Abstract
Water is essential for plants’ growth and development, but water in soils tends to be heterogeneously distributed. So to acquire water, plant roots must continuously explore the soil by building a highly complex, branched architecture and at the same time, adjust their water transport capacity and water losses. However, the molecular bases underpinnings of these local and systemic responses to heterogeneous water availability, and their temporality, are largely unknown. To understand the underlying transcriptional mechanism, we assayed a split root culture system for Arabidopsis thaliana seedlings where half of the root system can be subjected to an osmotic stress. To achieve this, we treated wild-type Arabidopsis seedling roots with Polyethylene glycol 8000 (PEG8000) at 200g/L in a split-root hydroponic experiment (0/0 PEG, 0/200 PEG, 200/200 PEG) over 9 time points (0, 0.5, 1, 2, 4, 8, 24, 48 and 96h). This experimental design generated a set of root transcriptomes that will allow the identification of the molecular bases of the response to heterogeneous water as a function of time. Preliminary analyses clearly identified an early and late molecular response to heterogeneous water availability and a massive local response. The early responses are closely related to abscisic acid (ABA), hypoxia and Nitrogen compounds, while the late response are related to photosynthesis, primary metabolism and secondary metabolism