Diversité fonctionnelle des Pseudomonas producteurs d'antibiotiques dans les rhizosphères de conifères en pépinières et en milieu naturel

Authors: Allaire, Mathieu
Advisor: Hamelin, Richard C.; Bernier, Louis
Abstract: Fluorescent Pseudomonas spp. that produce antibiotics such as 2,4-diacetylphloroglucinol and phenazines show biocontrol activity against many important soil borne fungal pathogens. We isolated several strains of Pseudomonas carrying genes for DAPG and PCA synthesis from the rhizosphere of black spruce (Picea mariana) and white spruce (Picea glauca) in two different conifer nurseries and in one natural stand. Sequence analysis of a portion of the phlD gene revealed that one dominant genotype was present in both nurseries and that a different genotype was dominant in the natural forest. Strains from the natural forestwere also found to have the genes for pyrrolnitrin synthesis but lack pyoluteorin biosynthesis genes. Furthermore, in vitro anitfungal assays against Cylindrocladium floridanum showed a much stronger inhibition by strains isolated from natural forest than from nursery. Analysis of phenazine genes revealed 3 groups of phenazines-producers; one from a nursery and two from natural stand.
Document Type: Mémoire de maîtrise
Issue Date: 2005
Open Access Date: 11 April 2018
Permalink: http://hdl.handle.net/20.500.11794/18046
Grantor: Université Laval
Collection:Thèses et mémoires

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