Bioscience Methods 2025, Vol.16, No.1, 1-10 http://bioscipublisher.com/index.php/bm 4 Figure 2 Diagram of a proposed model for regulation of IbSnRK1 in abiotic stress tolerance in transgenic sweet potato. ↑ indicates up-regulation of genes coding these enzymes (proteins) (Adopted from Ren et al., 2020) 3.4 Heat shock proteins and molecular chaperones Heat shock proteins (HSPs) and molecular chaperones play a pivotal role in protecting sweet potato from abiotic stresses by maintaining protein stability and preventing aggregation. HSPs are dynamically regulated in response to stress and are involved in the detoxification of ROS, thereby enhancing membrane stability and overall stress tolerance (Haq et al., 2019). The expression of HSPs is often induced by ROS signaling, which acts as a trigger for their production. This regulatory mechanism ensures that HSPs are available to counteract the damaging effects of abiotic stresses, such as heat and drought. The role of HSPs in sweet potato is further supported by the upregulation of stress-related genes, including those encoding HSPs, in transgenic plants overexpressing various stress-responsive genes (Gangadhar et al., 2016). 4 Molecular and Genetic Mechanisms Underpinning Stress Tolerance 4.1 Key genes involved in abiotic stress response Several key genes have been identified in sweet potato that contribute to abiotic stress tolerance. The gene IbC3H18, a non-tandem CCCH-type zinc-finger protein, is one such gene that enhances tolerance to salt, drought, and oxidative stresses by regulating the expression of stress-responsive genes involved in ROS scavenging, ABA signaling, photosynthesis, and ion transport pathways. Another important gene is IbSnRK1, which confers tolerance to salt, drought, and cold by activating the ROS scavenging system and controlling stomatal closure via the ABA signaling pathway (Ren et al., 2020). Additionally, IbMIPS1 enhances salt and drought tolerance by up-regulating genes involved in inositol biosynthesis, PI and ABA signaling pathways, and the ROS-scavenging system (Zhai et al., 2016). 4.2 Role of transcription factors Transcription factors (TFs) play a crucial role in regulating gene expression in response to abiotic stress. The ItfWRKY70 transcription factor from Ipomoea trifida has been shown to increase drought tolerance in sweet potato by up-regulating genes involved in ABA biosynthesis, stress response, and the ROS-scavenging system (Sun et al., 2022). The IbMYB73 transcription factor regulates root growth and stress tolerance by influencing the transcription of genes in the ABA pathway and forming homodimers to activate the transcription of the abscisic
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