Tomato serves as an important model organism for Solanaceae in both molecular and agronomic research. With whole genome sequencing in progress, there is a need to study functional genetics through mutant lines that exceed the practical limitations imposed by the popular research cultivar, Micro-Tom. This project utilized Agrobacterium transformation and the transposon tagging construct, Ac-DsATag-Bar_gosGFP, to produce activation tagged and knockout mutants in the processing tomato variety, M82. The construct contained hygromycin resistance (hyg), green fluorescent protein (GFP), and maize transposase (TPase) on the stable Ac element, along with a 35S enhancer tetramer and glufosinate herbicide resistance (BAR) on the mobile Ds element. An in vitro propagation strategy was used to produce a population of 25 T0 plants from a single transformed plant regenerated in tissue culture. A T1 population of 10,568 selfed and M82 backcross progeny was produced from the functional T0 line. This population was screened by spraying with 0.05% Liberty® herbicide, followed by a 100 mg/L hygromycin leaf painting procedure to select for Ds only (herbicide tolerant and hygromycin sensitive) individuals. The T-DNA genotype of Ds only plants was confirmed through multiplex PCR and the location of insertions within the genome was determined through TAIL-PCR. Resulting product sequences were blasted against the pre-publication tomato genome browser to determine insertion sites. A population of 309 independent transposants dispersed to all twelve chromosomes from the original insertion site on chromosome five has been developed. The transposon tagged lines are currently being immortalized in seed stocks. / Master of Science

La rhizosphère est le siège de multiples interactions biotiques, contrôlées au moins en partie par l’échange de molécules signal entre les racines des plantes et les microorganismes qui leur sont associés. Dans le contexte des symbioses associatives entre les PGPR (Plant-Growth Promoting Rhizobacteria) et les plantes, le rôle et l’importance de ces molécules restent encore largement méconnus. Ainsi, l’influence de différents signaux rhizosphériques sur l’expression génique et les propriétés phytobénéfiques des PGPR a été étudiée par, (i) la caractérisation chimique d’une nouvelle molécule phytobénéfique d’Azospirillum et de son impact sur l’architecture du système racinaire, (ii) une approche ciblée portant sur l’analyse de l’expression in situ du gène phytobénéfique acdS de PGPR, et (iii) une approche globale permettant d’identifier la réponse du transcriptome d’Azospirillum à un métabolite secondaire bactérien. Ces travaux ont permis d’identifier des signaux rhizosphériques impliqués dans le contrôle de la colonisation racinaire et/ou des propriétés de phytostimulation des PGPR sur leur plante hôte / In rhizosphere, numerous biotic interactions are controlled by molecular signals exchanged between plant roots and microorganisms. In the case of the associative symbiosis between PGPR (Plant-Growth Promoting Rhizobacteria) and plants, the role and importance of these molecules are largely unknown. The impact of several rhizospheric signals on PGPR gene expression and plant beneficial properties was thus studied by performing (i) the chemical characterization of a new Azospirillum plant-stimulatory molecule whose positive impact on root development was revealed, (ii) an approach targeting the in situ expression of the acdS plant beneficial gene in PGPR, and (iii) a global approach to identify the Azospirillum transcriptomic response to a bacterial secondary metabolite. This works allowed the identification of rhizospheric signals controlling PGPR root colonization and/or plant growth promotion