Institute of Crop Science, Nutritional Crop Physiology, University of Hohenheim, Fruwirthstr. 20, 70593, Stuttgart, Germany.
Physiol Plant. 2021 Mar;171(3):328-342. doi: 10.1111/ppl.13113. Epub 2020 May 31.
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 (NH NO = NN, NH Cl = NNH and KNO = NNO ). 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) of wheat (Triticum aestivum) 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.
传统的小麦生产使用各种形式的氮肥。尽管在高浓度下铵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品质。因此，我们研究了不同氮源（NH 4 NO 3 = NN、NH 4 Cl = NNH 3 和 KNO 3 = NNO 3 ）对冬小麦幼苗的反应。用铵态氮培养的生长情况更好。然而，单一铵的浓度升高会导致严重的毒性症状和生物量积累的显著减少。我们通过收集小麦（Triticum aestivum）的铵转运体（AMT）概述来解决铵摄取的分子背景，并对假定的高亲和力 TaAMT1 转运体进行了特征描述。TaAMT1;1 和 TaAMT1;2 在酵母和非洲爪蟾卵母细胞中均具有活性，并表现出饱和的高亲和力铵转运特性。有趣的是，氮饥饿以及向饥饿幼苗中补充铵都会触发 TaAMT1 的表达增加。硝酸盐的存在无缝地抑制了它们的表达。我们得出的结论是，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大响应能力。
