title: Finding a nitrogen niche: a systems integration of local and systemic nitrogen signalling in plants.
abstract: The ability of plants to sense their nitrogen (N) microenvironment in the soil and deploy strategic root growth in N-rich patches requires exquisite systems integration. Remarkably, this new paradigm for systems biology research has intrigued plant biologists for more than a century, when a split-root framework was first used to study how plants sense and respond to heterogeneous soil nutrient environments. This systemic N-signalling mechanism, allowing plants to sense and forage for mineral nutrients in resource-rich patches, has important implications for agriculture. In this review, we will focus on how advances in the post-genomic era have uncovered the gene regulatory networks underlying systemic N-signalling. After defining how local and systemic N-signalling can be experimentally distinguished for molecular study using a split-root system, the genetic factors that have been shown to mediate local and/or systemic N-signalling are reviewed. Second, the genetic mechanism of this regulatory system is broadened to the whole genome level. To do this, publicly available N-related transcriptomic datasets are compared with genes that have previously been identified as local and systemic N responders in a split-root transcriptome dataset. Specifically, (i) it was found that transcriptional reprogramming triggered by homogeneous N-treatments is composed of both local and systemic responses, (ii) the spatio-temporal signature of local versus systemic responsive genes is defined, and (iii) the conservation of systemic N-signalling between Arabidopsis and Medicago is assessed. Finally, the potential mediators, i.e. metabolites and phytohormones, of the N-related long-distance signals, are discussed.
authors: Center for Genomics and Systems Biology, Department of Biology, New York University, New York, NY 10003, USA.
authors: Ying
authors: Y
authors: Li
authors: Institut de Biologie Intégrative des Plantes-Claude Grignon, Unité Mixte de Recherche 5004, Biochimie et Physiologie Moléculaire des Plantes, Agro-M/Centre National de la Recherche Scientifique/Institut National de la Recherche Agronomique/SupAgro/Université Montpellier 2, F-34060 Montpellier, France.
authors: Gabriel
authors: G
authors: Krouk
authors: Center for Genomics and Systems Biology, Department of Biology, New York University, New York, NY 10003, USA.
authors: Gloria M
authors: GM
authors: Coruzzi
authors: Institut de Biologie Intégrative des Plantes-Claude Grignon, Unité Mixte de Recherche 5004, Biochimie et Physiologie Moléculaire des Plantes, Agro-M/Centre National de la Recherche Scientifique/Institut National de la Recherche Agronomique/SupAgro/Université Montpellier 2, F-34060 Montpellier, France sandrine.ruffel@supagro.inra.fr.
authors: Sandrine
authors: S
authors: Ruffel
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000502:physiology*; D053263:Gene Regulatory Networks; D029902:Medicago / Q000235:genetics / Q000502:physiology*; D009566:Nitrates / Q000378:metabolism*; D009584:Nitrogen / Q000378:metabolism*; D010937:Plant Growth Regulators / Q000378:metabolism; D018517:Plant Roots / Q000378:metabolism; D015398:Signal Transduction; D049490:Systems Biology; D018511:Systems Integration; D059467:Transcriptome
chemical_list: D009566:Nitrates; D010937:Plant Growth Regulators; D009584:Nitrogen
keywords: Local signalling; long-distance messenger; nitrogen response; phytohormone; root; split-root; systemic signalling; systems biology; transcriptome.