Cotton Genomics and Genetics 2025, Vol.16, No.1, 12-20 http://cropscipublisher.com/index.php/cgg 15 shown their advantages in many crop studies. For cotton, many key traits, such as drought resistance and salt resistance, are often controlled by several core sites. Using these high-precision tools to "adjust parameters" is not only less prone to errors, but also reduces the interference of irrelevant mutations (Saleem et al., 2024). Therefore, they are indeed a more suitable choice for gene fine-tuning. 4 Molecular Targets for Abiotic Stress Resistance 4.1 Transcription factors (e.g., DREB, NAC, WRKY) Whether cotton can "handle things" sometimes depends on how the genes are arranged, especially those transcription factors that play a commanding role. DREB is one of the more famous examples. It can bind to dehydration-related sequences, thereby driving a group of stress resistance genes to "go online". This method makes cotton less likely to "break down" when it is short of water, high salt, low temperature or even high temperature (Sadau et al., 2024). Of course, DREB is not the only one that can do it. Some MYB-type transcription factors, such as GhMYB36, have shown good drought and disease resistance. Its method is to increase the expression level of defense genes such as PR1 (Liu et al., 2021). Another example is the BRX family. This category is also very "resistant". They can regulate the activities of some stress marker genes and enhance the performance of antioxidant enzymes. They are quite good at dealing with salinity and low temperature. Overall, there may not be many transcription factors, but they are really useful at critical times-editing the right site can increase resistance. 4.2 Genes regulating osmolyte biosynthesis and ion transport (e.g., P5CS, NHX1) Sometimes, whether a cell is stable or not does not entirely depend on the external environment, but on whether it can adjust itself internally. For example, when faced with drought or salt stress, the expression of genes such as GhSAMS2 will increase rapidly. It participates in anti-oxidation and protects cell membranes, and is a "first aid" player (Kilwake et al., 2023). Look at NHX1, this type of ion transporter is mainly responsible for sodium-potassium balance. Without them, cotton is basically difficult to survive in saline-alkali land. Other related genes cannot be ignored, such as GhSOS1 and GhCIPK6. Although they do not directly transport ions, they can indirectly help by regulating signal pathways. As for GbPLA1-32, it is related to lipid signals and stress responses. Once this gene is "turned off", cotton's tolerance to salt will be significantly reduced (Zhang et al., 2021a). From these examples, it can be seen that not all regulation is in the foreground, and some are also critical in the "backstage". 4.3 Stress-responsive signaling components It’s not that cotton doesn’t react, but it needs a “signal” to be transmitted first. When the external environment changes, the first to “sens” is a class of signal transduction molecules. For example, the calcium sensor GhCBL10 can interact with GhSAMS2 to activate the salt resistance mechanism. This linkage relationship may not be obvious, but neither can be missing. In addition, kinases such as GhSnRK2.6 and GhCIPK6 are generally activated at the beginning of stress. They are not directly resistant to stress, but trigger a series of protective reactions (Wei et al., 2024). There are also antioxidant enzymes such as SikCuZnSOD3, whose function is to maintain the balance of reactive oxygen species (ROS) and prevent cell damage (Zhang et al., 2021b). In short, as long as these “first response” mechanisms can be understood and they can be “tuned” through editing methods, cotton’s ability to cope with environmental stress can indeed be greatly improved. 5 Case Study: Application of CRISPR/Cas9 in Enhancing Drought Resistance 5.1 Targeting GhDREB2 for improved drought tolerance in field trials Not all drought-resistant traits can be selected through breeding, especially in crops with complex genomes such as cotton. Therefore, the researchers simply "made changes" and turned their attention to the key transcription factor GhDREB2. This gene is usually responsible for helping plants cope with drought, with fast response and obvious effects, so it seems natural to use it to "start". The use of CRISPR/Cas9 technology here is not complicated, and the goal is clear-to transform GhDREB2 so that cotton can activate its self-protection mechanism in time when it is short of water. In this way, the field performance is more stable, and the yield will not fluctuate greatly due to drought (Erdoğan et al., 2023). Of course, some people may ask, what is the essential
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