Résumé
A fundamental question in biology is how gene expression is regulated to give rise to a given phenotype. However, it is still a mystery how multiple phenotypes can derive from a single genotype in one environment. While transcriptional variability, or noise, could be the cause of this unexpected observation, it is still largely unexplored in multicellular organisms. It is known that gene expression is often noisy rather than uniform with different individuals showing variable gene expression behaviours. Such transcriptional variability has been proposed to be beneficial when environmental conditions are unpredictable. However, little is known about transcriptional variability in plants. We are analysing gene expression variability between individuals in Arabidopsis thaliana, and how this could be of importance for the response to environment. Using transcriptomic approaches we characterised, over a 24 hours time-course, the level of gene expression variability between individuals growing in controlled conditions. We identified hundreds of genes that exhibit high inter-individual variability in gene expression and found that many are involved in the response to environment. We also identified factors that might be facilitating gene expression variability, such as gene size, the number of transcription factors regulating a gene and the chromatin environment. These results will bring a new light into the impact of transcriptional variability in gene expression regulation in plants.