Signalling mechanisms underlying the morphological responses of the root system to nitrogen in Arabidopsis thaliana.
Signalling mechanisms underlying the morphological responses of the root system to nitrogen in Arabidopsis thaliana.
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DOI：
10.1093/jxb/erm114
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发表时间：
2007-07
影响因子：
6.9
通讯作者：
Hanma Zhang;Honglin Rong;D. Pilbeam
中科院分区：
文献类型：
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作者：
Hanma Zhang;Honglin Rong;D. Pilbeam
植物响应不断变化的环境条件而表现出相当大的发育可塑性。根系对氮供应变化的适应是这种发育可塑性的一个很好的例子。在拟南芥中，对氮供应的四种形态适应已被表征：（i）外部硝酸盐对侧根伸长的局部刺激作用； (ii) 高组织硝酸盐浓度对侧根分生组织活化的全身抑制作用； (iii) 通过高 C:N 比率抑制侧根萌生，以及 (iv) 通过外部 L-谷氨酸抑制初生根生长和刺激根分枝。这些反应为植物氮信号传导的研究提供了有价值的实验系统。本文将重点介绍利用拟南芥根系进行的研究在这个方向上取得的一些最新进展。最近值得注意的一项进展是硝酸盐转运蛋白在某些反应中发挥调节作用的新证据。据报道，AtNRT1.1 (CHL1) 双亲和力硝酸盐转运蛋白作用于 ANR1 MADS box 基因的上游，介导局部硝酸盐供应对侧根增殖的刺激作用。 AtNRT2.1 高亲和力硝酸盐转运蛋白似乎参与了高碳氮比对侧根萌生的抑制。高硝酸盐供应对侧根发育的系统抑制作用是由脱落酸 (ABA) 介导的，可能与最近发现的 ABA 受体 FCA 有关。新发现的根结构对外部 L-谷氨酸的反应可能为研究植物谷氨酸受体和氨基酸信号传导的生物学功能提供有价值的实验工具。
Plants display considerable developmental plasticity in response to changing environmental conditions. The adaptations of the root system to variations in N supply are an excellent example of such developmental plasticity. In Arabidopsis, four morphological adaptations to the N supply have been characterized: (i) a localized stimulatory effect of external nitrate on lateral root elongation; (ii) a systemic inhibitory effect of high tissue nitrate concentrations on the activation of lateral root meristems; (iii) a suppression of lateral root initiation by high C:N ratios, and (iv) an inhibition of primary root growth and stimulation of root branching by external L-glutamate. These responses have provided valuable experimental systems for the study of N signalling in plants. This article will highlight some recent progress made in this direction from studies using the Arabidopsis root system. One recent development of note has been the emerging evidence of a regulatory role of nitrate transporters in some of the responses. It has been reported that the AtNRT1.1 (CHL1) dual-affinity nitrate transporter acts upstream of the ANR1 MADS box gene in mediating the stimulatory effect of a localized nitrate supply on lateral root proliferation. The AtNRT2.1 high-affinity nitrate transporter seems to be involved in the repression of lateral root initiation by high C:N ratios. The systemic inhibitory effect of high nitrate supply on lateral root development, which is mediated by abscisic acid (ABA), may be linked to the recently identified ABA receptor, FCA. The newly discovered root architectural response to external L-glutamate potentially offers a valuable experimental tool for studying the biological function of plant glutamate receptors and amino acid signalling.