Bt Research 2025, Vol.16, No.6, 259-268 http://microbescipublisher.com/index.php/bt 260 countries, policy decisions have been clearly influenced by public opinion and political games, while discussions at the technical level have been marginalized. In major agricultural countries like China and India, the development of Bt crops is deeply restricted by these non-technical factors (Gupta and Matharani, 2025). This study will critically examine the regulatory framework and risk assessment process for genetically modified Bt crops, with a focus on their effectiveness in promoting sustainable agricultural practices while ensuring environmental and food safety. It will identify the shortcomings and challenges of current regulatory approaches (including scientific, socio-political, and implementation aspects), and propose improvement plans that balance innovation and prevention. This study aims to support informed decision-making, thereby promoting the responsible use of Bt crops, enhancing food security, and reducing ecological risks, especially in developing countries where regulatory capacity may be limited. This research helps to gain a broader understanding of how the regulatory system ADAPTS to emerging biotechnologies and issues of public concern. 2 Biological Basis of Bt Transgenic Crops 2.1 Characteristics of Bacillus thuringiensis and its insecticidal genes The name "Bt" is often heard by people in the agricultural circle. It is actually a kind of bacteria that lives in the soil, with the full name of Bacillus thuringiensis. It is most famous for its ability to produce insecticidal proteins (ICPs) "incidentally" when spores form. These proteins, especially the Cry and Vip types, are basically the weapons it uses to "deal with bugs". In fact, these proteins are encoded by different cry and vip genes, and these genes are distributed differently on the Bt genome. Some are even hidden on plasmids. This arrangement is quite ingenious - it can synthesize different types of toxin mixtures to cover various pests, and the effect is more stable. For instance, the BtG strain contains seven cry genes, covering a rather wide range (Arsov et al., 2023). More importantly, Bt has little toxicity to humans and non-target organisms, so it is regarded as one of the representatives of environmentally friendly insecticidal methods (Metz, 2024). Of course, not all Bt strains are equally effective. The crystal shapes and toxin types expressed by different strains vary. Some are suitable for dealing with Lepidoptera, while others specialize in Coleoptera. Molecular sieve selection revealed that many native isolated strains carry genes such as cry1, cry2 and vip3, especially for chronic pests like cotton bollworms and fall armyworms, the killing rate can reach 100% (Gothandaraman et al., 2022). The cry9A and vip3A genes of some strains are still on the same plasmid, and when combined, they are quite useful for the rice stem borer (Wang et al., 2020). It is precisely these genetic characteristics that make the application of Bt in genetically modified crops possible and increasingly precise. 2.2 Expression and transformation methods of bt genes in major crops (e.g., Maize, Cotton) The process by which Bt becomes a "crop with inherent insecticidal function" is not as simple as spraying. Instead, its genes need to be firmly implanted into crops such as corn and cotton. This relies on gene transformation technology. There are two commonly used methods: Agrobacterium-mediated and gene gun. No matter which one it is, the purpose is the same - to introduce the cry gene into crop cells and ensure that it is expressed only at the required location through a specific promoter, saving energy and improving efficiency. Nowadays, the common Bt crops in the market are mostly single plants expressing multiple toxin combinations. For instance, Bollgard 3 cotton simultaneously expresses Cry1Ac, Cry2Ab and vip3A to control more lepidoptera pests (Holman et al., 2025). However, this expression is not simply "More is better". Scientists have to carefully adjust the accumulation level of toxins, which should neither be too little nor too much to affect the normal growth of crops. At present, the regulation of expression intensity has been relatively mature. Proteomics research has also confirmed the existence and activity of these proteins in plants, which not only kill pests but also do not hold back yields. Even better, the whole genome sequencing of Bt strains provided more candidate genes, giving transgenic engineering more combination space (Pacheco et al., 2021). These technological advancements have paved the way for the commercialization of Bt crops and also explain why they have been widely promoted in so many countries.
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