Enrobage de semences de concombre (Cucumis sativus) à base de silicium additionné d’un Trichoderma : augmentation de la biodisponibilité du silicium et réduction de l'intensité de la fonte des semis causée par Pythium ultimum

Authors: Kane, Papa Demba
Advisor: Beauchamp, Chantal Jeanne
Abstract: Some Trichoderma spp. are biological control agents known to control phytopathogenic soilborne microorganisms, including Oomycota Pythium spp. In addition, silicon (Si) is knownfor its prophylactic role against Pythium spp. The aim of this study was to demonstrate the potential of Trichoderma to increase the plant biodisponibility of Si and reduced the severityof damping-off by studying the model : cucumber (Cucumis sativus) - P. ultimum. The enzymatic and microbial confrontation characterizations made it possible to build the phylogenetic tree separating the Trichoderma strains. Hemicellulase was effective for allstrains in opposite to lignase who was effective for seven strains and cellulase for one strain.The confrontation test showed the potential antagonist of some strains, and the Trichoderma strain A, isolated from field horsetail (Equisetum sp.), had an inhibitory effect, due to the production of antibiotics (sorbicillinoids). The addition of wollastonite and husk powders,alone or in combination in sterile water allowed Si solubilization (measured as silicic acid);on top of that, the addition of a Trichoderma strain increased Si solubilization. In the plantcucumber bioassay, aerial dry weights and disease severity were similar between the controland the Trichoderma treatments. In cucumber, the highest total Si content was measured forthe treatments coated with strains A and C (from the collection of Université Laval # 16). Inconclusion, coating cucumber seeds with mixed wollastonite and rice husk powders and astrain of Trichoderma partially confirms the hypothesis; some strains of Trichoderma allowed a better bioavailability of silicium for the plant, while tending to limit the severityof damping-off caused by Pythium.
Document Type: Mémoire de maîtrise
Issue Date: 2021
Open Access Date: 25 October 2021
Permalink: http://hdl.handle.net/20.500.11794/70724
Grantor: Université Laval
Collection:Thèses et mémoires

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