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Étude de la biodiversité des bactéries symbiotiques des nématodes entomopathogènes, définition de nouvelles espèces, et mise en évidence d'une co-spéciation

Abstract : Bacteria associated with entomopathogenic nematodes (Steinernema and Heterorhabditis) from a large survey around the Caribbean basin, were isolated and characterized. The diversity of Xenorhabdus and Photorhabdus symbionts was investigated by Restriction Fragment Length Polymorphism analysis of PCR-amplified 16S rDNA. The five Xenorhabdus isolates exhibited a high degree of polymorphism ; in contrast a very little variability was found among the 72 Photorhabdus isolates. The comparison with ecological data showed that the bacterial genotype diversity was in congruence with the host species diversity. This study gave a more comprehensive view of the biodiversity within both genera, that allowed a systematic bacteriology analysis. By combining genomic data (DNA-DNA hybridization and comparison of 16S rDNA sequences) and phenotypic characterization, we proposed new species and subspecies for the genus Photorhabdus. This work provides new insights in the taxonomy of the genus Photorhabdus which was unresolved, and shows the huge diversity of the genus Xenorhabdus, where new species have to be defined. In both cases, the superposition of hosts and symbionts taxonomies emphasizes a phenomenon of co-speciation between the partners of the symbiosis.
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https://hal.inrae.fr/tel-02842362
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Submitted on : Sunday, June 7, 2020 - 3:38:51 PM
Last modification on : Saturday, June 25, 2022 - 9:27:55 PM

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  • HAL Id : tel-02842362, version 1
  • PRODINRA : 70177

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Marion Fischer-Le Saux. Étude de la biodiversité des bactéries symbiotiques des nématodes entomopathogènes, définition de nouvelles espèces, et mise en évidence d'une co-spéciation. Sciences du Vivant [q-bio]. Université Montpellier 2 (Sciences et Techniques), 1999. Français. ⟨tel-02842362⟩

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