Influence of Pythium oligandrum biocontrol on fungal and oomycete population dynamics in the rhizosphere

Jessica Vallance 1, 2 Gaétan Le Floch 1 Franck Déniel 1 Georges Barbier 1 C. André Lévesque 3 Patrice Rey 1, 2, *
* Auteur correspondant
1 LUBEM - Laboratoire Universitaire de Biodiversité et Ecologie Microbienne
2 SV - Santé Végétale
3 Agriculture and Agri-Food Canada Eastern Cereal and Oilseed Research Centre
Abstract : Fungal and oomycete populations and their dynamics were investigated following the introduction of the biocontrol agent Pythium oligandrum into the rhizosphere of tomato plants grown in soilless culture. Three strains of P. oligandrum were selected on the basis of their ability to form oospores (resting structures) and to produce tryptamine (an auxin-like compound) and oligandrin (a glycoprotein elicitor). Real-time PCR and plate counting demonstrated the persistence of large amounts of the antagonistic oomycete in the rhizosphere throughout the cropping season (April to September). Inter-simple-sequence-repeat analysis of the P. oligandrum strains collected from root samples at the end of the cropping season showed that among the three strains used for inoculation, the one producing the smallest amount of oospores was detected at 90%. Single-strand conformational polymorphism analysis revealed increases in the number of members and the complexity of the fungal community over time. There were no significant differences between the microbial ecosystems inoculated with P. oligandrum and those that were not treated, except for a reduction of Pythium dissotocum (ubiquitous tomato root minor pathogen) populations in inoculated systems during the last 3 months of culture. These findings raise interesting issues concerning the use of P. oligandrum strains producing elicitor and auxin molecules for plant protection and the development of biocontrol.
Keywords : Rhizosphere Population dynamics Fungi Biological control
Type de document :
Article dans une revue
Applied and Environmental Microbiology, American Society for Microbiology, 2009, 75 (14), pp.4790-4800. 〈10.1128/AEM.02643-08〉
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Contributeur : Violaine Garguilo <>
Soumis le : mercredi 12 janvier 2011 - 11:05:34
Dernière modification le : mercredi 10 janvier 2018 - 14:42:39

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Jessica Vallance, Gaétan Le Floch, Franck Déniel, Georges Barbier, C. André Lévesque, et al.. Influence of Pythium oligandrum biocontrol on fungal and oomycete population dynamics in the rhizosphere. Applied and Environmental Microbiology, American Society for Microbiology, 2009, 75 (14), pp.4790-4800. 〈10.1128/AEM.02643-08〉. 〈hal-00555082〉

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