State Key Laboratory of Plant Physiology and Biochemistry, College of Natural Resources and Environmental Science, Zhejiang University, Hangzhou, 310058, China.
State Key Laboratory of Plant Physiology and Biochemistry, College of Natural Resources and Environmental Science, Zhejiang University, Hangzhou, 310058, China.
Sci Total Environ. 2020 Dec 1;746:141244. doi: 10.1016/j.scitotenv.2020.141244. Epub 2020 Jul 30.
Global climate change has exacerbated flooding in coastal areas affected by soil salinization. Ammonium (NH) is the predominant form of nitrogen in flooded soils, but the role played by NH in the plant response to salt stress has not been fully clarified. We investigated the responses of Arabidopsis thaliana, Oryza sativa, and Nicotiana benthamiana plants fed with NH. All species were hypersensitive to NaCl stress and accumulated more Cl and less Na than those fed with NO. Further investigation of A. thaliana indicated that salt hypersensitivity induced by the presence of NH was abolished by removing the Cl but was not affected by the removal of Na, suggesting that excess accumulation of Cl rather than Na is involved in NH-conferred salt hypersensitivity. The expression of nitrate transporter NRT1.1 protein was also up-regulated by NH treatment, which increased root Cl uptake due to the Cl uptake activity of NRT1.1 and the absence of uptake competition from NO. Knockout of NRT1.1 in plants decreased their root Cl uptake and retracted the NH-conferred salt hypersensitivity. Our findings revealed that NH-aggravated salt stress in plants is associated with Cl over-accumulation through the up-regulation of NRT1.1-mediated Cl uptake. These findings suggest the significant impact of Cl toxicity in flooded coastal areas, an issue of ecological significance.
全球气候变化加剧了受土壤盐渍化影响的沿海地区的洪水泛滥。铵（NH）是水淹土壤中氮的主要形式，但 NH 在植物对盐胁迫的反应中所起的作用尚未完全阐明。我们研究了喂食 NH 的拟南芥、水稻和烟草原生质体的反应。所有物种对 NaCl 胁迫都高度敏感，与喂食 NO 的相比，积累了更多的 Cl 和更少的 Na。对拟南芥的进一步研究表明，NH 存在引起的盐敏感被去除 Cl 所消除，但不受去除 Na 的影响，这表明 Cl 的过量积累而不是 Na 参与了 NH 引起的盐敏感。硝酸盐转运蛋白 NRT1.1 蛋白的表达也被 NH 处理上调，这增加了根 Cl 的摄取，因为 NRT1.1 的 Cl 摄取活性和缺乏与 NO 的摄取竞争。植物中 NRT1.1 的敲除降低了它们的根 Cl 摄取，并减弱了 NH 引起的盐敏感。我们的研究结果表明，NH 加剧了植物中的盐胁迫，与通过上调 NRT1.1 介导的 Cl 摄取导致的 Cl 过度积累有关。这些发现表明，在受洪水影响的沿海地区，Cl 毒性具有重要影响，这是一个具有生态意义的问题。
