Bt Research 2024, Vol.15, No.1, 1-9 http://microbescipublisher.com/index.php/bt 7 effects against different pest species or under different environmental conditions. By analyzing and comparing genetic diversity, B.t. strains with specific characteristics can be identified, allowing for more targeted applications in agricultural production and pest control strategies. 5 The Impact of Gene Evolution on The Control of Phenacoccus solenopsis ByB.t. 5.1 The diversity and efficacy of insect resistance genes B.t. is an important biological pesticide in the prevention and control of Phenacoccus solenopsis. The insecticide toxin produced by B.t. is encoded by its genome's insect resistance genes, and the diversity and potency of these genes are crucial for the prevention and control of Phenacoccus solenopsis (Tawfik-Abbas, 2018). There are multiple different insect resistance genes present in the genome of B.t. strains. These insect resistance genes encode different toxin proteins that have insecticidal activity against Phenacoccus solenopsis. Different B.t. strains have different combinations of insect resistance genes and toxin expression levels, leading to diversity in their insecticidal potency. Some B.t. strains may be rich in multiple insect resistance genes, with broad-spectrum insecticidal activity, while others may only have certain specific insect resistance genes, targeting specific pests. The diversity of insect resistance genes in B.t. strains is closely related to their insecticidal potency. A variety of combinations of insect resistance genes can provide a broader spectrum of insecticidal activity, effectively controlling different genotypes of Phenacoccus solenopsis pests. Additionally, the expression levels of different genes and the characteristics of insecticidal toxins also affect the insecticidal potency. Some insect resistance genes have higher insecticidal activity and stable expression levels, resulting in better control effects on Phenacoccus solenopsis. Understanding the diversity and potency of insect resistance genes in B.t. strains is of guiding significance for selecting and developing biologically active pesticides with efficient insect resistance capabilities. By analyzing the diversity of insect resistance genes, strains with higher insecticidal potency can be selected, and further research and improvement can be conducted to enhance their application in the prevention and control of cotton red wax scale. Additionally, understanding the diversity of insect resistance genes in different B.t. strains can also help reduce the occurrence of resistant strains and maintain the long-term effectiveness of B.t. 5.2 Gene evolution and the enhancement of insect resistance ability and its mechanism Bacterial evolution of B.t. plays an important role in the enhancement of insect resistance in the prevention and control of Phenacoccus solenopsis. B.t. strains have high genetic plasticity and can enhance their insect resistance through gene evolution. They interact with pests in the natural environment over long periods of time, leading to genetic variation and accumulation. When B.t. strains are subject to selection pressure from pests, only genotypes with strong insecticidal activity can survive and reproduce. This evolutionary selection promotes the gradual increase in the frequency of insect resistance genes in B.t. strains, thereby enhancing their insect resistance against cotton red wax scale. Gene evolution can also enhance the insect resistance of B.t. strains through the mechanism of horizontal gene transfer. B.t. strains can absorb new insect resistance genes from other strains or the environment through horizontal gene transfer and integrate them into their own genome. In this way, B.t. strains can acquire new insect resistance genes and may exhibit broader or more effective insecticidal activity. This mechanism of horizontal gene transfer can promote the enhancement and diversity of insect resistance in B.t. strains (Malkie et al., 2018). Bacterial evolution of B.t. in the prevention and control of Phenacoccus solenopsis can also enhance insect resistance through the mechanism of mutation and selection. Mutation refers to changes in the DNA sequence of the genome, which may lead to the production of new insect resistance genes or changes in existing genes. When mutant individuals with stronger insecticidal activity appear, they have a greater survival advantage under selection pressure for insect resistance. This allows B.t. strains to enhance their insect resistance through natural selection and adapt to the constantly changing pest environment.
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