Field Crop 2024, Vol.7, No.2, 58-69 http://cropscipublisher.com/index.php/fc 58 Review Article Open Access Nitrogen Fixation in Legumes: Genetic Mechanisms and Agricultural Applications Wenzhong Huang Hainan Institute of Tropical Agricultural Resources, Tropical Animal and Plant Resources Research Center, Sanya, 572025, Hainan, China Corresponding email: wenzhong.huang@hitar.org Field Crop, 2024 Vol.7, No.2 doi: 10.5376/fc.2024.07.0007 Received: 13 Jan., 2024 Accepted: 24 Feb., 2024 Published: 16 Mar., 2024 Copyright © 2024 Huang, 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: Huang W.Z., 2024, Nitrogen fixation in legumes: genetic mechanisms and agricultural applications, Field Crop, 7(2): 58-69 (doi: 10.5376/fc.2024.07.0007) Abstract Biological nitrogen fixation (BNF) in legumes is a critical process that significantly contributes to sustainable agriculture by reducing the need for synthetic fertilizers. This study provides a comprehensive examination of the historical background, genetic mechanisms, symbiotic relationships, agricultural applications, and environmental impacts of nitrogen fixation in legumes. Key discoveries in legume nitrogen fixation and the evolution of symbiotic nitrogen fixation (SNF) research are highlighted, along with the identification of essential genes and genetic pathways involved in SNF. Advances in genetic modification techniques aimed at enhancing nitrogen fixation are discussed. This study also explores the role of rhizobia in nodule formation, plant-microbe signaling, and the benefits of incorporating legumes into cropping systems. Case studies demonstrating successful agricultural implementations and the environmental benefits of BNF are presented, emphasizing the reduction in synthetic fertilizer use and improvements in soil health. A detailed analysis of a case study on genetic modification in soybeans is included, providing insights into future agricultural practices. This study concludes by addressing the challenges and limitations of current genetic and agronomic approaches, proposing potential solutions, and highlighting future research directions. The integration of emerging technologies in genetic engineering and microbiome manipulation, along with the prospects for transferring nitrogen-fixing capabilities to non-legume crops, are discussed. This study underscores the importance of continued research and development in enhancing nitrogen fixation for sustainable agriculture. Keywords Biological nitrogen fixation; Legumes; Symbiotic nitrogen fixation; Genetic modification; Sustainable agriculture 1 Introduction Nitrogen fixation is a critical biological process that allows certain plants, particularly legumes, to convert atmospheric nitrogen (N₂) into a form that is usable by plants, such as ammonia (NH₃). This process is facilitated by symbiotic relationships between legumes and nitrogen-fixing bacteria, primarily rhizobia, which inhabit root nodules of the host plants. The symbiotic relationship between legumes and rhizobia is highly specialized and involves complex signaling pathways and genetic mechanisms that ensure successful colonization and nitrogen fixation (Mahmud et al., 2020; Kebede, 2021). The ability of legumes to fix atmospheric nitrogen not only benefits the legumes themselves but also enhances soil fertility, making nitrogen available to subsequent crops in a rotation system (Liu et al., 2011; Iannetta et al., 2016). Biological nitrogen fixation (BNF) plays a pivotal role in sustainable agriculture by reducing the need for synthetic nitrogen fertilizers, which are associated with environmental issues such as nitrate pollution and greenhouse gas emissions (Mahmud et al., 2020; Ma et al., 2022). The integration of legumes into cropping systems can significantly improve soil health and productivity by increasing the availability of nitrogen and other nutrients, breaking pest cycles, and enhancing soil microbial activity (Olivares et al., 2013; Kebede, 2021). Moreover, BNF contributes to the overall nitrogen balance in agricultural ecosystems, supporting higher yields and reducing the dependency on chemical fertilizers (Iannetta et al., 2016; Batista and Dixon, 2019). The adoption of legume-based cropping systems and the development of biofertilizers that exploit BNF are essential strategies for achieving sustainable agricultural practices and mitigating the adverse effects of intensive fertilizer use (Olivares et al., 2013; Ma et al., 2022).
RkJQdWJsaXNoZXIy MjQ4ODY0NQ==