Glutamine synthetase (GS) and the glutamate synthase (GOGAT) cycle are closely related to plant nitrogen (N) uptake, translocation, and remobilization, but little attention has been paid to their role in intercropping systems. A two-factor field trial involving two planting patterns (mono-cropped wheat [MW] and wheat intercropped with faba bean) and four N levels (N0, N1, N2, and N3 with respective application rates of 0, 90, 180, and 270 kg ha⁻¹ for wheat) were studied. Nitrogen accumulation and allocation were determined, and the GS and GOGAT activities and their gene expression in the leaves were analyzed. The results showed that wheat total aboveground N accumulation and grain N accumulation were increased when wheat was intercropped with faba bean. Intercropped wheat (IW) presented higher N translocation efficiency (NTE) than MW (except for the N3 level during 2018–2019) during the reproductive growth stage. Thus, the grain yield (except for the N3 level), N harvest index (NHI), and apparent N recovery rate (ANR) were higher in IW than in MW. In addition, total GS, Fd-GOGAT, and NADH-GOGAT activities in the wheat leaves were increased by 27 %–42 %, 17 %–44 %, and 15 %–25 %, respectively, under the N0, N1, and N2 levels from the stem elongation to filling stages when wheat was intercropped with faba bean. On average, GS1, GS2, Fd-GOGAT, and NADH-GOGAT gene expression in the IW flag leaves was 1.4–4.3 times, 1.2–3.6 times, 1.2–2.2 times, and 1.4–6.7 times higher, respectively, than that in MW. Both GS and GOGAT activity and gene expression were tightly related to straw N accumulation and NTE rather than grain N accumulation based on simple correlation analysis. In addition, wheat total N accumulation at maturity was more sensitive to GS and GOGAT activity and gene expression in the flag leaves during the heading, flowering, and filling stages, and ANR only linked with GS and GOGAT activity at the filling stage. Hence, it could be concluded that up-regulated GS and GOGAT activity and gene expression induced by intercropping during the reproductive growth stages contributed to higher NTE and NUE in intercropping. These findings suggest that interspecies interactions modulated GS and GOGAT, which play a crucial role in the intercropping advantage and provide insight into the mechanism of enhanced NUE under intercropping.

谷氨酰胺合成酶 (GS) 和谷氨酸合成酶 (GOGAT) 循环与植物氮 (N) 吸收、易位和再动员密切相关，但很少有人关注它们在间作系统中的作用。一项双因素田间试验，涉及两种种植模式（单作小麦 [MW] 和与蚕豆间作的小麦）和四种氮水平（N0、N1、N2 和 N3，施用量分别为 0、90、180 和270 公斤公顷^-1小麦）进行了研究。确定氮的积累和分配，并分析GS和GOGAT活性及其在叶片中的基因表达。结果表明，小麦与蚕豆间作提高了小麦地上总氮积累量和籽粒氮积累量。在生殖生长阶段，间作小麦（IW）的氮转运效率（NTE）高于MW（2018-2019年期间的N3水平除外）。因此，IW 的谷物产量（N3 水平除外）、N 收获指数（NHI）和表观 N 回收率（ANR）高于 MW。此外，小麦叶片中总 GS、Fd-GOGAT 和 NADH-GOGAT 活性在 N0、N1、当小麦与蚕豆间作时，从茎的伸长到灌浆阶段的 N2 水平。平均而言，IW 旗叶中 GS1、GS2、Fd-GOGAT 和 NADH-GOGAT 基因表达量分别是 IW 旗叶的 1.4-4.3 倍、1.2-3.6 倍、1.2-2.2 倍和 1.4-6.7 倍。兆瓦。基于简单的相关分析，GS和GOGAT活性和基因表达与秸秆N积累和NTE密切相关，而不是谷物N积累。此外，小麦成熟期全氮积累对抽穗期、开花期和灌浆期旗叶中GS和GOGAT活性及基因表达更为敏感，ANR仅与灌浆期GS和GOGAT活性相关。因此，可以得出结论，在生殖生长阶段间作诱导的GS和GOGAT活性和基因表达上调有助于提高间作NTE和NUE。这些发现表明，种间相互作用调节了 GS 和 GOGAT，它们在间作优势中起着至关重要的作用，并提供了对间作下 NUE 增强机制的深入了解。