Genomic Insights Into Bacillus thuringiensis Strain JSd1 From Bangladesh: A Whole Genome Sequencing Approach.

Abstract

Bacillus thuringiensis (Bt) is a well-known entomopathogenic bacterium widely used in biopesticide formulations due to its diverse arsenal of insecticidal toxins and environmental adaptability. However, the genetic diversity and virulence potential of native Bt strains from South Asia remain underexplored. In this study, we performed whole-genome sequencing and comparative genomic analysis of B. thuringiensis strain JSd1, isolated from Bangladeshi soil. The high-quality draft genome, assembled at 75x coverage, comprises 5.39 Mb in 64 contigs with a GC content of 35.28% and 99.26% completeness. Genome annotation revealed 5,833 genes, including 5,756 protein-coding sequences and numerous non-coding RNAs. It also harbors 4 different plasmids. Importantly, we identified 25 genomic islands harboring mobile elements and hypothetical proteins, highlighting the strain's dynamic genome evolution. The genome encodes a diverse array of virulence factors linked to insecticidal activity. Notable genes include cry22A and vip3A homologs, multiple bmp1-like metalloproteases, enhancin, cytK, and chiA, as well as various chitinases and serine proteases. The co-occurrence of chromosomal and plasmid-encoded virulence factors suggests modular acquisition mechanisms. Secondary metabolite biosynthetic clusters, such as those for petrobactin, bacillibactin, thuricin CD, and other novel RiPPs and NRPs, were detected, supporting the strain's potential in biological control. Phylogenetic analysis positioned JSd1 within the B. cereus sensu lato group, forming a highly supported clade with B. thuringiensis serovar konkukian and B. anthracis. Comparative genomic and pan-genome analyses revealed substantial genomic diversity among B. thuringiensis strains. The strain's genome contains 2,237 core genes and a large accessory genome, reflecting its ecological adaptability. Our findings suggest that B. thuringiensis JSd1 is a promising candidate for development as a biopesticide targeting insect pests in Bangladeshi agriculture. The comprehensive genomic insights lay the groundwork for further functional validation and field applications, contributing to sustainable pest management strategies in the region.