Zhu Yunna, Huang Xinmin, Hao Yanwei, Su Wei, Liu Houcheng, Sun Guangwen, Chen Riyuan, Song Shiwei
College of Horticulture, South China Agricultural University, Guangzhou, China.
College of Yingdong Agricultural Science and Engineering, Shaoguan University, Shaoguan, China.
Front Plant Sci. 2020 Feb 4;10:1776. doi: 10.3389/fpls.2019.01776. eCollection 2019.
The provision of ammonium (NH ) and nitrate (NO ) mixture increases the total nitrogen (N) than the supply of sole NH or NO with the same concentration of total N; thus, the mixture contributes to better growth in . However, the underlying mechanisms remain unknown. In this study, we analyzed NH and NO fluxes using a scanning ion-selective electrode technique to detect under different N forms and levels in roots. We observed that the total N influxes with NH and NO mixture were 1.25- and 3.53-fold higher than those with either sole NH or NO . Furthermore, NH and NO might interact with each other under coexistence. NO had a positive effect on net NH influx, whereas NH had a negative influence on net NO influx. The ammonium transporter (AMT) played a key role in NH absorption and transport. Based on expression analysis, differed from other in being upregulated by NH or NO . According to sequence analysis and functional complementation in yeast mutant 31019b, AMT1.2 from may be a functional AMT. According to the expression pattern of , β-glucuronidase activity, and the cellular location of its promoter, BcAMT1.2 may be responsible for NH transport. Following the overexpression of in , -overexpressing lines grew better than wildtype lines at low NH concentration. In the mixture of NH and NO , NH influxes and NO effluxes were induced in -overexpressing lines. Furthermore, transcripts of N assimilation genes (, , and ) were significantly upregulated, in particular, and were increased by 2.85-8.88 times in roots, and and were increased by 2.67-4.61 times in leaves. Collectively, these results indicated that may mediate in NH fluxes under the coexistence of NH and NO in .
提供铵（NH₄⁺）和硝酸盐（NO₃⁻）混合物比供应相同总氮浓度的单一NH₄⁺或NO₃⁻能增加总氮（N）含量；因此，该混合物有助于[植物名称]更好地生长。然而，其潜在机制仍不清楚。在本研究中，我们使用扫描离子选择性电极技术分析了[植物名称]根系在不同氮形态和水平下的NH₄⁺和NO₃⁻通量。我们观察到，NH₄⁺和NO₃⁻混合物的总氮流入量分别比单一NH₄⁺或NO₃⁻高1.25倍和3.53倍。此外，NH₄⁺和NO₃⁻在共存时可能相互作用。NO₃⁻对净NH₄⁺流入有积极影响，而NH₄⁺对净NO₃⁻流入有负面影响。铵转运蛋白（AMT）在NH₄⁺吸收和运输中起关键作用。基于表达分析，[植物名称]与其他[植物名称]不同，其受NH₄⁺或NO₃⁻上调。根据序列分析和酵母突变体31019b中的功能互补，[植物名称]的AMT1.2可能是一种功能性AMT。根据[基因名称]的表达模式、β - 葡萄糖醛酸酶活性及其启动子的细胞定位，BcAMT1.2可能负责NH₄⁺运输。在[植物名称]中过表达[基因名称]后，过表达株系在低NH₄⁺浓度下比野生型株系生长更好。在NH₄⁺和NO₃⁻混合物中，过表达株系诱导了NH₄⁺流入和NO₃⁻流出。此外，氮同化基因（[基因名称1]、[基因名称2]和[基因名称3]）的转录本显著上调，特别是[基因名称1]和[基因名称2]在根中增加了2.85 - 8.88倍，[基因名称3]和[基因名称4]在叶中增加了2.67 - 4.61倍。总体而言，这些结果表明[基因名称]可能在NH₄⁺和NO₃⁻共存时介导[植物名称]中的NH₄⁺通量。
