Erysiphe necator) and downy mildew (Plasmopara viticola) are very important grapevine diseases (Vitis vinifera). These two biotrophic pathogens, which are native to the United States, infect green vine tissues and cause significant economic loss as well as environmental damage through the repetitive applications of fungicides. To reduce their environmental impact efforts should be made to develop strategies to protect innovative alternative or complementary to reduce pesticide inputs.In this study, the efficacy and the role of Benzothiadiazole (BTH), a salicylic acid analogue, and two phosphonate derivatives strengthen plant defence mechanisms against various isolates of downy and powdery mildews (Plasmopara viticola and Erysiphe necator). These compounds showed differences in their efficacy depending on the variability of mildews and highly dependent on plant genetics, environmental conditions and selection pressure. The plant defense stimulation could be an alternative or additional method to traditional pest management in the grapevine.Tools âBioMolChemâ were developed to better assess the defence status of the plant defences in vitro and in natura. Transcript kinetics of selected defence-related genes and polyphenol contents profiles, during Vitis vinifera-biotrophic pathogen interaction, were characterized, and the impact of pathogen diversity was investigated in the absence or presence of elicitation. In vineyard, under strong pathogen pressures, it is thus possible to protect leaves and clusters, with SDP and assays of association or alternation with conventional fungicides show the potential interest of the use of these SDP in the vineyard.The grapevine defense mechanisms are complex, depending on the elicitor, leading to the coordinated accumulation of pathogenesis-related proteins (PR), the production of phytoalexins, and the reinforcement of plant cell walls.On the way, within the framework of an innovative and sustainable viticulture, the SDP was applied to hybrid genotypes (V. vinifera x M. rotundifolia). We reveal that according to the level of intrinsic resistance of the genotypes (more or less resistant to powdery and to downy mildew), it is possible to increase the level of the expressed resistance. The SDP could become allies of interest in the use of partially resistant grapevine varieties.The present findings provide insights into the potential use of transcripts and stilbenes as markers of the defense status of grapevine leaves with or without elicitation or infection, which should allow us to exploit and develop a better use of elicitors in alternative or complementary strategies in grapevine pest management
Study of the effectiveness of different genotypes of Vitis vinifera defenses induced by elicitation face to the genetic diversity of pathogens (Plasmopara viticola and Erysiphe necator) : from gene to the field
La vigne est soumise Ă la pression de nombreux bioagresseurs dont des parasites obligatoires tels que lâoĂŻdium et le mildiou. La lutte contre les maladies causĂ©es par les pathogĂšnes biotrophes nĂ©cessite une utilisation souvent intensive de fongicides. Le vignoble consomme Ă lui seul 16% des fongicides commercialisĂ©s chaque annĂ©e en France. Pour rĂ©duire leur impact environnemental qui conduit Ă lâacquisition de la rĂ©sistance aux pesticides des pathogĂšne et la prĂ©sence de rĂ©sidus dans les vins et dans lâatmosphĂšre, des efforts doivent ĂȘtre entrepris pour dĂ©velopper des stratĂ©gies de protection innovante de remplacement ou complĂ©mentaire permettant de rĂ©duire les intrants pesticides.Les stimulateurs des dĂ©fenses des plantes permettent de limiter le dĂ©veloppement des bioagresseurs en conditions contrĂŽlĂ©es. Toutefois, leurs efficacitĂ©s in natura sont variables et souvent dĂ©cevantes. Suite au grand nombre de produits potentiellement stimulateurs des dĂ©fenses des plantes, et Ă lâintĂ©rĂȘt que leur portent les viticulteurs, il est nĂ©cessaire de disposer de connaissances et dâoutils qui permettent dâĂ©valuer leus efficacitĂ©s et mieux connaitre leurs potentiels de protection du vignoble. Pour ce faire, une mĂ©thode dâĂ©valuation de lâefficacitĂ© de produits potentialisateurs ou Ă©liciteurs a Ă©tĂ© dĂ©veloppĂ©e au niveau biologique, molĂ©culaire (expression de gĂšnes impliquĂ©s dans les dĂ©fenses) et biochimique (analyses qualitatives et quantitatives des polyphĂ©nols), nommĂ©e "BioMolChem". Cette mĂ©thode a permis dâĂ©valuer lâefficacitĂ© de deux phosphonates et dâun analogue de lâacide salicylique, sur diffĂ©rents gĂ©notypes et phĂ©notypes de mildiou de la vigne et dâoĂŻdium. Cette approche mĂ©thodologique "BioMolChem" a permis dâĂ©tablir des corrĂ©lations entre lâexpression de gĂšnes de dĂ©fense, la prĂ©sence de certains stilbĂšnes et une efficacitĂ© des dĂ©fenses de Vitis vinifera cv. Cabernet-Sauvignon vis-Ă -vis de lâoĂŻdium et du mildiou. Les modifications des patrons dâexpression des 19 gĂšnes suivis dans les feuilles de vigne et les profils HPLC de polyphĂ©nols rĂ©vĂšlent des mĂ©canismes de dĂ©fense multigĂ©niques et complexes. Ainsi, les rĂ©actions de dĂ©fense de la plante sont-elles modulĂ©es, en fonction de lâĂ©liciteur considĂ©rĂ©, mais aussi en fonction de la diversitĂ© phĂ©notypique et gĂ©nĂ©tique des agents pathogĂšnes contre lesquels elle se dĂ©fend. Ces dĂ©fenses se caractĂ©risent par une sur-expression dâun ensemble de gĂšnes de dĂ©fense et une accumulation de composĂ©s phĂ©noliques spĂ©cifiques.Les marqueurs (gĂšnes et molĂ©cules) ainsi identifiĂ©s, la mĂ©thode "BioMolChem" a Ă©tĂ© appliquĂ©e in natura et a confortĂ©, pour partie, les rĂ©sultats obtenus au laboratoire. Dans des conditions de fortes pressions parasitaires, il est donc possible de protĂ©ger les feuilles et les grappes, Ă lâaide de SDP et des essais dâassociation ou dâalternance avec des fongicides conventionnels montrent lâintĂ©rĂȘt potentiel de lâemploi des SDP au vignoble. Chemin faisant, dans le cadre dâune viticulture innovante et durable, les SDP et la mĂ©thode "BioMolChem" ont Ă©tĂ© appliquĂ©s sur des gĂ©notypes hybrides (Vitis vinifera x Muscadinia rotundifolia). Nous rĂ©vĂ©lons que selon le niveau de rĂ©sistance intrinsĂšque des gĂ©notypes (plus ou moins rĂ©sistants Ă lâoĂŻdium et au mildiou), il est possible dâaugmenter le niveau de la rĂ©sistance exprimĂ©e par Ă©licitation. Ainsi, les SDP pourraient-ils sâavĂ©rer des alliĂ©s dâintĂ©rĂȘt pour lâutilisation de variĂ©tĂ©s partiellement rĂ©sistantes et limiter potentiellement le contournement des QTL de rĂ©sistance. Lâensemble de ce travail, Ă but appliquĂ©, a conduit Ă lâobtention de rĂ©sultats qui nous permettent de mieux comprendre comment la vigne rĂ©agit aux SDP dans son environnement agronomique. Leur exploitation et leur finalisation devraient nous permettre dâexploiter et de mettre en place une utilisation des Ă©liciteurs mieux adaptĂ©e, Ă des stratĂ©gies alternatives ou complĂ©mentaires de la gestion des bioagresseurs de la vigne.Powdery (Erysiphe necator) and downy mildew (Plasmopara viticola) are very important grapevine diseases (Vitis vinifera). These two biotrophic pathogens, which are native to the United States, infect green vine tissues and cause significant economic loss as well as environmental damage through the repetitive applications of fungicides. To reduce their environmental impact efforts should be made to develop strategies to protect innovative alternative or complementary to reduce pesticide inputs.In this study, the efficacy and the role of Benzothiadiazole (BTH), a salicylic acid analogue, and two phosphonate derivatives strengthen plant defence mechanisms against various isolates of downy and powdery mildews (Plasmopara viticola and Erysiphe necator). These compounds showed differences in their efficacy depending on the variability of mildews and highly dependent on plant genetics, environmental conditions and selection pressure. The plant defense stimulation could be an alternative or additional method to traditional pest management in the grapevine.Tools âBioMolChemâ were developed to better assess the defence status of the plant defences in vitro and in natura. Transcript kinetics of selected defence-related genes and polyphenol contents profiles, during Vitis vinifera-biotrophic pathogen interaction, were characterized, and the impact of pathogen diversity was investigated in the absence or presence of elicitation. In vineyard, under strong pathogen pressures, it is thus possible to protect leaves and clusters, with SDP and assays of association or alternation with conventional fungicides show the potential interest of the use of these SDP in the vineyard.The grapevine defense mechanisms are complex, depending on the elicitor, leading to the coordinated accumulation of pathogenesis-related proteins (PR), the production of phytoalexins, and the reinforcement of plant cell walls.On the way, within the framework of an innovative and sustainable viticulture, the SDP was applied to hybrid genotypes (V. vinifera x M. rotundifolia). We reveal that according to the level of intrinsic resistance of the genotypes (more or less resistant to powdery and to downy mildew), it is possible to increase the level of the expressed resistance. The SDP could become allies of interest in the use of partially resistant grapevine varieties.The present findings provide insights into the potential use of transcripts and stilbenes as markers of the defense status of grapevine leaves with or without elicitation or infection, which should allow us to exploit and develop a better use of elicitors in alternative or complementary strategies in grapevine pest management
Art et artisanat, figure double de la créativité
Dufour-El Maleh Marie-Cécile. Art et artisanat, figure double de la créativité. In: Horizons Maghrébins - Le droit à la mémoire, N°33-34, 1997. Itinérances. Art contemporain marocain. La question de la critique d'art. pp. 33-44
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