INRA ENESAD, UMR 102 génétique et ecophysiologie des légumineuses (UMR LEG), 17, rue Sully, BP 86510, 21065 Dijon cedex, France.
C R Biol. 2009 Nov;332(11):1022-33. doi: 10.1016/j.crvi.2009.09.009. Epub 2009 Oct 14.
An integrative biology approach was conducted in Medicago truncatula for: (i) unraveling the coordinated regulation of NO3-, NH4+ and N(2) acquisition by legumes to fulfill the plant N demand; and (ii) modeling the emerging properties occurring at the whole plant level. Upon localized addition of a high level of mineral N, the three N acquisition pathways displayed similar systemic feedback repression to adjust N acquisition capacities to the plant N status. Genes associated to these responses were in contrast rather specific to the N source. Following an N deficit, NO3- fed plants maintained efficiently their N status through rapid functional and developmental up regulations while N(2) fed plants responded by long term plasticity of nodule development. Regulatory genes associated with various symbiotic stages were further identified. An ecophysiological model simulating relations between leaf area and roots N retrieval was developed and now furnishes an analysis grid to characterize a spontaneous or induced genetic variability for plant N nutrition.
（i）揭示豆科植物协调调控硝酸盐、铵和氮气吸收以满足植物氮需求的机制；（ii）模拟整个植物水平上出现的新特性。在局部添加高水平的矿质氮后，三种氮吸收途径显示出相似的系统反馈抑制，以调整氮吸收能力以适应植物的氮状态。与这些反应相关的基因与氮源相对特异。在氮缺乏后，硝酸盐喂养的植物通过快速的功能和发育上调来有效地维持其氮状态，而氮气喂养的植物则通过根瘤发育的长期可塑性来响应。进一步鉴定了与各种共生阶段相关的调节基因。开发了一个模拟叶面积和根系氮回收之间关系的生理生态模型，现在提供了一个分析网格，用于表征植物氮营养的自发或诱导遗传变异。
