Conventional wheat production utilizes fertilizers of various nitrogen forms. Sole ammonium nutrition has been shown to improve grain quality, despite the potential toxic effects of ammonium at elevated concentrations. We therefore investigated the responses of young seedlings of winter wheat to different nitrogen sources (NH4 NO3 = NN, NH4 Cl = NNH4 + and KNO3 = NNO3 - ). Growth with ammonium-nitrate was superior. However, an elevated concentration of sole ammonium caused severe toxicity symptoms and significant decreases in biomass accumulation. We addressed the molecular background of the ammonium uptake by gathering an overview of the ammonium transporter (AMT) inventory of wheat and characterized the putative high affinity TaAMT1 transporters. TaAMT1;1 and TaAMT1;2 were both active in yeast and Xenopus laevis oocytes and showed saturating high affinity ammonium transport characteristics. Interestingly, nitrogen starvation, as well as ammonium resupply to starved seedlings triggered an increase in the expression of the TaAMT1s. The presence of nitrate seamlessly repressed their expression. We conclude that wheat showed the ability to respond robustly to sole ammonium supply by adopting distinct physiological and transcriptional responses. This article is protected by copyright. All rights reserved.

中文翻译：

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小麦幼苗对铵盐的浓度依赖性生理和转录适应

传统的小麦生产使用各种氮形式的肥料。尽管铵在高浓度下具有潜在的毒性作用，但单一的铵营养已被证明可以改善谷物质量。因此，我们研究了冬小麦幼苗对不同氮源（NH4 NO3 = NN、NH4 Cl = NNH4 + 和 KNO3 = NNO3 - ）的响应。硝酸铵的生长是优越的。然而，单一铵浓度的升高会导致严重的毒性症状和生物量积累的显着减少。我们通过收集小麦铵转运蛋白 (AMT) 清单的概述来解决铵吸收的分子背景，并对假定的高亲和力 TaAMT1 转运蛋白进行表征。TaAMT1;1 和 TaAMT1; 2 在酵母和非洲爪蟾卵母细胞中均具有活性，并显示出饱和的高亲和力铵转运特性。有趣的是，氮饥饿以及对饥饿幼苗的铵补给引发了 TaAMT1s 表达的增加。硝酸盐的存在无缝地抑制了它们的表达。我们得出结论，小麦通过采用不同的生理和转录反应，表现出对单一铵供应的强烈反应的能力。本文受版权保护。版权所有。我们得出结论，小麦通过采用不同的生理和转录反应，表现出对单一铵供应的强烈反应的能力。本文受版权保护。版权所有。我们得出结论，小麦通过采用不同的生理和转录反应，表现出对单一铵供应的强烈反应的能力。本文受版权保护。版权所有。