Bt_2024v15n3

Bt Research 2024, Vol.15, No.3, 154-163 http://microbescipublisher.com/index.php/bt 161 biopesticidal metabolites, such as zwittermicin and various dioxygenases, which highlight the potential of Bt strains like MORWBS1.1 for biotechnological applications. The complete genome sequencing of multidrug-resistant strains, such as HM-311, has elucidated the presence of numerous antibiotic and heavy metal resistance genes, providing a reference for understanding the co-selection of resistance traits. Comparative genomic and proteomic analyses have shown that not all annotated genes are expressed, with some being silenced or expressed at very low levels, which is crucial for constructing highly virulent engineered bacteria. Additionally, the complete genome sequencing of various Bt strains has identified novel plasmids and unique cry genes, which are essential for the entomopathogenic properties of Bt. Genomic studies in Bacillus thuringiensis are of paramount importance for several reasons. They provide a comprehensive understanding of the genetic basis for Bt's biopesticidal properties, which is critical for developing effective and sustainable pest control strategies. These studies help in identifying and characterizing resistance genes, which is essential for managing the spread of antibiotic and heavy metal resistance in agricultural and environmental settings. The comparative genomic and proteomic approaches enhance our ability to identify and manipulate key functional elements, thereby facilitating the development of genetically engineered Bt strains with improved efficacy and safety profiles. Lastly, the genomic data contribute to the taxonomic and phylogenomic classification of Bt, aiding in the accurate identification and differentiation of Bt strains from closely related species within the Bacillus cereus group. Future research on the genomic architecture of Bacillus thuringiensis should focus on several key areas. Firstly, there is a need for more comprehensive comparative genomic studies to explore the diversity and distribution of biopesticidal genes across different Bt strains, which will aid in the identification of novel biocontrol agents. Secondly, further investigation into the mechanisms of gene silencing and low-level expression in Bt is necessary to optimize the expression of key insecticidal proteins and enhance the efficacy of Bt-based biopesticides. Thirdly, the role of plasmids and other mobile genetic elements in the horizontal transfer of resistance and virulence genes should be studied in greater detail to understand their impact on the evolution and adaptability of Bt. Additionally, integrating genomic data with functional studies, such as transcriptomics and proteomics, will provide a more holistic understanding of the regulatory networks and metabolic pathways in Bt. Finally, efforts should be made to develop standardized genomic and molecular markers for the accurate identification and classification of Bt strains, which will facilitate their use in both research and practical applications. Acknowledgments We would like to express our gratitude to the two anonymous peer researchers for their critical assessment and constructive suggestions on our manuscript. Conflict of Interest Disclosure The authors affirm that this research was conducted without any commercial or financial relationships that could be construed as a potential conflict of interest. References Adeniji A., Ayangbenro A., and Babalola O., 2021, Genomic exploration of Bacillus thuringiensis MORWBS1.1-candidate biocontrol agent, predicts genes for biosynthesis of zwittermicin, 4,5-DOPA dioxygenase extradiol, and quercetin 2,3-dioxygenase, Molecular Plant-Microbe Interactions: MPMI, 34(6): 602-605. https://doi.org/10.1094/MPMI-10-20-0272-SC Amadio A., Benintende G., and Zandomeni R., 2009, Complete sequence of three plasmids fromBacillus thuringiensis INTA-FR7-4 environmental isolate and comparison with related plasmids from the Bacillus cereus group, Plasmid, 62(3): 172-182. https://doi.org/10.1016/j.plasmid.2009.07.005 Auwera G., Andrup L., and Mahillon J., 2005, Conjugative plasmid pAW63 brings new insights into the genesis of the Bacillus anthracis virulence plasmid pXO2 and of the Bacillus thuringiensis plasmid pBT9727, BMC Genomics, 6: 103. https://doi.org/10.1186/1471-2164-6-103 Barbosa L., Farias D., Silva I., Melo F., Ribeiro B., and Aguiar R., 2015, Draft genome sequence of Bacillus thuringiensis 147, a Brazilian strain with high insecticidal activity, Memórias do Instituto Oswaldo Cruz, 110: 822-823. https://doi.org/10.1590/0074-02760150273 Bolotin A., Gillis A., Sanchis V., Nielsen-Leroux C., Mahillon J., Lereclus D., and Sorokin A., 2017, Comparative genomics of extrachromosomal elements in Bacillus thuringiensis subsp. israelensis, Research in Microbiology, 168(4): 331-344. https://doi.org/10.1016/j.resmic.2016.10.008

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