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Titre :
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Analyse moléculaire et fonctionnelle des effecteurs du parasitisme des nématodes à galle Meloidogyne spp.
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Auteurs :
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G. Dubreuil, - Auteur ;
Université de Nice-Sophia Antipolis,Faculté des Sciences,Nice (FRA), Organisme de soutenance
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Type de document :
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thèse/mémoire
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Année de publication :
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2007
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Format :
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200 p.
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Langues:
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= Français
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Mots-clés:
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NEMATODES PHYTOPARASITES
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SECRETIONS
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GLUTATHION S-TRANSFERASE
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PEROXYREDOXINE
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ARN
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Résumé :
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Root-knot nematodes, genus Meloidogyne, are obligate biotrophic parasites. During a compatible interaction, the second stage juveniles (J2) penetrate into the root, migrate intercellularly and become sedentary to initiate the differentiation of a feeding site formed by 5 to 7 giant cells in the vascular cylinder. Secreted proteins play a key role during the plant/nematode interaction. A typical gall is formed around the feeding site. Stylet secretions are produced in oesophageal glands and injected in the root during parasitism. The first objective of this work was the identification of biological functions involved in the adaptation of the parasite to its host environment and in the modulation the host responses. We initiated a differential approach and a candidate gene approach and identified proteins of unknown function, proteases, a putative secreted protein a glutathione S-transferase (GST) and a peroxiredoxine (PRX). The GST was localized in the subventral oesophageal glands of infective J2 and detected in M. Incognita stylet secretions purified from infective J2. The PRX was localised in the excretory pore of infective J2 and in the hypodermis of sedentary stages. The role of these two proteins in parasitism is discussed. Root-knot nematodes have been so far refractory to transformation. Recent works demonstrated the efficiency of RNAi for the silencing of parasitism genes on J2. This strategy is limited by the recovery of targeted transcripts a few days after J2 treatment. In order to ensure a long-lasting silencing we developed a new and original tool, presented in a last chapter.
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Note de contenu :
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Diplôme :
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Docteur en Biologie cellulaire et moléculaire
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