Arabidopsis NRT1.5 Is Another Essential Component in the Regulation of Nitrate Reallocation and Stress Tolerance
Arabidopsis NRT1.5 Is Another Essential Component in the Regulation of Nitrate Reallocation and Stress Tolerance
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拟南芥 NRT1.5 是调节硝酸盐重新分配和胁迫耐受性的另一个重要组成部分
DOI：
10.1104/pp.112.199257
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发表时间：
2012-08-01
期刊：
影响因子：
7.4
通讯作者：
Gong, Ji-Ming
中科院分区：
文献类型：
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作者：
Chen, Chun-Zhu;Lv, Xin-Fang;Gong, Ji-Ming
在逆境条件下，硝酸盐向植物根系的再分配频繁发生，最近发现拟南芥（Arabidopsis thaliana）中硝酸盐转运蛋白1.8（NRT1.8）对硝酸盐向植物根系的再分配有着积极的调控作用，是植物对逆境胁迫的一种常见反应。然而，基本的机制在很大程度上仍有待确定。在这项研究中，表征NRT1.5，木质部硝酸盐装载转运蛋白，表明NRT1.5的mRNA水平下调盐，干旱和镉处理。NRT1.5的功能破坏增强了对盐、干旱和镉胁迫的耐受性。进一步的分析表明，硝酸盐，以及Na+和Cd 2+水平，显着增加在nrt 1. 5根。Na+/H+交换子1、盐过度敏感子1、吡咯啉-5-羧酸脱氢酶1、脱水响应子29 A、植物螯合素脱氢酶1和NRT 1.8等逆境应答途径中的重要基因在nrt 1.5突变体中表达稳定上调。有趣的是，改变积累的代谢产物，包括脯氨酸和丙二醛，也观察到nrt 1.5植物。这些数据表明，NRT1.5参与硝酸盐分配到根和随之而来的耐受几种压力，在一种机制可能与NRT1.8共享。
Nitrate reallocation to plant roots occurs frequently under adverse conditions and was recently characterized to be actively regulated by Nitrate Transporter1.8 (NRT1.8) in Arabidopsis (Arabidopsis thaliana) and implicated as a common response to stresses. However, the underlying mechanisms remain largely to be determined. In this study, characterization of NRT1.5, a xylem nitrate-loading transporter, showed that the mRNA level of NRT1.5 is down-regulated by salt, drought, and cadmium treatments. Functional disruption of NRT1.5 enhanced tolerance to salt, drought, and cadmium stresses. Further analyses showed that nitrate, as well as Na+ and Cd2+ levels, were significantly increased in nrt1.5 roots. Important genes including Na+/H+ exchanger1, Salt overly sensitive1, Pyrroline-5-carboxylate synthase1, Responsive to desiccation29A, Phytochelatin synthase1, and NRT1.8 in stress response pathways are steadily up-regulated in nrt1.5 mutant plants. Interestingly, altered accumulation of metabolites, including proline and malondialdehyde, was also observed in nrt1.5 plants. These data suggest that NRT1.5 is involved in nitrate allocation to roots and the consequent tolerance to several stresses, in a mechanism probably shared with NRT1.8.