Abstract
Whole-genome sequencing (WGS) was conducted to characterize the potent mosquitocidal bacterium Bacillus thuringiensis subsp. israelensis VCRC B668, isolated from soil in Tamil Nadu, India. Sequencing using the Illumina MiSeq platform produced a 6.25 Mb genome with 34.97% GC content, 6,441 coding sequences, 115 tRNAs, and 16 rRNAs. Annotation and analysis through RAST, Prokka, and BV-BRC confirmed its close relation to Bti strains AM65-52 and BGSC 4Q1 based on ANI and dDDH values. Seven plasmids were detected, including one resembling pBtoxis carrying major cry and cyt toxin genes. Sixteen insecticidal genes were identified, including cry4Aa, cry4Ba, cry11Aa, and cyt1Aa. SDS–PAGE analysis revealed expression of protein bands at approximately 130 kDa, 70 kDa, and 25 kDa, which were subsequently identified by LC–MS/MS as Cry4Ba, Cry11Aa, and Cyt1Aa, respectively. Bioassays confirmed high larvicidal activity against Aedes aegypti, Culex quinquefasciatus, and Anopheles stephensi, with LC₅₀ values ranging from 0.0076 to 0.0098 mg/L, highlighting its strong biocontrol potential.