Maize Genomics and Genetics 2025, Vol.16, No.6, 294-303 http://cropscipublisher.com/index.php/mgg 294 Research Insight Open Access CRISPR/Cas9-Mediated Knockout of Drought-Sensitive Genes Improves Maize Tolerance Xingzhu Feng Hainan Institute of Biotechnology, Haikou, 570206, Hainan, China Corresponding author: xingzhu.feng@hibio.org Maize Genomics and Genetics, 2025, Vol.16, No.6 doi: 10.5376/mgg.2025.16.0027 Received: 20 Sep., 2025 Accepted: 30 Oct., 2025 Published: 20 Nov., 2025 Copyright © 2025 Feng, 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, CRISPR/Cas9-mediated knockout of drought-sensitive genes improves maize tolerance, Maize Genomics and Genetics, 16(6): 294-303 (doi: 10.5376/mgg.2025.16.0027) Abstract Maize (Zea mays L.) plays a crucial role in ensuring global food security, yet its productivity is severely threatened by recurrent drought stress in many regions. Conventional breeding approaches have achieved limited success in improving drought resilience due to the complex and polygenic nature of drought tolerance. In this study, we explore the application of CRISPR/Cas9 genome editing technology as a precise and efficient strategy for enhancing drought tolerance in maize. By reviewing recent advances, we identified key drought-sensitive genes such as ZmNAC111, ZmPP2C-A10, and ZmDREB2A, which were targeted for knockout using various transformation techniques including Agrobacterium-mediated and biolistic methods. Functional validation and field evaluations of CRISPR-edited maize lines demonstrated significant improvements in physiological and agronomic traits under drought conditions, including enhanced root development, reduced stomatal conductance, better water retention, and higher yield stability compared to wild-type plants. The findings highlight that gene knockouts effectively mitigate drought-induced physiological stress and optimize water use efficiency. Although challenges remain regarding off-target effects, regulatory frameworks, and public acceptance, CRISPR/Cas9 offers a transformative platform for integrating molecular precision with traditional breeding. This study underscores the potential of genome editing in developing drought-resilient maize varieties and anticipates future advancements through multiplex editing and next-generation CRISPR technologies. Keywords CRISPR/Cas9; Drought tolerance; Maize; Gene knockout; Genome editing 1 Introduction Corn (Zea mays L.) is the star on the dining tables in many countries and an important source of industrial raw materials and feed. Its significance is no longer merely as a staple food; it is related to the nutritional intake and livelihood stability of millions of people around the world. However, the problem is not small either. In recent years, droughts caused by climate change have become increasingly frequent. Sometimes they not only last for a long time but also have a high intensity. Corn has naturally become one of the "victims", with its output declining and the global food system also affected (Sami et al., 2021). Drought is not a new term, but it is indeed one of the most troublesome abiotic stresses. It not only disrupts the growth rhythm of plants but may also affect the entire physiological process (Kumar et al., 2023). Especially for crops like corn that are more sensitive to water, the blow is even more obvious. In addition to reduced production, drought may also affect grain quality and even plant health. Ultimately, it affects not only farmland, but the entire supply chain and farmers' income (Peer et al., 2024). However, things are not that simple. Want to solve the problem of drought resistance through breeding? The difficulty is much greater than imagined. On the one hand, behind the drought resistance of corn lies a complex genetic network, with many genes working together (Chen, 2025). On the other hand, although traditional breeding methods are quite experienced in improving some traits, they are inadequate in enhancing drought resistance. The reasons include long time consumption and low efficiency. In addition, alleles with drought resistance characteristics are also rare in natural germplasm (Lorenzo et al., 2022). As for genetically modified organisms? Technically, there is some hope, but in reality, it is often limited by policy restrictions and public concerns (Joshi et al., 2020).
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