Cotton Genomics and Genetics 2025, Vol.16, No.6, 269-277 http://cropscipublisher.com/index.php/cgg 269 Feature Review Open Access Regulatory Role of Promoter Variants in Cotton Stress-Responsive Genes Jinhua Cheng, Mengting Luo Institute of Life Science, Jiyang College of Zhejiang A&F University, Zhuji, 311800, China Corresponding email: mengting.luo@jicat.org Cotton Genomics and Genetics, 2025, Vol.16, No.6 doi: 10.5376/cgg.2025.16.0027 Received: 07 Sep., 2025 Accepted: 20 Oct., 2025 Published: 10 Nov., 2025 Copyright © 2025 Cheng and Luo, 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: Cheng J.H., and Lou M.T., 2025, Regulatory role of promoter variants in cotton stress-responsive genes, Cotton Genomics and Genetics, 16(6): 269-277 (doi: 10.5376/cgg.2025.16.0027) Abstract Cotton, as one of the world's important economic crops, often faces abiotic stresses such as drought, saline-alkali conditions and extreme temperatures. These environmental pressures severely restrict its growth and development as well as the stability of its yield. In recent years, molecular genetic studies have shown that promoter variations play a key role in regulating the expression of stress response genes in cotton. This study systematically reviewed the structure and function of promoters, the classification and characteristics of cotton stress-response genes, as well as the types of promoter variations involved in regulation. It focused on analyzing how promoter polymorphisms lead to transcriptional regulatory differences under stress conditions and affect cotton's adaptability to environmental stress. The molecular mechanisms such as sequence variations in the promoter region, DNA methylation, histone modification, and transcription factor interactions were also deeply explored. Key stress response genes such as AtDREB1A, GhHSP70, and GhERF1 were selected, and the specific functional manifestations of their promoter variations in salt tolerance, heat resistance, and drought resistance traits were introduced. This research is expected to provide new ideas for a deeper understanding of the regulatory network of plant environmental adaptability and promote the functional exploration and stress resistance improvement of cotton germplasm resources. Keywords Cotton (Gossypiumspp.); Promoter mutation; Stress response gene; Gene expression regulation; Abiotic stress tolerance 1 Introduction When it comes to which crop is the most "reliable", cotton (Gossypiumspp.) is definitely on the list. It is not only the most important source of natural fibers in the global textile industry, but also directly related to the basic agricultural economy in many countries. Growing cotton has supported the livelihoods of many families. For some developing countries, it is even a pillar of industry. However, it doesn't mean that having land guarantees good cotton cultivation. Whether it is drought, salinity and alkalinity, high temperature or low temperature, these abiotic stresses have long plagued farmers in cotton-growing areas, causing considerable impacts on yield and quality (Tang et al., 2024). In recent years, with the continuous improvement of genomics and transcriptomics tools, researchers have gradually drawn a regulatory map of cotton's "self-rescue" in adverse conditions. Transcription factors such as MYB, NAC, AP2/ERF, GLK, and bZIP, as well as some enzyme genes related to stress response, have been successively discovered (Zafar et al., 2022; Gu et al., 2023; Wang et al., 2024). But for these genes to "speak", there must be promoters behind them to cooperate. Especially when facing complex environmental signals, the regulatory role of the promoter region is often more crucial than people imagine. Not all promoters are the same. Some cis element variations can make gene expression stronger or more precise. Genes such as GhNAC2 or GhHSP70-26 have multiple regulatory elements related to hormone or stress responses in their promoter regions. Once such structures change, they may directly affect the binding sites of transcription factors (Hamid et al., 2024; Naresh et al., 2024). Bao et al. (2020) pointed out that sequence changes at some key positions might be the cause of differences in gene expression and thus the varying degrees of tolerance. Interestingly, the launcher is not only a "console" but also a "transformation entry point". Shaban et al. (2018) and Guo et al. (2023) found that if the response capabilities of certain promoter components are precisely controlled, the performance of cotton in adverse conditions can be significantly enhanced. In other words, these variations are not only the research subjects but also likely to be the breakthrough points for future stress-resistant breeding.
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