Abstract
A key question in biology is to understanding how a phenotype is generated by a given genotype. However, it exists some situations where we observe multiple phenotypes forgenetically identical plants in the same environment. This observation cannot be explained by plasticity (response to environmental changes) or genetic variation (differences between mutant or ecotypes). This phenotypic variability might be partly caused by variability in gene expression between plants.We are interested in understanding if this transcriptional variability might be of use for plants in their natural environment. For this, we study the impact of mild as well as strong environmental changes on this inter-individual transcriptional variability.We are focusing on genes involved in nitrate nutrition as several ones have a high variability. Moreover, nitrate is one of the most determining factors in the growth, survival and reproduction of plants, but fluctuates a lot in the soil. A sensitive regulation of the expression for genes involved in its uptake and its transport is therefore decisive.We show that the high affinity nitrate transporter NRT2.1 is a highly variable gene and that this transcriptional variability as phenotypic consequences. We confirm also that these differences in expression between seedlings for NRT2.1 are stable and maintained over time but not transmitted to the next generation. We are trying to understand at what point in the plant's life these differences are established and why.Finally, we highlight that variability for NRT2.1 is only affect by a sudden and drastic environmental change like nitrate starvation. These results will be essential to define if this mechanism could be beneficial for a population of plants facing a sudden and drastic environmental change