Nitrogen (N) uptake and nitrogen utilization are two major components of nitrogen use efficiency (NUE), where N-utilization is a function of N-assimilation and N-remobilization. Transcription factor Dof1 regulates Carbon (C) metabolism in the TCA cycle and also controls the NUE in the plant by ensuring optimum C-skeleton supply for N-assimilation. In this study, four diverse wheat genotypes were selected based on their varied response to N stress in a field experiment conducted during 2012–2013. These genotypes are subjected to N-stress in Pots in the next two consecutive years (2014, 2015), where N stress level on year 2 (2015) was higher than year 1 (2014). Expression of Tadof1 was studied in leaf tissue from two growth stages, 30 (stage 1) and 60 (stage 2), days after sowing. TaDof1 expression was found upregulated during year 1 and gradually down-regulated at stage 2 of year 2 when the N-stress was maximum. HS-277, an Efficient NUtE genotype, shows relatively highest TaDof1 expression under limited N-stress; however, the downregulation was also maximum under severe stress. In optimum N supply, GS2 (Glutamine synthetase) and NADH-GOGAT (Glutamate synthase) activity increased in wheat leaves when the plants grew up from stage 1 to stage 2. However, the activity reduced significantly under severe N-stress in the low NUtE genotypes, Sujata and VL-401. Our result shows that role of TaDof1 varies among the wheat genotypes, and this variation is probably one of the factors affecting N-assimilation and ultimately yield as well as NUE.

氮 (N) 吸收和氮利用是氮利用效率 (NUE) 的两个主要组成部分，其中氮利用是氮同化和氮再活化的函数。转录因子 Dof1 调节 TCA 循环中的碳 (C) 代谢，并通过确保 N 同化的最佳 C 骨架供应来控制植物中的 NUE。在这项研究中，在 2012-2013 年进行的田间试验中，根据它们对氮胁迫的不同反应选择了四种不同的小麦基因型。这些基因型在接下来的连续两年（2014 年、2015 年）在 Pots 中受到 N 胁迫，其中第 2 年（2015 年）的 N 胁迫水平高于第 1 年（2014 年）。在播种后 30 天（第 1 阶段）和 60 天（第 2 阶段）的两个生长阶段的叶组织中研究了Tadof1 的表达。TaDof1在第 1 年发现表达上调，在第 2 年第 2 阶段 N 应力最大时逐渐下调。HS-277 是一种高效的 NUtE 基因型，在有限的 N 胁迫下表现出相对最高的TaDof1表达；然而，在严重压力下，下调也是最大的。在最佳施氮条件下，小麦叶片的GS2（谷氨酰胺合成酶）和NADH-GOGAT（谷氨酸合成酶）活性随着植株从第1阶段生长到第2阶段而增加。然而，在低NUtE的严重氮胁迫下，活性显着降低基因型，Sujata 和 VL-401。我们的结果表明，TaDof1 的作用在小麦基因型中有所不同，这种变异可能是影响 N 同化和最终产量以及 NUE 的因素之一。