Li Yang, Li Juanqi, Yan Yan, Liu Wenqian, Zhang Wenna, Gao Lihong, Tian Yongqiang
Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, College of Horticulture, China Agricultural University, Beijing, China.
College of Horticulture, Henan Agricultural University, Zhengzhou, China.
Front Plant Sci. 2018 Jun 1;9:722. doi: 10.3389/fpls.2018.00722. eCollection 2018.
Nitrogen (N) is a macronutrient that plays a crucial role in plant growth and development. Nitrate ( ) is the most abundant N source in aerobic soils. Plants have evolved two adaptive mechanisms such as up-regulation of the high-affinity transport system (HATS) and alteration of the root system architecture (RSA), allowing them to cope with the temporal and spatial variation of . However, little information is available regarding the nitrate transporter in cucumber, one of the most important fruit vegetables in the world. In this study we isolated a nitrate transporter named from cucumber. Analysis of the expression profile of the showed that is a high affinity nitrate transporter which mainly located in mature roots. Subcellular localization analysis revealed that CsNRT2.1 is a plasma membrane transporter. In N-starved knock-down plants, both of the constitutive HATS (cHATS) and inducible HATS (iHATS) were impaired under low external concentration. Furthermore, the knock-down plants showed reduced root length and lateral root numbers. Together, our results demonstrated that CsNRT2.1 played a dual role in regulating the HATS and RSA to acquire effectively under N limitation.
氮（N）是一种大量元素，在植物生长发育中起着关键作用。硝酸盐（ ）是有氧土壤中最丰富的氮源。植物已经进化出两种适应性机制，如上调高亲和力运输系统（HATS）和改变根系结构（RSA），使它们能够应对硝酸盐的时空变化。然而，关于世界上最重要的果蔬之一黄瓜中的硝酸盐转运蛋白，目前所知甚少。在本研究中，我们从黄瓜中分离出一种名为 的硝酸盐转运蛋白。对 的表达谱分析表明， 是一种主要位于成熟根中的高亲和力硝酸盐转运蛋白。亚细胞定位分析显示，CsNRT2.1是一种质膜转运蛋白。在氮饥饿的 敲低植株中，在低外部硝酸盐浓度下，组成型HATS（cHATS）和诱导型HATS（iHATS）均受损。此外， 敲低植株的根长和侧根数量减少。总之，我们的结果表明，CsNRT2.1在氮限制条件下调节HATS和RSA以有效获取硝酸盐方面发挥了双重作用。
