Dissertationen zum Thema „Phytoparasites“
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Fortuner, Renaud. „Variabilité et identification des espèces chez les nématodes du genre Helicotylenchus“. Lyon 1, 1986. http://www.theses.fr/1986LYO19023.
Der volle Inhalt der QuelleNotareschi-Leroy, Hélène. „Caractérisation d'éléments transposables de la super famille Tc1-mariner chez les nématodes phytoparasites du genre Meloidogyne“. Aix-Marseille 2, 2000. http://www.theses.fr/2000AIX22014.
Der volle Inhalt der QuelleAli, Nadine. „Communautés de nématodes phytoparasites associés à l'olivier : réponse aux forçages anthropiques et environnementaux“. Thesis, Montpellier, SupAgro, 2015. http://www.theses.fr/2015NSAM0015/document.
Der volle Inhalt der QuelleHuman activities increasingly frequent and persistent in ecosystems on one hand, and cropping system intensification on the other hand partly with radical methods to control pests and diseases of crops, raise questions about the ecological risks related to biotop changes, including disturbances of living organism communities. Plant-parasitic nematodes (PPN), microscopic round soil-borne worms that cause significant losses of crop production, are everywhere present in communities. They respond quickly to external forces (e.g. human and environmental) by changing the structure of their communities. In this thesis, we seek to better understand the effect of the factors involved in the assemblage of PPN species in communities associated with the Mediterranean olive tree and to determine the response of these communities to forces imposed by olive domestication, by crop intensification and by various environmental factors. The study was conducted in all olive-growing regions in Morocco (traditional low density and high density orchards), in refugia areas for wild olive (oleaster) and on feral olive trees. The soil and climatic factors that characterize the sampling sites were also considered. The analysis of the nematofauna revealed a wide species diversity, many species being described for the first time on olive tree, and a new species (Meloidogyne spartelensis) have been discovered. The diversity, the species / trophic / functional structure of the communities, the dominance of the taxa, and the community patterns are strongly affected by the various forces considered. The increasing anthropogenic gradient (wild vs feral vs traditional cultivation vs high-density cultivation) is the variable that mostly impacts the diversity by reducing the species richness and increasing the abundance of PPN. A particular attention was attributed in this study to the diversity of root-knot nematodes Meloidogyne, a major pest of the olive tree. It revealed that M. javanica is widespread in orchards and olive feral, while other species (M. arenaria, M. hapla and M. spartelensis) are confined in oleaster refuge areas. In order to analyse the genetic diversity, morphological and molecular markers have revealed a significant diversity between and within different Meloidogyne populations. These thesis studies confirm that both the diversity and the structure of the PPN communities could be relevant indicators to assess soil health in agro and ecosystems, by correlating diversity and pathogenicity of communities. They therefore emphasize the importance of parasite diversity as a main variable to consider for inspiring pest control strategies based on the concept of diversity resilience (even if it concerns parasites) for sustainable management of PPN communities and for environment preservation
Ali, Nadine. „Communautés de nématodes phytoparasites associés à l'olivier : réponse aux forçages anthropiques et environnementaux“. Electronic Thesis or Diss., Montpellier, SupAgro, 2015. http://www.theses.fr/2015NSAM0015.
Der volle Inhalt der QuelleHuman activities increasingly frequent and persistent in ecosystems on one hand, and cropping system intensification on the other hand partly with radical methods to control pests and diseases of crops, raise questions about the ecological risks related to biotop changes, including disturbances of living organism communities. Plant-parasitic nematodes (PPN), microscopic round soil-borne worms that cause significant losses of crop production, are everywhere present in communities. They respond quickly to external forces (e.g. human and environmental) by changing the structure of their communities. In this thesis, we seek to better understand the effect of the factors involved in the assemblage of PPN species in communities associated with the Mediterranean olive tree and to determine the response of these communities to forces imposed by olive domestication, by crop intensification and by various environmental factors. The study was conducted in all olive-growing regions in Morocco (traditional low density and high density orchards), in refugia areas for wild olive (oleaster) and on feral olive trees. The soil and climatic factors that characterize the sampling sites were also considered. The analysis of the nematofauna revealed a wide species diversity, many species being described for the first time on olive tree, and a new species (Meloidogyne spartelensis) have been discovered. The diversity, the species / trophic / functional structure of the communities, the dominance of the taxa, and the community patterns are strongly affected by the various forces considered. The increasing anthropogenic gradient (wild vs feral vs traditional cultivation vs high-density cultivation) is the variable that mostly impacts the diversity by reducing the species richness and increasing the abundance of PPN. A particular attention was attributed in this study to the diversity of root-knot nematodes Meloidogyne, a major pest of the olive tree. It revealed that M. javanica is widespread in orchards and olive feral, while other species (M. arenaria, M. hapla and M. spartelensis) are confined in oleaster refuge areas. In order to analyse the genetic diversity, morphological and molecular markers have revealed a significant diversity between and within different Meloidogyne populations. These thesis studies confirm that both the diversity and the structure of the PPN communities could be relevant indicators to assess soil health in agro and ecosystems, by correlating diversity and pathogenicity of communities. They therefore emphasize the importance of parasite diversity as a main variable to consider for inspiring pest control strategies based on the concept of diversity resilience (even if it concerns parasites) for sustainable management of PPN communities and for environment preservation
Lecouls, Anne-Claire. „Spectre d'activité et marquage moléculaire du gène Ma1 contrôlant la résistance aux nématodes Meloidogyne chez Prunier myrobolan“. Aix-Marseille 2, 2000. http://www.theses.fr/2000AIX22031.
Der volle Inhalt der QuelleFischer-Lesaux, Marion. „Etude de la biodiversité des bactéries symbiotiques des nématodes entomopathogènes, définition de nouvelles espèces, et mise en évidence d'une co-spéciation“. Montpellier 2, 1999. http://www.theses.fr/1999MON20042.
Der volle Inhalt der QuelleGautier, Camille. „Les exsudats radiculaires de plantes comme nouveaux produits de biocontrôle contre les nématodes phytoparasites“. Thesis, Rennes, Agrocampus Ouest, 2020. http://www.theses.fr/2020NSARC145.
Der volle Inhalt der QuelleCyst nematodes are among the most harmful pests of cultivated crops causing important economic losses. For cyst nematodes, the hatching is stimulated by root exudates released by the host plant. The removal of chemical nematicides requires development of alternative approaches to protect crops. For this purpose, root exudates may constitute an effective and innovative biocontrol method that could be used in the absence of the host plant to induce a “suicide hatching” of nematode and to control cyst nematodes’ pressure on crop. This work aimed to anticipate the effectiveness of the suicide hatching strategy, taking into account the influence of the genetic diversity of nematode populations and the microbial composition of soils. First, the level of dependence between root exudates from wildSolanum species and Globodera pallida populations for the hatching trait was evaluated and highlighted a strong effect of the geographical location of root exudates. Second, root exudates from different plant species were tested on the hatching of representative populations of the genetic diversity for three cyst nematodes. Significant differences were obtained among populations for a given nematode species but root exudates provided a high level of hatching of nematodes. Third, the impact of microbial communities of soil on the efficiency of root exudates to stimulate the hatching was measured. Significant differences of suicide hatching between different soils were obtained but the hatching rate remained high. These research efforts provide key elements for the development of root exud
Jourand, Philippe. „Les légumineuses du genre "Crotalaria" : symbiose fixatrice d'azote et activités biologiques contre les nématodes phytoparasites“. Montpellier 2, 2003. http://www.theses.fr/2003MON20127.
Der volle Inhalt der QuelleBelliardo, Carole. „Étude des transferts horizontaux de gènes chez les nématodes phytoparasites par l'exploitation de métagénomes du sol“. Electronic Thesis or Diss., Université Côte d'Azur, 2022. http://theses.univ-cotedazur.fr/2022COAZ6032.
Der volle Inhalt der QuellePlant-parasitic nematodes (PPN) are among the most important crop pests and threaten the world's food production. Besides the need to understand their biology to develop new control strategies, they are fascinating organisms in terms of genomic evolution. Plant parasitism has evolved several times independently in nematodes with some convergent evolutionary processes. For instance, all studied PPN have acquired bacterial and fungal genes by horizontal gene transfers (HGT). Some of the acquired genes are involved in essential parasitic functions like plant cell wall degradation or processing nutrients from the plant. However, several major questions concerning their origin, evolutionary fate and distribution in the genomes and timing of acquisition events remain unsolved. Most PPN live in soil; thus, we hypothesised that these genes originated from soil-dwelling microorganisms. However, the underrepresentation of soil microorganisms in generalist sequence libraries has previously limited HGT analyses.To circumvent this problem, we built a protein library including more than 6,800 soil metagenomes from the Joint Genome Institute's IMG/M server. The first challenge was to make this massive dataset more accurate and suitable for HGT analysis in PPN genomes. An important issue in metagenomic data is the underrepresentation of eukaryotes and their annotation with prokaryotic tools. To better represent the pool of genes present in the natural environments of PPN, we identified eukaryotic contigs and re-predicted proteins using Augustus, a eukaryotic dedicated gene predictor. Moreover, we reduced the protein sequence redundancy and refined the taxonomic assignment. After all these steps, we obtained an improved and non-redundant database that was more representative of the soil's natural biodiversity. This soil protein library, two times larger than the classic library, contains mainly organisms genetically divergent than lab-cultured.Then, we performed an HGT detection on proteins from 18 plant-parasitic nematode genomes of the Tylenchina clade, constituting a highly diverse group of PPN phenotypes, against our library enriched with soil protein. After manual curation, the proportion of genes acquired by horizontal transfers with phylogenetic confirmation is between 0.5 to 1.9% to protein-coding genes originating from HGT in PPN genomes. Those genes mainly originate from bacteria, but we also observed HGT from eukaryotic kingdoms such as fungi, protists and plants. The most represented taxa in donors are soil-dwelling species of clades Burkholderiaceae, Proteobacteria, Actinobacteria, Rhizobiales and Dikarya. The usage of metagenomic data clarified the history of previously described HGTs but also identified hundreds of new HGTs. Functional analyses of the newly identified HGTs indicate a wide diversity of potential functions whose biological implications can be more precisely described in in-vitro experiments. Integrating environmental data in our reference library has allowed us to extend the detection of HGTs and to complete the catalog of potential donor offspring
Vieira, Paulo. „Cell cycle maneuvering : a strategy taken by plant parasitic nematodes to induce specialized feeding sites in plant roots“. Nice, 2012. http://www.theses.fr/2012NICE4114.
Der volle Inhalt der QuelleAït, Hamza Mohamed. „Communautés de nématodes phytoparasites et de champignons nématophages en pépinières oléicoles au Maroc : caractérisation et gestion microbiologique“. Thesis, Montpellier, SupAgro, 2016. http://www.theses.fr/2016NSAM0021.
Der volle Inhalt der QuelleThe management of plant parasitic nematodes (PPN) is a major challenge for many agricultural operators. In Morocco, the development of an intensive agriculture in the " Morocco Green Plan" will necessarily induce the emergence of plant diseases, including nematodes. On olive tree, they imperil production in nurseries and in high-density orchards. On the other hand, nurseries are a major source of introduction of PPN in orchards by transplanting rooted plants. In this context, the study of the diversity of PPN communities was conducted in 25 olive nurseries located in the main olive producing areas in Morocco (Souss, Haouz, Guerouane, Jbala). A total of 305 soil samples were analyzed. The NPP detected belonged to the Hoplolaimidae (Helicotylenchus spp., Rotylenchus spp.), Telotylenchidae (Tylenchorhynchus spp.), Meloidogynidae (Meloidogyne spp.) and Tylenchidae (Trichotylenchus spp.) families. Although no symptom have been observed on roots, the mean abundance of these genera was very high (up to 56,640 individuals/dm3 of soil). Biochemical (PAGE) and molecular (SCARS) diagnosis was focused on root knot nematodes (Meloidogyne spp.), that are major pests of olive trees. It indicated a dominance of M. javanica (72%) on M. incognita (25.5%), while M. arenaria was detected in one nursery only. This study shows the necessity for nurse producers to provide a health guarantee seedlings through traceability of substrates.To control the development of PPN in nurseries and orchards after transplantation, microbiological control using nematophagous fungi (NF) proves a suitable alternative to nurseries (inoculation to substrates). Thus, 70 soil fungal strains were isolated, including a large diversity of Orbiliaceae with trapping organs (Arthrobotrys spp., Dreschlerella spp., Monacrosporium spp.) and of toxic Hypocreaceae (Trichoderma asperellum, T . harzianum, T. longibrachiatum, Talaromyces assiutensis). Egg-parasitic species such as Paecilomyces lilacinus (dominant) and Pochonia chlamydosporia were also present. Several endoparasitic species were also observed as Catenaria anguilullae, Nematoctunus leiosporus and Haptoglossa heterospora. In vitro predation tests revealed that T. assiutensis was able to kill 100% of the M. javanica juveniles. The Orbiliaceae strains killed 50 to 80% of the juveniles. Multivariate statistical analyses (PCA, co-inertia, K-tables) pointed out the main impact of climate variables (rainfall and minimum temperatures) and of the substrate origins (ecological habitats) on the diversity of both PPN and NF communities. Mineral amendments (NPK), organic matter, acidity (pH) and clayey substrates have less significant impacts. The varieties multiplied had no effect.Co-structure analyses between PPN and NF communities indicated significant correlations between Orbiliaceae and Meloidogyne spp., which confirms the interest of NF as biocontrol agents for the management of PPN.The experimental monitoring of growth and sporulation physiology of the NF strains exhibited high fitness for the Trichoderma species while the Orbiliaceae have low growth and sporulation.The studies commissioned as part of this thesis (i) confirm that the diversity of PPN communities may be relevant indicators to assess the health of substrates in olive nurseries for certification purposes, and (ii) offer future prospects for the development of microbiological management strategies of these parasites respectful of the environment
Aït, Hamza Mohamed. „Communautés de nématodes phytoparasites et de champignons nématophages en pépinières oléicoles au Maroc : caractérisation et gestion microbiologique“. Electronic Thesis or Diss., Montpellier, SupAgro, 2016. http://www.theses.fr/2016NSAM0021.
Der volle Inhalt der QuelleThe management of plant parasitic nematodes (PPN) is a major challenge for many agricultural operators. In Morocco, the development of an intensive agriculture in the " Morocco Green Plan" will necessarily induce the emergence of plant diseases, including nematodes. On olive tree, they imperil production in nurseries and in high-density orchards. On the other hand, nurseries are a major source of introduction of PPN in orchards by transplanting rooted plants. In this context, the study of the diversity of PPN communities was conducted in 25 olive nurseries located in the main olive producing areas in Morocco (Souss, Haouz, Guerouane, Jbala). A total of 305 soil samples were analyzed. The NPP detected belonged to the Hoplolaimidae (Helicotylenchus spp., Rotylenchus spp.), Telotylenchidae (Tylenchorhynchus spp.), Meloidogynidae (Meloidogyne spp.) and Tylenchidae (Trichotylenchus spp.) families. Although no symptom have been observed on roots, the mean abundance of these genera was very high (up to 56,640 individuals/dm3 of soil). Biochemical (PAGE) and molecular (SCARS) diagnosis was focused on root knot nematodes (Meloidogyne spp.), that are major pests of olive trees. It indicated a dominance of M. javanica (72%) on M. incognita (25.5%), while M. arenaria was detected in one nursery only. This study shows the necessity for nurse producers to provide a health guarantee seedlings through traceability of substrates.To control the development of PPN in nurseries and orchards after transplantation, microbiological control using nematophagous fungi (NF) proves a suitable alternative to nurseries (inoculation to substrates). Thus, 70 soil fungal strains were isolated, including a large diversity of Orbiliaceae with trapping organs (Arthrobotrys spp., Dreschlerella spp., Monacrosporium spp.) and of toxic Hypocreaceae (Trichoderma asperellum, T . harzianum, T. longibrachiatum, Talaromyces assiutensis). Egg-parasitic species such as Paecilomyces lilacinus (dominant) and Pochonia chlamydosporia were also present. Several endoparasitic species were also observed as Catenaria anguilullae, Nematoctunus leiosporus and Haptoglossa heterospora. In vitro predation tests revealed that T. assiutensis was able to kill 100% of the M. javanica juveniles. The Orbiliaceae strains killed 50 to 80% of the juveniles. Multivariate statistical analyses (PCA, co-inertia, K-tables) pointed out the main impact of climate variables (rainfall and minimum temperatures) and of the substrate origins (ecological habitats) on the diversity of both PPN and NF communities. Mineral amendments (NPK), organic matter, acidity (pH) and clayey substrates have less significant impacts. The varieties multiplied had no effect.Co-structure analyses between PPN and NF communities indicated significant correlations between Orbiliaceae and Meloidogyne spp., which confirms the interest of NF as biocontrol agents for the management of PPN.The experimental monitoring of growth and sporulation physiology of the NF strains exhibited high fitness for the Trichoderma species while the Orbiliaceae have low growth and sporulation.The studies commissioned as part of this thesis (i) confirm that the diversity of PPN communities may be relevant indicators to assess the health of substrates in olive nurseries for certification purposes, and (ii) offer future prospects for the development of microbiological management strategies of these parasites respectful of the environment
Quénéhervé, Patrick. „Étude de l'influence du système racinaire du bananier (sous-groupe Cavendish, cv. Poyo) et des facteurs de l'environnement sur les dynamiques de population de nématodes phytoparasites“. Paris 11, 1988. http://www.theses.fr/1988PA112225.
Der volle Inhalt der QuelleIn order to study the population dynamics of plants-parasitic nematodes associated with bananas (sub-group Cavendish), a new sampling method has been used in relation with the specific growth of the root system. Then, owing to the diversity of soil types in banana-growing areas in the Ivory Coast, multi-local experiments were set up. Faunistic study has allowed to list 21 differents species, in which four are prevalent: Radopholus similis, Helicotylenchus multicinctus, Hoplolaimus pararobustus and Cephalenchus emarginatus. Multivariate analysis of their distribution in relation with some soil variables has shown important differences in nematode trends; R. Similis, contrary to the others species, seems not too affected by these variables. On organic soil H. Multicinctus is predominant, whereas R. Similis remains the main endoparasitic species on mineral soil. Host-parasite relationship with respect to the main nematode species, and the vegetative way of banana propagation, leads to their dissemination through the cortex of the planting material. Study of the emergence of the nematodes from this planting material in hydrophonic culture has shown that, after planting, it is the inoculum brought by the corm, alone or in combination with the one from the soil, which infests rapidly the root system, because each root is produced free of nematodes. On mineral soil, population dynamic of R. Similis results from several factors such as, the phenology of the renovation of the roots, the rainfall and the competition with the others species. On organic soil, in favourable conditions of soil type for H. Multicinctus, rainfall appears as the only factor involved in the population dynamics, contrary to R. Similis for which competition with the other nematodes seems to be the prevalent factor. These results have allowed us to determine new strategies of nematode control in order to optimize the pest management
Neveu, Cédric. „Etude de la virulence du nématode à galles "Meloidogyne incognita" par une approche transcriptomique“. Montpellier 2, 2003. http://www.theses.fr/2003MON20108.
Der volle Inhalt der QuellePate, Emmanuelle. „Analyse spatio-temporelle des peuplements de nématodes du sol dans les systèmes de culture à jachères, au Sénégal“. Lyon 1, 1997. http://www.theses.fr/1997LYO10365.
Der volle Inhalt der QuelleDubreuil, Géraldine. „Analyse moléculaire et fonctionnelle des effecteurs du parasitisme des nématodes à galle Meloidogyne spp“. Nice, 2007. http://www.theses.fr/2007NICE4036.
Der volle Inhalt der QuelleLes nématodes à galle du genre Meloidogyne sont des vers microscopiques biotrophes, endoparasites obligatoires des racines. Lors de l’interaction compatible, la larve de second stade (L2) pénètre dans la racine, migre de façon intercellulaire, se sédentarise et initie la formation d’un site nourricier formé de 5 à 7 cellules géantes dans la zone du cylindre vasculaire. Les protéines des sécrétions des nématodes jouent un rôle majeur lors de l’interaction plante/nématode. Les sécrétions du stylet sont produites dans les glandes oesophagiennes et injectées dans la racine au cours du parasitisme. L’objectif de ce travail était d’abord d’identifier les fonctions biologiques impliquées dans l’adaptation du parasite à l’environnement de la plante et dans la modulation des défenses de la plante. Par une approche différentielle et une approche gène candidat, des protéines de fonction inconnue, des protéases, une protéine potentiellement sécrétée, une glutathion S-transférase (GST) et une péroxirédoxine (PRX) ont été identifiées. La GST, localisée dans les glandes œsophagiennes, est présente dans les sécrétions du stylet de L2 infestantes de M. Incognita. La PRX est localisée au niveau du pore excréteur des L2 et de l’hypoderme des stades sédentaires. Le rôle de ces deux protéines dans le processus parasitaire est discuté. L’analyse fonctionnelle de gènes du nématode est limitée par l’absence d’outils de transformation. L’efficacité transitoire de l’ARN interférence pour inhiber des gènes du parasitisme dans les L2 a été démontrée. Afin de garantir un « silencing » durable, la mise au point d’un nouvel outil sera développée dans une dernière partie
Medina, Clémence. „Caractérisation des petits ARN régulateurs impliqués dans la formation des cellules géantes induites par les nématodes phytoparasites du genre Meloidogyne“. Thesis, Université Côte d'Azur (ComUE), 2017. http://www.theses.fr/2017AZUR4046/document.
Der volle Inhalt der QuelleRoot-Knot-Nematodes are obligate plant parasites able to infect a large panel of cultivated plants. These parasites have the ability to induce redifferentiation of five to seven root cells into specialized giant cells, hypertrophied, multinucleated and metabolically overactive. These giant cells form the feeding site upon which nematodes feed continuously until reproduction. Giant cells development leads to a root deformation, named gall, which disturbs plant nutrients absorption causing its weakening. Transcriptomic studies showed that a huge transcriptional reprogramming occurs during gall development. This project aims to characterize the role of small RNAs, non-coding RNAs, during gall development induced by M. incognita. Small non-coding RNAs are key regulators of gene expression and include two major families: microRNAs (miRNAs) and small interfering RNAs (siRNAs). Thus, small RNAs from roots of the model plant Arabidopsis thaliana healthy or infected by M. incognita were characterized by Next Generation Sequencing at 7 and 14 days after infection, two important stages of gall development. This study led to the identification of 24 plant microRNAs differentially expressed in galls compared to uninfected roots. Functional analysis of these miRNAs validated the expression pattern in galls of five miRNAs and demonstrated the role of miR159 in the plant response to M. incognita. In addition, a genome-wide approach was used to identify genes that could be regulated by siRNAs during the interaction. In conclusion, this work contributed todemonstrate, on one hand, the involvement of microRNAs in the plant - RKN interaction and allowed the identification of genes potentially regulated by small interfering and involved in the formation of giant cells induced by root-knot nematodes
Medina, Clémence. „Caractérisation des petits ARN régulateurs impliqués dans la formation des cellules géantes induites par les nématodes phytoparasites du genre Meloidogyne“. Electronic Thesis or Diss., Université Côte d'Azur (ComUE), 2017. http://www.theses.fr/2017AZUR4046.
Der volle Inhalt der QuelleRoot-Knot-Nematodes are obligate plant parasites able to infect a large panel of cultivated plants. These parasites have the ability to induce redifferentiation of five to seven root cells into specialized giant cells, hypertrophied, multinucleated and metabolically overactive. These giant cells form the feeding site upon which nematodes feed continuously until reproduction. Giant cells development leads to a root deformation, named gall, which disturbs plant nutrients absorption causing its weakening. Transcriptomic studies showed that a huge transcriptional reprogramming occurs during gall development. This project aims to characterize the role of small RNAs, non-coding RNAs, during gall development induced by M. incognita. Small non-coding RNAs are key regulators of gene expression and include two major families: microRNAs (miRNAs) and small interfering RNAs (siRNAs). Thus, small RNAs from roots of the model plant Arabidopsis thaliana healthy or infected by M. incognita were characterized by Next Generation Sequencing at 7 and 14 days after infection, two important stages of gall development. This study led to the identification of 24 plant microRNAs differentially expressed in galls compared to uninfected roots. Functional analysis of these miRNAs validated the expression pattern in galls of five miRNAs and demonstrated the role of miR159 in the plant response to M. incognita. In addition, a genome-wide approach was used to identify genes that could be regulated by siRNAs during the interaction. In conclusion, this work contributed todemonstrate, on one hand, the involvement of microRNAs in the plant - RKN interaction and allowed the identification of genes potentially regulated by small interfering and involved in the formation of giant cells induced by root-knot nematodes
Rosso, Marie-Noëlle. „Synthèse et caractérisation d'anticorps simple-chaînes dirigés contre les sécrétions amphidiales et salivaires des nématodes phytoparasites Meloidogyne spp. Et Globodera spp“. Aix-Marseille 2, 1996. http://www.theses.fr/1996AIX22039.
Der volle Inhalt der QuellePIOTTE, CHRISTINE. „Organisation du genome chez les nematodes phytoparasites du genre meloidogyne : etude de la fraction repetee. utilisation en typage moleculaire et phylogenie“. Paris 6, 1993. http://www.theses.fr/1993PA066450.
Der volle Inhalt der QuelleSawadogo, Abdoussalam. „Contribution à l'étude de la nématofaune et de la mycoflore antagoniste dans les cultures maraîchères du Burkina Faso“. Montpellier 2, 1990. http://www.theses.fr/1990MON20125.
Der volle Inhalt der QuelleGarcia, Nathan. „Analyse exploratoire des variables structurant la capacité des communautés de nématodes phytoparasites à limiter l’implantation du nématode d e quarantaine Meloidogyne chitwoodi“. Thesis, Rennes, Agrocampus Ouest, 2017. http://www.theses.fr/2017NSARC132/document.
Der volle Inhalt der QuellePlant-parasitic nematodes (PPN) are microscopic worms that occur in communities in almost every agricultural soils. Commonly found PPN are usually harmless for the plants. However, M. chitwoodi, a PPN highly regulated in EU can induce important yield losses. In order to improve risk assessment of M. chitwoodi implantation, we studied French native PPN communities to identify those that can limit its establishment shortly after an introduction. We firstly described PPN communities in various agrosystems, at a landscape scale and then in nine French regions. Despite the quite homogeneous species richness observed across the fields sampled, we highlighted strong PPN taxa abundance variations. Environmental variables seemed to mainly drive the PPN communities structure at a large geographic scale but cultural practices(tillage and pesticides uses) seemed to explain the communities variation at the local scale. Secondly, we studied the capacity of different PPN communities to limit M. chitwoodi development through competition. It appeared that PPN communities with high global abundance, regardless of the taxa present, are able to decrease M. chitwoodi multiplication. The results of this PhD thesis bring some elements about the structure and functioning of PPN communities in French fields and their ability to reduce the M. chitwoodi establishment in order to predict its implantation risk
Berry, Shaun David. „Diversité et dynamique des communautés de nématodes phytoparasites en culture de canne à sucre en Afrique du Sud : répercussion sur la plante“. Montpellier 2, 2006. http://www.theses.fr/2006MON20221.
Der volle Inhalt der QuelleA study of the diversity of the species of nematodes associated with sugarcane showed that five species or genera are dominant: Helicotylenchus dihystera, Meloidogyne javanica, Pratylenchus zeae, Paratrichodorus spp. And Xiphinema spp. . The relative proportions of the species constituting the community determine the extent of damage to the crop. In pots, inoculation with Helicotylenchus dihystera resulted in an increase in the aboveground biomass of the cane. In a field trial, the reproduction of cultural practices as used in Burkina Faso was accompanied with an increase in the relative proportion of Helicotylenchus dihystera and a decrease in the proportion of Xiphinema elongatum. But the associated increase in yield was not significant. Mimicking the cultural techniques employed in Australia also led to a slight increase in yield but this was not as a result of the change in nematode communities. For studying diverse communities, newer molecular biological methods were employed. Significant differences in the amount of nucleic acid extracted from different species were found. Using differences in ITS1 amplification product size for identifying and discriminating between species was successful to a point, however only as a crude diagnostic method. Examining the genetic diversity of this gene region within sugarcane nematode specimens enabled phylogenetic relationships between species, and genera, to be investigated. Differences in nucleotide composition could be utilized to develop species-specific diagnostic primers for use in conventional and real-time, quantitative PCR testing
Tabarant, Perrine. „Effet d'apport de matières organiques sur le contrôle biologique des nématodes parasites du bananier en Guadeloupe“. Phd thesis, AgroParisTech, 2011. http://pastel.archives-ouvertes.fr/pastel-01002831.
Der volle Inhalt der QuelleTixier, Philippe. „Conception assistée par modèle de systèmes de culture durables : application aux systèmes bananiers de Guadeloupe“. Montpellier, ENSA, 2004. http://www.theses.fr/2004ENSA0019.
Der volle Inhalt der QuelleGuadeloupe banana cropping systems are threatened by agronomic (low yield due to phytoparasitic nematode development), environmental (pesticide leaching to water, particularly important in a fragile insular setting) and economic (seasonal variations in fruit prices, manpower costs) unsustainability. New systems have to be designed to solve both economic and environmental problems. Rotations with other crops or fallows, biodiversity restoration, pesticide management are some current investigated solutions. Modelling tools have been developed to combine practices, explore and optimise such systems. Banana cropping systems have some characteristics that cannot be taken into account by generic crop models; a specific model called SIMBA has been developed. The evolution of the banana population structure over time is a key point; it is simulated by SIMBA-POP, a cohort population model. Parasitism dynamics mainly due to phytoparasitic nematodes lower cropping sustainability and lead to massive use of pesticides; this is simulated by the dynamic SIMBA-NEM module. SIMBA also simulates plant growth, the soil cover and structure or water balance. Cropping practices are taken into account by decision rules that give rise to realistic technical recommendations. Qualitative, integrated and dynamic indicators are linked to biophysical modules and allow evaluation of the pesticide leaching risk, erosion risk and soil fertility. SIMBA provides agronomic (yield), environmental and economic (profit margin) outputs for multicriteria evaluation of the simulated system based on different viewpoints. An original 2-step method has been used to prototype new cropping systems with SIMBA (first a global exploration then a specific optimisation). Some interesting cropping systems have thus been highlighted and should be tested in the field. This scientific approach permits to develop some significant progress in the banana modelling by aggregating the existing knowledge and highlight the missing ones
Quénéhervé, Patrick. „Etude de l'influence du système racinaire du bananier, sous-groupe Cavendish, CV. Poyo, et des facteurs de l'environnement sur les dynamiques de population de nématodes phytoparasites“. Grenoble 2 : ANRT, 1988. http://catalogue.bnf.fr/ark:/12148/cb376176912.
Der volle Inhalt der QuelleFould, Sabine. „Détection dans le sol de Pasteuria penetrans, parasite obligatoire des nématodes phytoparasites du genre Meloidogyne et influence des facteurs telluriques abiotiques sur la distribution du complexe parasitaire“. Lyon 1, 1999. http://www.theses.fr/1999LYO10333.
Der volle Inhalt der QuelleBerthold, François. „Grapevine fanleaf virus replication : viral proteins and host factors“. Strasbourg, 2015. http://www.theses.fr/2015STRAJ086.
Der volle Inhalt der QuelleMateille, Thierry. „Contribution a l'etude des relations hote-parasite entre le bananier musa sp. (sous-groupe cavendish aaa) et trois nematodes phytoparasites : radopholus similis, helicotylenchus multicinctus et hoplolaimus pararobustus (tylenchida)“. Paris 11, 1990. http://www.theses.fr/1990PA112296.
Der volle Inhalt der QuelleNoir, Sandra. „Diversité des gènes de résistance au sein du génome des caféiers (Coffea L. ). Analyse génétique de la résistance au nématode à galles, Meloidogyne exigua, chez C. Arabica“. Montpellier 2, 2002. http://www.theses.fr/2002MON20184.
Der volle Inhalt der QuelleChabrier, Christian. „Survie et dissémination du nématode Radopholus similis (Cobb) Thorne dans les sols bruns-rouilles à halloysites (nitisols) : Effets de l'état hydrique et des flux hydriques“. Phd thesis, Antilles-Guyane, 2008. http://www.theses.fr/2008AGUY0218.
Der volle Inhalt der QuelleThe burrowing nematode Radopholus similis is a major pest of bananas and plantains all over the world. . Recent development of new cropping systems reduced its impact; but additional knowledge is required to understand its persistence in soil and to prevent its dispersal. The capacity of survival of R. Similis in soils was evaluated. We recovered after six months from 1. 7 to 9. 3 % of the initial population in the nitisol and from 9. 5 to 11. 9 % in the andosol. Considering the adults, the decreasing curves of R. Similis populations could generally be adjusted either with an exponential model or with a Teissier’s model. We studied the dispersion of R. Similis by water flows; on soil surface with rainfall simulators and along soil depth with soil cylinders. These studies were completed by a field trial. The passive dissemination seems very weak inside the soil and affects only a marginal fraction of the populations. It seems that R. Similis resorts to a behaviour of fleeing from leaching to resist water flows. On soil surface, this phenomenon is restricted to “disaster” events at the scale of the nematode: destruction of its environment by tropical showers with heavy runoff. Actually, R. Similis leaching by runoff water is sufficient to contaminate a banana plot in less than two years. All these studies showed that the behaviour of R. Similis is an essential knowledge to understand its survival and dispersal. Its biology allows good adaptation to the long-lasting cultures with vegetative reproduction, such as banana plants
Chabrier, Christian. „Survie et dissémination du nématode Radopholus similis (Cobb) Thorne dans les sols bruns-rouilles à halloysites (nitisols) : effets de l'état hydrique et des flux hydriques“. Phd thesis, Université des Antilles-Guyane, 2008. http://tel.archives-ouvertes.fr/tel-00697213.
Der volle Inhalt der QuelleProt, Jean-Claude. „Contribution à l'étude des migrations dans le sol des juvéniles de second stade des nématodes du genre Méloidogyne“. Paris 11, 1986. http://www.theses.fr/1986PA112263.
Der volle Inhalt der QuelleSecond stage juveniles of Meloidogyne ore capable of moving at least 50 cm and penetrating host roots within 7 days. Vertical migrations are faster and greater than horizontal migrations. Juveniles of Meloidogyne javanica are attracted towards host plant roots. Soil and agar from tomato plant culture, germinatlng tomato seeds and root culture attract juveniles of M. Javanica. In addition, movement of juveniles is more important in soils which have supported plant growth. Soil texture influences the migration of Meloidogyne incognito. In natural soils the percentage of juveniles migrating 20 cm decreases when the percentage of clay and silt increases ; no migration is observed when the soil contains more than 30% clay plus silt. However, the clay particles appear to have a function in attracting nematodes over large distances. No migration occures in pure silica sand ; when 5 or 10% of clay are mixed to silica sand 34 and 26%, respectively of the juveniles are able to migrate 20 cm. Temperature influences migrations. The migrations of M. Incognito begin at about 18°C and reache a maximum at 22°C. Juveniles of Meloidogyne hapla have the ability to migrate at lower temperatures than M. Incognita juveniles. Mineral salts exhibit a repulsive effect on Meloidogyne juveniles. Placed in a gradient of mineral salts, these juveniles move preferentiolly towords the region having the lower salt concentration. These nematodes possess sense argons which allow them to orient their movements over gradients of salts created in agar by salt solutions at 0,26 and 10 x 10⁻²M/1. A method of control of Meloidogyne using chemicals which stop their migration is possible. Polycyclic lactones extracted from Hannoa undulata and Hannoa klaineana prevent invasion of tomato roots by stopping movement of javanica juveniles when they are in concentration of 5 ppm in the soil water
TIXIER, Philippe. „Conception assistée par modèle de systèmes de culture durables : Application aux systèmes bananiers de Guadeloupe“. Phd thesis, Ecole nationale superieure agronomique de montpellier - AGRO M, 2004. http://tel.archives-ouvertes.fr/tel-00010937.
Der volle Inhalt der QuelleL'évaluation et la conception de tels systèmes de culture innovants nécessitent l'utilisation d'outils de modélisation spécifiques qui rendent compte des caractéristiques particulières du système. Un modèle spécifique appelé SIMBA à été développé dans ce sens. SIMBA simule l'évolution de la structure du peuplement de bananiers au cours des cycles de culture, point clé qui conditionne l'ensemble de la dynamique du système. La composante parasitaire, qui influe sur la pérennité de la bananeraie et conditionne l'emploi des produits phytosanitaires est également prise en compte. Le parasitisme des nématodes phytoparasites est simulé, en interaction avec la croissance et la structure du peuplement, l'état du sol et l'emploi de nématicides. SIMBA simule également la croissance des bananiers et leur productivité, la structure du sol, la couverture du sol et le bilan hydrique. Des indicateurs qualitatifs et intégrateurs, conçus spécifiquement, permettent, couplés à ces modules biophysiques, l'évaluation au cours du temps de risques environnementaux comme le risque de pollution des eaux par les produits phytosanitaires et le risque d'érosion. Les pratiques culturales sont prises en compte à travers des règles de décision qu'il est ainsi possible d'évaluer. Le modèle SIMBA, en fournissant des sorties agronomiques, environnementales et économiques (marge brute), permet ainsi l'évaluation multicritère de systèmes de culture simulés selon plusieurs points de vue.
SIMBA a ensuite été utilisé selon une méthode originale de prototypage en deux étapes (exploration globale puis optimisation spécifique). Les résultats obtenus ont permis d'identifier certains systèmes de culture qu'il conviendra de tester ‘au champ'. Cette approche systémique et fonctionnelle, qui a permis des avancées significatives au niveau de la modélisation des systèmes bananiers, constitue un outil performant pour la conception de systèmes de culture durables.
Mukhaimar, Maisara. „Sources naturelles de la résistance contre les nématodes à galles Meloidogyne javanica chez la plante modèle Arabidopsis thaliana“. Thesis, Paris 11, 2015. http://www.theses.fr/2015PA112033/document.
Der volle Inhalt der QuellePlant-parasitic nematodes are a serious threat for global food production. They are responsible for 14% of global yield loss, equivalent to an economic value of more than 100 billion US$ per year. Pest management is challenging, in particular since the most efficient nematicide has been banned due to its devastating effect on the environment. Hence, novel sources for nematode management are urgently required. This work investigates whether the model plant Arabidopsis thaliana could serve as a natural source for resistance genes against plant-parasitic nematodes. It finds natural genetic variation among Arabidopsis accessions for resistance against the root-knot nematode Meloidogyne javanica, identifies several QTL for nematode resistance, and fine-maps one of these resistance QTL
Nilusmas, Samuel. „Gestion durable des nématodes à galles en culture maraîchère par la modélisation et l’optimisation du déploiement de variétés résistantes“. Thesis, Université Côte d'Azur, 2020. http://www.theses.fr/2020COAZ4086.
Der volle Inhalt der QuelleRoot-knot nematodes are obligate soil-borne endoparasites of plant roots that cause major yield losses throughout the world. Environmentally-friendly plant protection methods against root-knot nematodes are mainly based on the use of resistant plant cultivars. These cultivars efficiently control nematode populations naturally present in the field, but they favour the emergence of virulent variants that circumvent the resistance genes carried by these cultivars. Since virulence is associated with fitness costs, which limit the virulent nematode ability to infest plant roots or reproduce, susceptible crops counter-select virulent nematodes. The aim of this thesis is to identify effective and sustainable resistance deployment strategies to control root-knot nematodes in horticultural crops. To this end, we developed a semi-discrete epidemiological model describing the nematode dynamics in the soil and in the roots of a resistant or susceptible plant during its growing season, as well as the survival of nematodes in the soil between cropping seasons. The model was fitted to experimental data of within-season infestation of susceptible tomato roots. It was used to determine the rotation strategies alternating susceptible and resistant plants that maximise an average yield proxy, over different time horizons and for different combinations of epidemiological intensity and genetic parameters (mutation rate and virulence costs). Moreover, sensitivity analyses were performed to assess the robustness of the plant resistance deployment strategies. Our results show that carefully designed rotation strategies would not only increase crop yield, but also preserve the sustainability of resistance genes. Sensitivity analyses were performed to evaluate the robustness of our results. This thesis opens both experimental and modelling perspectives for a better control of root-knot nematodes
Cabral, do Nascimento Danila. „La biogenèse des galles induites par des phyto-nématodes dépend de l'hyperactivation du cycle cellulaire : études fonctionnelles des nouveaux acteurs du cycle mitotique et de l'endocycle dans les cellules géantes“. Electronic Thesis or Diss., Université Côte d'Azur (ComUE), 2019. http://theses.univ-cotedazur.fr/2019AZUR6001.
Der volle Inhalt der QuelleDuring the last twenty years, Arabidopsis thaliana has been successfully used as a model plant accelerating discoveries at the molecular and cellular level in numerous plant-pathogen interactions. Arabidopsis is susceptible to a number of pathogens including nematodes, responding to pathogen attack in a similar manner to cultivated plant species. Meloidogyne incognita is a crop parasite causing extensive economic losses of billions of dollars yearly for the agriculture worldwide. Root-knot nematodes induce feeding sites within the host root inducing up to eight giant-feeding cells within the root vascular cylinder by injecting secretions. These giant cells become hypertrophied and contain multiple enlarged nuclei as a result of numerous mitotic events of which cytokinesis is absent or interrupted. Throughout expansion, giant cells become highly polyploid via successive endoreduplication cycles. Thus, a crucial feature for root-knot nematode development is the hyperactivation of the plant host cell cycle in galls. The eukaryotic cell cycle is conserved and characterized by four phases: The S phase (DNA replication) is followed by the M phase (mitosis), cytokinesis and cell division. These are intercalated by the G1 phase (first gap) which connects the end of mitosis to the start of DNA synthesis, and the G2 phase (second gap) which connects the end of DNA synthesis to the start of mitosis. The endocycle is a variant of the cell cycle in which replication occurs without mitosis, resulting in a doubling of cellular DNA content for each endocycle round. The hyperactivation of the cell cycle is essential for the nematode-induced gall biogenesis, and a precise balance between mitotic and endocycle phases is essential for the successful compatible interaction. As a broad question of my PhD, we addressed which the pre-requisites are needed to establish a functional gall induced by root-knot nematodes. More specifically, I essentially focused on the functional studies of particular plant cell cycle genes playing a role in the mitotic and the endocycle during plant-root-knot nematode interaction. To address this question, functional studies of new players in the cell cycle of the plant host, stimulating (E2F genes), inhibiting (ABAP1 and an interactor AIP10 genes) or controlling (WEE1 gene) the cell cycle, were investigated in galls induced in our model host Arabidopsis thaliana. The results obtained demonstrate that the genes here studied are critical for, as well the formation as the maintenance of nematode feeding sites. Overall, our functional study and molecular analysis show that the absence of E2Fa and E2Fb transcription factors will severely affect gall development and nematode reproduction. As well, overexpression of E2Fa and E2Fb will disrupt the cell cycle in galls, validating their importance for nematode feeding site development. We further investigated if nematode induced stress might trigger a checkpoint control during cell cycle progression in galls. Therefore, functional analysis of the WEE1 transcription factor was performed and showed that its absence induced galls prematurely to enter mitosis, thus affecting feeding site development and nematode reproduction. Performing drug treatments and the use of the stress marker SMR7 and a DNA repair promoter reporter line PARP1 suggested the induction of checkpoint activation in galls at G1/S phase of the cell cycle. The data presented in this thesis provided fundamental knowledge for a better understanding of cell cycle control during gall biogenesis as well sideways for plant development. Currently, our results are being managed for application initially in Arabidopsis, and promising strategies will be conducted and extended towards different crop species in order to better control nematode attack. Here, we specifically aimed at generating genetically modified plants by silencing E2Fa genes as an anti-nematode strategy in the field
Deloné, Brunise. „Alternatives agro-écologiques à l’usage d’intrants chimiques dans les bananeraies plantains : Le cas de deux régions de la Caraïbe : Guadeloupe et Haïti“. Thesis, Antilles-Guyane, 2014. http://www.theses.fr/2014AGUY0758/document.
Der volle Inhalt der QuellePlantain (Musa paradisiaca) is the staple food of millions of people worldwide and its cropping generates ongoing revenues for many farmers who are planting small or medium size areas. As in other tropical regions, plantain cultivation in Guadeloupe and Haiti is under heavy parasitic constraints terrestrial (plant-parasitic nematodes and banana weevil) as well as aerial (black Sigatoka in particular). Conventional means of control based on the use of synthetic products which adverse effects on the environment (soil, water, animals ...) as on human health are not bearable any more. It is thus urgent to think about agroecological solutions allowing to restore the biological balances, to maintain good soil quality and optimal plantain cropping systems.This is the ultimate goal of this thesis which couples the realization of an agroecological diagnosis in peasants’ plots, and the test of agroecological alternatives in semi-controlled conditions. To do this, a typology of plantain cropping systems was carried out from an agrienvironmental survey in the two study areas. It allowed to select 23 plots in Guadeloupe and 12 in Haiti in which an agroecological diagnosis was implemented. Based on this diagnosis and the research of agroecological alternatives to the use of chemicals, a field experiment was set up in Guadeloupe, in an experimental station allowing the test of three innovative practices for plantain cultivation (alone and combined), namely : i) the introduction of a cover-crop Paspalum notatum for weed control while reducing the use of herbicides ; ii) the input of worms’ compost to control plant-parasitic nematodes specific to plantain and to fertilize it ; iii) the use of healthy “PIF” plants (plants issued from stem fragments) free from telluric pests (nematodes and weevil’s larvaes).The typology of plantains cropping systems shows: i) in Guadeloupe the previous crops are: fallow pineapple and plantain predominate with a low level of intensification (low and infrequent chemical inputs) or high (high and frequent chemical inputs); ii) in Haiti, the previous crops are: fallow, plantain and cassava predominate with a low level or no intensification at all (no inputs). The results of the agroecological analysis show that : i) when the level of intensification is low, perennial plantain and pineapple as previous crops help maintaining a good soil quality and a good regulation of the telluric pests ; ii) when the level of intensification is strong, the soil engineers drastically reduce, while the density of telluric parasites increases without affecting good levels of instantaneous yields (plots where the previous crop is pineapple or mostly fallow) ; iii) when the fertilization is totally missing, it decreases the biological activity of the soil furthermore the plantain yields, exacerbated by the choice of the previous crop (cassava or plantain), in connection with soils and climate constraints and the black Sigatoka caused by Mycosphaerella fijiensis, especially in the Haitian plots ; iv) the crop succession plantain/plantain is the most critical regarding the plantain’s cropping, because whatever the level of intensification, the yields remain relatively low in connection with a degradation of the health state, compared to other previous crops.The driving of an experiment in a research station shows that on the scale of one year, the three tested innovative practices allow maintaining a good soils quality. Healthy plants "PIF" have a better health state (absence of plant parasitic nematodes in the roots) which helps a significant increase of the yields. Cover-crop P. notatum helps the weeds and the soil pests control and favors the improvement of soil biological activity and plantain yields. Worms’ compost contributes to the maintenance of a better soils quality while allowing the regulation of the populations of plant-parasitic nematodes of the plantains
Nguyen, Vu Phong. „Caractérisation d’effecteurs de virulence du nématode à galles Meloidogyne incognita chez le riz (Oryza sativa)“. Thesis, Montpellier 2, 2013. http://www.theses.fr/2013MON20247.
Der volle Inhalt der QuelleRoot-knot nematode, Meloidogyne sp., are telluric pests causing severe agricultural lost in almost all plants growing system including cereals. These obligate biotrophic parasites affect the rice production in all cultivated countries. Meloidogyne incognita establishes a compatible interaction with the plant host thanks to effectors produced by esophageal glands and secreted in the plant cell through the stylet. The objective of this work was to identify secreted proteins involved in the virulence of the nematode. The compatible interaction between rice variety Nipponbare and two species of RKN (Meloidogyne incognita and Meloidogyne graminicola) was chosen as a model and decrypted by histology and transcriptomic approaches. Three new proteins of M. incognita which were specifically expressed during early stages of interaction have been identified. Two genes Mi-SP1 (Minc17980) and Mi-SP4 (Minc16281) were pioneers with no homolog in databanks and Mi-SP5 (Minc14137) encodes for a putative destabilase, belongs to lysozyme family. Mi-SP1 and Mi-SP5 were expressed in the subventral glands whereas Mi-SP4 was expressed in the dorsal gland of the parasitic larva called “juvenile stage 2 (J2)". The two pioneer proteins Mi-SP1 and Mi-SP4 were localized in both the nucleus and the cytoplasm of tobacco cell after heterologous expression whereas Mi-SP5 was located in the onion epidermal cell wall. The silencing of three effectors by soaking approach using siRNAs leads to a significant reduction in nematode reproduction in rice. In addition, Mi-SP1 can suppress the plant defences PTI triggered by the PAMP flg22. Knock-down Mi-SP5 by host-delivered RNAi also causes a significant reduction in nematode reproduction in rice. The functional analysis of Mi-SP1 and Mi-SP5 showed that these two effectors are able to play important roles in rice-nematode interaction
Nguyen, Van Chung. „Diversité génétique du nématode vecteur Xiphinema index sur vigne et application pour optimiser la stratégie de résistance“. Electronic Thesis or Diss., Université Côte d'Azur (ComUE), 2018. http://www.theses.fr/2018AZUR4079.
Der volle Inhalt der QuelleThe ban of most nematicides renders urgent control alternatives against plant-parasitic nematodes and breeding for resistant plant varieties is promising. In vineyards, the nematode Xiphinema index has a high economical impact by transmitting Grapevine fanleaf virus (GFLV), the main virus of ‘Court-noué’ disease and the first grapevine viral disease worldwide. Resistant rootstocks are being selected in grapevine, using Muscadinia rotundifolia (muscadine) as a resistance source to the vector, in order to arrest or delay GFLV transmission. In this crop, a previous study had shown that this meiotic parthenogenetic nematode is able to reproduce sexually (rarely) in the field. A preliminary phylogenetic work had allowed to reveal the predominant diversity groups and to select representative populations for the creation of single-female lines. Resistance durability is a real challenge that must consider the key information of the nematode diversity. In this context, the PhD project first completed and deepened our phylogeographical approach using an extended geographic coverage of the worldwide nematode distribution. Our results allow proposing strong hypotheses to locate the native area of X. index in the Middle-East and trace its dissemination routes from the Antiquity. They also highlight the close link since this epoch between dissemination of the nematode and domesticated grapevine by man. The second part of the PhD project has then evaluated the durability of muscadine-derived rootstock material in greenhouse (non viruliferous nematodes on plants aged 3 to 6 years) and field (viruliferous nematodes on plants aged 16 years) conditions. In the greenhouse, F1 and BC1 resistant accessions, previously obtained from both in vitro and hardwood-cutting propagation, were inoculated with 4 mixed representative X. index lines, traceable each with microsatellite markers. We showed that nematodes from plants obtained from in vitro progressively overcame the resistance while the material obtained from cuttings displayed a durable resistance. Nematode progressive multiplication in resistant accessions obtained only from in vitro removes a priori the hypothesis of a nematode genetic adaptation and appears linked to a different architecture of the root system in this propagation type. This type may have induced discrete but durable physiological changes in apical root tissues from where nematodes feed. Nematode microsatellite genotyping allowed detecting a low but increasing rate of hybrid individuals from 4 to 6 years, which confirms data from the vineyard. As the hybrid occurrence appears independent from the propagation type and the resistance status of the plant, our data discard hybridization as the mode of adaptation of the nematode underlying resistance breakdown from in vitro plants. In field conditions, after 16 years, nematodes were almost undetectable on the resistant BC1 accession, also almost unaffected by the viral attacks, while higher numbers were detected on a susceptible control accession, whose plants were by contrast in high majority dead or poorly vigorous. Taken all together, our results show that the muscadine-derived resistance strategy appears durable. This strategy focused on vector control will significantly contribute to reduce the impact of GFLV transmitted by X. index
Jaouannet, Maëlle. „Caractérisation fonctionnelle d'effecteurs du nématode phytoparasite Meloidogyne incognita participant au succès de l'infection et à la suppression des défenses de l'hôte“. Nice, 2011. http://www.theses.fr/2011NICE4096.
Der volle Inhalt der QuelleRoot-knot nematodes (RKN), Meloidogyne sp. , are obligate biotrophic parasites that maintain a compatible interaction with their host during the 5-8 weeks and induce the differentiation of parenchyma root cells into hypertrophied and polynucleated feeding cells that provide the nematode with the nutrients necessary for development and reproduction. The interaction plant-Meloidogyne incognita, whose genome was recently sequenced, provides a fascinating model for studying fundamental aspects of parasitism success. The nematode effectors produced in the esophageal glands and secreted via the stylet in the plant tissues play a major role in this interaction. I identified in M. Incognita three new effectors specifically expressed during the early steps of the interaction. Among them, two are encoded by pioneer genes with no homolog in databanks and one is a putative metallopeptidase. The two pioneer effectors EFF14 and EFF25 localized respectively in the nucleus and the cytoplasm of tobacco cells after heterologous expression. The calreticulin Mi-CRT, an effector previously identified in the group, is secreted in the apoplasm of giant cells. In this work, the functional analysis of EFF14 and Mi-CRT showed that the two effectors are able to suppress plant basal defenses. The current hypothesis is that Mi-CRT is modulating calcium signaling in the apoplasm whereas EFF14 is active in the nucleus for plant defense suppression. This work provides the first demonstration that a nematode effector is targeted to the nucleus of infected cells and the first functional characterization of plant defense suppression by nematode effectors. This work shows that a panel of effectors active in different compartments of plant cells contributes to the success of infection
DELAVILLE, LISE. „Etude des structures spatio-temporelles de la nematofaune phytoparasite associee a la canne a sucre. Relations avec les caracteristiques physico-chimiques du sol“. Paris 6, 1995. http://www.theses.fr/1995PA066066.
Der volle Inhalt der QuelleBelval, Lorène. „Caractérisation fonctionnelle de la protéine de capside et de la protéine de mouvement du Grapevine fanleaf virus“. Thesis, Strasbourg, 2016. http://www.theses.fr/2016STRAJ012.
Der volle Inhalt der QuelleGrapevine fanleaf virus (GFLV) is the main agent of grapevine fanleaf degeneration disease. Its coat protein (CP) self-assembles in virions necessary for viral genome protection, for cell-to-cell movement using tubules formed by the movement protein (MP) of the virus, and for the transmission of GFLV by its nematode vector Xiphinema index.Main results: 1. An outer surface-exposed CP motif has been identified as critical for GFLV transmission by X. index and could be a determinant of transmission specificity. 2. Fluorescent tubules have been produced by constitutive expression in planta. They allow the complementation in trans of a GFLV deleted of its MP coding sequence. 3. Transient expression of the GFLV CP leads to the production of virus-like particles. They can be easily modified and show that GFLV capsid is a unique biotechnology platform. In addition, they are a powerful tool to study the biology of the virus
Qu, Yanyan. „Interactions indirectes médiées par la plante sous contraintes biotiques multiples“. Electronic Thesis or Diss., Université Côte d'Azur (ComUE), 2019. http://theses.univ-cotedazur.fr/2019AZUR6035.
Der volle Inhalt der QuelleIn the agroecosystem, plant crops are the primary trophic producer that can be consumed/parasitized by a plethora of organisms, including viruses, bacteria, fungi, nematodes and many herbivore insects. On one hand, plants support these organisms as food resources; on the other hand, plants defend themselves against those consumers by employing constitutive and induced defenses. Both features might be involved in plant-mediated indirect interactions when multiple pests share the same host plant. It means that the presence of one pest might have an indirect effect on another plant through the modification of some plant host features (nutritional quality or defense). During my Ph.D. study, I assessed the modulating factors (both abiotic and biotic factors) that might affect the plant-mediated indirect interactions, and also investigated the influences of such indirect interactions at long term and on a tri-trophic system, and finally analyzed the underlying phytochemical mechanisms by mechabolomics analyses. Firstly, sublethal effects of beta-cypermethrin, a pyrethroid pesticide as the abiotic factor, were assessed on the interspecific interactions between the specialist aphid Aphis glycines, and the generalist aphid Aulacorthum solani on soybeans. Sublethal concentration (LC5) of beta-cypermethrin accelerated the interspecific competition between the two species of aphids. Induced susceptibility of soybean plants to one species of aphids caused by the other species would be significantly impaired by the exposure to sublethal beta-cypermethrin.Secondly, various pest species abundance and feeding strategies, i.e. the piercing-sucking aphid, the chewing caterpillar, the plant fungus and the root-knot nematode, were introduced on tomato plants, Solanum lycopersicum to evaluate the plant-mediated indirect interactions among these pests. In the results, insect performances, i.e. the number of aphid individuals and development rate of caterpillar larva, were correlated to the abundance of indirect interactions whether pests attacked tomato plants sequentially or simultaneously. When pests attacked tomato plants at the same time, insect performances were positively correlated to the abundance of indirect interactions. Nevertheless, when pests infested tomato plants in sequence, the insect performances were negatively correlated to the abundance of indirect interactions. However, such a correlation was not detected with the pathogenic organisms (fungi and nematodes). Thirdly, the population dynamic of aphid M. euphorbiae was also monitored under a tri-trophic system. We found that the aphid population, involved in the above-belowground interactions, slowed down in both the short term and long term via reduced survival of nymph aphids and facilitating induction of winged aphids. Furthermore, parasitism efficiency of the natural enemy Aphidius ervi to aphids and tomato yields were also reduced by such above-belowground interactions. Lastly, following an untargeted metabolomic approach, we detected many significant chemical variations between non-infested and infested plants, disregarding the pest infestation. Most of them are probably induced by the presence of nematodes, the only belowground pest. On the opposite, we did not observe many chemical differences in roots metabolome when we compared the different types of infestation, meaning that the presence of nematodes probably lead the metabolomic signal in infested roots, disregarding the presence of other pests aboveground. All the studies may contribute to a comprehensive understanding of the diverse interactions among plants, pesticides, various pests, and natural enemies, and optimizing the integrated pest management in the agroecosystem
Andriankaja, Andry. „La régulation transcriptionnelle du gène MtENOD11 au cours des endosymbioses racinaires : caractérisation des éléments cis-régulateurs spécifiques de la réponse aux facteurs Nod“. Toulouse 3, 2006. http://www.theses.fr/2006TOU30033.
Der volle Inhalt der QuelleWe have undertaken a detailed functional analysis of Medicago truncatula ENOD11 gene promoter during endosymbiotic infections and in response to specific rhizobial signals known as Nod factors (NFs), which play a key role in the establishment of the N-fixing symbiosis. First, we defined a 257 bp promoter sequence sufficient to direct expression during rhizobial infection, arbuscular endomycorrhizal (AM) fungi association and Meloidogyne incognita parasitic root knot nematode interaction. We characterized an AT-rich motif required for both rhizobial- and mycorrhizal-related infection, thus providing the first direct evidence for similarities in gene regulatory mechanisms during endosymbiotic root colonization. Subsequently, we were able to define a 33 bp novel regulatory unit (named NF-box), sufficient to confer NF-dependent, epidermal-specific expression. We further demonstrated that the NF-box unit comprises at least three adjacent trans-factor binding motifs which are important for this response. Finally, we initiated yeast one-hybrid screening and candidate gene approach to identify trans-factors involved in NF-mediated activation
Chauvin, Camille. „Influence de l’utilisation de plantes de services sur les communautés de nématodes et les fonctions du sols dans un agroécosystème bananier en phase d’interculture“. Thesis, Montpellier, 2015. http://www.theses.fr/2015MONTS049/document.
Der volle Inhalt der QuelleIncreased plant diversity may alter soil food web structure and soil function in agroecosystems. This thesis sets the basis for an experimental approach in order to select some plant species in regard to several functional traits and to assess their effect on soil food web and soil functioning. We focused on cover-crops able to induce regulation of the banana parasitic nematodes Radopholus similis and Pratylenchus coffeae and to promote decomposition of organic matter during the fallow period in banana plantations in the French West Indies (FWI). We used functional analysis of nematode communities as a soil food web bio-indicator. Bibliography studies show us that “plant host status” with respect to plant-parasitic nematodes, “biochemical characteristics of litters” and “primary productivity of plants” are functional traits involved in plant species effects on soil food web and on the ecosystemics service we targeted. We therefore use those traits to perform a typology of cover-plants. Furthermore, to study the effects of litter inputs with contrasted biochemical characteristics we pick out the plant species Paspalum notatum, Crotalaria zanzibarica and Acacia auriculiformis which show differential hemicellulose, cellulose, lignin and nitrogen content. A microcosm assay shows that biochemical characteristics of litter determine ecological successions in nematode communities and promote, in a contrasted manner, the decomposition pathway of organic matter. We discussed the mechanisms of plant parasitic nematodes suppression involved by those litter inputs. We also confirm that the culture of those three plant species can diminish the population of R.similis in soils. We also assessed the effects of plant covers composed of P. notatum and C. zanzibarica and a mix of those two plant species on nematodes communities during a field trial. In order to do so, we cultivated those cover-plants during a nine months period and then destroyed them to restitute plant litter in soils surface. Our results showed that cover-plant alters differentially plant-parasitic nematodes and the infectious potential of soils. Cover-crop cultivation also induced bottom-up and top-down regulations in plant parasitic nematode communities. After litter restitution, we observed high abundance of nematodes involved in litter decomposition within the soil surface layer. The latter provides underlying soil layers with mineral nitrogen and improves omnivore and predator nematode abundances. It results in the formation of a structured and diversified nematode community concomitantly with R. similis and P. coffeae regulation in soils. We observed greater effects with the cover-crop composed of C. zanzibarica and the mix of C. zanzibarica and P. coffeae. This study confirms that the functional traits of “host status”, “biochemical composition of litter” and “primary production” of plant species are decisive in the selection of cover-crop for the fallow period in banana plantation
Nguyen, Van Chung. „Diversité génétique du nématode vecteur Xiphinema index sur vigne et application pour optimiser la stratégie de résistance“. Thesis, Université Côte d'Azur (ComUE), 2018. http://www.theses.fr/2018AZUR4079/document.
Der volle Inhalt der QuelleThe ban of most nematicides renders urgent control alternatives against plant-parasitic nematodes and breeding for resistant plant varieties is promising. In vineyards, the nematode Xiphinema index has a high economical impact by transmitting Grapevine fanleaf virus (GFLV), the main virus of ‘Court-noué’ disease and the first grapevine viral disease worldwide. Resistant rootstocks are being selected in grapevine, using Muscadinia rotundifolia (muscadine) as a resistance source to the vector, in order to arrest or delay GFLV transmission. In this crop, a previous study had shown that this meiotic parthenogenetic nematode is able to reproduce sexually (rarely) in the field. A preliminary phylogenetic work had allowed to reveal the predominant diversity groups and to select representative populations for the creation of single-female lines. Resistance durability is a real challenge that must consider the key information of the nematode diversity. In this context, the PhD project first completed and deepened our phylogeographical approach using an extended geographic coverage of the worldwide nematode distribution. Our results allow proposing strong hypotheses to locate the native area of X. index in the Middle-East and trace its dissemination routes from the Antiquity. They also highlight the close link since this epoch between dissemination of the nematode and domesticated grapevine by man. The second part of the PhD project has then evaluated the durability of muscadine-derived rootstock material in greenhouse (non viruliferous nematodes on plants aged 3 to 6 years) and field (viruliferous nematodes on plants aged 16 years) conditions. In the greenhouse, F1 and BC1 resistant accessions, previously obtained from both in vitro and hardwood-cutting propagation, were inoculated with 4 mixed representative X. index lines, traceable each with microsatellite markers. We showed that nematodes from plants obtained from in vitro progressively overcame the resistance while the material obtained from cuttings displayed a durable resistance. Nematode progressive multiplication in resistant accessions obtained only from in vitro removes a priori the hypothesis of a nematode genetic adaptation and appears linked to a different architecture of the root system in this propagation type. This type may have induced discrete but durable physiological changes in apical root tissues from where nematodes feed. Nematode microsatellite genotyping allowed detecting a low but increasing rate of hybrid individuals from 4 to 6 years, which confirms data from the vineyard. As the hybrid occurrence appears independent from the propagation type and the resistance status of the plant, our data discard hybridization as the mode of adaptation of the nematode underlying resistance breakdown from in vitro plants. In field conditions, after 16 years, nematodes were almost undetectable on the resistant BC1 accession, also almost unaffected by the viral attacks, while higher numbers were detected on a susceptible control accession, whose plants were by contrast in high majority dead or poorly vigorous. Taken all together, our results show that the muscadine-derived resistance strategy appears durable. This strategy focused on vector control will significantly contribute to reduce the impact of GFLV transmitted by X. index
Sabeh, Michael. „Étude des déterminants génétiques de la pathogénicité chez les nématodes du genre Globodera“. Thèse, 2019. http://hdl.handle.net/1866/22697.
Der volle Inhalt der QuelleCraig, James P. „Analysis and characterization of vitamin B biosynthesis pathways in the phytoparasitic nematode Heterodera glycines“. 2009. http://proquest.umi.com/pqdweb?did=1963690771&sid=1&Fmt=2&clientId=36305&RQT=309&VName=PQD.
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