Résumé
Gene expression levels can be variable between individual cells or individual plants even if there have the same genotype and are grown in the same environmental conditions. This transcriptional variability is not the same as plasticity and genetic variation. Transcriptional variability has been shown to be one of the mechanisms that could enable individuals in a population to survive sudden stresses (Grimbergen et al., 2015, Levy et al., 2012). Many genes of Arabidopsis thaliana have a high level of transcriptional variability between seedlings, including some involved in nitrogen nutrition (Cortijo et al., 2019). As nitrate availability in the soil is often fluctuating in time and space, transcriptional variability between plants for genes involved in nitrogen nutrition might be useful in this context. Although quite well documented in animals and micro-organisms, knowledge on this subject in plants is not very extensive and the mechanisms behind transcriptional variability are not very well identified. Previous work indicate that chromatin could be one of the factors influencing the level of inter-individual variability of a gene. Indeed, the lowly variable genes (LVGs) and highly variable genes (HVGs) in Arabidopsis thaliana have a di↵erent chromatin environment, especially with regard to the distribution of the histone variant H2A.Z. The question we are therefore asking is whether the histone variant H2A.Z is involved in inter-individual transcriptional variability in Arabidopsis thaliana, and more specifically for genes involved in nitrogen nutrition. To answer these questions, we are using a mutant that a↵ects H2A.Z deposition. With a combination of imaging, transcriptomic and ChIP approaches we are studying the impact of this mutation on the level of inter-individual transcriptional variability for genes involved in nitrogen nutrition.