Résumé
Gene expression levels can be variable between individual cells or individual plants evenif there have the same genotype and are grown in the same environmental conditions. Thistranscriptional variability is not the same as plasticity and genetic variation. Transcriptionalvariability has been shown to be one of the mechanisms that could enable individuals in a pop-ulation to survive sudden stresses (Grimbergen et al., 2015, Levy et al., 2012). Many genes ofArabidopsis thaliana have a high level of transcriptional variability between seedlings, includingsome involved in nitrogen nutrition (Cortijo et al., 2019). As nitrate availability in the soil isoften fluctuating in time and space, transcriptional variability between plants for genes involvedin nitrogen nutrition might be useful in this context. Although quite well documented in animalsand micro-organisms, knowledge on this subject in plants is not very extensive and the mecha-nisms behind transcriptional variability are not very well identified. Previous work indicate thatchromatin could be one of the factors influencing the level of inter-individual variability of agene. Indeed, the lowly variable genes (LVGs) and highly variable genes (HVGs) in Arabidopsisthaliana have a di↵erent chromatin environment, especially with regard to the distribution ofthe histone variant H2A.Z. The question we are therefore asking is whether the histone variantH2A.Z is involved in inter-individual transcriptional variability in Arabidopsis thaliana, andmore specifically for genes involved in nitrogen nutrition. To answer these questions, we areusing a mutant that a↵ects H2A.Z deposition. With a combination of imaging, transcriptomicand ChIP approaches we are studying the impact of this mutation on the level of inter-individualtranscriptional variability for genes involved in nitrogen nutrition.