Bt Research 2025, Vol.16, No.3, 86-94 http://microbescipublisher.com/index.php/bt 88 threats. Changes in temperature and precipitation can alter the competition among pests, affecting the resistance of host plants and the number of natural enemies. Some minor pests have strong adaptability, or when natural enemies decrease, they may suddenly break out (Bajwa et al., 2020; Malhi et al., 2021; Subedi et al., 2023). In addition, climate change will also accelerate the spread of invasive pests, increase the emergence frequency of new pests and pathogens, and bring new challenges to agriculture and ecosystems (Pureswaran et al., 2018; Linnakoski et al., 2019). 4 Climate Change Effects on Bt Efficacy 4.1 Direct impacts on Bt proteins Climate change, especially the increase in temperature and carbon dioxide, may affect the stability, degradation rate and residence time of Bt protein in the environment. These changes will directly or indirectly reduce its insecticidal ability. The adsorption, decomposition and residue time of Bt protein in soil can be affected by environmental factors. Climate change may cause Bt protein to decompose more rapidly in the environment or combine with soil components, thereby affecting its activity and duration and reducing the field insecticidal effect (Li et al., 2022). In addition, the Bt proteins in genetically modified crops and those in natural Bt strains are inherently different in structure and function. Climate change may amplify the impact of these differences on environmental performance and insecticidal efficacy (Figure 1). Figure 1 Environmental behaviors of Bt protein (A) and its three-dimensional structures (B). I, II, and III: domains I, II, and III (Adopted from Li et al., 2022) 4.2 Plant physiology changes Climate change can affect the physiological processes of plants, such as growth rate, nutrient distribution and defense mechanisms, which will also indirectly influence the content and distribution of Bt protein. Some seasonal changes or environmental stresses may reduce the Bt protein in Bt crops, thereby reducing their ability to control pests. The responses of plants to climate stress, such as enhancing stress resistance or adjusting the growth cycle, may also change the distribution and concentration of Bt protein in different parts, which will affect the dose consumed by pests and thereby affect the insecticidal effect (Matzrafi, 2018). 4.3 Pest physiology and resistance evolution Climate change can also affect the physiological state, metabolic capacity and generation cycle of pests, thereby accelerating their adaptation and resistance evolution to Bt protein. High temperatures and increased carbon dioxide levels may enhance the detoxification ability of pests, making them less sensitive to Bt protein in specific environments. This situation is known as "conditional resistance" (Matzrafi, 2018). Meanwhile, climate change may accelerate the generational replacement of pests, accelerate the accumulation of resistance genes, and
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