Bt Research 2024, Vol.15, No.1, 42-52 http://microbescipublisher.com/index.php/bt 49 8 Applications in Pest Management 8.1. Development of targeted Bt crops The development of genetically engineered crops that produce Bacillus thuringiensis (Bt) toxins has revolutionized pest management by providing a targeted approach to controlling insect pests. Bt crops, such as corn and cotton, produce insecticidal proteins that are highly specific to certain pests, reducing the need for broad-spectrum insecticides and minimizing harm to non-target organisms (Huang et al., 2020; Gassmann and Reisig, 2022). The success of Bt crops in managing pests has been demonstrated in various regions, leading to regional suppression of pest populations and increased profits for farmers (Tabashnik et al., 2008). However, the evolution of resistance in some pest populations poses a significant challenge to the long-term efficacy of Bt crops (Tabashnik et al., 2009). 8.2 Strategies to overcome resistance To address the issue of resistance, several strategies have been proposed and implemented. One approach is the use of pyramided Bt crops, which produce multiple Bt toxins with different modes of action. This strategy aims to reduce the likelihood of pests developing resistance to all toxins simultaneously (Carrière et al., 2015). Additionally, modified Bt toxins that can overcome resistance mechanisms, such as those involving mutations in cadherin receptors, have been developed. These modified toxins have shown effectiveness against resistant pest populations (Soberón et al., 2007). Another strategy involves the use of refuges, which are areas planted with non-Bt crops to maintain a population of susceptible pests. This approach helps to delay the evolution of resistance by promoting the survival of susceptible individuals that can mate with resistant ones, thereby diluting resistance alleles in the population (Tabashnik, 2015). 8.3 Integration with other pest control methods Integrating Bt crops with other pest control methods can enhance the sustainability and effectiveness of pest management programs. Integrated pest management (IPM) strategies that combine Bt crops with biological control agents, crop rotation, and the use of conventional insecticides can provide a more comprehensive approach to pest control (Gassmann and Reisig, 2022). For example, increasing the prevalence of refuges and using IPM practices have been recommended to delay resistance and improve the durability of Bt crops (Gassmann and Reisig, 2022). Additionally, understanding the genetic and ecological factors that influence resistance can inform the development of more effective management strategies (Carrière et al., 2010). By combining multiple control methods, it is possible to reduce the selection pressure for resistance and achieve more sustainable pest management outcomes. 9 Concluding Remarks The research on Bt toxin-receptor interactions has significantly advanced our understanding of insect specificity. Key findings include the identification of specific receptor binding sites and the molecular mechanisms underlying these interactions. For instance, the Manduca sexta Bt-R1 receptor interacts with Cry1A toxins through specific epitopes, highlighting the importance of structural determinants in toxin binding. Multiple receptors, such as cadherin, alkaline phosphatase, and aminopeptidase-N, have been identified as targets for Cry toxins in mosquitoes, demonstrating the complexity of these interactions. Additionally, the role of ATP-binding cassette (ABC) transporters, such as ABCC2 and ABCC3, in mediating Cry toxin susceptibility has been elucidated, with transcription factors like FOXA playing a regulatory role. The identification of a 106-kDa aminopeptidase as a receptor for Cry11Ba in Anopheles gambiae further expands the repertoire of known Bt toxin receptors. Continued research in this field is crucial for several reasons. Understanding the molecular basis of Bt toxin-receptor interactions can aid in the design of new toxins to overcome insect resistance, a growing problem in pest management. The identification of multiple receptors and their roles in toxin binding and insect mortality can lead to the development of more effective and targeted biopesticides. Moreover, insights into the regulatory
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