Dynamique de la diversité génétique dans les populations naturelles et artificielles de plantes autogames

National audience

DNA polymorphism at the FRIGIDA gene in Arabidopsis thaliana : extensive nonsynonymous variation is consistent with local selection for flowering time

FRIGIDA (FRI) is a major gene involved in the regulation of flowering time in Arabidopsis thaliana. Nucleotide variation at this gene was investigated by sequencing 25 field ecotypes collected from western Europe. Genetic diversity at FRI was characterized by a high number of haplotypes and an excess of low-frequency polymorphisms. A large excess of intraspecific nonsynonymous variation associated with low synonymous variation was detected along the first exon in the FRI gene. In contrast, no excess of nonsynonymous divergence was detected between A. thaliana and A. lyrata. The Tajima and McDonald and Kreitman tests, however, suggested that this gene has evolved in a nonneutral fashion. Non…

A la recherche des gènes de la précocité de floraison

National audience; La date de floraison conditionne l'adaptation des plantes annuelles à leur environnement et demeure un critère important des programmes de sélection variétale. Grâce à l'avancée réalisée en génomique fonctionnelle chez Arabidopsis thaliana, l'identification de l'ensemble des gènes impliqués semble possible. Cependant, des interrogations subsistent sur le nombre et les effets des facteurs génétiques à l'origine de la variation naturelle de ce trait

The dominance of the herbicide resistance cost in several Arabidopsis thaliana mutant lines

Abstract Resistance evolution depends upon the balance between advantage and disadvantage (cost) conferred in treated and untreated areas. By analyzing morphological characters and simple fitness components, the cost associated with each of eight herbicide resistance alleles (acetolactate synthase, cellulose synthase, and auxin-induced target genes) was studied in the model plant Arabidopsis thaliana. The use of allele-specific PCR to discriminate between heterozygous and homozygous plants was used to provide insights into the dominance of the resistance cost, a parameter rarely described. Morphological characters appear more sensitive than fitness (seed production) because 6 vs. 4 differen…

Molecular evolution within and between populations of Arabidopsis thaliana: the FRIGIDA gene