Center for Genomics and Systems Biology, Department of Biology, New York University, New York, NY 10003, USA.
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.
J Exp Bot. 2014 Oct;65(19):5601-10. doi: 10.1093/jxb/eru263. Epub 2014 Jun 24.
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.
植物感知土壤中氮 (N) 微环境并在富含 N 的斑块中部署战略性根系生长的能力需要精细的系统集成。值得注意的是，这种系统生物学研究的新范式已经引起了植物生物学家一个多世纪的兴趣，当时首次使用分根框架来研究植物如何感知和响应不均匀的土壤养分环境。这种系统的 N 信号机制使植物能够感知和寻找富含矿物质营养的斑块，这对农业具有重要意义。在这篇综述中，我们将重点介绍在后基因组时代的进展如何揭示了系统 N 信号的基因调控网络。在定义了如何使用分根系统从分子研究中实验区分局部和系统 N 信号之后，我们将回顾已证明介导局部和/或系统 N 信号的遗传因素。其次，将这个调节系统的遗传机制扩展到整个基因组水平。为此，将公开的 N 相关转录组数据集与以前在分根转录组数据集中鉴定为局部和系统 N 响应的基因进行比较。具体来说，(i)发现均匀 N 处理触发的转录重编程由局部和系统反应组成，(ii)定义了局部与系统响应基因的时空特征，以及 (iii) 评估拟南芥和紫花苜蓿之间系统 N 信号的保守性。最后，讨论了 N 相关长距离信号的潜在介导物，即代谢物和植物激素。
