Triticeae Genomics and Genetics, 2025, Vol.16, No.6, 269-277 http://cropscipublisher.com/index.php/tgg 269 Feature Review Open Access Transgenic Improvement of Nitrogen Use Efficiency in Wheat Using Root-Specific Promoters Xingzhu Feng Hainan Institute of Biotechnology, Haikou, 570206, Hainan, China Corresponding email: xingzhu.feng@hibio.org Triticeae Genomics and Genetics, 2025, Vol.16, No.6 doi: 10.5376/tgg.2025.16.0030 Received: 30 Oct., 2025 Accepted: 16 Dec., 2025 Published: 31 Dec., 2025 Copyright © 2025 Ma and Wang, This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Preferred citation for this article: Feng X.Z., 2025, Transgenic improvement of nitrogen use efficiency in wheat using root-specific promoters, Triticeae Genomics and Genetics, 16(6): 269-277 (doi: 10.5376/tgg.2025.16.0030) Abstract Improving the nitrogen fertilizer utilization efficiency (NUE) of wheat is of great significance for achieving high-yield and low-pollution agriculture. Traditional breeding and fertilization strategies are difficult to achieve precise regulation, while the transgenic expression of key nitrogen metabolism genes driven by root-specific promoters provides a new idea for enhancing the NUE of wheat. This study systematically screened and validated a batch of root-specific promoters (such as OsRCc3 and ZmRCP1), constructed expression vectors of them and candidate highly efficient nitrogen metabolism genes (such as NRTs, GS, etc.), and evaluated the application potential of key promote-gene combinations under different ecological conditions through field experiments. The feasibility of this strategy in ecological security, environmental friendliness and sustainable agriculture was also explored, emphasizing the value of root-specific regulation in precision breeding. The research results show that under low-nitrogen conditions, these transgenic plants exhibit stronger root structures, higher nitrogen absorption capacity, as well as superior nitrogen fertilizer utilization efficiency and yield performance. This research provides theoretical support and technical foundation for achieving the parallel application of reduced nitrogen fertilizer and high yield, and is expected to promote the targeted utilization of rhizosphere functional genes and the development of transgenic nitrogen efficiency breeding. Keywords Nitrogen use efficiency (NUE); Root-specific promoter; Genetically modified wheat; Key genes for nitrogen metabolism; Precision breeding 1 Introduction Whether nitrogen fertilizer is applied or not is a key variable determining whether the yield can be increased. Especially for wheat, nitrogen, as a nutrient, is almost indispensable. However, in reality, giving too much is not necessarily a good thing. Nowadays, a considerable amount of nitrogen fertilizer is applied in the fields, but the proportion that is actually absorbed and utilized by the wheat is not high. Where did the remaining nitrogen go? Some entered groundwater, some volatilized into the air, and some even contributed to soil acidification (Tiong et al., 2021; Jiao et al., 2024). It seems that the more input, the higher the output, but in fact, it may bring a double burden on the ecology and economy. Improving the utilization efficiency of nitrogen fertilizers is clearly not only for the sake of yield, but also for the sustainability of farming. In dealing with this problem, traditional methods are not useless. Selecting wheat varieties with high "nitrogen-consuming efficiency" through breeding and agronomic measures has indeed played a role. However, problems have also emerged. For instance, some varieties, although having a strong nitrogen absorption capacity, have seen a decline in granular nitrogen content, making it difficult to achieve both yield and quality. Moreover, breeding itself is slow and has a long cycle, which is not suitable for rapid response to changes in the agricultural environment (Peng et al., 2022). Another point that is often overlooked is that these methods can actually do very limited in revealing exactly how nitrogen is absorbed, transported and utilized in wheat. Therefore, some people have begun to attempt to use genetically modified means for precise regulation. Although the idea is new, it is precisely the breakthrough point that deserves close attention at present. This study focuses on analyzing the use of root-specific promoter driver gene expression to enhance the nitrogen utilization efficiency of wheat through transgenic methods, aiming to optimize the absorption and assimilation of nitrogen by the root system and evaluate the effects of targeted transgenic expression on the growth, nitrogen
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