Bt Research 2025, Vol.16, No.5, 194-203 http://microbescipublisher.com/index.php/bt 196 core genes that are common to Bacillus cereal complex, and also carries a large number of variable plasmids, which often carry different insecticidal toxin genes and auxiliary virulence genes (Reyaz et al., 2019). By comparing the genome of high and low virulence strains, researchers can lock in potential key regulatory genes. Aarthi et al. (2024) conducted a joint genome and proteome analysis of a highly virulent Bt strain and found that in addition to the classic Cry toxin, this strain also carries several novel insecticidal-related genes, which may be regulated by different regulators. Genomics also helps identify the location and sequence characteristics of Bt gene regulatory elements, such as promoter conserved sequences, transcription terminators, operon structures, etc., and establish a "component library" for Bt regulatory networks (Aarthi et al., 2024). Figure 1 Deletion of hfqresults in reduced Bt motility Image caption: (A) Motility assay of BMB171, Δ1hfq,Δ2hfq, andΔ3hfqon LB plates containing 0.5% agar. The scale bar is 1 cm. (B) Colony diameters of different strains. Motilities of BMB171, Δ1hfq, Δ2hfq, andΔ3hfq were correspondent to colony diameter. (C) RT-qPCR measurements of 11 flagella formation-related genes in BMB171 and Δ3hfq. The values are means ± SDs for triplicate assays. Significances of differences by Student’s t-test are indicated. ***p < 0.001; **p < 0.01; *p < 0.05 (Adopted from Yu et al., 2022b) 3.2 Transcriptomics: analysis of Bt gene expression profile under different conditions By sequencing and quantifying genome-wide mRNA, transcriptomics can dynamically reveal the changes in the Bt gene regulatory network under different physiological conditions and environmental stimuli. The life history of Bt includes the vegetative growth period, transition period and bud formation period, and there are time-sequence changes in gene expression at each stage. Comparative transcriptome analysis has become a powerful tool for analyzing this dynamic regulation. Xie Junyan et al. selected three key time points during the growth process of high-virulent Bt strain 4.0718 and compared transcriptome sequencing in order to improve the molecular map of the formation mechanism of bud and companion cell crystals. Results identified thousands of genes that were differentially expressed in the initial, mid- and end-stage spores, including many regulatory factors and structural genes related to spore formation and toxin synthesis. This type of research fills the gap from genomic static information to functional dynamic information (Wang et al., 2013). Through comparative analysis, genes expressed differentially in different periods may belong to the same regulatory module, thereby inferring the corresponding regulatory pathway. In addition to the developmental stage, the effect of environmental conditions on the Bt gene network can also be captured by the transcriptome.
RkJQdWJsaXNoZXIy MjQ4ODYzNA==