Biology Department Special Seminar | Sandrine Ruffel and Gabriel Krouk, INRA Montpellier France | A Systems View of Nitrogen Signaling Interactions

Plants need to adapt to a myriad of combined signals coming from i) their environment and ii) their own metabolism1. Gene Regulatory Networks (GRNs) leading to these adaptations and signal integration are the central point of our research. First, by focusing on Nitrate (NO3-)-related signaling(s) we have shown that part of these signals are part of a long distance communications between roots and shoots. These systemic signaling are conveyed in part by hormones/cytokinins 2,3,4. Second, by focusing on NO3- regulated transcription factors (TFs) and their genome wide activity, using a technique called TARGET (Transient Assay Reporting Genome wide Effect of Transcription factors5), we were able to identify several important signaling cross-talks between NO3-, Phosphate (PO43-) 6,7 and Reactive Oxygen Species (ROS) pathways8. These studies open perspectives at the same time on i) applied biotechnology [since we discovered genotypes with an enhanced NO3- transport activity] 8, as well as on ii) basic understanding of large GRN function, dynamics9, emerging properties, and topology in plants10.