Protéome et bilan photosynthétique de la pomme de terre (Solanum tuberosum L.) en réponse au doryphore de la pomme de terre (Leptinotarsa decemlineata Say)

Authors: Duceppe, Marc-Olivier
Advisor: Michaud, DominiqueCloutier, Conrad
Abstract: Higher plants have developed, over time, a variety of protection mechanisms allowing them to survive and cope with a variety of biotic stress cues in their surrounding environment. The main goal of this three-part doctoral thesis was to characterize the biochemical and the physiological responses of potato (Solanum tuberosum) to defoliation by the coleopteran insect herbivore Colorado potato beetle (Leptinotarsa decemlineata). The first objective of the project was to characterize the impact of the insect on the host plant's leaf proteome, using as a model plants treated with potato beetle larvae, mechanically wounded plants and plants infested with a sucking/piercing insect, the potato aphid (Macrosiphum euphorbiae). The second objective was to gain some insight about the proteome of potato beetle oral secretions, with the aim of assessing the relative incidence of insect and host plant proteins at wound sites generated during insect feeding. The third objective, finally, was to determine the impact of leaf proteome alterations on photosynthetic capacities of the host plant, and to determine the possible impact of the plant's own molecular constituents on the responses observed. In brief, our results showed that several proteins involved in the primary and the secondary metabolisms, including photosynthesis-related proteins, were regulated in leaves in response to potato beetle feeding. However, the negative impact of the insect on several photosynthetic proteins, notably photosystem I proteins, only had negligible effects on the light capture process by the plant. The second phase of photosynthesis, on the other hand, was significantly affected by the insect, presumably via molecular effectors from both the insect and the host plant itself. These findings suggest, overall, a specific, but somewhat limited impact of Colorado potato beetle larvae on the leaf proteome and photosynthetic capacities of the potato host. They also suggest the possible induction of compensatory mechanisms in planta and the high plasticity of primary metabolism functions in the plant upon herbivore feeding.
Document Type: Thèse de doctorat
Issue Date: 2011
Open Access Date: 17 April 2018
Grantor: Université Laval
Collection:Thèses et mémoires

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