Shoot-to-root mobile polypeptides involved in systemic regulation of nitrogen acquisition
Shoot-to-root mobile polypeptides involved in systemic regulation of nitrogen acquisition
复制标题
DOI：
10.1038/nplants.2017.29
复制
发表时间：
2017-04-01
期刊：
影响因子：
18
通讯作者：
Matsubayashi, Yoshikatsu
中科院分区：
文献类型：
--
作者：
Ohkubo, Yuri;Tanaka, Mina;Matsubayashi, Yoshikatsu
植物从土壤中吸收的氮主要以硝酸盐的形式存在。然而，硝酸盐在自然土壤中的分布往往是不均匀的。因此，植物具有系统的长距离信号传导机制，通过该机制，根一侧的N饥饿导致另一侧的N富营养侧的补偿性N吸收（1，2）。这种系统性的氮吸收反应是由根到芽的移动的肽激素，C-胰蛋白酶编码肽（CEP）触发的，它起源于氮饥饿的根（3，4），但是下行的芽到根信号的分子本质仍然是难以捉摸的。在这里，我们表明，韧皮部特异性多肽，诱导叶根源CEP的感知作为下降的长距离移动的信号易位到每个根。这些拍摄衍生的多肽，我们命名为CEP下游1（CEPD 1）和CEPD 2，上调硝酸盐转运蛋白基因NRT 2.1在根中的表达，特别是当硝酸盐存在于根际。拟南芥植物在这一途径的缺陷表现出受损的系统N获取反应伴随着N缺乏症状。这些基本的机制的见解应该提供一个概念框架，了解系统的养分吸收植物的反应。
Plants uptake nitrogen (N) from the soil mainly in the form of nitrate. However, nitrate is often distributed heterogeneously in natural soil. Plants, therefore, have a systemic long-distance signalling mechanism by which N starvation on one side of the root leads to a compensatory N uptake on the other N-rich side(1,2). This systemic N acquisition response is triggered by a root-to-shoot mobile peptide hormone, C-TERMINALLY ENCODED PEPTIDE (CEP), originating from the N-starved roots(3,4), but the molecular nature of the descending shoot-to-root signal remains elusive. Here, we show that phloem-specific polypeptides that are induced in leaves upon perception of root-derived CEP act as descending long-distance mobile signals translocated to each root. These shoot-derived polypeptides, which we named CEP DOWNSTREAM 1 (CEPD1) and CEPD2, upregulate the expression of the nitrate transporter gene NRT2.1 in roots specifically when nitrate is present in the rhizosphere. Arabidopsis plants deficient in this pathway show impaired systemic N acquisition response accompanied with N-deficiency symptoms. These fundamental mechanistic insights should provide a conceptual framework for understanding systemic nutrient acquisition responses in plants.