Beschreibung:
<p>Ammonium (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline">
<mml:mrow>
<mml:mi>N</mml:mi>
<mml:msubsup>
<mml:mi>H</mml:mi>
<mml:mn>4</mml:mn>
<mml:mo>+</mml:mo>
</mml:msubsup>
</mml:mrow>
</mml:math>) plays an important role in phosphorus-deficiency responses in rice, but its role in responses to Fe deficiency remains unknown. Here, we demonstrate that the accumulation of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline">
<mml:mrow>
<mml:mi>N</mml:mi>
<mml:msubsup>
<mml:mi>H</mml:mi>
<mml:mn>4</mml:mn>
<mml:mo>+</mml:mo>
</mml:msubsup>
</mml:mrow>
</mml:math> plays a pivotal role when <italic>Arabidopsis thaliana</italic> plants are subject to Fe deficiency. The <italic>Arabidopsis amt1-3</italic> mutant, which is defective in endogenous <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline">
<mml:mrow>
<mml:mi>N</mml:mi>
<mml:msubsup>
<mml:mi>H</mml:mi>
<mml:mn>4</mml:mn>
<mml:mo>+</mml:mo>
</mml:msubsup>
</mml:mrow>
</mml:math> sensing, exhibited increased sensitivity to Fe deficiency compared to WT (wild type; Col-0). In addition, exogenous application of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline">
<mml:mrow>
<mml:mi>N</mml:mi>
<mml:msubsup>
<mml:mi>H</mml:mi>
<mml:mn>4</mml:mn>
<mml:mo>+</mml:mo>
</mml:msubsup>
</mml:mrow>
</mml:math> significantly alleviated Fe deficiency symptoms in plants. <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline">
<mml:mrow>
<mml:mi>N</mml:mi>
<mml:msubsup>
<mml:mi>H</mml:mi>
<mml:mn>4</mml:mn>
<mml:mo>+</mml:mo>
</mml:msubsup>
</mml:mrow>
</mml:math> triggers the production of nitric oxide (NO), which then induces ferric-chelate reductase (FCR) activity and accelerates the release of Fe from the cell wall, especially hemicellulose, thereby increasing the availability of soluble Fe in roots. <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline">
<mml:mrow>
<mml:mi>N</mml:mi>
<mml:msubsup>
<mml:mi>H</mml:mi>
<mml:mn>4</mml:mn>
<mml:mo>+</mml:mo>
</mml:msubsup>
</mml:mrow>
</mml:math> also increases soluble Fe levels in shoots by upregulating genes involved in Fe translocation, such as <italic>FRD3 (FERRIC REDUCTASE DEFECTIVE3)</italic> and <italic>NAS1 (NICOTIANAMINE SYNTHASE1),</italic> hence, alleviating leaf chlorosis. Overall, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline">
<mml:mrow>
<mml:mi>N</mml:mi>
<mml:msubsup>
<mml:mi>H</mml:mi>
<mml:mn>4</mml:mn>
<mml:mo>+</mml:mo>
</mml:msubsup>
</mml:mrow>
</mml:math> plays an important role in the reutilization of Fe from the cell wall and the redistribution of Fe from root to shoot in Fe-deficient <italic>arabidopsis</italic>, a process dependent on NO accumulation.</p>